Atomik Blitz choking at half throttle

[terrapin_jk]

I have a 2010 Atomik Blitz and it goes great from take-off to about 1/3 throttle, but if I crank it open to full the bike chokes to the point where it can hardly keep moving. I've done a lot of searching on this site but haven't found anything to solve it.

So far I have chopped 120mm off the exhaust, added a Casoli racing cdi, done the valve clearances and checked the jets (37 &102 - which seem to be right from other posts). The carby is a Jenke 30mm. I've had a look at the spark plug and it's slightly black and sooty on the metal end but the porcelin part has a brownish tinge. Probably not perfect but I would have thought it's close enough. I've played with various settings of the fuel mixture screw but nothing has solved the problem.

Has anyone got any ideas what else to look for? Or is it just a rubbish carby and I should go out and buy an oko 26mm?

One thing I haven't done is replace the spark plug. It says it's an ngk, but who knows. Does anyone know what model number ngk plug would be suitable and what the gap should be set at?

 

[sean01]

change the spark plug straight up mate.

then check all the connections running to the coil.. other members on here have had similar drama's.

another common problem..check your fuel line isnt kinked or running weird..

they run a pumper carby standard i think, and from memory which should live in the rubbish..
upgrade to a 26mm oko.. look thru the forums here there should be a fitting thread..

also this cdi you fitted, does it have this problem with both the standard cdi and the aftermarket one?

spark gap should be perfect out of the box but from memory i think its about 0.8mm

 

[tim_]

yeah if its sounds like its struggling its starved of something either air or fuel... or its not getting the correct back pressure... i chucked my old carbi away and got a new one work perfectly...

 

[terrapin_jk]

Thanks for the replies.

Didn't think of the coil connections. Will have a look at those tonight.

The fuel line winds all over the place. MIght try re-routing it so it goes in a straight line from tank to carby. Butch3: could that be the back pressure you refer to?

Had another thought, is the pumper adjustable? If it's not squirting at the right moment on acceleration it mightn't be getting enough fuel.

But I should probably just bite the bullet and save myself a lot of time and buy a new carby!

Is the oko 26mm a straight bolt on job for the 2010 Blitz? I've read Thump's review of the 2008 model but wasn't sure if atomik had changed anything with the later model.

 

[tim_]

nah im meaning exhaust back pressure.. if its leaking from any where..