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I keep getting a leak in the same BASE gasket - H1
http://www.kawi2strokes.com/forum/viewtopic.php?f=14&t=4156		 Page 1 of 1
Author:  Knut [ Thu Aug 16, 2012 4:08 am ]
Post subject:  I keep getting a leak in the same BASE gasket - H1
I just copied yellowsnow's topic title, other than that my problem is the base gasket. It's the l.h. cylinder, it does not leak all the way round but on the outward facing side. Two-stroke oil streams down the stator cover if I ride at highway speed. I have replaced it once, made sure the surfaces were clean and level, and applied sealer. After one day it was leaking again. Using the correct torque and re-torqued after a few warm-ups.

First time it started leaking it hadn't been touched for years, so it can't be any sudden surface damage. The new gasket is of the same type as the old one, also the same type of sealer.

:?:
Author:  usernameandpassword [ Thu Aug 16, 2012 9:37 am ]
Post subject:  Re: I keep getting a leak in the same BASE gasket - H1
If the thin gasket don't do it for you, grab some thicker paper at advance auto or auto zone and cut one yourself with a razor blade and a drill. They mash down and fill small imperfections in the mating surfaces. Used on the s3 with no leaks. :thumbup:
Author:  Steve [ Thu Aug 16, 2012 10:13 am ]
Post subject:  Re: I keep getting a leak in the same BASE gasket - H1
Kind of off topic, but close enough I hope, Harbor Freight has a great gasket hole cutting set for only a couple dollars if you catch them on sale, a must have IMO for anyone cutting gaskets.

Image

http://www.harborfreight.com/9-piece-ho ... -3838.html
Author:  Nigel72iv [ Thu Aug 16, 2012 4:04 pm ]
Post subject:  Re: I keep getting a leak in the same BASE gasket - H1
You could try soaking the gasket in water overnight before assembly. A mate used to swear by it for problem gaskets. Swells all the fibers so they conform better when assembled.
Author:  Bugman Jeff [ Thu Aug 16, 2012 6:46 pm ]
Post subject:  Re: I keep getting a leak in the same BASE gasket - H1
What kind of sealer are you using?
Author:  Looney Cylinders [ Thu Aug 16, 2012 9:43 pm ]
Post subject:  Re: I keep getting a leak in the same BASE gasket - H1
I had the identical problem on my H1a (LH cylinder base leaks at outer transfer port area). This seem to only leak when I flogged it (blue oil streak back across iggy cover) I replaced the gasket once and used permatex on the gasket (kept well clear of oil gallery) This lasted a couple of years. The leak came back in the same spot this year (pulling even more power now). This time I backed off the head bolts one by one and re-torqued to 18lbs. Seemed to work for a while until my 11,000 over rev when I bent the crank end.

Wondering if this oil leak is a vibration thing caused by crank flexing/rotor imbalance at the higher rpms? In all 4 spare crankcases I have, the LH outer main bearing saddle shows signs of the bearing race working....Have you missed any shifts? Perhaps have a look and see if your alternator rotor is still running true?

I now have copper base gaskets to try next on the new engine build.

J
Author:  Knut [ Fri Aug 17, 2012 4:03 am ]
Post subject:  Re: I keep getting a leak in the same BASE gasket - H1
I use regular gasket sealer, the good old gooey stuff that you apply with a brush, found in my fathers garage, he use it on all his vintage bikes and cars. Don't know the brand.

Haven't had any over revs for years. However the crank/rotor can still be out of true. I haven't checked this but perhaps I should, the crank was rebuilt in 2004. The oil streak and leak seem only to occur when I ride at higher rpm, 6-7K. But I have not noticed any abnormal vibrations, but it may not be noticeable when riding (rubber mount cases)... I had to replace a condencer recently as the bracket broke off. Hmm...

I wonder... if there is a connection here that the points/cdi (starfire) setup won't go much past 7.5-8K without bogging, that an untrue rotor or crank affects the points at high revs.
Author:  Looney Cylinders [ Fri Aug 17, 2012 11:01 am ]
Post subject:  Re: I keep getting a leak in the same BASE gasket - H1
The cranks do flex during operation. On the CDI H1A the pickup gap must not be reduced less than about .015in or the risk of striking the pickup with the rotor exists.

If the crank is bent (or main bearing failing/failed) the timing will vary at the higher revs, especially with a point fired engine.

My present engine still runs ok (CDI), but its vibration has increased (felt it in the seat and foot pegs). Using a feeler gauge I found the alternator rotor is now wobbling within the stator by .012in. :(

J
Author:  two-stroke-brit [ Fri Aug 17, 2012 12:08 pm ]
Post subject:  Re: I keep getting a leak in the same BASE gasket - H1
it could be a crack in the top cassing opening up at higher rpm .
just my .02
good luck
Author:  Knut [ Wed Aug 22, 2012 4:27 am ]
Post subject:  Re: I keep getting a leak in the same BASE gasket - H1
Thanks for all input. I haven't found the time to replace the gasket yet (I'm moving house, lots of work), and I also have to check other things to see if there is an underlying cause for this.

However, I was thinking riding to an event Sunday, a 120-mile round trip. As there is an oil leak through the gasket making a stream down the engine cover, do you think there is a chance of oil starvation in that cylinder or crank bearings...? Perhaps I shouldn't worry but I'm asking for peace of mind.

I could ride a GT550 that I have on loan for a while but I rather use the H1 ;)
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