<![CDATA[SRV250 Forums - Tech Talk / エンジンやパーフォーマンス関係]]>

<![CDATA[SRV250 Forums - Tech Talk / エンジンやパーフォーマンス関係]]> https://yamahasrv250.com/ Thu, 04 Jun 2026 22:27:25 +0000 MyBB <![CDATA[Upgrade to MOSFET Regulator/MOSFETレギュレータへの換装（アップグレード）]]> https://yamahasrv250.com/showthread.php?tid=254 Fri, 06 Mar 2026 08:58:31 +0000 Chief_Mechanic]]> https://yamahasrv250.com/showthread.php?tid=254 従来型の「シャント式」レギュレータからMOSFET式レギュレータへの変更

MOSFET vs. Standard: Standard regulators dump excess energy as heat, often burning themselves out. MOSFETs run much cooler and provide more stable voltage.
MOSFET vs. 従来型（シャント式）：従来型のレギュレータは、余剰電力を熱として逃がす構造のため、熱でパンク（破損）してしまうことが多々あります。対してMOSFET式は、発熱が大幅に抑えられるだけでなく、より安定した電圧供給が可能になります。

Regulator.1.jpg (Size: 111.09 KB Downloads: 1)

バッテリーはほぼほぼ新品なのに、どうにもその日一発目の始動で、セルの回りが渋い。
The battery is basically brand new, but for some reason, the first start of the day feels sluggish—the starter motor just isn't turning over smoothly.

そこまで固いオイルでもない（15W-40）し、電力起因ぽい回り方。
It’s not like the oil is super thick (15W-40), and the way it’s cranking feels like an electrical issue.

色々測ってみてると、3000rpm、5000rpmと回していったときに、15.8V
ありゃー、全然兆候なかったけど、バッテリー虐めてたのかぁ。
After measuring a few things, I saw it hitting 15.8V when revving to 3,000 and 5,000 rpm. Yikes... there weren't any warning signs, but it looks like I’ve been cooking the battery.

Regulator.2.jpg (Size: 86.14 KB Downloads: 1)

2000円の5Pの最廉価で済ませても良かったのではあるが・・・（Sence線は無視）
I could have just settled for the cheapest 5-pin option for 2,000 yen... (and just ignored the Sense wire).

MOSFETから選択して「翌日着」「日本製」に絞ったところ。MOSFETで最廉価に仕上げるよりも、1万近く余分にかかった（涙）
But once I narrowed it down to MOSFET types that were "Made in Japan" and available for "Next-day delivery," it ended up costing me nearly 10,000 yen more than the cheapest MOSFET build would have (cries).

MOSFETは5Pだけど、自己出力から12Vを読むそうな。
The MOSFET unit is a 5-pin, but apparently, it reads the 12V from its own output.
*Sence線 (Sense Wire): Many older regulators have a brown "sense" wire to monitor battery voltage. Modern MOSFET units often do this internally (detecting voltage at the output terminal), which simplifies the wiring.

Regulator.3.jpg (Size: 38.56 KB Downloads: 0)

新しいほう、コネクタのロック角がメスになってる。
On the new unit, the locking tab on the connector is female.
ロックはかからずとも、車体側に嵌るだけは嵌るものの・・・ゆるゆるなんで純正コネクタに組み換え。
While it technically fits into the vehicle-side plug even without the lock engaging... it’s way too loose, so I’m swapping the terminals into the OEM connector housing.

Regulator.4.jpg (Size: 54.36 KB Downloads: 0)

純正と同じ取り回しには、コード長が若干不足というより、コネクタがフレームに当たって無理なので。
Trying to follow the same routing as the original part didn't quite work. It’s not just that the cable length is slightly short; the connector actually hits the frame, making it impossible.
180度ひっくりかえして、ダストカバーに切れ込み入れてコネクタ通した。
Instead, I flipped the unit 180 degrees, cut a notch into the dust cover, and threaded the connector through that way.

Regulator.5.jpg (Size: 51.39 KB Downloads: 0)

レギュレータ取り付けボルト...老眼で、明暗差キツい奥まったとこがほとんど見えず大苦戦
The regulator mounting bolts... man, with my aging eyes, it was a real struggle. I could barely see anything in those deep, recessed spots where the contrast between light and shadow is so harsh.

Regulator.6.jpg (Size: 87.57 KB Downloads: 0)

復活。　5000rpmでも14V台前半でピタっと安定。
Back in business. Even at 5,000 rpm, the voltage stays perfectly stable in the low 14V range.
しばらく様子見して怪しいようなら、虐められてたバッテリーを再チェックかな。
I’ll keep an eye on things for a while, and if anything seems off, I’ll have to re-check the battery—it definitely took a beating from that overcharging.

転載は特に問題ないです。Everything is working fine.
ご利用ください。Please feel free to use this as a reference.
配線については
車両側6P
DC入力プラス（赤）Sense（12V参照）DC入力マイナス（黒）
AC出力（灰）×３
レギュレータ側5P
DC出力プラス（赤）　　　　　　　　DC出力マイナス（黒）
AC入力（灰）×３
As for the wiring:
Vehicle Side (6-Pin):
• DC Input Positive (Red): Battery connection.
• Sense (12V Reference): Voltage monitoring line.
• DC Input Negative (Black): Ground.
• AC Output (Gray) ×3: Stator/Alternator phases.
Regulator Side (5-Pin):
• DC Output Positive (Red)
• DC Output Negative (Black)
• AC Input (Gray) ×3

をそのままつなぐだけです。
Simply connect these directly.

