Honda Spree and Elite 50 Forums

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

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

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!

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

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.

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!

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

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.

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

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

That thought crossed my mind.

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.

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)

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 $$

Very interesting!

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