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Strange noise after engine reseal.
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thr3shold
Strange noise after engine reseal.
I resealed the top end of my 1980 GS1100E. I took it down to the barrels and resealed it with a gasket kit from Athena. The reason I did this was that I needed to replace the rear timing chain guide. Previous to this the timing chain slipped quite a lot on one occasion (the manual tensioner had backed all the way out) and bent some valves. I examined all of the valves and found they were only 5-10 thousands bent at the tip end. This is so slight, it may have not been from the pistons, though a tick did develop after that slippage incident. Going against everything I've heard I clamped the valve stems with some aluminum jaws and trued them up (I'm only mentioning this in an effort of full disclosure so that I can find out what is causing the noise). I resealed everything, retimed it and started it. During this process with the cams on I pulled out the front chian guide to look at it and then reinserted it. It took a long time to start, but eventually it did, though it ran poorly. It wouldn't idle, I had to give it a little gas to keep it running and it sounded strange. I opened it back up to retime it and I think I was off a tooth. I retimed it, triple checking to make sure I got it right and started it again. It sounded and ran much better. However, this time there was a definite "Shhhuu Shhhuu Shhhuu Shhhuu Shhhuu Shhhuu". Does anyone have any ideas what this may be? Thanks!Tags: None
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Matchless
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rudy
Did you use new exhaust gaskets? Just thinking of a simple thing, rather than telling you your valves are screwed.
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manual cam chain tensioners are evil when used on a street bike by a non-tinker-er or mechanic.
when these are installed you can break and or damage the rear cam chain guide.
if you have an older manual tensioner...
those puppy's didnt have a fat head on the (guide)side and would bore a hole clean through.
do you have your tensioner over tightened maybe?
yeah,
your location would help as there may be someone in your area that actually has more knowlage of sounds and the workings of the internals in your engine than a hobby type of mechanic.
the sound you describe sounds to me like a set of straight cut primary gears in a kawi z1/kz engine.
but the gs stuff except for the 8v. 750's have helical primary gears.
if you was stranded in the middle of no where and had no choice but to straighten your own valves...
that would have been ok.
if you didnt put the valves in a valve grinder and spin them..im sure there still out some.
also, someone correct me if im wrong but i believe factory valves are 2 piece so that gives them a chance at failing at any givin time.
seems like this project was maybe doomed from the start.
take it back apart and get a set of used valves, a valve job and re-examine all the parts in the top end(timing chain/guides/ and maybe install a good factory tensioner.
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Forum LongTimerGSResource Superstar
Past Site Supporter
Super Site Supporter- Mar 2006
- 35619
- Torrance, CA
Originally posted by thr3shold View PostI examined all of the valves and found they were only 5-10 thousands bent at the tip end. This is so slight, it may have not been from the pistons, though a tick did develop after that slippage incident. Going against everything I've heard I clamped the valve stems with some aluminum jaws and trued them up (I'm only mentioning this in an effort of full disclosure so that I can find out what is causing the noise).
You "trued" up bent valves by clamping them in a vice? The total valve runout spec is something in the range of .001" max - not the kind of tolerance that can be maintained by eyeballing the straightness.
I don't know what the noise is but this doesn't sound good.Ed
To measure is to know.
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Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846
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KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection
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*Quote*
(the manual tensioner had backed all the way out) and bent some valves.)
a funtional (stock) tensioner would not had let this happen.
unless this is a hi-perf application...not stock internals/runs wide open day in and day out ect..
does anyone expect most of the guys on this site to adjust there (manual) tensioner on a regular basis?
i think not!
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asetech
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TheCafeKid
May be a dumb question, but did you RESET the tensioner as per the manuals instructions?? As BWringer has pointed out on numerous occasions, a common mistake that people make when re-installing the cam chain tensioner is that they LOCK DOWN the set screw. This is wrong. When installing the tensioner, after you allow the tensioner arm to expand, you should tighten the set screw down, then back it off about 1/4 to 1/2 turn, and then tighten the lock nut. Often times people tighten the set screw all the way down, and then the lock nut, and the tensioner is unable to move. The set screw rides in a little channel that keeps the arm from coming out all the way. If you lock it down in the channel, the arm cannot extend or retract as needed to keep tension on the guide rail.
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TheCafeKid
Originally posted by blowerbike View PostGUYYYYS,
he stated earlier that he has a manual tensioner.
am i missing something?
where did he state that he went back to a stock cam chain tensioner?
if i missed this...someone point this out to me.
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thr3shold,
Welcome to GSR.
I have no comment about your valve nor your tensioner.
About the shuuu schuuu noise:
You say you took it down to the barrells, so if I understand you correctly, you had the cyclinder head off.
Maybe concider the possibility that the noise you are hearing is an head gasket leak.
What can you do to better locate where the noise is comming from? Maybe move around from side to side and around. Then move you hand over different areas and find where it makes the sound change.
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TheCafeKid
Originally posted by Redman View Postthr3shold,
I have no comment about your valve nor your tensioner.
About the shuuu schuuu noise:
You say you took it down to the barrells, so if I understand you correctly, you had the cyclinder head off.
Maybe concider the possibility that the noise you are hearing is an head gasket leak.
What can you do to better locate where the noise is comming from? Maybe move around from side to side and around. Then move you hand over different areas and find where it makes the sound change.
.
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thr3shold
Answers to everyone in no particular order since I'm running out the door to drive down to LA. I'm in Tulare, CA. I had the manual tensioner on there when I was trying to find out what was wrong with it when it was making another sound and I hadn't figured out it was the chain guide. Rebuilding it I put the old stock automatic tensioner into it since it was still good and I had had the bad episode with the manual tensioner. I did not true up the valves by eye, I put a depth gauge with a magnetic base and found out where it was off. All of the deflection in the valves were in the base and not the stem, I made sure of that. After I was done there was no more than 0.003" deflection and I gave it a simple leak down test which it failed miserably before, but passed after truing. I also hand lapped the valves until a good wear pattern formed on the valve seat area. I considered it being a gasket leak, but I thought I should shut it off and ask you guys before I let it run any longer trying to pin point the source of the leak.
Happy Thanksgiving.
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