runs like crap...what am i missing?

evilone · Post by **evilone** » Sat May 12, 2012 8:30 pm

What causes "popping out the pipe" and "falling on its face" when you twist the throttle? Spark plug? Motor is running choppy and likes to pop and stumble. Pressure tested and vacuum tested at 7 psi and both drop about 1 psi over 30-60 seconds then stay stable.

I installed the Ruima 50mm bore and cannot get this thing running good enough to tune. I tried a 55 and a 58 pilot along with a 138, 140, and 142 main with no luck. Setup below...

Ruima 50mm
stage 6 intake
OKO 28mm
Uni filter
SEF Black pipe
B8HS NGK plug .024

evilone · Post by **evilone** » Sat May 12, 2012 8:32 pm

Just thought about it. I didn't check compression after some work to the cylinder and rings...before it was 150.

Madman · Post by **Madman** » Sat May 12, 2012 8:54 pm

I feel for you man! I'm having the similar epic on mine going to do pressure test this week but sad to here your having problems after yours!

evilone · Post by **evilone** » Sat May 12, 2012 8:56 pm

I take it you didn't find an obvious leak?

Trafficjamz · Post by **Trafficjamz** » Sat May 12, 2012 11:15 pm

evilone wrote:What causes "popping out the pipe" and "falling on its face" when you twist the throttle? Spark plug? Motor is running choppy and likes to pop and stumble. Pressure tested and vacuum tested at 7 psi and both drop about 1 psi over 30-60 seconds then stay stable.

I installed the Ruima 50mm bore and cannot get this thing running good enough to tune. I tried a 55 and a 58 pilot along with a 138, 140, and 142 main with no luck. Setup below...

Ruima 50mm
stage 6 intake
OKO 28mm
Uni filter
SEF Black pipe
B8HS NGK plug .024

a bad cdi caused me months of grief last summer.

Madman · Post by **Madman** » Sun May 13, 2012 12:50 am

evilone wrote:I take it you didn't find an obvious leak?

crank seals are new and in place crank case is sealed perfectly no obvious places so replace all gaskets on intake and will do pressure test to confirm with new head and piston kit will post results!

veedubh20 · Post by **veedubh20** » Sun May 13, 2012 1:36 am

check the reeds not broken.

lose ngk boot cap.

runs on any taiwan racing pipe. still have to tune grams up/down on the weight

elitedio · Post by **elitedio** » Sun May 13, 2012 8:18 am

You only tried a vary narrow range of jetting. I would try something leaner. Is the engine free rev or is it being bogged down by the transmission.

swimmingfree · Post by **swimmingfree** » Sun May 13, 2012 9:15 am

have you look at the coil???
my spark plug cap when bad and it sputter and made me feel like it was running way rich ..
swimmingfree

evilone · Post by **evilone** » Sun May 13, 2012 11:59 am

Trafficjamz wrote:a bad cdi caused me months of grief last summer.

That thought crossed my mind.

evilone · Post by **evilone** » Sun May 13, 2012 12:05 pm

elitedio wrote:You only tried a vary narrow range of jetting. I would try something leaner. Is the engine free rev or is it being bogged down by the transmission.

I tried them jets since they are close to a previous similar setup. With the 55 pilot installed i can twist throttle and it bogs and dies, so that is too lean. The 142 main jet caused it to 4 stroke. It has the same symptoms on the stand or trying to run it down the road just worse down the road.

evilone · Post by **evilone** » Sun May 13, 2012 12:08 pm

swimmingfree wrote:have you look at the coil???
my spark plug cap when bad and it sputter and made me feel like it was running way rich ..
swimmingfree

I'll check that too, it seemed fine but will make sure. I'll get a new plug tomorrow...plug is a used one i had laying around (cycle shop i get my plugs at was closed)

evilone · Post by **evilone** » Sun May 13, 2012 7:18 pm

Trafficjamz wrote:a bad cdi caused me months of grief last summer.

1 point for trafficjamz. Replaced cdi with an extra i had and it ran a lot better. It went down the road so now i can tune the carburetor

I will be dropping to a 21mm or 24mm when i have the extra $$

Madman · Post by **Madman** » Sun May 13, 2012 10:25 pm

Very interesting!

Bear45-70 · Post by **Bear45-70** » Sun May 13, 2012 11:26 pm

I would also suspect your idle mixture screw is too lean as well as you pilot jet.

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