Valve check numbers ST1100

[DeanR]

Just did a valve check on my 91 ST1100. First time for me. My numbers are below.
I'm thinking I will just button it back up. Seems that a few intakes could be better. But erring on the loose side is somewhat OK, correct?
I used the 'rotate the rear wheel until the cam lobes point up' method, as many here have referred to. Kinda difficult to tell the position, but sounds like it's not critical for checking the clearances.
By .008 tight, I mean the feeler went in with difficulty, but did go in.

The sealing washers on the 91 do look slightly compressed as compared to the 99. I will be putting the 99 covers, washers, gaskets, bolts on the 91. Same as just about all the other parts I've swapped out.

If temporarily putting the covers back on, is it ok to skip any sealant if the rubber is in nice shape?

 

[dwalby]

Hi Dean,

I'd leave the tight .008s alone, that's close enough for me. The 1100 is the simplest bike I've ever owned to swap shims though, but I'd still leave it alone and check it again in another 15k.

your call on the sealant, I used to never use it, but then my RHS gasket just didn't want to seal one day, so a little sealant on the trouble spots and its dry again.

 

[John OoSTerhuis]

Depends, Dean. What are the changes from the check at 65K?

Just me, but I'd take the opportunity to center them all. Also, I'd wait to see if the covers leak/seep/weep after R&R'g the shims.

John

 

[DeanR]

John, 65 K was when I got the bike. No valve check then or since, and no record prior.

Doug, since I can't really be without use of the bike while I'm waiting for the shim kit, and since I'm not thrilled with the idea of pulling the cams, I'll likely just close it up.

A question though. How would valves that are a bit loose manifest itself?

 

[dwalby]

John, 65 K was when I got the bike. No valve check then or since, and no record prior.

Doug, since I can't really be without use of the bike while I'm waiting for the shim kit, and since I'm not thrilled with the idea of pulling the cams, I'll likely just close it up.

A question though. How would valves that are a bit loose manifest itself?

I'm certainly no expert, but I would think your marginally loose intake valves are of no consequence at all. You're not even a full thousandth out of spec if they're 'tight' like you say. I know exactly what you mean by 'tight', you have to really force the gauge in there, but it will go if you force it. That's certainly not a true 0.008 measurement, its probably more like 0.0075. A low performance engine like the ST1100 isn't likely to know the difference in 0.0005 out of spec.

The real danger is if they're too tight, in theory they are susceptible to burning around the seats as the valves may not fully seal into their seats if they're too tight. What I've never seen mentioned is just how far out of spec they need to be for actual damage to occur, probably varies from engine to engine as a function of the performance level of the engine. Too loose has little consequence unless they're so loose that there's too much play and they start clanging around because of too much slop. Again, not sure how far out they need to be for that to occur, but I'll bet you a beer its more than 0.0005.

Do not fear cam removal, its the simplest thing to do because there's no cam chain to deal with. The worst case scenario is you put it back in off by a tooth on the cam drive gear and you have to do it over again. You'll know if you're off by a tooth because the marks on the cams won't line up, so you just do it again one tooth over. I forget exactly how many cam bearings there are, its like 6-8 bolts for each cam. I think you can also mark the drive gear and cam gear with a sharpie before taking it out, then just align your marks back up when you install.

 

[ST1100Y]

...I'd take the opportunity to center them all...

+1...
And I'd also start to check the clearances thoroughly at latest every 24Tkm/15Kmiles... the worst that can happen is that you'll find them well within specs and need to spend on a set of gaskets and grommets.
Proper clearances provide ideal opening angle/gas exchange, low wear on the valves/train/cams, a smooth, efficient and powerful engine...

How would valves that are a bit loose manifest itself?

By an audible "ticking" in idle, but on the long run increased wear on cams and buckets...

 

[DeanR]

Back together. Running great as usual. No shim change. Will re-check next year.