GK73a SP Won't Rev Nicely 11k to Redline Any Ideas?

[Mazzerdod]

Hi Guys I've stripped the carbs replaced o'rings set everything as per manual.... i.e. mixture screws etc and the bike starts fine, ticks over lovely and rides perfect sub 10k.

However when you try to accelerate hard in any gear it goes fine low and mid range but hit about 10k and it starts to stummble if you keep it pinned it will with a fight and small throttle alterations get round to 12-13k but does not pull cleanly!

I guess at full throttle above 10k nothing can effect the performance other than the jet size?

i.e the needle and sildes are fully open and the main jets are flat out.... so could it be the jetting?

It has stock SP jets, the airbox is on the carbs but no filter element because I can't find a stock filter element anywhere.

Also the plugs are CR9E where as you guys seem to use the CR9EK.

Any ideas?

What would be your next move?

Cheers!

[stripes1976]

you are running lean and have turbulent air across the carb slides so they are fluttering.
put a filter in and it will sort it out. if you don't worse case is melted pistons.
not sure on the 73a but try calling michelle at robinsons foundry

[Mazzerdod]

Cheers stripes.

Hope I don't melt anything I tend to give her a tweak and try it down the road n back, she isn't been ridden like it she's in the workshop until I get it sorted.

I'll try them on Monday to see if they can source a filter or I will have to look for something similiar that I can make fit!

Once I've got a filter on her I'll take her up the road and report back, but I probably won't get chance until next weekend now