Valve Clearance help

[prometheus578]

'Thanks for clearing that up..."

What?
Valves can only get bent by piston strike... has nothing to do with spark. Valves are in time with the pistons via the cam chain, as we all know.
Jump a tooth or two, piston comes up and slaps the valve silly. Of course, you could also over-rev the engine, valves could float(not having time to fully move back upward)and here comes Mr. Piston again.
125 PSI is pretty low, as the standard calls for 142.
Pul all the plugs, twist the throttle wide open and recheck your compression. If it's good, then recheck your valve clearances... just 'cause I say so. (The compression check would read low for a bent valve, and if you have a "bender", you'll also find a valve clearance gap that's way too wide on the offending valve.
A bent or sticking intake valve will cause a carb backfire, but so would certain unrelated vacuum issues or lean conditions.
If the compression and clearances check out, we shall pursue other avenues.
"Holler back... when you have something of substance to report.

[Flatlander]

Will do.

Over rev is probably what happened to the valve/valves, since I was at the time driving it like I stole it!
But seeing that irregular spark, well sent me sailing down the wrong path!
I will give updates of what I find.
Thanks for the input.
Not giving up quite yet!

[trbig]

Riding it like you stole it shouldn't be a problem. I don't think you could float a valve on these bikes under 9 or 10k rpm, and I don't know anyone who rides them that high. The problem usually comes when you are on it and go to make a 7-8k shift, and hit a false neutral... pegging the tach.


Tod

[Flatlander]

Rode it like I stole it!!!

I was (which I never do) racing! On the XS that is.
Twisted the throttle and flew through the gears. Tires turning, wheel lifting (it does happen) and taking names later. About the time I was hitting the brakes I noticed a little noise....... 5 miles home...... parked it......a little more......... a little more.......... then tore it down to find that noise. That's all I got.
Put about 20k miles on it, before it got its little noise, no problems, and that is why I am working on it. It deserves it since it was not its fault, because I just was a little hard on the old girl!
And boy let me tell you is 81' giving me pay backs!!!!!

[Flatlander]

Re: 'Thanks for clearing that up..."

Originally posted by prometheus578
What?
Valves can only get bent by piston strike... has nothing to do with spark. Valves are in time with the pistons via the cam chain, as we all know.
Jump a tooth or two, piston comes up and slaps the valve silly. Of course, you could also over-rev the engine, valves could float(not having time to fully move back upward)and here comes Mr. Piston again.
125 PSI is pretty low, as the standard calls for 142.
Pul all the plugs, twist the throttle wide open and recheck your compression. If it's good, then recheck your valve clearances... just 'cause I say so. (The compression check would read low for a bent valve, and if you have a "bender", you'll also find a valve clearance gap that's way too wide on the offending valve.
A bent or sticking intake valve will cause a carb backfire, but so would certain unrelated vacuum issues or lean conditions.
If the compression and clearances check out, we shall pursue other avenues.
"Holler back... when you have something of substance to report.

Update on the compression check.
With the engine warm (now #2, and #4 is now backfiring, and #1 has stopped )
Here is my readings.
#1=130, #2=125, #3=127, #4=125
With oil in cylinders.
#1=142, #2=140, #3=140, #4=137
I have not been able to do a valve check yet. Will post that asap!
Is that compression increase with oil, within tolerance or your likings?

[Flatlander]

Oh and she will only run on full choke and part choke after warm. Push in choke and she will quit! I did a carb clean, soaked parts in parts cleaner, did not put the body's in.

[DiverRay]

Take a DEEP breath, and let's start from the beginning.
1. Valve cover off, crank pointer on TDC, and camshaft lines up.
2. Check ALL valves for clearance! (I like mine on the lower side of the spec.)
3. Battery is GOOD and Fully Charged.
4. CARBS/PLUGS Read plugs if it will run. Pull carbs, clean, reset floats and DO A BENCH TEST of float needles!!!!
5. Pick up coils. Check the wires for breaks, check for correct gap between coil and trigger.
The Oil and rise in compression tells me you have a little wear in the rings. I would NOT worry to much yet, but you may end up doing some work on it, as in new rings, or a "big bore kit".

