Were my cams installed incorrectly? Valve clearance woes...

[pbear62]

Like JL said - it definately pays to shop around for prices. I would have thought that all Yamaha dealers would charge the same for parts but when I recently did the rings & stem seals etc on mine, I found that one dealer was heaps cheaper than another. (can't remember exactly how much but it was something like $100.00)

[DOBBO]

How many kms should you get out of the camchain before you replace it ?

[cobbadiggabuddyblooo]

Decided to shout myself a new one at 100,000km as a treat ...

[DOBBO]

Yeah I figured about every second valve clearance 84000kms. Thanks cobba.

[JL]

Well, picked up parts today but the valve quantities ordered were mixed up - 2 instead of 4 and 4 instead of 2! Luckily I picked it up looking through the parts pdf and my receipt this morning before going in to collect. I have decided that since I will be removing the head, I may as well do the rings, even though it's digging more into the savings it's not that much more considering I'm doing head work. Extra parts ordered came to $95 - this was for the base gasket and cylinder o-rings, all the gaskets, o-rings and circlips for the oil pump (when replacing cam chain), o-rings and gaskets for where water pipes will be removed etc. What was not included was piston rings ($71 per cylinder) - I will wait until I have the cylinders measured, hopefully I can still use standard size. I also inquired about the valve guides - $64 each(!), plus a little extra for the circlips. Again, will have to wait until valves are out to measure these. Perhaps an engineer may have a cheaper alternative? I've noticed a motorcycle head workshop around the corner, I think I'll get a quote for doing the measurements, honing etc next week when they open. Has anyone got any recommendations in Melbourne? I'm in two minds on this, never done it before and a bit nervous about stuffing up the valve lapping and getting the measurements wrong, but I've got a mechanic mate who is willing to lend a hand with tools and show me how to lap. I guess if it doesn't work I can always take it to a workshop and get them to do it. I suppose I will have to use their services if new valve guides are needed anyway. This is getting expensive, but the TRX is such a classic bike and I couldn't part with it. I've just picked up a running '78 xs650 special I was hoping to customise a little, but that was before discovering just how far into the trixy I would need to go At least the parts for the xs are cheaper and available from the 'states.

[dfh]

Slightly off topic but still relevant - anyone know why the '96TDM doesn't seem to suffer from "valve stretch" - same engine..................

What I understand is that the TRX has a more aggressive inlet cam profile than the TDM with longer duration even though the lift is the same. What I am not sure about is if the valve springs are stiffer or not but regardless of the spring rate the same valve is being open and closed faster in the TRX will have greater stresses than one installed in the TDM. I suffered the 96 TRX valve stretch issue @ 85,000 and had them replaced with the later model inlets. There was no valve seat issues. Now @ 107,000km I have recently redone my valve clearances and have plenty of shim range to choose from.

DFH

[Smithers]

I have just posted a question regarding valve noise and have the same sprocket mark alignment issue that you have. In effect both cam shafts are retarded in relationship to the crankshaft indicated TDC, with the inlet camshaft being more retarded than the exhaust. My engine has done 42000km, shows minimal internal wear, the cam chain tensioner and slippers show virtually zero wear (which gives me hope that the chain may not be too worn) though a previous life of being beaten along at high revs may have not have helped the chain for stretch, but I have know way of knowing the bikes past use.......my conclusion was that this was a manufacturing error and I set the TDC to camshaft timiings to be as close to spec as possible given this error. My bike ended up having the inlet camshaft set at about a third of a tooth advanced and the exhaust at about a third of a tooth retarded. The engine seems to run well, as it did before.........I always set cams at the heel of the cam ie. the butt end of the cam profile. The previous mechanic had obvoiusly done this with my bike and the settings were at spec......Hope this helps. Cheers

[dandywarhol]

Slightly off topic but still relevant - anyone know why the '96TDM doesn't seem to suffer from "valve stretch" - same engine..................

What I understand is that the TRX has a more aggressive inlet cam profile than the TDM with longer duration even though the lift is the same. What I am not sure about is if the valve springs are stiffer or not but regardless of the spring rate the same valve is being open and closed faster in the TRX will have greater stresses than one installed in the TDM. I suffered the 96 TRX valve stretch issue @ 85,000 and had them replaced with the later model inlets. There was no valve seat issues. Now @ 107,000km I have recently redone my valve clearances and have plenty of shim range to choose from.

DFH

interesting stuff - I understand the cams and part numbers to be the same on the TRX and TDM - can anyone confirm this?

[dfh]

interesting stuff - I understand the cams and part numbers to be the same on the TRX and TDM - can anyone confirm this?

ahhh... from the old dart are we? Been down this track before. Yamaha UK were a lot less "candid" about all of this and still live in a world of denial. Having had this discussion with other early TRX owners in NZ, Germany, France & Sweden all the respective national Yamaha importers except the UK importer list both the 95 to 97 inlet part numbers & the 98 on part numbers so you can order the replacements with confidince. In the UK it is an act of faith, but I would be surprised if the still sold the old valves.

DFH

[dandywarhol]

.....................and the cam profiles???

[dfh]

.....................and the cam profiles???

Dunno.... never replaced them

DFH

[Smithers]

an update from my post regarding cam shaft sprocket line positions and my positioning the sprockets to be closest to standard line positions using a moderately worn chain......the bike went fine but but the valves were noisier and the bike would was mildly surg at 4000rpm. Power was nice and tractable at low revs and it appeared to have plenty of gusto over 4000rpm. It would occasionally stall when idling....so enough of this, I installed a new camchain and voila, no valve noise, the exhaust sprocket line matches the head gasket face at crankshaft TDC and the inlet sprocket is about a third of a tooth retarded......the bottom line being that the valve noise, and hopefully the surging may have been a result of my advancing the inlet sprocket slightly.....it appears that the inlet sprocket markings will always appear retarded ..... good luck with your rebuild

[Tigcraft TRX]

- Cam lines will not line up in an engine that's done a load of miles. Both crank/cam sprockets wear, and the chain does stretch as Hans said. If you're on a budget just replace the chain, which will bring the lines nearer, you can't do naff all with the crank sprocket.
- The reason the shims get tight is the usual Yam soft valve seat. Anyone had an FZR?? FZR 400's especially prone. If it gets 2 bad, you need new seats. But serious/race use tuner's advise stainless valves in Yam's.

- I have a 7000 mile head (dunno year) for bits if anyone needs valves/buckets etc.

[dandywarhol]

.....................and the cam profiles???

No - I mean, are the TDM and TRX cam profiles different?

[JL]

Well, parts FINALLY arrived, so I have begun the dismantling...

Ewww...

Probably a good thing I decided to pull it apart, there's a lot of crud in there, don't you think?
Will be pulling the cylinder block tomorrow, couldn't really see any honing marks there either. I wonder what kind of condition the valves are in... Don't want to look at it again tonight!