F2 drop in power then ok?

[antos]

Need a bit of help lads,
My newly rebuilt engine has about 450 miles on her now and I'm giving her a bit stick now, but sometimes at around 8k it just falls off a cliff so to speak so I shut it off and bike seems fine, it doesn't always do it sometimes it revs all the way and pulls through the gears lovely, but it's a bit worrying any thoughts as to what it may be?

Fully rebuilt f2 engine new powervalves seals etc, carbs rebuilt new jets seats airline through them emulsion tubes etc. The timings fixed on these isn't it so I'm stumped

[jon]

It's so difficult to diagnose without riding the bike yourself.

However one possibility could be the CDI breaking down intermittently. I think I'd try another one as a quick test.

Jon

[kostas]

+1
Seems to be an electrical fault.

Kostas

[antos]

Thanks lads, I've checked everything I can think of I'll let you know if I find the problem
.cheers antos.

[antos]

Well I'm nearly certain it's electrical guys, been out tonight it pulls right round in each gear fine, but when I'm in top and at about 90-95 it cuts power instantly. No splutter just looses power feels flat, slow down and it's fine again, so either coils or as was suggested earlier cdi unit or generator. I'm thinking cheaper to try a coil first? Thoughts please? Cheers antos