車両側にあるSenseはMOSFETでは使用しません。
従来型レギュレータでは5Pでも6Pでも使えますが、6Pのほうが無難ではあります。
The Sense wire on the vehicle side is not used with this MOSFET regulator. While you can use either a 5-pin or 6-pin version of a conventional (shunt) regulator, the 6-pin is generally a safer bet for those types.

This post was translated with permission from this site. 著者の許可を得て、こちらのサイトより記事を翻訳・転載しています。
You can check out his other posts here.他の投稿はこちらからチェックできます。]]> 従来型の「シャント式」レギュレータからMOSFET式レギュレータへの変更

MOSFET vs. Standard: Standard regulators dump excess energy as heat, often burning themselves out. MOSFETs run much cooler and provide more stable voltage.
MOSFET vs. 従来型（シャント式）：従来型のレギュレータは、余剰電力を熱として逃がす構造のため、熱でパンク（破損）してしまうことが多々あります。対してMOSFET式は、発熱が大幅に抑えられるだけでなく、より安定した電圧供給が可能になります。

Regulator.1.jpg (Size: 111.09 KB Downloads: 1)

Regulator.2.jpg (Size: 86.14 KB Downloads: 1)

Regulator.3.jpg (Size: 38.56 KB Downloads: 0)

Regulator.4.jpg (Size: 54.36 KB Downloads: 0)

Regulator.5.jpg (Size: 51.39 KB Downloads: 0)

Regulator.6.jpg (Size: 87.57 KB Downloads: 0)

復活。　5000rpmでも14V台前半でピタっと安定。
Back in business. Even at 5,000 rpm, the voltage stays perfectly stable in the low 14V range.
しばらく様子見して怪しいようなら、虐められてたバッテリーを再チェックかな。
I’ll keep an eye on things for a while, and if anything seems off, I’ll have to re-check the battery—it definitely took a beating from that overcharging.

転載は特に問題ないです。Everything is working fine.
ご利用ください。Please feel free to use this as a reference.
配線については
車両側6P
DC入力プラス（赤）Sense（12V参照）DC入力マイナス（黒）
AC出力（灰）×３
レギュレータ側5P
DC出力プラス（赤）　　　　　　　　DC出力マイナス（黒）
AC入力（灰）×３
As for the wiring:
Vehicle Side (6-Pin):
• DC Input Positive (Red): Battery connection.
• Sense (12V Reference): Voltage monitoring line.
• DC Input Negative (Black): Ground.
• AC Output (Gray) ×3: Stator/Alternator phases.
Regulator Side (5-Pin):
• DC Output Positive (Red)
• DC Output Negative (Black)
• AC Input (Gray) ×3

をそのままつなぐだけです。
Simply connect these directly.

車両側にあるSenseはMOSFETでは使用しません。
従来型レギュレータでは5Pでも6Pでも使えますが、6Pのほうが無難ではあります。
The Sense wire on the vehicle side is not used with this MOSFET regulator. While you can use either a 5-pin or 6-pin version of a conventional (shunt) regulator, the 6-pin is generally a safer bet for those types.

This post was translated with permission from this site. 著者の許可を得て、こちらのサイトより記事を翻訳・転載しています。
You can check out his other posts here.他の投稿はこちらからチェックできます。]]> <![CDATA[Carb alternatives for the SRV250.]]> https://yamahasrv250.com/showthread.php?tid=250 Fri, 15 Oct 2021 18:26:33 +0000 Nate90]]> https://yamahasrv250.com/showthread.php?tid=250 <![CDATA[Fuel Flooded Carbs]]> https://yamahasrv250.com/showthread.php?tid=249 Tue, 28 Sep 2021 08:21:19 +0000 Chief_Mechanic]]> https://yamahasrv250.com/showthread.php?tid=249
I have had problems ranging from rough running, petrol leaking over the garage floor and cylinders that are so full of fuel that the bike does not turn over due to "hydraulic lock" all depending on how long the bike is left for. Clearly there was a problem with fuel passing through the fuel tap (petcock), even in the off position, and then past the float valves, that also should close off the supply.

[Image: Flooded_Carbs.jpg]

First I tried a carburetor rebuild with new float needles and a good clean . Second I put a new diaphragm in the vacuum operated valve in the fuel tap (petcock). I even tried replacing the fuel pump after reading every single carburetor or fuel related comment ever made on the SRV250 forum!!! However I could not find out why the fuel issue continued.

But here is the solution. To the right hand side of the fuel tap (petcock) is an extra fuel line marked "return" which is connected to one of the carburetors. The fuel appears to go from the tank, to the fuel tap (petcock), to the vacuum operated valve, to the pump, to carburetor 1, to carburetor 2 then back to the fuel tap (petcock). Inside this return connection on the fuel tap (petcock) is a spring and a valve that while the engine is running and fuel flowing has pressure that opens the valve and allows fuel to return to the fuel tap (petcock). When the engine stops the spring closes the valve. This is similar to the vacuum operated valve on the other side of the fuel tap (petcock) in that it is designed to stop fuel leaking into the carburetors or cylinders when the engine is not running.
[Image: Petcock.jpg]

So many forums and workshop manuals refer to the diaphragm operated valve as being the cause of all these problems but no other bike has the complicated system that the SRV250 has in that there is an additional valve on the other side of the fuel tap (petcock). I removed it and inside it was corroded and jammed in the open position allowing fuel to drain, via gravity, from the tank into one of the carburetors bypassing all other valves designed to stop fuel leaking. A good clean of the valve seat & a new tiny oil seal on the valve has now cured the problem. Perhaps this highly unusual valve that is not mention in workshop manuals, forums etc could also be a cause of other members fuel related problems that they have not been able to resolve by normal well known methods. I know this has been a long explanation of this issue but this is a very rare return valve that nobody other than SRV250 owners have and all our bikes are now old and therefore likely to have these corroded malfunctioning valves.]]> <![CDATA[Tank fuel filter assy needed!]]> https://yamahasrv250.com/showthread.php?tid=248 Sat, 17 Jul 2021 23:01:53 +0000 Villamarin]]> https://yamahasrv250.com/showthread.php?tid=248
The tank fuel filter on my Renaissa has been internally affected by corrosion and maybe beyond repair. I have tried repairing it with epoxy but some parts (connection to hoses and inner seats) have been compromised.

