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Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 07:13 pm Jan 05 2019
by B737driver
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Piston

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 07:17 pm Jan 05 2019
by B737driver
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Piston

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 07:19 pm Jan 05 2019
by B737driver
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Maybe a little blow by where the upper ring comes together.

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 07:29 pm Jan 05 2019
by B737driver
Anyway, that's what I've got. Going to rebuild the bottom end and work on the air boot to carb junction a bit more.

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 11:25 pm Jan 05 2019
by KDXGarage
Yeah, maybe the left seal is leaking:

send off crankshaft for connecting rod kit
new mains and seals
new piston
new rings
new gaskets
new coolant and engine oil

GOOD TO GO

The little lines look like dirt scratches on the piston and cylinder.

If there is aluminum streaking on the cylinder walls, read up on muriatic acid.

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 10:23 pm Jan 10 2019
by SS109
I'm really curious about the crank damage. Did you explode a piston at some time?

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 11:01 am Jan 11 2019
by B737driver
I was surprised at the look of it as well. No history of broken pistons. I've done multiple top ends through the years and never noticed this, but I really wasn't looking. The bottom end was always good.....till it wasn't that is.

I looked at some images of other KDX cranks and surprisingly saw similar marks (metal apparently missing) in the exact same area. Based on this, I'm trying to convince myself that it may be normal.

Update: Dropped the bottom end off with my mechanic. He thinks that the races on one of the main bearings is coming apart and fortunately I caught it before the bearing completely came apart. I hope to get pics when he splits the cases.

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 11:40 am Jan 11 2019
by KDXGarage
If you are seeing the same thing, then it may very well be.

OFF TO THE RACES!! :-)

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 03:43 pm Jan 11 2019
by Julien D
Nice, I hope it all gets worked out. I would like to see those if you do get pics.

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 12:43 pm Feb 07 2019
by Dan 250sr
That's a siezed or nearly seized piston, autolube or premix? I put a 38carb on my 250 and got it wrong. Before mine locked up it was making a ticking sound.
The piston skirt is getting to hot and pinching. Is piston the correct size for barrel?

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 06:51 pm Feb 07 2019
by Vossman
Any updates b737driver?

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 07:44 pm Feb 07 2019
by B737driver
Well the bottom end is currently being rebuilt. The main bearing on the water pump side was in the process of "letting loose". Really hoping to get some pics when he pulls it apart. He just rebuilt the crank and installed a new rod. He thinks that the metal shavings from the race coming apart were getting into the top end during combustion causing the piston scoring. He hasn't pulled the seal on that side yet to totally expose the bearing.

Obviously, I'm doing a new top end as well. I've always used Motul at 40:1 (premix) and I guess 15 years is pretty good for the bottom end to hold together. It's been ridden hard and never failed me before. I'm no expert rider but I do use all the power bottom to top where appropriate. It's been bulletproof and I hope to get another 15 years out of it after the rebuild.

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 08:00 pm Feb 07 2019
by B737driver
Kinda getting tired of this look...can't wait to ride it again,
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Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 08:11 pm Feb 07 2019
by KDXGarage
Soon!

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 08:24 pm Feb 07 2019
by Vossman
Very cool. Thanks.

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 12:53 pm Feb 08 2019
by Dan 250sr
I use motul 32.1 I'm not that brave... maybe main jet is restricted/ blocked that will make it run lean at top end. Worth checking before you start her up.
I got stitched up with a Chinese copy 38 keinlin, surpossed to be sudco tuned. It wrecked my original sr barrel and piston, and also started to siez kx barrel I put on , all my pistons looked just like yours. Also if crank seal is gone that will draw air in through seal instead of carb. Could possibly make it run lean. Still think it's nipping up... you would have marks on top of piston if anything was flying around in the cylinder.. just my opinion please correct me if I'm wrong

Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 08:27 am Feb 22 2019
by B737driver
Well here is what I've got. The inner race on the main bearing (water pump side) was being chewed up. The metal that it was producing is what was getting into the combustion chamber. That metal is what you see on the piston. Fortunately, I caught it early enough to not mess up the cylinder or head. Lesson here is, if something doesn't sound right...shut it down before further damage occurs. Crazy thing is, the bike was still running normal.
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It was also pointed out that the cases were not flush in some areas allowing pressure to move around in the bottom end where it shouldn't. Here is the image from the mechanic showing those areas. I guess it was a casting flaw from Kawi since this is the first time the cases have been split. He's going to clean that up and should have it back in a week or so. So... new top end, crank rebuilt, new rod, new bearings throughout...should be good to go for years.
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Re: KIPS rattle with a new MUCH louder rattle...help me out guys (with video and pics)

Posted: 09:15 am Feb 22 2019
by KDXGarage
And now we know...
the REST of the story.

Good day.

...Thank you for the follow up. It is always good to get the autopsy report.