Just like it sounds, when the throttle is wide open the motor starts bogging and hesitating badly, no power to speak of. Runs fine from idle to 3/4 throttles, starts easy but no top end. Thoughts before I start pulling the carbs apart? Thank you,

Could be a number of things but we need more info first. 1. Has this always happened since you have owned the bike or has it just started happening? 2.Have you made any changes recently to any part of the bike? 3. What is your maintenance schedual like? How long since the bike has been pulled down?
I could take an absolute stab and guess it is a carb issue possibly a blocked jet, or a power valve issue or an electrical issue but we realy need some more info.

mtec666 wrote:Could be a number of things but we need more info first. 1. Has this always happened since you have owned the bike or has it just started happening? 2.Have you made any changes recently to any part of the bike? 3. What is your maintenance schedual like? How long since the bike has been pulled down?
I could take an absolute stab and guess it is a carb issue possibly a blocked jet, or a power valve issue or an electrical issue but we realy need some more info.

Thanks and to answer your questions:

1) It's always done this but then I've only had the bike since December and have put maybe 200 miles on it.

2) The bike is completely stock with the exception of no air filter. The old one was completely dried out and was sucked through the carbs (possible cause or related?). New filter en route from Tyga.

3) As far as I know the bike has never had any kind of major work done, it's only got 11K km on it. Compression is 130 in both cylinders. Only mx I've done so far is to the brakes and chain.

Thank you for the help!

2) The bike is completely stock with the exception of no air filter. The old one was completely dried out and was sucked through the carbs (possible cause or related?). New filter en route from Tyga.

Do not start the motor until you fit an air filter!!!! That could likely cause a seizure from running a weak mixture .Have a look at the colo(u)r of the plugs.

Hi There
It is possible that if all or most the foam air filter was swallowed parts of it could be interfering with the powervalve operation even stuck in the crankcase itself,for the sake of 2 base gaskets I would certainly be having a look in and around the crankcase,barrel and powervalve area to ensure all of it has blown out and remove whats left before starting it again,
good luck with it all the best,
jonmac
_________________
John

bushman wrote:2) The bike is completely stock with the exception of no air filter. The old one was completely dried out and was sucked through the carbs (possible cause or related?). New filter en route from Tyga.

Do not start the motor until you fit an air filter!!!! That could likely cause a seizure from running a weak mixture .Have a look at the colo(u)r of the plugs.

Thank you. I was actually running around with no air filter for a little bit but didn't see any temp issues or hear any pinging, detonation or preignition. When I pulled the plugs last weekend to do the compression check they were a nice chocolate brown so mixture doesn't seem to be an issue at the moment.

Johnnymac wrote:Hi There
It is possible that if all or most the foam air filter was swallowed parts of it could be interfering with the powervalve operation even stuck in the crankcase itself,for the sake of 2 base gaskets I would certainly be having a look in and around the crankcase,barrel and powervalve area to ensure all of it has blown out and remove whats left before starting it again,
good luck with it all the best,
jonmac

That had occurred to me as well. The air filter quite literally disintegrated into fine particulate matter. When I opened the airbox I thought the filter had been removed as there was no sign of it ever being there. It was when I noticed the sticky residue and thin ring of what was left that a deduced its demise. That and the black rings on the tips of the cans What little bit I could find just vaporized in my fingers so I doubt there was anything large enough to stick inside the motor. I'll have to investigate the power valves though, I don't know anything about them (this is my first two stroke).

Fortunately I have finally stumbled across the maintenance manual on this site so I'm a lot more comfortable tearing the carbs down. I've already got two bikes with carbs out, might as well add a third since the weather is finally getting nice around here

Thanks everyone.


Last edited by milleR on Thu Mar 17, 2016 11:22 pm; edited 1 time in total

If possible,put everything back to stock settings,and work from there.

bushman wrote:If possible,put everything back to stock settings,and work from there.

Completely agree. Thanks for the feedback!

Seems to be squared away, though I still need to do a good street run. The bowls were badly varnished and the slow jets were completely clogged up. Almost an hour of fighting with the airbox and the thing just won't secure itself to the carbs so I've ordered a pair of Uni's. Thanks to everyone for their help, this is a great site!

milleR wrote: Almost an hour of fighting with the airbox and the thing just won't secure itself to the carbs so I've ordered a pair of Uni's. Thanks to everyone for their help, this is a great site!

Mille,
On another thread Andy suggested the use of a hairdryer to gently expand the rubber somewhat so that you can then get it onto the carbs..

HTH