No Compression in #2

[Larrym]

A Good Feeling

Rickrod3,

Don't bail on your standard feeler gauge just yet, ok?

There was a recent thread here where I and anyone else who cared to read it found out a way to use the standard feelers plus not have to use that "chart":

http://www.xs11.com/forum/showthread.php?t=27275

Thing is that the thread pointed the way back to something "prometheus578" found out/shared about how to do the valve shimming:

http://www.xs11.com/forum/showpost.p...91&postcount=9

Bikerphil says the same thing in the shimming thread too.

I read it and immediately understood it. Recognized it as much simpler way to go about things. (Not really a fan of charts/conversions anyways...)

I mean there it was all the time right in front of everybody with out us seeing it. That is until owners/gurus like Bikerphil or Prom hits us in the back of the head and says, "D'uh, dude!!"

[Rickrod3]

Bent #3 exhaust

Well I did another compression check of #2 and it was 160 PSI.
Maybe the adapter was loose.
I can't for the life of me figure out how I bent #3 exhaust and only #3 exhaust All others are fine.
followed manual step by step timing marks line up.
Man this sucks.

Rick

[Larrym]

Hardy Boys Mystery: The Bending Valves

Rickrod3,

I agree and might I add it sucks royally.

My line of thinking is that f'shizzle #3 exhaust valve had to hit the piston. (Unless of course Uri Geller was bending them with his mind like he bends spoons...)

In particular the assembly "steps" by design are in that order so nothing is "rotated" until the mechanical timing is set. Thing is that with cams in place first, cam sprockets attached to the chain next, followed by the sprockets being bolted to the cams, and lastly the chain being tensioned/CCT installed, it shoulda been fine.

Only thing I can think of is that the firing order of these beasts is 1-3-4-2. Forget about the wasted spark system for now.. While #1 was a TDC and ready to fire, #3 (and its mechanical running partner #2 of course...) was at BDC. The very first revolution/turn would bring #1 down and #3 up at the same time.

#3 would be on the compression or exhaust stroke cause it's next in the order getting ready to fire. So the valves are either safely closed or the exhaust valve would be the first to be hit in the very first CW revolution done by hand. CCW and all bets are off.

I'm just a little fuzzy right now on whether #3 fires at the top of the next TDC immediately after #1 or not.

What I'm thinking is that during the initial set-up/manual rotation of the individual parts, #3 was apparently far away enough from the piston so that any amount of "tweaking" back and forth to get things lined up was not enough to bend things. The collision had to occur when the initial "turn by hand" was done.

I mean if the whole she-bang was out of time there'd be multiple valves damaged.

This situation where you've looked at it yourself yet not come up with a solution is a sure sign that you're missing something. A second set of eyes and hands involved might "crack the case/solve the crime" for ya. It's a valid troubleshooting technique that unfortunately doesn't get used a lot.

HTH

[Rickrod3]

What I'm thinking is that during the initial set-up/manual rotation of the individual parts, #3 was apparently close enough to the piston so that any amount of "tweaking" back and forth to get things lined up was enough to bend things. You wouldn't have done any of that, eh?

I mean if the whole she-bang was out of time there'd be multiple valves damaged.

I did do a lot of fusing with the sprockets to get the dots to line up with TDC.

I replaced the valve and got the head back on the bike going to take a break maybe tomorrow will work out better.

Rick

[kjohnson]

I'm just a little fuzzy right now on whether #3 fires at the top of the next TDC immediately after #1 or not.

The power stroke of a cylinder would, in conjunction with the counterweights of the crankshaft, be "powering" the compression stroke of the next cylinder in the firing order as well as the exhaust stroke of the previous cylinder. At least in most 4+ cylinder engines something along that lines happens. My XS750 triple OTOH, I have no idea

So yes, #3 would fire on its next TDC after #1 fires.

[Larrym]

Transfer of Power between Cylinders.

kjohhson,

thanks. Every time I have to picture the inside of a motor it's a cake-walk if everything is static/stationary. One and two cylinders= no problem still.

But the 4-cyl get's real busy/real quick when they spin. (at least for me.)

"powering" the compression stroke of the next cylinder in the firing order as well as the exhaust stroke of the previous cylinder.

Should help me make it stick in the ole grey matter for a while.

THX.

[Rickrod3]

Got defeated this weekend Too

Well I was feeling pretty clueless.
I remembered a thread started by Trbig. Read through the first page, got my flash light out and started looking down the cam chain tunnel and there was the chain sitting on the side of the sprocket.

It took some doing to get it on the sprocket, so I would imagine that if I just lifted the chain and put it on the sprockets that it wasn't centering itself.

To make a long story short I got the chain on the crank sprocket, assembled the cams and watched the crank sprocket and chain while rotating the motor.

Rotated it several times by hand wincing as I was going.
checked all the valve clearances all good.
So far so good.
Then got brave and did a compression test Cylinder 1, 150, #2 160, #3 150 #4 150

I got to believe I never had it right from when I first started it up in December and it would only run with the choke since it was on three cylinders.

I kind of thought it would be okay since one day I let it run about 15 Min's on the choke and then it sort of idled. that was the day I also found the pinched gas line but it turned out to be more than that also.

waiting for partnmore to get me my valve cover gasket and tribond.
In the meantime I'll put back the carbs exhaust etc.

Hope this saga is finally over
See I'm still waiting for something to happen

It's all in the threads you just have to find them.

Rick

[Larrym]

Rickrod3,

So #3 exhaust valve wasn't bent???

[Rickrod3]

#3 was definitely bent.
I replaced it yesterday but was too chicken to reassemble the cams till I had a reasonable hypothosis as to why I was bending them.

After reading the thread telling about the cam chain on the side of the crank sprocket; I figured this may be my problem.
Just a little surprised that I spun the motor so many times and only bent one valve each time. Most guy's that have this happen have damage to more than one valve. There have been a few reported instances in which no damage occurred so; I guess it is possible.

Rick

[Geezer]

Just a little surprised that I spun the motor so many times and only bent one valve each time. Most guy's that have this happen have damage to more than one valve. There have been a few reported instances in which no damage occurred so; I guess it is possible.
Rick

I think the valve was bent before you rotated the engine. Any chance you turned the cams before you lined them up? Valves can bend if the hit each other on over lap...

Geezer

[Rickrod3]

I do not believe so

I think the valve was bent before you rotated the engine. Any chance you turned the cams before you lined them up? Valves can bend if the hit each other on over lap...

Geezer

The first bent valve I possibly may have but; the second I do not believe so. when I installed the cams I was pretty sure I put them in with the dots facing up almost lined up with the arrow on the #3 caps.

after both installtions (resulting in a bent valve) I do recall a noise that did not seem right so far I have not yet heard that noise and the motor seems to turn smoother.

I guess due to my inexperiance I was unable to detect when it actually happened especially the first time.

I guess just one bent valve is curious to you too.
Would be good to figure it out but; at this point I'll just be happy with no bent valves
Rick

[Rickrod3]

What I'm thinking is that during the initial set-up/manual rotation of the individual parts, #3 was apparently far away enough from the piston so that any amount of "tweaking" back and forth to get things lined up was not enough to bend things. The collision had to occur when the initial "turn by hand" was done.

Larry's observation kinda elimiates damage caused by rotating the cams on installtion you would have to be close to a half rotation to damage an exhaust valve on #2 or #3

#4 exhaust was making me nervous but knock on wood that one escaped harm.

Rick