It seems that Yamaha do not manufacture the part anymore and none of the suppliers I have contacted has been able to provide one.

The part number is:

4DN-24560-01
Filter Assy

Another option would be to adapt a filter assy from other model but I have no idea which would be compatible with the tank... any idea?

Thanks in advance for your help!

Jorge]]>
The tank fuel filter on my Renaissa has been internally affected by corrosion and maybe beyond repair. I have tried repairing it with epoxy but some parts (connection to hoses and inner seats) have been compromised.

It seems that Yamaha do not manufacture the part anymore and none of the suppliers I have contacted has been able to provide one.

The part number is:

4DN-24560-01
Filter Assy

Another option would be to adapt a filter assy from other model but I have no idea which would be compatible with the tank... any idea?

Thanks in advance for your help!

Jorge]]> <![CDATA[Making Exhaust Silencers]]> https://yamahasrv250.com/showthread.php?tid=238 Mon, 25 May 2020 12:15:41 +0000 Chief_Mechanic]]> https://yamahasrv250.com/showthread.php?tid=238
I'm basically just running my headers as my exhaust, so this is how I went about it.
You'll need a small diameter pipe that will fit into your exhaust. About half the diameter and preferably made of stainless steel. I placed the length of pipe into my header and measured where it needed to be cut.

Then I cut that and drilled holes every 3cm or so, alternating 90 degrees and offsetting by 1.5 cm. (See the pic)
Next, I drilled and tapped a hole in the header for a bolt to hold the silencer in place.
[Image: silencer_1]

Next, I wrap the silencer with steel wool. Again, stainless is best (or even heat resistant fiber glass if you can find it) then wrap that with wire to keep it in place. On the short front header, I needed to provide more back pressure, so I also stuffed the silencer with the much larger grain stainless steel (from a kitchen sponge type thing.) Make sure you do that before you wrap the outside, so when you run the wire through the holes, it also secures the steel wool inside the silencer.
[Image: silencer_3]

Now, carefully insert the silencer into the exhaust while rotating so the steel wool doesn't bunch up. When you you get it in place, tighten the bolt to hold the silencer pipe and you should be good. The picture below shows the placement of the silencer in the longer header pipe before the bolt was tightened.
[Image: silencer_2]

This method provided the bike with the back pressure needed to run smoothly and also gives me the opportunity to adjust the silencer when I feel it's necessary.

If you give it a shot, I hope it works out for you as well as it did for me.]]>
I'm basically just running my headers as my exhaust, so this is how I went about it.
You'll need a small diameter pipe that will fit into your exhaust. About half the diameter and preferably made of stainless steel. I placed the length of pipe into my header and measured where it needed to be cut.

Then I cut that and drilled holes every 3cm or so, alternating 90 degrees and offsetting by 1.5 cm. (See the pic)
Next, I drilled and tapped a hole in the header for a bolt to hold the silencer in place.
[Image: silencer_1]

This method provided the bike with the back pressure needed to run smoothly and also gives me the opportunity to adjust the silencer when I feel it's necessary.

If you give it a shot, I hope it works out for you as well as it did for me.]]> <![CDATA[Acewell Digital Meter Installation]]> https://yamahasrv250.com/showthread.php?tid=237 Tue, 05 May 2020 13:26:06 +0000 Chief_Mechanic]]> https://yamahasrv250.com/showthread.php?tid=237
I've removed the original headlight, but other than that have a standard wiring harness on my 1993 4DN2.

Detail　　ー　　Bike　ー　Meter
Neutral light　ー　Sb　ー　Purple
Key Switch　ー　L　ー　Red
Ground　　ー　 B　ー　Black
L. Turn Signal　ー　Dg　ー　Orange
R. Turn Signal　ー　Ch　ー　White
Tach Signal　ー　Y/B　ー　Yellow (separate plug)
High Beam　ー　 Y　ー　Light Green

Meter Clock Power ー Brown ー run line to battery (+)

Unused Meter - Oil warning light - Grey (not available on SRV)
Unused Bike - Turn Signal (+) - Br/W
　　　　　　 Various Switch (+)? - Br

Yamaha Wire Color Code
Sb = Sky Blue
L = Blue
B = Black
Dg = Dark Green
Ch = Chocolate
Y/B = Yellow with black stripe
Y = Yellow
Br = Brown
Br/W = Brown with white stripe

So, that's pretty much it at this point. Once you've removed your headlight and stock meter assembly you'll be left with two black connectors which will have the majority of those wires. The turn signal wires need to be directly connected with the individual direction wires since the stock meter only gives you a general signal, not left or right.
[Image: Meter_Connections-scaled.jpg]

The small connector with 3 wires (B, L, Br) is basically power. The other connector (Br/W, Y/B, Y, Sb) is for individual warning lights. The Sb wire really looked Grey until I stripped the wiring harness back and saw some of the un-weathered bit.

The Yellow wire for high beam warning comes from the headlight connector and there is also an additional ground that you'll want to keep installed in the harness.

