Go buy yourself a lottery ticket your damb lucky, good to hear you found it.

 

You may have bent a stem from the gross angle of attack that a backed out adjuster may allow, not sure though. If so, the valve may have stuck open in the guide and dinged a piston that way.

The head comes out in the frame and isn't a terribly worse job than what you've done already. Additionally, the rad and exhaust have to come off but I don't think much more. You can even get the exhaust off in one piece but it might be easier to remove the mufflers. The exhaust gaskets will probably not require replacement if you're going back in with the same components. Free the bolts up nicely on the clamps while it's apart.

If the stem bent internally causing it to stick, the guide may be damaged. If so, heating in the oven is required to remove the guide as well as installing new. The seats are hard so there's a good chance that the seat will be OK and just lapping a new valve will be sufficient to re-seat, not requiring a full re-grind of the seats with the associated expense. The manual has a decent run-down of the procedure.

A quick and dirty compression check to see if the compression IS low, is to engage the engine kill switch, open the carbs, and crank with the starter. If there's an extremely low hole, the extremely irregular cranking will announce it.

If you do a compression check with a gauge, be sure to open the throttle full while cranking or you will get erratic readings caused by the inability of the cylinder to get an un-restricted full charge of air. The most minor irregularity in the carb synching will show dramatically in the compression readings. Any compression check on any engine should be performed with the butterflies open but on typical auto engines where the intake is drawing from a large, common manifold, the readings may tend to be lower than actual but at least uniform or accurately indicative of trouble because each cylinder gets an equal intake charge, even if less than full. On bikes, or any engine where there are individual intake runners with individual butterflies, the readings can be skewed due to varying cylinder initial fill caused by the butterfly restrictions varying slightly due to less than perfect synching. Another way to restate this that may help understanding is that these engines are 10.5:1 compression ratio, therefore every small error on initial fill is multiplied by 10.5. More than a few folks have torn down engines due to bad readings from an improperly executed compression check.

 

Well folks I have diagnosed the problem and I am not F**king happy!!!

One thing I didn't mention (Because I thought it was ilrelavent) was that I did not put the bike back together after the locknut came undone as I was too crook (had a tooth extraction go wrong OUCH!). So I gave it to a "trusted" mechanic who reassembled it for me.

So I start to take the thing to bits again and I realise that the f**king useless mechanic has put the cams in the wrong way round. Ie left is where right is. This of course would have messed up the whole show.

I really hope no permament damage has been done.

Now the mechanic did it for free as a favour to a freind of mine who owed me a favour. I am wondering that since no $$$ exchanged hands do I have any recourse. If not I will tell every single bike rider in town to avoid this monkey.

I'll keep you guys updated.

 

Well I finally have the bike back together and it is running well. Despite my mechanics best efforts the bike isn't ****ed.

A couple of things that were interesting.

1. I could not get the timing marks on the cams to line up exactly with the head! If I moved the sprocket one link over it would sit either a few mm below or above the head. That has got me stumped.

2. This has got to be the worst ****ing bike to do a locknut type valve adjustment on. Why dont honda just use a screwdriver instead of the poxy 3mm allen key adjustment. The inlet Cam clearance gave me grief as well. The difference between too tight and too loose was 1/16th of a turn on the Allen Key. Well I managed to go over 40,000k's without the need to adjust them so hopefully it will be the same again.

 

Aren't the #1 and #4 exhausts a pain to get? Man! Anyway, since a slightly loose adjustment is better than a slightly tight adjustment, and because you have +/- .001 to play with (at least on my '91 you do), there is an easier way than trying for exactly on. Take the feeler guage that is .001 inch larger than the 'dead on' figure and adjust the valve so it takes a good pull to get the guage out. Now take the specified guage and slide it in. If the specified guage slides in easily, and the .001 guage either won't go in or takes a great deal of force to go in, you have your valve set approximately .0005 loose. Give or take a couple ten-thousandths. With a little practice and a delicate touch you'll be able to tell what is tight enough by feel almost every time. This, by the way, is called the go/nogo procedure for setting valves. It saves an incredible amount of time, reduces frustration tremendously and gives the valves a little bit of saftey factor.

I couldn't get the timing marks exactly on either when putting the cams back in. If the intake is dead on, the exhaust is a degree or so advanced, if the exhaust is dead on, the intake is a degree or so retarded. At least it was when the bike was being assembled. I suspect, but can't prove, that once the bike is running enough slack is taken out of the chain by the CCT to bring the cams into perfect time. Even if that doesn't happen it doesn't seem to matter as my bike runs stronger now than it did when I got it last year.