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[blaster003]

I have a 2003 yamaha blaster running on maxima formula k2 at 32:1 and it has a full rebuild on the motor with a wiseco rebuild kit and I was riding yester day and in the middle of the day I was riding and I heard a loud ping sound in the topend and it died I was not riding fast when this happened we then later roll started it and it ran fine then it died again and when I kicked started it and I heard a rattling sound in the topend and then it lost more and more compression after it was kicked each time it has a full professional rebuild at my dealer thanks if anyone could help me it would be appreciated

 

[jus_me]

leak test first, then comp test.. Take a look into exhaust port and see if u can see any piston damage.. did you or the builder do heat cycles? also what was the reason for the rebuild and about how many hours ago?

 

[Fast6hand]

Did the dealer leak test it? Was it properly broke in? What was the compression after the rebuild? Do you pre mix your gas?

 

[blaster003]

It was not leak tested and it has premix and not sure if it was broke in right

 

[Blaaster]

Did you do the break in?

Break in comprises of 3 - 5 heat cycles, re tensioning of head and cylinder bolts.

Running 2tanks of fuel through at no more than 3/4 throttle.

Please list your mods and jetting.

Are you aware that a forged piston warrants a full warm up before you start to ride, otherwise damage can be done to the piston due to uneven expansion.

 

[tbrooks]

It was not leak tested and it has premix and not sure if it was broke in right

There you go.. sure signs that your prob gonna need a rebuild, again!! The builder can do the best job in the world, but if its not broke in properly and leaktested your just asking for trouble

 

[blaster003]

Ok thanks and it was rebuilt because of the same problem the jetting is 260 and 32.5 and it has about 200 miles since the rebuild

 

[Blaaster]

What pipe and mods please!

 

[blaster003]

Fmf power core 2 gold series

 

[Blaaster]

With premix I feel the main jet should be larger, FMF alone calls for a #260 main.

If you have an aftermarket air filter 1 or 2 sizes bigger again!

 

[blaster003]

It wouldn't run without the airbox lid off so that's why I didn't go any bigger

 

[Larry's Shee]

make sure you give it a bath before you start taking it apart

 

[tfaith08]

If it was rebuilt at a dealer, there is a very high chance that it wasn't leak tested. Of the 4 dealerships that I've been around, none of them have ever done a leakdown test. They generally just spray a gasket sealant on the gaskets and make sure everything is tight.

How long has it been since the engine was rebuilt?

 

[blaster003]

About 7 weeks ago

 

[Blaaster]

It wouldn't run without the airbox lid off so that's why I didn't go any bigger

Have you done a plug chop run to confirm the jetting of did you just guess the size?

Ok thanks and it was rebuilt because of the same problem the jetting is 260 and 32.5 and it has about 200 miles since the rebuild

Re-built because up the same problem, was the cause for the previous engine demise investigated, or was everything just slapped back on just the same?

 

[blaster003]

I bought the bike for 500 and the previous owner rebuilt the top end and the piston or crank was in a bind and we got it running but it needed a rod bearing so we had the whole motor rebuilt

 

[blaster003]

Ok I pulled the head off and the piston has this concrete like material on top does this mean I need to mix more oil or go up in jets and could this affected my bottom end any

 

[Herpderplol]

"concrete material" would be your melted piston. and yes it could have affected the bottom end

 

[speedyslyder]

oh boy got a pic ? lets see it

 

[tfaith08]

No pics of the piston needed because it's time for a rebuild if the owner described it like that, but we can always use pics of deto/lean/pre-ignition victims to show others. You now have a cool little ashtray with a story.

What we really need are pictures of your cylinder and chamber (bottom of your head) and for you to tell us how much play your rod has at the crank. While you're at it, go ahead and start finding a workbench to build an engine on.