Pa-50 throttle like BLUUUUHH

cheetahchrome . /
cheetahchrome
Jun 07, 2009 12:38AM

So my new Pa-50 build as follows:

treat DR 70 kit

treat 21mm delorto and intake kit

proma cirtcut

so the bike starts up right away and idles perfect, running

on the stand it will rev so high, right away, it vibrates the

stand across the shop floor.

soon as I put the wheel down and try to give it about quarter throttle to drive away its like Bluuuuuuuuhh and I have to back out of it. If I leave the throttle cracked about an eighth

of the way it will slowly pick up speed and accept more and more throttle and after about 100 yards its goin weeeeeee

eeeeee and i'm doin like 40mph.

The carb came out of the package with a 90 jet and to be safe

I put in a 95 in case I was too lean for the new kit. Since then Ive put the 90 back in, then the 95 again, now ive

got a 100 in there and still cant get this thing to come on

from a dead stop. The jets I got from a yamaha shop

out of their jet assortment bin from under the counter,

they are shaped a little different but the threads are the

same and they dont touch the bowl. the guy said

they were molossi jets, does this matter?

So what do you think. Should I start changing the brass

metering rods? I've turned my mixture screw in and out so much I'm lost.

whats a good default setting for the mix screw? All the way in

then 1 3/4 turns out?

Dudes I'm close but still fucked. over

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Re: Pa-50 throttle like BLUUUUHH

rockles /
mikerock
Jun 07, 2009 02:07AM

air leak. how are your gaskets?

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Re: Pa-50 throttle like BLUUUUHH

cheetahchrome . /
cheetahchrome
Jun 07, 2009 02:17AM

Ya know Mike it's a new build, bearings,seals so I never broke out the carb spray and checked around the cases. I guess I'll try that in the morning. It idles so nice it should be easy. over

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Re: Pa-50 throttle like BLUUUUHH

davey /
daveypi
Jun 07, 2009 03:19AM

in athens i was running a 92 jet, in san fran i have an 88 in there. anything bigger than a 92 gave me black plug chops. one thing you can try (and fuck what anyone else says, i know this to be true) you can advance the timing. pull the woodruff key out and advance the timing a bit, the taper will hold the cam on if you tap it on with a hammer.

other than that, yeah i'm with mike, air leak.

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Re: Pa-50 throttle like BLUUUUHH

cheetahchrome . /
cheetahchrome
Jun 07, 2009 03:53AM

So pull the key and turn the cam counter-clockwise what, about the whidth of the key then smack it on hard?

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Re: Pa-50 throttle like BLUUUUHH

davey /
daveypi
Jun 07, 2009 04:02AM

not super hard. the crank turns clockwise, so you turn the cam counter, yes. the tap it on good and tight, but dont beat the shit out of it or anything. it should hold fine. none of my hobbits have woodruff keys anymore, i set em like you would a moby and its awesome.

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Re: Pa-50 throttle like BLUUUUHH

cheetahchrome . /
cheetahchrome
Jun 07, 2009 10:59AM

So Davey, how far should I advance it at first? I was thinking about the width of the key.

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Re: Pa-50 throttle like BLUUUUHH

davey /
daveypi
Jun 07, 2009 12:43PM

thats probably a good place to start.

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Re: Pa-50 throttle like BLUUUUHH

davey /
daveypi
Jun 07, 2009 12:50PM

wait, i totally fucked up. the crank turns clockwise, so to advance it you would turn it clockwise. sorry. i'm an idiot, total brain fail.

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Re: Pa-50 throttle like BLUUUUHH

Tate /
madtownmick
Jun 07, 2009 10:52PM

Play with the needle setting at all? It sounds lean of course, and I found that with my phbg anyway, the needle and the filter make a huge difference as to the acceleration. Its almost like, main jet decides top speed, needle and filter decide acceleration. Phbgs do have a lot of variables though.

Usually if a bike idles perfectly, in my experience anyway, its likely not an air leak but it could be. Best to make sure its not before you go trying to tune it richer.

Also, with those new hobbit pipes, I noticed the header on mine didn't seal perfect. I put in 2 of the copper crush ring things and little liquid gasket, and was all good, but that could be another source of leanness.

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