93 KX250 original piston weight and vibration???

[chipped tooth]

Anyone have a original std size piston out if a 93 KX250

I would like the weight of the piston, rings, and pin all seperate in grams.

Clips to if you want.

Since I did the 265 on mine the Vibration threw the bars really wears my arms/hands out.

I'm wondering if the new heavier piston is what causing it.

There is a 22 gram difference between the new Wiseco to the same size older piston.

I showed the differences in a earlier post

I have the bar isolators in and thick anti vibe grips but it's still worse than my 500.

Any idea guys???

[Foxx4Beaver]

did you have the crank balanced?, that should give you next to no vibration...
if not, that's where a lot of your vibes are originating...then straight to your arms/hands.

[DoldGuy]

Chipped,

I can assure you it's not the 22 grams of piston weight. I have a 74mm piston in one & it weighs ALOT more than a stock or wiseco 66.4 piston. Like Foxx said its in the crank / crank bearing causing that much vibration.

DoldGuy

[chipped tooth]

This is a 68.50mm piston, it's 22 grams heavier than a earlier Wiseco 68.50 piston of the same part number that was superseded for the 93 KX250.

Look at the Wiseco pistons getting cheaper thread, those are my pistons.

No I didn't have it balanced but the crank was rebuilt with a Hot rods rod kit and trued, crank bearings are new.

Previous owner had it done and he sprung a radiator leak witch caused it to melt enough and pinch the ring on the exhaust side so it was hard to start, (low compression).
I bored it to 68.50, runs great but the vibes get to me after a while.

I would like to know the stock weight of the oem stuff and see how far off my balance is.

[hybridkdx]

 the big question here is did you ever ride the bike before piston change to know there was no vibration before the bigger piston??? Have added bigger pistons before with no change. I would bet the crank or bearings are your culprit. Especially if someone changed rod on the original crank they didn't get it completly true.

[chipped tooth]

I did ride it once I got it home but only a trip around the yard, had to roll start it.

And I couldn't tell ya on where the Vibration was on that ride.

I should probably pull it down and check, I never have much faith in other people's work.

[chipped tooth]

Update on my vibration issue.....

After the ride last time out I pretty much thaught the worst case scenario....... I tend to over think things from time to time.

Anyways I was set on tearing the engine completely down and checking everything out yesterday.

But before I did I thaught to myself when was the last time I checked the tightness of the engine mount fasteners........

Long story short that's all it was 2 of the frame mount bolts wer only snug........ D'OH !!!!!!

 So instead of wrenching on it Saturday I went riding !!!!!
I took the time instead to jet my 39.5 carb...

Thanks all who commented........ It was only a Rookie mistake LOL

[sandblaster]

The cool thing is you figured it out and it only cost you some time.
And who knows, someone may benefit from your experience.
Thanks for the update.

[Foxx4Beaver]

Thanks all who commented........ It was only a Rookie mistake LOL

eh, it happens to even seasoned mechanics sometimes....at least it wasn't the front wheel you forgot to tighten

[chipped tooth]

Lol Foxx

I went over everything after that just to be sure 

[Foxx4Beaver]

Lol Foxx

I went over everything after that just to be sure 

yup, I hear ya...the way I swill beers and frozen mudslides on a daily basis, I have to re-check everything 2-3 times before I'm sure it's safe.