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Bad backfire when starting


Nighty

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Hey all,

 

I replaced the stator and flywheel on my banshee and i have the feeling i retarded the timeing 4 degrees instead of advancing 4 degrees.

 

The bike started like normal. i rode around to heat up the bike some and after about a mile it started bogging and would only keep running full trotthle. (and not rev up)

So i stopped right away since i dont like the idea of full trotthle and no go. :shoothead:

 

When i tried to start the bike there was a flame shooting out the back of the left exhaust pipe.

a few kicks later and the right exhaust shooted a flame aswell.

then i decided to shut the full valve and as i reached down to close the valve i burned my fingers without even thouching the pipes.... damned crispy

So the pipes where flamingly hott after just a small ride.

 

Well i guessed a clogged jet at first but both sparkplugs look really way to black nowhere near lean. so the fuel must be ok.

 

Would 4 degree retarded timeing cause something like this?

I'll pull off the flywheel cover tomorrow to checkout the flywheel aswell, i really cant imagine it came off since i used quite alot of force on the flywheel nut.

 

other things i did on the bike.

-replaced oem filter for k&n filter

-rejeted carbs (4 richer on the mains) <-- thats why i suspected a clogged jet.

-also fiddled with the wires for the turn signals (only a reroute)

 

oh and i disconnected the tors think unit right under the fuel tank to make sure it wasnt screwing me over.. all the other tors crap is still connected.

 

Thanks for any tips and oppinions on the 4 degree retarded timing

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Sounds very lean on the bottom end. You replaced your filter with a K&N, and rejetted the main, but you didn't do anything to the pilot or needle. Your plugs could be black, from being to rich on top, but you could still be lean on the pilot, and/or needle.

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update:

 

The flywheel and stator look ok.

timing is 4 degrees advanced. no weird things there.

 

the right carb is cleaned and the pilot jet seemed to have a minor tiny wee bit of sand in it.

after cleaning the hole looked bigger.

 

working on the left carb at the moment.

I wonder....

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mine was doing this a week ago.the stator was junk. try a new pick up coil.the little black box next to the flywheel. make sure you have the proper air gap set on that.i think it is 17-20 thousandths.not sure on that spec though.also,try a cdi box.sounds like both cylinders are firing 180 out of time.that is what mine was doing.you could barely kick it,it almost broke my foot when trying to start it.then if i got it running,you had to hold it wide open and it would only hit like 2000 rpms.the pipe was getting really hot.i dropped in a stator i had for it and it runs fine.one more thing,make sure your flywheel key did not shear and move the flywheel.

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Thanks for the replies.

 

The carb cleaning didnt fix my problem, compression is ok spark is good

 

it MUST be the timing.. monday ill jank the flywheel off to see whatsup with the key.

 

The gap between the pickup coil and flywheel seemed ok didnt measure it

could the gap cause backfire?

 

 

The stator came of a running bike.

Maybe i overtightend the flywheel.. *sigh*

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The gap was out of spec but didnt fix my problem.

after i adjusted the pickup coil gap and rotated the flywheel i noticed a difference in the pickup coil gap.

 

So i grabbed my tools and it turned out the flywheel wasnt seated correctly.

took the flywheel off and checked the flywheel key.

minor damage to the key and also minor damage to the flywheel itself.

 

slammed it back on tightend it up good by hand this time holding the flywheel with a fuel/oil filter tool.

 

Took it out for a ride .. ran like a champ.. 3 miles from home.. and the sound of a major piston failure.. i figured oh crap.. here we go again.. flywheel must have come off.

 

So i pushed the bike back home, had the bike appart in record time and yes.. flywheel came off again.

 

brought out the power tools.. pneumatic stuff and a dap of lock tite

no damage to stator or flywheel.. key is fine aswell.

used the air tool on the flywheel nut.. and will go for another test ride tomorrow.

 

 

oh and now the clutch is slipping.. new found power must be too much.

Problem solved thanks for looking.

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