My Bike Keeps Cutting OUT?????

P

panheadsully

Member
Hello,
Well, I got my bike back together and seems to run and start ok. When I get on it, at about 4K RPM's, the bike cuts out. At first I thought It was getting into a lean condition so I fattened up the carb.

Same result with really no improvement. It has the factory ignition in it.

New battery and spark plugs. I do notice the rear cylinder seems to be idling a small pop every once in awhile. When I throttle up at idle in neutral, I can hear a miss at those high rpm's.

Anyone have any suggestions. I really want to ride this thing.

Thanks
 
Brew

Brew

Troop Supporter
Make sure you have good gas in the tank (no water). Not sure how long you've been down. Mine acted the same way when I got into higher RPMs, when it came back down in RPMs it barely idled and or just quit. It would start back up fine, but when I started going up in RPMs it would quit again. The bike ran fine before fueling it up at the local gas station. That's when my problem began. I ended up draining my tank and pulling my carb float bowl and draining it. I went to a different gas station and got some gas. Bike hasn’t had a problem since. I hope your problem is as simple as mine.
 
mobsta

mobsta

Well-Known Member
might try blowing out the jets with air,when you say you fatten it up did you rejet or adjust?just my 2 cents,more info on what you did on the down time
 
P

panheadsully

Member
KK

K, I just put new 92 Octane fuel in it.

Marv, what's the best way to check for an intake leak? I adjusted the carb per instructions on this website with no improvement.

It seems like the rear cylinder is running rougher then the front. What could cause this? Ignition, Valve Seals, etc?

Thanks
 
mobsta

mobsta

Well-Known Member
spray around intake with parts cleaner.i use cleaner for plastic and metal wont hurt paint,i thought some one said they also use wd40
 
P

panheadsully

Member
Used WD

Alright, sprayed around intake and it is sealed up good. No changes in idle.

It runs up good until it hits that point that it just cuts out. I keep thinking rev limiter, but there is not even close to 5 or 55K RPM's. Although this does not mean the speedo tach could be inaccurate. It seems like when the butterfly in the carb is opened all the way, it begins to cut out?
 
mobsta

mobsta

Well-Known Member
did you do any mods like air cleaner anything like that? what was the bike apart for/
 
E

Eric

Banned
check plug wires,, & coil wire connections,, possible wire breaking down.. or plug,, I know you said it was new but it could still be a bad one..
 
Little-Boo

Little-Boo

Well-Known Member
Troop Supporter
Now that you have determined that there are no leaks you should consider changing you intimate jet. If the bike is popping or or sneezing in the air cleaner you should go up one size on the intermediate jet. You may have 0.28 go to a .0295 or if you have 0.0295 go to a .031 and so on. To test you main jet ride the bike at a steady speed of 50 MPH and roll it up to 70 or so if it back fires increase the main jet say from .074 to .076 and so on till you get it right or if the engine is flat and will not accelerate then decrease the main jet to the next lower size.

Hope that helps

Carlos :whoop:
 
mobsta

mobsta

Well-Known Member
would be nice to know why the bike was down in the first place,might be able to help more
 
Raywood

Raywood

The Pirate
Staff member
Calendar Participant
Troop Supporter
Good recommendations so far.

What did you do the bike when you had it apart and how long.
Did by chance put a fuel filter on it? Some can't keep up with demand.
Anther thought is maybe the vent in your gas cap is clogging up and causing a vacuum. Clean it out too or just throw it out.

:cheers:
 
P

panheadsully

Member
I took the bike down to do some modifications to it. I decked the cylinders, cc'd the heads, installed a 600 Lift Cam and the compression is right at 10.8 to 1.

When I had the heads CC'd the machinist mentioned that it was leaking so he did a valve job on one head. Could this cause any related to any of this?

One thing to keep in mind, I did notice this high speed cutting out when the bike was stock. (before I did the work) It is much more noticeable now.

I did check both jets and what I had was a 31 intermediate and a 76. I left the intermediate and went to an 80 on the main. As i said before, not much change at all. The plugs looked lean that is why I upped the main. I did not actually test ride pull over etc and check that way.

It seems like it is missing a bit at idle. There is much more flow out of the exhaust on the front cylinder than the rear and it misses just a bit on the rear. Any suggestions here? Could this be part of the trouble?

I'm checking the fuel cap now.

Thanks
 
RRRUFF

RRRUFF

Well-Known Member
Don't know if you pulled your coil, but if you did. Be sure you have the yellow wire on the front coil terminal, red wire in the middle, & blue wire on the rear terminal.

If this is not it then tell us what all you did to the bike.
 
P

panheadsully

Member
I've got a dyna 3 ohm coil. I've got a red and a yellow on each side. That are all the connections I've got besides plug wires. I tested the Ohms and they are within spec.

Besides doing the engine work, I did install the WirePlus Kit and deleted the stock box.
 
mobsta

mobsta

Well-Known Member
maybe timing or something,man im sorry for your trouble,maybe someone with more no how can help here,its gettn a little over my head now,again sorry i cant help you more:cheers:
 
mobsta

mobsta

Well-Known Member
just a stupid question here but have you ran the bike in the dark?maybe a plug wire arcing,like i said stupid question
 
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