I'll post some pics once I get it wheeled out of the shed.

Here it is post install:
[Image: Acewell_Meter.1-scaled.jpg]

]]>
I've removed the original headlight, but other than that have a standard wiring harness on my 1993 4DN2.

Detail　　ー　　Bike　ー　Meter
Neutral light　ー　Sb　ー　Purple
Key Switch　ー　L　ー　Red
Ground　　ー　 B　ー　Black
L. Turn Signal　ー　Dg　ー　Orange
R. Turn Signal　ー　Ch　ー　White
Tach Signal　ー　Y/B　ー　Yellow (separate plug)
High Beam　ー　 Y　ー　Light Green

Meter Clock Power ー Brown ー run line to battery (+)

Unused Meter - Oil warning light - Grey (not available on SRV)
Unused Bike - Turn Signal (+) - Br/W
　　　　　　 Various Switch (+)? - Br

Yamaha Wire Color Code
Sb = Sky Blue
L = Blue
B = Black
Dg = Dark Green
Ch = Chocolate
Y/B = Yellow with black stripe
Y = Yellow
Br = Brown
Br/W = Brown with white stripe

So, that's pretty much it at this point. Once you've removed your headlight and stock meter assembly you'll be left with two black connectors which will have the majority of those wires. The turn signal wires need to be directly connected with the individual direction wires since the stock meter only gives you a general signal, not left or right.
[Image: Meter_Connections-scaled.jpg]

]]> <![CDATA[SRV250 Specs]]> https://yamahasrv250.com/showthread.php?tid=225 Mon, 02 Mar 2020 12:23:23 +0000 Chief_Mechanic]]> https://yamahasrv250.com/showthread.php?tid=225 ※[]内はSモデル / ※[] Figures in brackets are for the 'S' models

全長-Length / 幅-Width / 高-Height
2095 / 720 / 1055mm
[2095 / 720 / 1105mm]

シート高 / Seat Height
760mm

車軸距離 / Wheelbase
1390mm

車体重量 / Weight
144kg(乾)
[146kg(乾) ]

燃料消費率 / Gas Mileage
56.0km/L
※定地走行テスト値 / Tested on flat surface

燃料容量 / Fuel Capacity
13.0L

エンジン / Engine
空冷4サイクルOHC2気筒
Air Cooled 4-cycle Overhead Cam 2 Cylinder

総排気量 / Total Engine Displacement
248cc

最高出力 / Max. Metric Horsepower
27ps@8500rpm

最高トルク / Max. Torque
2.5kg-m/6500rpm

変速機 / Transmission
常時噛合式5速リターン / Constant Mesh 5 Speed Return

タイヤサイズ / Tire Size
前-Front 90/90-18(51S)
後-Rear 110/90-18(61S)

バッテリー / Battery
YTX7A-BS

プラグ / Spark Plug
CR7HSA

オイル容量 / Oil Capacity
全容量-Full Capacity 2.0L
交換時-On Oil Change 1.6L
フィルター交換時-When Changing Filter 1.8L

スプロケ - Sprockets
前-Front 15｜後-Rear 45

チェーン
サイズ-SIze 520｜リンク-Links 106

車体価格 Base Price

449,000円（税別）(Without Taxes)
[479,000円（税別）]]]> ※[]内はSモデル / ※[] Figures in brackets are for the 'S' models

全長-Length / 幅-Width / 高-Height
2095 / 720 / 1055mm
[2095 / 720 / 1105mm]

シート高 / Seat Height
760mm

車軸距離 / Wheelbase
1390mm

車体重量 / Weight
144kg(乾)
[146kg(乾) ]

燃料消費率 / Gas Mileage
56.0km/L
※定地走行テスト値 / Tested on flat surface

燃料容量 / Fuel Capacity
13.0L

エンジン / Engine
空冷4サイクルOHC2気筒
Air Cooled 4-cycle Overhead Cam 2 Cylinder

総排気量 / Total Engine Displacement
248cc

最高出力 / Max. Metric Horsepower
27ps@8500rpm

最高トルク / Max. Torque
2.5kg-m/6500rpm

変速機 / Transmission
常時噛合式5速リターン / Constant Mesh 5 Speed Return

タイヤサイズ / Tire Size
前-Front 90/90-18(51S)
後-Rear 110/90-18(61S)

バッテリー / Battery
YTX7A-BS

プラグ / Spark Plug
CR7HSA

オイル容量 / Oil Capacity
全容量-Full Capacity 2.0L
交換時-On Oil Change 1.6L
フィルター交換時-When Changing Filter 1.8L

スプロケ - Sprockets
前-Front 15｜後-Rear 45

チェーン
サイズ-SIze 520｜リンク-Links 106

車体価格 Base Price

449,000円（税別）(Without Taxes)
[479,000円（税別）]]]> <![CDATA[Two questions about: 1) engine oil and 2) choke]]> https://yamahasrv250.com/showthread.php?tid=223 Mon, 21 Oct 2019 03:59:00 +0000 kskippi]]> https://yamahasrv250.com/showthread.php?tid=223
I've just got my first bike, a[attachment=163] 1994 SRV250 - she's a beauty!

Ok question number 1:
I noticed the dipstick on the oil cap is missing.. can this be replaced with a standard 2-stroke engine cap or something like that? Can't find anything online and it didn't come with a service (or any other kind of) manual..

Also what type of engine oil do we put in these bikes?
SAE 20W-40? I live in a place that gets really cold in winter and really hot in summer..

Question number 2:
I bought the bike with the choke disconnected and removed Sad

Can't find any aftermarket choke mechanisms online for this particular bike.. Is there an alternative choke that could be used for the SRV250? Like maybe one from a Virago or something??

