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Rebuilt motor problem


fummins350

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So my buddy had his motor rebuilt on his banshee and now it wont run right. The reason for havin it rebuilt was had an aftermarket cdi box on it which went bad and made his motor run Backwards and it blew up. So this is the list of stuff he has done to it.... 4 mill stroker with the long rods, bored .40 over, vforce 4 reeds, cool head with 22cc domes, k&n airfilter, boost bottle, dmc pipes, it was a brand new fly wheel and stator but there not anything crazy aftermarket like, they are the stock carbs with the TORS removed. Right now we havent touched the carbs it will start up but when you give it gas it bogs down and shuts off. And it kinda sounds like its not firing right either. I dont know what it could be if the carbs need adjusted and need to know what jets to run in them and if the timing could be off or what to do with it... If someone could please help me that would be great. Thank you!!!

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There should be a auto message for all new members, hi welcome to bhq, before proceeding; have you done a compression test, leakdown test, tors and parking break properly eliminated,  choke tube installed, carbs cleaned thoroughly, synced properly, made note of current jets installed. checked reeds,  tested stator and coil, trimmed wires back/reinstalled caps, new plugs. Carry on then

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There should be a auto message for all new members, hi welcome to bhq, before proceeding; have you done a compression test, leakdown test, tors and parking break properly eliminated, choke tube installed, carbs cleaned thoroughly, synced properly, made note of current jets installed. checked reeds, tested stator and coil, trimmed wires back/reinstalled caps, new plugs. Carry on then

X2 - should be a welcome pack lol

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Stilll running the setup that made it run backwards? And really... a cdi did that?

Adjustable timing plate or not?

Still got the stock flywheel? Try that. If that doesn't work, try swapping the trigger wires at the plug... believe they are wht/grn and wht/red.

If none of that works, put the aftermarket cdi back on, retime for reverse rotation, and get rear view mirrors

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I had a flywheel key get pushed out and I didn't notice. The flywheel musta turned just enough that it wanted to fire, and kicked back hard enough I thought my foot was broken the next day, but it looked like it was trying to spin backwards.

Older outboard boat engines, especially Evinrudes, had a safety on the crank that would kill the ignition if they popped themselves backwards at an idle.

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My advise is sense it starts but dies out when you give it throttle it's from the reeds to the air filters and anything in between.

 

30 pilots 440 mains to start with needle clip in the middle air screw 2 turns out. IMO those carbs are too small. Soak the carbs in some gas to clean them for a day/overnight

 

Check the timing plate and pickup for damage and for out of tolerance for the pickup. Also check the timing key don't go past +4 unless you know what your doin.

 

If it was a leak down issue it should rev up and take a long time to drop down to idle

 

Compression should be 130-140 could be more due to porting and domes. Less just makes a hard start once it's warmed up.

 

A bad stator will only show its issue under load. Revving it is not under load. Check it with an ohm meter. Your clymer book has the specs.

 

 

Sent from my iPhone using Tapatalk

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