weak to no spark - need help

[The Faster Cracker]

Ok so I jsut put the banshee back together. I put my coolhead on and adjustable timing plate at plus 5 degrees. Runs great. It starts frist kick and we start and stop it about 15 times. Load it up and bring it home to my house from my buddys and replace the spark plugs just to do it. I went to a BR7ES from the 8. Would not start. So we pull it behind another four wheeler and it starts but if the RPMs drop to low it bogs and it wont rev back up. I think it is a few prob so i pull both carbs and clean them. They are now cleaned and synched once again. still wont start. If it does happen to start by kickstarting it is ever so breif and it just dies out. Next thing i check is spark. no spark on left side. Dissconect TORS and and check that pickup coil and timing plate are still together since i just replaced them. Pick up coil is good, timing plate is still at plus 5 degrees. come to find out that the left side plug was bad. replace plugs and go back to BR8ES. Spark looks weak. Notice that spark plug caps are a tad loose on top of plug. ( they have been like that for about the past 20-30 hours of engine run time and have not given me a problem - could they be presenting a problem now?) still have to pull start it, wont kick start. While engine running can hear pinging in exhaust adn the engine misses on both cylinders. still seems to have good power but once again if the rpms got to low and you gave it gas it would bog the engine and die. I am headed out to work and on the way i am going to get some new spark plug caps and replace them to see if that would help. Is it possible that the timing plate is out of adjustment? OH- I did put my stock head back on because i screwed up the o-rings for the cool head and did not have any replacements. so i am running the advance timing wiht a stock head. is that bad or good? the engine is a 4 mil +5 stroker on stock cylinders. As i said i have a race this weekend and it would be great if i could get it running. I would appreciate any help yall could give me. If if it is to say that i am a dumb ass. Im starting to stress out about the damn thing not running

[AKheathen]

why would you run a 7? r u running half kerosene? :biggrin: lol j/k anyways, I'm going to assume that you are running a spacer plate for your cylinders if you can run an uncut head. check your compression and report back, and altitude too, for dealing with the +5.

 

now on to the spark. plug caps can give issues as described, but also wiring and pickup gap. when you said your pickup tested good, did you mean by ohming it, or setting the gap? the gap should be a business card, or around 16-20 thousandths, and the pickup ohms around 110 ohms +/-20, and the coil on the red and green wires should read 13-20 ohms. check the grounds between the frame/motor for good continuity with the black wires at the coil and cdi.

[The Faster Cracker]

Well i found out what it was. My coil went bad. Threw me for a loop since it was running one minute then not the next. Oh well.

 

thanks for the help AKheathen

 

I was wondering if yall think that running plus 5 degrees on the timing is to much for a stock head? Yes i do have the spacer gasket to run the stroker crank. Im running VP but i have to switch to pump gas with amsoil ocatne boost casue my fuel supplier quit carrying the stuff. Do i need to back off on the timing or what?

[zach45]

Well i found out what it was. My coil went bad. Threw me for a loop since it was running one minute then not the next. Oh well.

 

thanks for the help AKheathen

 

I was wondering if yall think that running plus 5 degrees on the timing is to much for a stock head? Yes i do have the spacer gasket to run the stroker crank. Im running VP but i have to switch to pump gas with amsoil ocatne boost casue my fuel supplier quit carrying the stuff. Do i need to back off on the timing or what?

 

check the pickup gap?

[The Faster Cracker]

check the pickup gap?

 

 

thats next. doing this in between dealing with customers

[fastbanshee8]

Octane boost does not provide much in the way of octane. It only boosts the octane a few tenths, plus it makes two strokes run a lot hotter, or at least that's what happened with my brother's Shee.

[AKheathen]

octane booster will not do much in terms of decreasing detonation.

[The Faster Cracker]

Ok so i repalced the coil. Primary coil is has been OHMed twice and it checks out. all grounds are good. all connections in wiring harness are good. still ahve intermitent to no spark and any spark is weak. Going to replace the CDI with a Dynatek. Any opinions on Dynatek?

 

also noticed there seemed to be a bit of rust or some kind of buildup on the inside of the rotor. couldnt pull it off since i didnt have the puller. it would throw a few sparks out fo the rotor/stator

Edited March 7, 2009 by The Faster Cracker

[sleeper06]

It shouldnt be throwing sparks,What is your compression with the stock head,Timing and compression go hand and hand with fuel.If your motor is pinging either back timing out of it.Let us know what your compression is at with the stock head

[Mustang78]

I had a similar situation but it was after i left the bike sitting for 4-6 months and it would spark once per kick, not multiple times like it should.. causing it to not start no matter what.. replaced coil, sanded mounting spots, checked pickup coil gap, spark plug gap, coil resistance, ohm checked the stator, checked kill switch, etc with no luck, only after hitting the stock 1987 CDI box with the handle of a screwdriver did it start, and only took 3 kicks after that.. i would smack it just because it's there and a smack test is a valid test for auto ECM's

Edited March 7, 2009 by Mustang78

[locogato11283]

check the tabs that the coil bolts to. they need to be bare metal for the coil to ground properly.

[Mustang78]

they dont need to be, but why not sand em just to be sure? the bolt threads and the underside of the bolt head make a decent ground as it is.. BTW to update my previous post, my CDI box cuts out when it wants to, i get off and whack it with my hand, a rock or whatever is handy and she's good to go for a while.. from what i learned today i would give it the tap test just because

[AKheathen]

what do you mean by throwing sparks? rust and shit in there can mess with the spark, definitely. clean it out the best you can wit some electrical cleaner and compressed air, bot the best thing to do is get the puller and clean it. shake the flywheel to see if it rattles, but don't try to get away with a jaw puller, or you will need a new flywheel.

[The Faster Cracker]

UPDATE:

 

Everything checked outas far as electrial goes. i also replaced the coils, plug wires and caps. the only thing not tested was the cdi.

I jsut got the Dynatek in that i ordere but i am not sure what the three extra wires are for. They are black, brown and blue. the stock cdi only had the the two terminal plugs and thats it. where do the three wires hook up?

[The Faster Cracker]

ok so i got everything fixed. thanks everyone for the help. it turned out to be the red wire coming out of the stator. it had a small cut in ti and it was to the back of the wire. i checked it earlier but did not see it. i noticed the next time when i was going to go and take the adjustable timing plate off. cost me a coli and cdi! oh well. once again thanks for everyones help