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Discussion Starter #1
i have a 96 trailblazer 250 , brand new topend from ritter cycle has spark has fuel has compression, so it should run right?!..wrong... well all i get is the occasional backfire it will not start at all, the crank seals are good, im running oil injector, also running premix 93 octane and klotz 2 stroke oil. also the timing is dead on

i have checked everything over and over again and all is showing good spark is strong,

what can it be that im missing please help
 

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Discussion Starter #3
it ran very poorly due to low compression, i had to shoot chain lube in the intake just to seal the rings enough to fire it up to move it to its final resting spot, the old piston was shot, all of his work checks out good

me and mr rick have had quite a few conversations over this engine, but hes 3 states away so he cant physically put his hands on it
 

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Discussion Starter #8
Running premix and injector to rule out bad oil injector.... I'm thinking that's why I lost compression in the first place. No matter what I do I cannot get this engine to fire off for even a few seconds... The carb is not the issue it's good, I'm leaning towards a problem with ty flywheel ... Anyone ever had one go bad but still throw spark at the wrong time? Again... Keyway is not sheared...
 

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Running premix and injector to rule out bad oil injector.... I'm thinking that's why I lost compression in the first place. No matter what I do I cannot get this engine to fire off for even a few seconds... The carb is not the issue it's good, I'm leaning towards a problem with ty flywheel ... Anyone ever had one go bad but still throw spark at the wrong time? Again... Keyway is not sheared...
Never had the flywheel cause timing to be off without the key being sheared, but have had bad pulse generators and stator coils throw the timing off. Easy to check - mark the 'F' mark on the flywheel with white or yellow paint and check with a timing light - remove the plug and lay it on the head to allow the engine to spin easily making it easier to see the mark.

Maybe I missed it, but how much compression did you say the engine has?
 

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Discussion Starter #11
Crank seals are brand new, 128 psi compression, stator/pickup new, coil is new, cdi brand new only thing not new is flywheel
 

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How about the whole story?

You say the top end was rebuilt by Ritters, but he's 3 states away? Hot did you get it to him and get it back? Or are you saying Ritter's performed some work and you did the rest of the work.

Please provide details - did you take the engine out, ship it to him, he rebuilt it and shipped it back? How long was it gone and how long after you got it back did it take to get it installed? You insist it has good spark and a good carb - how did you verify this?

128 psi compression is a little low, but it partly depends on the piston, rings, how the engine was assembled (too much/not enough lubricant on the cylinder walls) - was the engine bored out? Is the piston installed with the arrow pointing toward the exhaust port? Are the rings on the piston with the marked side up? Is the ground cable between the engine and the frame installed and installed correctly? How many different spark plugs have you tried?

I have seen fresh rebuilt engines that would not start because they were flooded with gas.
 

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Discussion Starter #13
I shipped the topend to him, also i made a typo I have 138 psi... Stock setup from factory was around 120, so id say that's well within reasonable compression. It's not flooded with fuel either

Whole story is pretty simple, my 96 trailblazer stock topend finally got weak 23 years later after it was manufactured and I had it bored over
 

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OK - so you assembled it

Did you oil the crankshaft, main bearings, wrist pin bearing and cylinder prior to assembly? The piston was installed with the arrow pointing toward the exhaust port? The rings were properly gapped before installation and installed with the top side up?

How much and what kind of oil was applied to the bearings and cylinder or piston?

What kind of gaskets did you use and how did you clean the gasket surfaces?
 

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Discussion Starter #15
Everything was assembled correctly, and in the proper positions in which each part needed to be in, the timing is off ... The keyway is NOT sheared, the flywheel IS stock and specific to the year of the quad. Pickup behind flywheel is in the stock location, now I'm wondering if the flywheel is defective
 
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