Any advice appreciated, ta!

IMG_2343.jpg (Size: 122.09 KB Downloads: 10)

]]>
I've just got my first bike, a[attachment=163] 1994 SRV250 - she's a beauty!

Ok question number 1:
I noticed the dipstick on the oil cap is missing.. can this be replaced with a standard 2-stroke engine cap or something like that? Can't find anything online and it didn't come with a service (or any other kind of) manual..

Also what type of engine oil do we put in these bikes?
SAE 20W-40? I live in a place that gets really cold in winter and really hot in summer..

Question number 2:
I bought the bike with the choke disconnected and removed Sad

IMG_2343.jpg (Size: 122.09 KB Downloads: 10)

]]> <![CDATA[Wheel & Brake upgrade]]> https://yamahasrv250.com/showthread.php?tid=221 Sun, 25 Aug 2019 03:01:57 +0000 Chief_Mechanic]]> https://yamahasrv250.com/showthread.php?tid=221 this link for the original.

Alumi_wheels.jpg (Size: 71.82 KB Downloads: 5)

This is a quick translation of the original post:

Yamaha R1-Z Front end:
wheel, axle, forks, disc, caliber, fender, meter gear

Apparently it's just plug and play except for the front master cylinder, which needs to be swapped for a dual caliber model.

Yamaha R1-Z Rear wheel, disc, caliber, chain adjuster
Yamaha Zeal caliber support
Suzuki GSX-R750 Rear caliber master cylinder
SRX400 1JL Swing arm (Same as SRV but the axle is 17mm so you need to use the R1-Z chain adjusters which are the same15mm as the wheel.)
He doesn't remember if he used the SRV250 or the SRX400 pivot shaft, though they are the same size. The width of the front of the swing arm is different so he's got 3 washers on each side of it. The end plates are listed as for the SRX400.
SRV250 Axle shaft (The R1-Z axle shaft is too short.)
Use 2 washers (spacers) on either side to make up for the difference in width.
SRV250 rear brake switch (With some modifications)

SRX250 Rear Step
Apparently the pitch didn't match up so he modified it. (See pictures) This mod moves the step back about 2cm.

The swing arm is longer so you'll need to change your chain. 520-120 link should do it. Since the mount points of the rear suspension have moved forward, you need to make some adjustments against interference with the rear step. (Again, without actually doing the mod, I'm not quite sure what he's talking about.)]]> <![CDATA[4DN-25104-00 Front Spoke Set]]> https://yamahasrv250.com/showthread.php?tid=73 Mon, 17 Sep 2018 15:13:43 +0000 solomon]]> https://yamahasrv250.com/showthread.php?tid=73
I am in the middle of rebuild and I have all the parts except for 4DN-25104-00 Front Spoke set. The available part for the same is 4DN-25104-20 which is not a replacement and I am not sure if it is. So guys if you know any links or leads please let me know. Many thanks.]]>
I am in the middle of rebuild and I have all the parts except for 4DN-25104-00 Front Spoke set. The available part for the same is 4DN-25104-20 which is not a replacement and I am not sure if it is. So guys if you know any links or leads please let me know. Many thanks.]]> <![CDATA[Engine Substitution (Virago XV250)]]> https://yamahasrv250.com/showthread.php?tid=62 Fri, 08 Dec 2017 02:07:09 +0000 flowerlandfilms]]> https://yamahasrv250.com/showthread.php?tid=62 I'd heard a lot of talk about an SRV engine being identical to a Virago, and that they could be swapped interchangeably, but I couldn't find anyone who had actually done it.
So when my 1995 SRV-250 engine seized, I SEIZED the opportunity, purchased a 1998 Virago 250 engine from a wreckers, and swapped it in.. and it works!
It was two weeks of hard slog, especially because I'm learning about motors as I go, and I've never been in an engine before now.
A lot of my SRV bolts and screws were stripped/rusted/frozen, and had to be drilled/coaxed/chiselled out, which didn't do my arms any favours.
But despite claims to the contrary there are some differences and incompatibilities people should be aware of. I hope this list helps if you are in the same predicament as me:

- The Cylinder Heads are NOT the same. Virago heads will fit in the SRV, but they will not be correctly spaced apart for the Carburettor joints for the twin carbs. The virago carb ports are flush with the fins, the SRV ports are recessed into the head, to make more room for the twin joints.
You could use the Virago heads with their own carb, or possibly with a different carb setup, but you must have the SRV heads to fit the SRV carbs. Virago heads could be turned into SRV heads if you took a hacksaw to the fins I think, but I aint that desperate.

- The Cams have different shaped lobes affecting performance, but each head will take each cam with no problems, the recommended valve clearances are the same for both bikes: Intake Valve 0.08 ~ 0.12 - Exhaust valve 0.10 ~ 0.14

- The Cam Sprockets are identical

- The 1995 SRV that I own mounted its drive sprocket with one big central nut, and a washer bent around it to hold it in place. The Virago sprocket has two screws either side which go through a guide plate. The sprockets were incompatible so I had to switch to the Virago sprocket.
You could probably drill two holes in an SRV sprocket to make them work, or if you wanted to you could probably replace the shaft and mount an SRV shaft in its place, but once again that seems like a lot of effort, I can just buy Virago sprockets from now on.
MY SRV chain length was fine and it fits the sprocket no problem, I believe the amount of teeth on the sprocket is the same if stock.

