Slap/clunky sound from engine.
Posted September 27, 2015 - 12:50 PM
So I warmed it up sounded fine, took off and when I decelled to a stop sign I heard a slappidy clank, very suddle, but can be heard best if your hands are on the bars cause you can slightly feel it.
It's slight enough that it took a few stop signs to determine there is somthing funny sounding.
No performance problem, and no sound when riding. I Have narrowed it down,,, you can have it idling on stand, just give suddle throttle and as the throttle comes back to idle you can hear the slap.
What you think ?
My thoughts were, if it was piston slap I would hear it during other modes of riding.
Maybe that cam chain tensioner broke some teeth and pulled back,, loose cam chain spanking due to looseness ?
Again, starts and runs great, not slap at all while riding,,,, but if coming into turn hard with clutch pulled in and rpm comes close to idle before nailing it you will hear it.
Does sound like coming from top of jug.
Posted September 27, 2015 - 01:57 PM
When was the last time you rebuilt the top end, or replaced the automatic cam chain tensioner ?
Pretty hard to say what it is without pulling it apart.....but if it is the tensioner failing, stop riding it and check it.
Posted September 27, 2015 - 05:14 PM
Posted September 27, 2015 - 05:49 PM
Yeah, it's time to do some maintenence.
You could be 99.9% of the way to a catistophic failure with the motor being 13 years old....Yamaha's don't exhibit any signs before going self destruct.........or not, but I would certainly plan on a top end while it's apart.....
Posted September 28, 2015 - 04:15 AM
Posted September 28, 2015 - 05:21 AM
The wrist pin bearing.
Do not buy a no-name ebay kit for your motor.
Posted September 28, 2015 - 05:27 AM
Posted September 28, 2015 - 06:13 AM
Do you mean Weisco?
I would not buy anything until you pull the motor apart and look.
Your crank could be shot.
Posted September 28, 2015 - 06:35 AM
Hoping it's a broken cam chain adjuster.
Posted September 30, 2015 - 06:57 AM
Posted September 30, 2015 - 07:02 AM
That's why I'm going into the motor I'm kind of expecting to find a broken lifter spring in a lifter is slow tapping the top of the piston.
Posted September 30, 2015 - 04:56 PM
The bike was low on oil when my kid rode it hard,, I'm beginning to think this was the start of piston slap.
Bore is 95mm so stocker,,,,, I did find 2 gaskets stacked on head,, never seen that on a 2 stroke.... anyone know if that's normal ?
Anyway, at this point I only can find skuffing that muratic acid will remove, no gouge. I see hone marks in the skuffs so that's good.
Piston slap ? That's what I think it was.
Any comments ?
Posted September 30, 2015 - 07:15 PM
Probably. Or the starter motor clutch system was not disengaging. Sometimes at really low rpms it can act strange.
You can re-cross hatch the cylinder if those marks are gone, if you own the tools, otherwise send it out.
I would do a valve train re-shiming, top end, hone the cylinder, and use OEM GASKETS only.
Take the head and turn it upside down and pour gas in it and see if the valves are sealing.
Posted October 01, 2015 - 04:48 AM
This bike no elec. Start,, 2002.
I'm gonna apply muratic acid to the cylinder walls,, done this to all my 2 strokes,, and scotch Brite by hand the cylinder wall, takes glaze off, never had issue in past with my 2 stroke bikes and sleds. I know everyone says hone, and that's great cause it's a quick 30 second process,, but if you have scotch Brite sheets,, 2 min., and some angular elbow grease you get the same result.
I will do the gas trick on head to verify seal on lifters. I'm assuming all good since I was still in spec and all looks good.
Posted October 11, 2015 - 12:12 AM
I may be missing something ttreewlkerr, but your bike isn't a 2 stroke. I hope I'm reading your post wrong. Double gaskets is either the POs way of putting a bandaid on a leak, or someone convinced him that the extra gasket would improve performance by creating space above the cylinder. Either way, I'd go back to one gasket, and +1 on the OEM stuff. But, I'm gonna bet you'll find your issue once you pull the clutch cover.
Posted October 11, 2015 - 04:43 AM
Posted October 11, 2015 - 05:06 AM
Posted October 11, 2015 - 04:38 PM
Sure seems like piston slap symptoms,,,,, yet I put new pistonkit in weseco, samesound. Maybe its just the bikes noise and I'm listening to much.
Posted October 11, 2015 - 05:21 PM