by Chief_Mechanic at 05-25-2020, 09:15 PM
I'd like to demonstrate how to make a silencer for a short exhaust system on a motorcycle. This will not just reduce the volume of your pipes, but more importantly will give you the necessary back pressure to help reduce the risk of burning out your valves and what-not from running way to lean.

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.
by Chief_Mechanic at 05-05-2020, 10:26 PM
I've installed an Ace-2802-2 Digital Meter on my bike as part of its rebuild and thought I'd detail the wiring for that install.  I've seen pics of them installed on other SRV's, but could find no info online.

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][Image: Acewell_Meter.2-scaled.jpg]
[Image: Acewell_Meter.3-scaled.jpg][Image: Acewell_Meter.4.png]
by BillDay at 03-09-2020, 03:39 AM
Hi everyone. I bought this 1992 SRV last fall, rode it 20 meters into my garage, and have been re-furbing it over the winter. I'm really glad to have found this forum! Look forward to learning from your projects and sharing mine.


[Image: 86634749_133619921481074_804168729518040...e=5E949385]
by Chief_Mechanic at 03-02-2020, 09:23 PM
主要諸元 / The Specs for the SRV250 4DN are as below:
※[]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

車軸距離 / Wheelbase

車体重量 / Weight
[146kg(乾) ]

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

燃料容量 / Fuel Capacity

エンジン / Engine
Air Cooled 4-cycle Overhead Cam 2 Cylinder

総排気量 / Total Engine Displacement

最高出力 / Max. Metric Horsepower

最高トルク / Max. Torque

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

プラグ / Spark Plug

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

サイズ-SIze 520|リンク-Links 106

車体価格 Base Price

449,000円(税別)(Without Taxes)
by brissy4rk at 10-23-2019, 04:30 PM
Hi from Brisbane, Australia. I am recently retired from work and looking for something to occupy my time, I purchased a 1994 SRV250 with 63,000 km in need of some TLC.

It had not been on the road since 2010 and had quite a few issues, front brakes seized, seized throttle cables, tank dents, taken a hit around the headlight area with bent headlight shell and instrument brackets, leaking fork seals, surface rust everywhere and previous home to some critters (mice, mud wasps and spiders).

Tore it down back to the frame, cleaned, painted and have replaced quite a few parts.  Professionally, I have had the tank repainted, forks re chromed and the headstem lockstop repaired with the frame checked for straightness.  The motor is untouched except for new plugs, valves clearances checked, lube service and carburetor jets, gaskets, o-rings & diaphragm membranes replaced.

After almost 2 years I have just put it back on the road, been for a few short rides and loving it. 

I came across the forum a while back while searching for info on the SRV. It has been very helpful, especially for part substitution, so thank you.
by kskippi at 10-21-2019, 12:59 PM
Hey everyone - 

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!
by Chief_Mechanic at 09-23-2019, 04:58 PM
From 9pm Sept. 22nd to about noon on the 23rd, the forum was offline due to a power outage caused by typhoon #17.


I kind of doubt anybody noticed, but do apologize for the inconvenience.  Hopefully it was the last one of the season.
by Chief_Mechanic at 08-25-2019, 12:01 PM
Found a great example of a wheel/brake upgrade.  Check out this link for the original.

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.)
by CamJoh at 08-22-2019, 04:28 AM
Hi All,

I have just purchased a 1994 Yamaha SRV in Sydney and looking forward into giving it a little TLC. Currently the fuel tank is off and being restored, giving me time to give it a deep clean, adjust the carby, reset valve clearances etc.
Seems this forum might be a little quiet at the moment but it would be great if it were to pick up again!

by Chief_Mechanic at 01-04-2019, 06:28 PM
Okay, this wasn't on my SRV, but I still wanted to post a ride report showing my favorite two hours of twisties.

Last day of my vacation and I finally managed to force some time for myself to join in the Japanese tradition of "The First add anything here of the year."  I got my first run in and it has been a couple of months. (My bike let me know by the battery just being strong enough to turn it over.)

The weather was cloudy and cold (about 10C) but the roads were dry as it was sunny yesterday.  Here's a link to my favorite stress release:  Nagasaki Twisties

This route will take you up behind the town of Omura in Nagasaki for anywhere from an hour and 30 minutes to 2 hours of riding.  It goes by 3 different dams and stays in the mountains for almost the entire time.  There are only a few places where the roads are narrow enough to be considered one-lane (by Japanese standards.)

I had a great ride and definitely didn't feel any cobwebs.  Concentrated on good lines through the corners and felt I was able to up my average cornering speed.

When I got back I topped off my tank with Hi-octane and then washed and waxed the bike.  The weather is gonna start getting cold now, so I probably won't be riding for a while.

Now if I can just motivate myself to get my SRV back up and running!!!!
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