- All the engine covers can be swapped so the Virago engine looks just like the SRV engine. (Of course apart from the ID Number, I went from 4DN-000136 to 3LV-021734 [Image: icon_oops.gif]

) The Virago engine had a plastic chain/sprocket cover, so I was happy to be able to use my steel SRV one.

- The cylinder head covers on the Virago mount from the top, whereas on the SRV, they mount from the side. Each engine has different shaped brackets to achieve this, so you will need SRV brackets to fit SRV head covers. But either bracket will fit on either engine.

- The screw which holds the clutch actuator arm in place, not sure what it's called but it's a specialty screw with a built in copper washer, and a notch cut out of the end, has a slightly different shaped notch for each bike.
I am not sure if this effects compatibility, it might just be a redesign of the part and work for both, but to be safe maybe use your own engines screw.

- There is a thick hose which comes off the back of the engine, I'm not sure where it goes, the Air Filter or something? Anyway it goes out to the right of the Virago engine, out to the left of the SRV engine.
The hose on the SRV will not be long enough to reach it due to the switched sides. You will need a longer hose. I got one at SCA, I think it was for a Holden Statesman.

It's running well, and i've not had any problems with it so far. Virago cam performance definitely has less "Up and Go", I'll see what effect this has on Fuel economy before going back to the SRV cams.]]> I'd heard a lot of talk about an SRV engine being identical to a Virago, and that they could be swapped interchangeably, but I couldn't find anyone who had actually done it.
So when my 1995 SRV-250 engine seized, I SEIZED the opportunity, purchased a 1998 Virago 250 engine from a wreckers, and swapped it in.. and it works!
It was two weeks of hard slog, especially because I'm learning about motors as I go, and I've never been in an engine before now.
A lot of my SRV bolts and screws were stripped/rusted/frozen, and had to be drilled/coaxed/chiselled out, which didn't do my arms any favours.
But despite claims to the contrary there are some differences and incompatibilities people should be aware of. I hope this list helps if you are in the same predicament as me:

- The Cylinder Heads are NOT the same. Virago heads will fit in the SRV, but they will not be correctly spaced apart for the Carburettor joints for the twin carbs. The virago carb ports are flush with the fins, the SRV ports are recessed into the head, to make more room for the twin joints.
You could use the Virago heads with their own carb, or possibly with a different carb setup, but you must have the SRV heads to fit the SRV carbs. Virago heads could be turned into SRV heads if you took a hacksaw to the fins I think, but I aint that desperate.

- The Cams have different shaped lobes affecting performance, but each head will take each cam with no problems, the recommended valve clearances are the same for both bikes: Intake Valve 0.08 ~ 0.12 - Exhaust valve 0.10 ~ 0.14

- The Cam Sprockets are identical

- The 1995 SRV that I own mounted its drive sprocket with one big central nut, and a washer bent around it to hold it in place. The Virago sprocket has two screws either side which go through a guide plate. The sprockets were incompatible so I had to switch to the Virago sprocket.
You could probably drill two holes in an SRV sprocket to make them work, or if you wanted to you could probably replace the shaft and mount an SRV shaft in its place, but once again that seems like a lot of effort, I can just buy Virago sprockets from now on.
MY SRV chain length was fine and it fits the sprocket no problem, I believe the amount of teeth on the sprocket is the same if stock.

- All the engine covers can be swapped so the Virago engine looks just like the SRV engine. (Of course apart from the ID Number, I went from 4DN-000136 to 3LV-021734 [Image: icon_oops.gif]

) The Virago engine had a plastic chain/sprocket cover, so I was happy to be able to use my steel SRV one.

- The cylinder head covers on the Virago mount from the top, whereas on the SRV, they mount from the side. Each engine has different shaped brackets to achieve this, so you will need SRV brackets to fit SRV head covers. But either bracket will fit on either engine.

- The screw which holds the clutch actuator arm in place, not sure what it's called but it's a specialty screw with a built in copper washer, and a notch cut out of the end, has a slightly different shaped notch for each bike.
I am not sure if this effects compatibility, it might just be a redesign of the part and work for both, but to be safe maybe use your own engines screw.

- There is a thick hose which comes off the back of the engine, I'm not sure where it goes, the Air Filter or something? Anyway it goes out to the right of the Virago engine, out to the left of the SRV engine.
The hose on the SRV will not be long enough to reach it due to the switched sides. You will need a longer hose. I got one at SCA, I think it was for a Holden Statesman.

It's running well, and i've not had any problems with it so far. Virago cam performance definitely has less "Up and Go", I'll see what effect this has on Fuel economy before going back to the SRV cams.]]> <![CDATA[Fork oil capacity]]> https://yamahasrv250.com/showthread.php?tid=57 Thu, 22 Jun 2017 20:13:54 +0000 Forest gump]]> https://yamahasrv250.com/showthread.php?tid=57
First of all I am new here so I would like to say hello to everybody. My story is short. I have yamaha srv 250 for about a year now. I am located in Ireland and I think that nobody have the same bike here so I consider myself as a lucky guy.

Now to the point. I changed fork oil seals today. Everything was good until I checked service manual. It says that i need 367 ml off oil and the level will be 125mm from the top. In my situation the level is around 150mm. My fork spring is also few cm shorter than in manual 394mm. Is it only on my bike like this or somebody had same problem?

Thanks for your help.]]>
First of all I am new here so I would like to say hello to everybody. My story is short. I have yamaha srv 250 for about a year now. I am located in Ireland and I think that nobody have the same bike here so I consider myself as a lucky guy.

Now to the point. I changed fork oil seals today. Everything was good until I checked service manual. It says that i need 367 ml off oil and the level will be 125mm from the top. In my situation the level is around 150mm. My fork spring is also few cm shorter than in manual 394mm. Is it only on my bike like this or somebody had same problem?

