Engine missing

[Shawn drifts]

Timing is 100% correct..... Retarded 1 tooth and advanced 1 tooth.... This is obly where is starts
Has trouble starting
Valve clearance is flawless
Have touched carb from when it was running good
Backfiring through carb

Im thinking coil or cdi
My cdi box has a huge nipple on 1 side of it from i guess getting too hot

Warning: turn volume down

http://s418.photobucket.com/albums/pp270/no_refuse/?action=view&current=3019d47c.mp4

 

[Shawn drifts]

Backfire is random
Cant open throttle or else is bogs

 

[Grimace]

Do you have an exhaust pipe or muffler or is the exhaust port just the open hole in the head? No exhaust can lead to a crystallized valve or at least a warped one which may cause the problem you are having.

 

[Shawn drifts]

Tried 2 different heads..... Both open head, no exhaust, same results..... Ill slap exhaust on right now and double check

 

[Bluethunder3320]

when you run an exhaust straight out of the block, the engine runs way too lean for stock carb jets

stalling out when you accelerate means its running lean

 

[Shawn drifts]

So exhaust SHOULD fix all the issues i am encountering?

 

[Bluethunder3320]

well i cant guarantee it, flipping the intake manifold back is a good idea (if you have clearance issues with that bar then i guess you cant.)

on some engines i notice the intake port/flange isnt symmetrical so if you flip it the gasket wont seal. not sure if this is the same case with yours.

also an air filter will help (similar to why you need an exhaust), the carb is tuned to run with a filter. you can buy a K&N foam pod filter for $20

 

[Shawn drifts]

Well we think we got it all figured out.....
We got this motor on the kart: http://www.hiwtc.com/products/cub-110cc-3843-86274.htm
But we have the cylinder and piston from this motor slapped on the motor above: http://futongmotor.en.alibaba.com/product/208337016-200432391/1P39FMB_150FMG_152FMH_engine.html

Do we think the compression ratio/stroke is all gucked up and we gotta mess with timing to get it right.

Keep ya posted

 

[Bluethunder3320]

idk about that... most of the time you cant take 2 different brand engines and combine internal parts unless theyre exact clone parts.

timing wouldnt change because the piston still tops out at the same time.

now a problem i can see is, if the strokes are different (because you keep the rod from the one motor) you can have low compression

do a compression check and if thats good i dont see a problem using the mixed parts

 

[Shawn drifts]

Well tdc is still the same.....

Hmmmm time to take off valve cover to double check when valves are opening.... Hmmm

I dont have an adapter for my compression tester :/

 

[Shawn drifts]

Im at a loss. Any other ideas guys?

 

[Bluethunder3320]

check the valve clearances thats a good idea... to narrow down the problem. however i dont know what engine you should check the clearances for? hahaha

put an exhaust on it, and air filter, that could be the problem

just read the part about the CDI... hmm

sorry im not much of a help anymore haha

 

[Doc Sprocket]

My cdi box has a huge nipple on 1 side of it from i guess getting too hot

What- it melted? Replace it. Troubleshooting is all about eliminating possibilities. Eliminate that one.