Bike won't get down and boogie

[Davo123]

Ive got a chinese crappa, had no end of troubles with it Snapped frame etc, pegs, pretty much the chinese works special.


The problem im haveing now days is, it just wont peak out, it hits a wall and stays there.

Im running an e-bay 2 piece head kit with insanly high compression. Fat boy zaust, Chinese plug rofl, and a pretty much stock as bog bottom end.


Im still running it at 25-1, though i have a feeling its running a little rich, Before when i had a cracked manifold It wouldnt idle very well kidna idled like an off chops older 2 stroke Any way, with the cracked manifold, it would peak realy high and just hammer. Now that ive fixed that, and swaped carby ( identical stocko's ) it only revs so far and refuses to go any more.

Im kind of half tempted to throw the cracked manifold back on and go to the track, but i dont realy want to rebuild my engin just yet Im geting close to it.

Perhaps theres a difference in the jetting sizes between the 2 stock carby's ? The original i got with the motor, and the one im useing now is an old one from a long forgoten friend i found laying around, im not sure if he had the jet drilled or not. Whatever the case it blows smoke

I just want to hear peoples thaughts before i go through all the fucking around involved with changing the carb, ripping the motor down checking for damage etc.

[Glen]

how does it stop? does it continue to run smooth but not at good power or does it surge back and forth etc.

with those dodge ass bikes you can never really pinpoint the problem. just have to go through and check everything. flush out the carb and fuel tank. put some good fuel in (25:1 is a bit much oil for me i always ran 35:1).

dont forget the lower the ratio the more oil is replacing fuel - aka you are running it more lean. perhaps this is just the problem..

plug could be crapped out, coil could be crapped out (check the coil gap between the flywheel and coil itself).

could be an air leak around the carb and manifold if it idles bad?

[mac90]

it wouldnt hurt to pull the top end off & inspect internals , with the cracked manifold it would have been running lean so less lube & prone to scoring or other internal damage to the piston, rings or bore

i would swap carbs back to start with if anyone has taken to the jet with a drill then its stuffed & probably pouring the fuel in in drops instead of atomizing

once you swap carbs back buy a NGK plug just take the old plug & about $4-$5 the chinese plugs are only good to block the hole when shipping

last thing is to go for a few high & mid speed runs see how it feels & inspect the plug for colour

you want a slightly dark browinsh damp plug is good
Grey white & dry is lean & bad for your engine go up 1-2 jet sizes 1 at a time (make sure you have no air leaks inlet side & head gasket)
really black & wet is 2 much fuel or 2 ritch go down 1-2 jet sizes 1 at a time

[Davo123]

Nah it doesnt surge, It kinda of behaves like when youve loaded it up ie held the break and twisted the throttle. Dont get me wrong this isnt down low, its takeing off fine and accelerating, it just hits a wall where i feel it shouldnt.

And no the idle is fine now since i replaced the cracked manifold.

As i was stateing with the cracked manifold it didnt hit this wall, it just climbed very high and ran very smooth. Though it didnt realy like idleing and the bike would rev its self up as the plastic manifold flexed and let more air in.

thats kinda of why i was leaning towards it running to rich.

It realy feels like somethings holding it back in a very big way. Feels like the motor has a lot more to give up high, it just cant spin past a certain point.

Coil should be good, gaps good, plug still fires

The bikes excelent from about 1/4 throttle upwards, it just bogs down low a bit when your takeing off, but once its moveing its good.

[Davo123]

Originally Posted by mac90

it wouldnt hurt to pull the top end off & inspect internals , with the cracked manifold it would have been running lean so less lube & prone to scoring or other internal damage to the piston, rings or bore

i would swap carbs back to start with if anyone has taken to the jet with a drill then its stuffed & probably pouring the fuel in in drops instead of atomizing

once you swap carbs back buy a NGK plug just take the old plug & about $4-$5 the chinese plugs are only good to block the hole when shipping

last thing is to go for a few high & mid speed runs see how it feels & inspect the plug for colour

you want a slightly dark browinsh damp plug is good
Grey white & dry is lean & bad for your engine go up 1-2 jet sizes 1 at a time (make sure you have no air leaks inlet side & head gasket)
really black & wet is 2 much fuel or 2 ritch go down 1-2 jet sizes 1 at a time

Do they make jet kits for the stocko carbs ? This bike has a rear swing arm which make it very hard to find a carb to fit.

And yes thats why i was going to pull it down, but the bike was running very well with the cracked manifold

[greeny]

it is rich. If it was running good with an air-leak it needs to be leaned out. Contrary to popular opinion, the more oil you mix the leaner the bike runs because there is less fuel to mix with the air.

Go for a leaner (smaller) main jet, run 30:1 (a good synthetic).

[Davo123]

Or it may of been able to suck more air then the stock carb will let it.

[mac90]

try a new NGK plug & the other carb first then think about a jet kit or new carb

but a top end inspection still wouldn't go astray