Thanks for your help.]]> <![CDATA[Australian SRV Rebuild #2]]> https://yamahasrv250.com/showthread.php?tid=55 Wed, 16 Nov 2016 12:51:14 +0000 Chief_Mechanic]]> https://yamahasrv250.com/showthread.php?tid=55

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Click on the thumbnails for bigger pics.]]>

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White_5.jpg (Size: 95.82 KB Downloads: 14)

Click on the thumbnails for bigger pics.]]> <![CDATA[Aussie SRV250 Restoration Project]]> https://yamahasrv250.com/showthread.php?tid=44 Mon, 29 Jun 2015 07:01:47 +0000 Aussie_T100]]> https://yamahasrv250.com/showthread.php?tid=44
This is the bike as I purchased it.

[Image: 001_zpsp5bbvy4j.jpg]

The bike had some accident damage on the right side and was fairly weathered from 20 years of use.

[Image: 026_zpszuceaon9.jpg]

]]>
This is the bike as I purchased it.

[Image: 001_zpsp5bbvy4j.jpg]

The bike had some accident damage on the right side and was fairly weathered from 20 years of use.

[Image: 026_zpszuceaon9.jpg]

]]> <![CDATA[Part Substitutions / 流用部品]]> https://yamahasrv250.com/showthread.php?tid=19 Fri, 12 Dec 2014 14:14:04 +0000 Chief_Mechanic]]> https://yamahasrv250.com/showthread.php?tid=19 Part Substitution Data (Most info from This Site!!)
流用部品の元データー

Wheel Size
ホイル・サイズ
Front wheel 18 x 1.85
Rear Wheel 18 x 2.15

Axle Sizes
Front Axle Shaft
フロントアクスルシャフト
Total Length (全長約) 23.5cm
Shaft Diameter (シャフト径) 15φ

Front Wheel Bearings
Wheel bearing number: Yamaha 93306-20205-00
Replacement:

Rear Wheel Bearings
Wheel bearing number: Yamaha 93306-20226-00
Replacement:

Tire Sizes
タイヤ・サイズ
Front Tire 90/90-18(51S)
Rear Tire 110/90-18(61S)

Brake Caliber
ブレーキキャリパー
SRV Standard / 標準 ⇒ Mounting Pitch / 取付けピッチ：100mm
　
　DS400あたりのものがポン付けできそうな気がしますピストン径が大きくなればひょっとして・・・
　キャリパーサポートを使ってΦ300のローター使えば４Ｐキャリパーも入りそうな感じです（ぎりぎり当たるかも）

Brake Rotor
ブレーキローター
SRV Standard / 標準 ⇒ Outer Diameter / 外形：Φ282mm　
　　Inner Diameter / 内径：Φ132mm
　　PCD：150mm
　　Offset / オフセット：0mm
　　Screws / ビス：6本
　
Models Using the Same Size / そのままの大きさでは
　　Renaissa / ルネッサ
　　DS250
　　XV250ビラーゴ (Virago)
　　SR125
　　XV125ビラーゴ (Virago)
　　他にもありますが、ベンチレートディスクのため、厚みがあるので、キャリパーがつきません (There are others but since they use a bench plate disc, they are thicker and the caliber won't fit.)
　
　　ワンサイズ拡大も取付けできます（Φ300mm）(You may be able to use one size larger. - a 300mm diameter rotor)
　　この場合キャリパーサポートを使ってキャリパーの位置を移動させてやれば良いかな？(In this case you may have to use a caliber support plate to change the position of the caliber.)

　　XV400ビラーゴ (Virago)
　　XV533ビラーゴ (Virago)
　　SR400　'01～06
　　DS400/DSC400
　　FZS100フェーザー　'01～05 (Fazer)
　　DSC1100　'00～08
　　DS1100　'99～08
　　BT1100　'02～06（フロント）(Front)
　　V-max　'93～07
　　ロイヤルスター　'96～00（フロント）(Royal Star Front Rotor)
　　XV1600ロードスター (Road Star)

Brake Master Cylinder
ブレーキマスター
SRV Standard / 標準 ⇒ Piston Diameter / ピストン径：14mm
　
　径を大きくするか小さくするかは各自のお好み次第。(You can choose a different size piston.)
　ちなみにルネッサは　1/2インチ　で小さいようですね。(The Renaissa is actually a 1/2 inch.)
　
List / リスト
　CB1300
　YZF-R1
　詳細はこちら　（PDFファイルです）(Click the link to open a PDF showing the brake master cylinder piston size of a bunch of bikes - It's Japanese but should be understandable.)
　
Front Fork
フロントフォーク
　SRV Standard / 標準 ⇒ Diameter / 太さ：Φ38mm (The outer pipe seems to be Φ59mm at the top - where you'd put boots on it)
　同径のフォークを使っているものです。(These Models use the same diameter fork - Can exchanges be made?)
　
　　Kawasaki / カワサキ
　　　　GPZ750R
　　　　GPZ900R A1～A6
　　　　Z1000R
　　Suzuki / スズキ
　　　　GSX-R400 '86～87 GK71F
　　　　RG500ガンマ (Gamma)
　　　　RG400ガンマ (Gamma)
　　Yamaha / ヤマハ
　　　　FZX750
　　　　SRX400 '90～ 3VN
　　　　SRX600 '90～ 3SX
　　　　DIVERSION600
　　　　DIVERSION400
　　　　FZR400 '86～'87
　　　　FZR400R '87
　　　　R1-Z
　　　　Zeal
　　　　FZR250R 3LN1～6 '89～94

