sr 125 carb/roller setup problem ??

hi guys i have a sr 125 just had a full engine rebuild about 100 miles ago, and i cant seem to get it running correctly, i was running a 125cc pm variator and 25mm carb open filter zx pipe, the bike was sluggish up till about 10 mph, i have tryed jets from 85-108 all the same the lower i went the better it got but still couldnt get the sluggish start out the way,
i now have original 20.5 carb airbox and runner 125 pipe have tryed gets from 82-88 and it still seems to be the same im not sure what weight rollers are in the bike, but i have allso noticed when i let off the throttle the bikes revs dont drop for 2-3 seconds just sounds like the engines been turned off and then when it slows down to around 10mph you will hear it idle again, any idea what could course this

 

If you've tried std parts and there's still a problem then it's in the engine, crank seal? air leak? inlet manifold? cases not fitted together properly?

 

I have checked Inlet thats all fine, it worked ok with 25mm an zx just really juttery from 0-10 mph and then would pick up fine but was loud and only getting around 40mpg and was running a 92 jet and filter that seemed way off but run best on it, not sure what else to try accept maybe clutch slipping or rollers light as its a new rebuild crank piston seals bearings rings the lot, and the person who fitted it all has built many engines b4 so dont think its anything he has done, with the standard set up it runs just seems like its really holding back takes awhile to hit just 40mph and theres no idel after I let off the throttle just the fan noise till it drops under 10mph, can only explain it as the engine getting turned off just the wineing of the fan thats about all you can hear then it idels again

 

firstly with the revs not drpping, remeber its an auto. the clutch is still engaged and as such as the bike rolls along about 10mph or so the bikes revs will stay a little higher. its because the belt is spiing the engine over

secondly the boggy start, have you tried clutch springs? as the variator dosent kick in for a good few seconds on take off its the clutch that does the work. your spring may be too soft or your clutch pads too low

 

Will check the clutch just waiting on an impact gun to get the rear nut off, just feels weird had 5-6 scoots b4 and never noticed it , jusoorderd some 13g rollers aswell to hopefully eliminate that problem.

 

Im allso running pm clutch bell with standard clutch if that makes abd difference

 

update bikes now not evern moving tryed going to work today and the bike just sits at 5mph evern at full throttle

 

Belt may be fubard or something lodged

Time to take the side case off and get digging

 

Ot the side caseing off, from what I can see everything looks ok,
Sruck new 13g rollers in it anyway and got a brand new standard clutch on the way as original was still in there from 2001
Hopefully that helps, if not im really stumped to what can be courseing this as now its a fully standard setup accept var and crank