Misfire at low revs

Message

marshall100 · #21 Post by **marshall100** » Fri Sep 28, 2012 9:34 pm

It's not this....

haulinit · #22 Post by **haulinit** » Sat Sep 29, 2012 12:12 am

Appears to have been wet in there.

cannondale27 · #23 Post by **cannondale27** » Sat Sep 29, 2012 1:42 am

What is your voltage at idle and what rpm does it go to 14v?

Flywheel Looks good.So what is cranking compression?

Just off chance remove the relay under airfilter and try it.One of those almost ended my race last weekend before it even started.Different symptoms but you never know.Those relays are P.O.S. that have bothered me for years.

marshall100 · #24 Post by **marshall100** » Sat Sep 29, 2012 10:03 am

Will check voltage in a bit when I finish work. A rider I know over here has stepped in when I put this pic on facebook. Transpires he owns an afr meter and is willing to assist. Might not have to retire this bike after all.....

marshall100 · #25 Post by **marshall100** » Sat Sep 29, 2012 3:29 pm

http://www.youtube.com/watch?v=9Ur1CIYXQgI...eature=youtu.be

That's the bike running adjusted with a flow rate of 2200 which is down from 2400. Not in this video, but I swapped the flywheels over to an old one, which while no worse (possibly better) doesn't really cure the low down gutteral snap you get from the exhaust at low revs. It also needed a much higher throttle setting to get it to idle properly and then it would fluctuate with a throttle % of 5.6 to 5.7 and rev from 2400 one minute, up to 3400 the next without any input from my thumb.

I've tried a few different flow rates and found that the 2200 runs the best.

Let me know what you think guys. There's definately some improvement there, but I'm not entirely convinced.

haulinit · #26 Post by **haulinit** » Sat Sep 29, 2012 6:37 pm

I have also had a crank bearing in the case going out on the stator side allowing the crank to walk and it caused it to do all kinds of crazy things...this was also on a older two stroke but it was messing with the pulse coil. Any chance this could be happening?

marshall100 · #27 Post by **marshall100** » Sat Sep 29, 2012 7:04 pm

I hope that's not what's going on. I put a new piston and sleeve in that engine in January

the crank semmed tight enough and there was no play in the bearings. You have made me wonder about play in the crank. It's easy enough to check.

haulinit · #28 Post by **haulinit** » Sun Sep 30, 2012 1:13 am

Sorry don't mean to make you fret, just throwing things out there and seeing if anythings stick. Disclaimer...I'm fairly new to diagnosing cannondale issues

marshall100 · #29 Post by **marshall100** » Sun Sep 30, 2012 8:26 am

Tested for play in the crank/flywheel bearing and there's no sign of it. I've had one before on an old road cannondale I had that was very obviously borked.

I wonder if this is flywheel related. Entrely possible that both are past their best.

Kuma · #30 Post by **Kuma** » Sun Sep 30, 2012 4:01 pm

How many spare parts do you have? at this point you could replace everything electrical, harness, sensors, coil, ECU, flywheel, stator, pickup coil, TPS and circuit on the throttle body, you already did the injectors right? if that cures it at least you know it was electrical and not something mechanical. after that start changing out with your old componants until you find what the problem was.