Rear Suspension
リアサス
SRV Standard / 標準 ⇒ Length / 長さ：330mm
　　　Bushings / 取付け穴 ⇒ Top & Bottom / 上下共 : Φ14mm

Brake Hose 4DN-25872-00-00
ブレーキホース

　　SRV Standard / 標準 ⇒ Length / 長さ800mm P-type fittings
ホース1:[20°バンジョー]+ストレートフィッティング-ストレートフィッティング+[20°バンジョー]/760[800]mm
ボルトピッチ:マスター側:1.25(シングル)、キャリパー側:1.25(シングル)

Clutch Cable 4DN-26335-00-00
クラッチワイヤー

　　SRV Standard / 標準 ⇒ Length / 長さ Outer 114, Inner 135]]> Part Substitution Data (Most info from This Site!!)
流用部品の元データー

Wheel Size
ホイル・サイズ
Front wheel 18 x 1.85
Rear Wheel 18 x 2.15

Axle Sizes
Front Axle Shaft
フロントアクスルシャフト
Total Length (全長約) 23.5cm
Shaft Diameter (シャフト径) 15φ

Front Wheel Bearings
Wheel bearing number: Yamaha 93306-20205-00
Replacement:

Rear Wheel Bearings
Wheel bearing number: Yamaha 93306-20226-00
Replacement:

Tire Sizes
タイヤ・サイズ
Front Tire 90/90-18(51S)
Rear Tire 110/90-18(61S)

Brake Caliber
ブレーキキャリパー
SRV Standard / 標準 ⇒ Mounting Pitch / 取付けピッチ：100mm
　
　DS400あたりのものがポン付けできそうな気がしますピストン径が大きくなればひょっとして・・・
　キャリパーサポートを使ってΦ300のローター使えば４Ｐキャリパーも入りそうな感じです（ぎりぎり当たるかも）

Brake Rotor
ブレーキローター
SRV Standard / 標準 ⇒ Outer Diameter / 外形：Φ282mm　
　　Inner Diameter / 内径：Φ132mm
　　PCD：150mm
　　Offset / オフセット：0mm
　　Screws / ビス：6本
　
Models Using the Same Size / そのままの大きさでは
　　Renaissa / ルネッサ
　　DS250
　　XV250ビラーゴ (Virago)
　　SR125
　　XV125ビラーゴ (Virago)
　　他にもありますが、ベンチレートディスクのため、厚みがあるので、キャリパーがつきません (There are others but since they use a bench plate disc, they are thicker and the caliber won't fit.)
　
　　ワンサイズ拡大も取付けできます（Φ300mm）(You may be able to use one size larger. - a 300mm diameter rotor)
　　この場合キャリパーサポートを使ってキャリパーの位置を移動させてやれば良いかな？(In this case you may have to use a caliber support plate to change the position of the caliber.)

　　XV400ビラーゴ (Virago)
　　XV533ビラーゴ (Virago)
　　SR400　'01～06
　　DS400/DSC400
　　FZS100フェーザー　'01～05 (Fazer)
　　DSC1100　'00～08
　　DS1100　'99～08
　　BT1100　'02～06（フロント）(Front)
　　V-max　'93～07
　　ロイヤルスター　'96～00（フロント）(Royal Star Front Rotor)
　　XV1600ロードスター (Road Star)

Brake Master Cylinder
ブレーキマスター
SRV Standard / 標準 ⇒ Piston Diameter / ピストン径：14mm
　
　径を大きくするか小さくするかは各自のお好み次第。(You can choose a different size piston.)
　ちなみにルネッサは　1/2インチ　で小さいようですね。(The Renaissa is actually a 1/2 inch.)
　
List / リスト
　CB1300
　YZF-R1
　詳細はこちら　（PDFファイルです）(Click the link to open a PDF showing the brake master cylinder piston size of a bunch of bikes - It's Japanese but should be understandable.)
　
Front Fork
フロントフォーク
　SRV Standard / 標準 ⇒ Diameter / 太さ：Φ38mm (The outer pipe seems to be Φ59mm at the top - where you'd put boots on it)
　同径のフォークを使っているものです。(These Models use the same diameter fork - Can exchanges be made?)
　
　　Kawasaki / カワサキ
　　　　GPZ750R
　　　　GPZ900R A1～A6
　　　　Z1000R
　　Suzuki / スズキ
　　　　GSX-R400 '86～87 GK71F
　　　　RG500ガンマ (Gamma)
　　　　RG400ガンマ (Gamma)
　　Yamaha / ヤマハ
　　　　FZX750
　　　　SRX400 '90～ 3VN
　　　　SRX600 '90～ 3SX
　　　　DIVERSION600
　　　　DIVERSION400
　　　　FZR400 '86～'87
　　　　FZR400R '87
　　　　R1-Z
　　　　Zeal
　　　　FZR250R 3LN1～6 '89～94

Rear Suspension
リアサス
SRV Standard / 標準 ⇒ Length / 長さ：330mm
　　　Bushings / 取付け穴 ⇒ Top & Bottom / 上下共 : Φ14mm

Brake Hose 4DN-25872-00-00
ブレーキホース

　　SRV Standard / 標準 ⇒ Length / 長さ800mm P-type fittings
ホース1:[20°バンジョー]+ストレートフィッティング-ストレートフィッティング+[20°バンジョー]/760[800]mm
ボルトピッチ:マスター側:1.25(シングル)、キャリパー側:1.25(シングル)

Clutch Cable 4DN-26335-00-00
クラッチワイヤー

　　SRV Standard / 標準 ⇒ Length / 長さ Outer 114, Inner 135]]>