loading up after new top end?

stainlesscycle · #1 08-28-2012, 03:24 PM

so i replated my top end, and it's been broken in. i still need to re-shim my pv, it clatters, i could see the slop when i reassembled, just haven't gotten to it. gonna do it when i fix my kicker.

but here's the issue:

it seems to load up when i wack the throttle, and struggles to get on the pipe/rev out. i can clutch it, and zing the throttle a few times and it cleans up/will rev out. or if i hold it wide open it will eventually get on the pipe. until then, it stutters like it's rich.

my normal jetting on this motor at this elevation and temperature has been perfect in the past:

1.5 a/s, n1eg #2, 172, 42pilot.

i dropped the needle to #1, and it didn't fix it.
i leaned the a/s to 1.75 and it didn't fix it.

the plug does not look rich, nor does the bike act rich except when i transition from the pilot directly to the main. like exiting the woods onto a big straight. 1/4 throttle to 3/4-wot...

i don't want to go leaner on the main, when it eventually gets on the pipe, it's running great, it's just the getting it to that point that's the issue. yes i've changed the plug. bike runs perfect up to 1/4 throttle, and if i stay on the pipe it runs great, it's just got this big stutter in between sometimes... i thought it was jetting, but maybe it's powervalve flutter? i don't have it against the stop yet, i can hear it clunking...

any suggestions????

Fred1956 · #2 08-28-2012, 04:56 PM

Make sure the power valve is working- many threads on proper preload. no preload will also cause the rattle to be worse.

stainlesscycle · #3 08-28-2012, 05:04 PM

yeah, pv is working, i know the preload procedure, just didn't do it - hadn't had a chance to get to it - was racing other bikes in the last few weeks, just through the top end on and went racing.. pv alignment changed when i put this top end back on. pv is definitely opening. also, i can hear it rattling against stop when it's fluttering.. would pv preload cause that much of a 'lag' i would think it's still opening properly, just not shutting properly..

either way, guess i gotta go in there and set it back up. maybe that will fix it.

GMP · #4 08-28-2012, 05:24 PM

PV won't do that. Sounds like bad reeds to me.

stainlesscycle · #5 08-28-2012, 05:53 PM

hadn't thought of that. haven't looked at them in about a year. might be time. 07 is vf3 right?

Jakobi · #6 08-28-2012, 06:05 PM

Lonetree had the same issue with his 09. Chased it around for weeks and it turned out the spark plug cap had untwisted a bit and would break up under high rpm. Go over the electrical agains and also check the reeds.