[CAM CHAIN TENSIONER NEEDED ASAP]

ANY ONE ABLE TO HELP. IM AFTER A NEW OR GOOD USED CAM CHAIN TENSIONER FOR MY YAMAHA SR125

ITS A 2001 X REG MODEL.CASH WAITING CHEERS.ALSO DOES ANYBODY KNOW HOW TO ADJUST THEM ONCE I HAVE FITTE IT. THANKS ALOT ANTH.

[Bizarre Yamaha SR125 problem.]

i dont think the timing chains have a link. when i changed mine i had to lower it down from the cam cover and loop it over the crank pulley.( a bit fiddly but can be done).i also tied a peice of string around chain in case i dropped it inside engine.this way you can just pull it back out without stripping down. good luck anth

Hello all.

I bought my SR125 last summer as a project bike and have yet to get it running properly.

To get you up to date on what' shappening here's a bit of a chronology.

Last year, bought the bike, front tyre flat, drums seized up, carb stuck open, crank flooded with petrol, indicators acting out.

In between, sorting out all that crap, dismantling, cleaning and reassembling the carb about a million times trying to figure out why on earth the engine

wouldn't run without the throttle in all the way, then running really fast and dropping of rapidly to barely ticking over then dying.

Last month, took the top end off, cleaned out the gunk, polished piston head, reassembled it all with new gaskets, checked valve clearances, changed spark plug for correct type(read the manual, duh!) started engine, rejoiced. Engine running sweet as, hardly any problems with idling.

The day after, started engine up went to adjust carb, revved engine a wee bit and PLINK! Both rocker arms snapped at same point in same way,

piston now has a lovely little stamping on it from where it whacked the valve, I'm assuming that it was the timing chain jumping, lots of white smoke before this happened. Checked head, loads of oil, so not a lubrication problem.

This week, finally got around to buying a new engine, swapped over starter motor from old eninge(this one didn't come with one) adjusted valve clearances(very fiddly, seems almost suspiciously hard to get it right and yes I'm using feeler gagues), timing is out by a bit so will need to take the chain off and stick it on the sprockets properly(waiting on a flywheel puller to do that) with the timing marks all lined up.

How do you split the cam chain? I've been looking for a link and can't find one, oh and how do you split the drive chain once the pin is on it? Can get it on, but not off!!

And now for the strange bit:

Both engines are from the same year ('89 as far as I can tell), so this may be an issue of the engine's manufacturing run.

On inspecting the cam chain on both engines, I've noticed that the sprocket end of the cam tunnel used to have a lip, I know this because I can see what's left of it on the old engine, however the new engine has none left, as it's been completely ground off by the cam chain, the old engine isn't so bad.

As you can imagine this is quite shocking, but my mind's been put to rest as I almost had a fit when I looked at the new engine's oil filter and saw that it was full of little bits of metal!!!!!

It would appear that the timing chains in these engines have been either slack and running for some time, or even worse that the camshaft's bearing is slightly on the wobbly side of things.

So anyway, i have now ordered a new cam chain to fit into the newer engine, as it seems that it's got the same problem aswell as the timing being off. I'm actually quite tempted to take the top end off to make sure that everything's ok.

Ah, and by the way how the hell do you guys get the cam sprocket off? I've been doing it according to the haynes book of lies and on the old engine the cam chain slipped and I don't want to go damaging anything. I'm hoping that the flywheel/clutch holder will let me undo that bolt more easily.

So yeah, quite a lot of time and money being gobbled up over the last year, if anyone has any idea as to how the cam chain could get so out of hand, then I would like to hear it.

Ta.

[yamaha sr 125]

My yamaha sr 125 speedo is in KHM i am looking for a speedo overlay or a replacement speedo head in MPH.

chers Anth

[yamaha sr 125 valve clearences]

The valve clearances are Inlet 0.05 - 0.09mm or 2 to 4 thou and Exhaust 0.11 - 0.15mm or 4 to 6 thou with the engine at TDC on the compression stroke with the engine cold. Tony.

thanks for the infomation. ill set them on saturday morning and try it. thanks again Anth.

[yamaha sr 125 valve clearences]

im after a bit help. i need the valve clearance settings for my yamaha sr 125. It starts and runs fine but its quite tappety.

if anybody can give me settings for inlet and exhaust valve,it would be great.