Valves worth doing ?

Hi All

Measured the clearance last night and got these (in thou. Exh/Int)

#1 7.5/6.5
#2 8.0/4.0-4.5
#3 6.5/4.0-4.5
#4 7.0/4.5

So a couple are a bit borderline I think (intakes 2 & 3) but since I understand they close rather than get wider I figured I could possibly leave te others I don't anticipate putting many miles on the bike < 1000 per year.

Cheers

J

 

Intakes two and three are likely tight; spec is .11mm ~.15mm; you're at .10 if they're .004" while .0045" is JUST barely in spec at .11mm.

Exhaust #3 bears watching, and I'd keep an eye on intake #1, it's loose which generally indicates a developing issue.

I'd re-measure using a true metric feeler set and go from there.

 

Thanks for the reply

EEK - now you've got me concerned ! What type of 'issue' can you imagine ?
Will get a set of metric feelers too.

 

As the valves recede Ito the head the clearances get tighter as the shim gets closer to the cam. If you have a clearance that is 'loose', you have something happening so that the valve is getting closer to the piston rather than closer to the cam.............could be as simple as a lot of carbon build up keeping the valve from closing, or it could be something much more serious.

Dave

 

Aw guys, stop it - what's the 'much more serious' thing. I'm not sure I can bear it much longer :cry:

Best

JS

 

A bent valve or a valve that is slightly distorted from overheating; both of these (besides carbon build up) can cause a valve to not close fully, as can a worn or split valve guide.

There could also be excessive wear occurring, on the tip of the valve or the underside of the bucket; but that's a bit of a stretch possibility wise.

 

Thanks BF. A burnt intake less likely than exhaust though right ?
The engine is on the bench right now with no carbs on so I can peek at a bit of the guide I think.

Thanks again folks

JS

 

agreed - start with the proper tools

 

If you are "new" to the bike, the PO coulda adjusted that one valve wrong.

Meaning - there might not be a problem.
(A burnt or tulipped valve would run tighter)

 

The engine is a 600 from a Radian that I got from ebay for 50 quid (it was sold as an XJ/FJ but hey ho..) the intention is to plant it to into an XJ550 (seca) that I bought in boxes last year. So far the only difference I noticed is the carb rubbers that are for the smaller Radian carbs - I (roughly with digital verniers) measured the intake lobes last night and they appear to be right of the FJ/XJ spec.

Picking up another engine on Friday with hopefully the correct rubbers and a starter motor - has a 'sticky exhaust valve' apparently - princely sum of 26 quid.. So will end up with three engines 8O

Incidentally - anyone know if the 550 YICS rocker cover fits the 600 ? Might add some fake authenticity (oxymoron ??)

Cheers

JS

 

Put in a "wrong item" complaint on E-Bay - - you'll win.

 

You're probably right but hopefully I can make it work. 160 mile round trip to return it would be more hassle and expense than it's worth...

I'll keep you informed..

Cheers

Js