[Flatlander]

Originally posted by DiverRay
Take a DEEP breath, and let's start from the beginning.
1. Valve cover off, crank pointer on TDC, and camshaft lines up.
2. Check ALL valves for clearance! (I like mine on the lower side of the spec.)
3. Battery is GOOD and Fully Charged.
4. CARBS/PLUGS Read plugs if it will run. Pull carbs, clean, reset floats and DO A BENCH TEST of float needles!!!!
5. Pick up coils. Check the wires for breaks, check for correct gap between coil and trigger.
The Oil and rise in compression tells me you have a little wear in the rings. I would NOT worry to much yet, but you may end up doing some work on it, as in new rings, or a "big bore kit".

Thanks, I needed that!!!
1. I got the bolts out tonight for the valve cover, but friend stopped by, needed help on truck.
2. Will do asap. And I'm going with you on that one even though some have said to go to the larger side, because they will seat more with time and wear.
3. Battery is new. But put it on a 2ma charge over night.
4. Plugs were black. Floats are set all equal. Wish I could remember measurement from base to bottom of float. Checked manual at that time was o.k.
5. Pick up coils, I have checked wiring, but never checked gap between coil and trigger. Will do though asap.
Thanks for the input on the compresion rise. I have aways thought a 10-20 psi increase was, shal I say, O.K. I am not an expert though. New rings sound like a great idea in the future. The bike has 30k on it and they probably have not seated yet ! A big bore kit is probably what this ole girl needs since I'm not too small.
Hey DriverRay, thanks!! I'll keep you posted here.

[DiverRay]

Black plugs are running way rich. VERIFY your float settings. If not sure, leave them just a little HIGHER than spec. This is only ~.5mm to 1mm change!! Higher float is LESS fuel in bowel, slightly leaner running. Do check your pilot jet/passages for blockage. That is the idle to ~3,000RPM part of the carb.

[Flatlander]

Originally posted by DiverRay
Black plugs are running way rich. VERIFY your float settings. If not sure, leave them just a little HIGHER than spec. This is only ~.5mm to 1mm change!! Higher float is LESS fuel in bowel, slightly leaner running. Do check your pilot jet/passages for blockage. That is the idle to ~3,000RPM part of the carb.

O.k. one more deep breath for me!
I think that the plugs look thataway because of the assembly lube. But not 100%. I'm also running a K&N filter in the air box with factory jetting. Also have been running and testing with the air box off. These carbs are clean......Well I think they are . I've never had these carbs be that tempermantal for me.?.

[Ken Talbot]

Originally posted by Flatlander
These carbs are clean......Well I think they are

There it is! They're not. Sorry.
DAMHIKIJD, BTDT, HTH...

[Flatlander]

Originally posted by Ken Talbot


There it is! They're not. Sorry.
DAMHIKIJD, BTDT, HTH...

What does DAMHIKIJD. BTDT, AND HTH mean?

Well checked calve cam lobe clearance......again. I need a new gasket .

...........#1...#2....#3....#4
Intake : .006 .008 .009 .008
Exhaust: .008 .010 .011 .013

Well it's not a valve beeing held slightly open.........Unless I'm off a tooth?

Did not tear into the carbs at this time. Only had a hour in me .

[DiverRay]

To answer some for Ken,
Don't Ask Me How I Know, I Just Do.
Been There, Done That.
Hope That Helps ( I think)

[Flatlander]

Thanks DriveRay.

O.K. One more question how am I sure that I'm properly timed? It's a 81'h. I get the tdc on #1. But am not seeing dots on the cams.?.

[Flatlander]

Found the dots!!!!

Originally posted by Flatlander
Thanks DriveRay.

O.K. One more question how am I sure that I'm properly timed? It's a 81'h. I get the tdc on #1. But am not seeing dots on the cams.?.

Did a search for "dot"....... amear 4 hrs. later found what I was loohing for. Under dicussions>Timing Problem, TRBIG had taken apicture and posted 8-19-07. THANK YOU TRBIG!!!!!
I knew they were there, but could not remember where they were!!! Bad eyes, back, and loss of patients. It was there all along..... covered by oil and could not see them until I took a rag to that area each time I came to tdc.
The next thing is now the timing mark's are not lining up when the dots are! I think i've found my problem.?. Quarter inch off!!! And she still ran!!!! Boy these things are beasts!!!