Gilera DNA 50 Issue

[supra3turbo]

Hi All,

So as some people may know, i rebuilt the engine with a new racing crank shaft, bearings, piston, reeds the lot, and as you may know he heat siezed it like 5 times because he didnt look at his temperature gauge, The bike came back to me i honed the barell replaced the piston and it was good to go, the bike was a quick little thing pulled really well, spent ages jetting it and making sure it was perfect, he did a few thousand miles on it before i get a call "its making a whirring noise"

After much conversation it turns out that he had found a place where there was a long hill and he had found out that he could get over 60mph down this hill, and after some more poking about he told me that it went past 12k on the revs....

Ive got the bike again stripped it down, and noticed some cracks in the nylon on the crank shaft either side of the conrod big end... the left hand crank bearing, the metal that goes over the ball bearings, the race had snapped a piece out, and mangled the piston.

I have put a new poloni crank shaft in, new bearings, seals new 50cc barell and piston, as we both decided this was best to save money, and he wants to sell it to get a 125 to do up before he turns 17.

I cant seem to get this bike to run wide open throttle, ive put the copper/brass plate back in the intake, changed the jetting a few times, and it just about goes full throttle, if i slightly cover the intake hole with my finger it revs fine... I just cant get my head around it, its like it needs more fuel or something? Yet i have an identical DNA 50 with no copper plate in that ive just done and it runs fine.

First thing im going to do is swap out the spark plug, but it really doesent sound like ignition breakup, you rev it, it revs up then just bogs and dies unless you let off the throttle?

Sick and tired of messing about with this now, just want it gone, then the other DNA 50 can be gone, then the YZ125 can be built and gone then i can have a free workshop again.

Hope someone has some positive feedback for me, is it the rollers that are too light maybe now? Im just not sure, i cant wait for him to get a geared bike haha

Thanks
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Hoda CBR 600 FX stolen from stalybridge 2017/2018 black
Current Project Suzuki RG125 Cafe Racer

[supra3turbo]

No the engine runs fine, its deffinatly the variator/rollers/clutch springs as soon as its on flat ground now ive swapped the reeds and re jetted, it revs to about 6k and sits there moving at about 3mph then once the belt/clutch whatever grips it starts to accelerate, come to a hill and its done for, just sits at 6k slipping the belt.... as far as i can tell, good jesus im sick of this thing now
____________________
Hoda CBR 600 FX stolen from stalybridge 2017/2018 black
Current Project Suzuki RG125 Cafe Racer