Fresh rebuild and only running on one cyl

[GOIN FAST AND HAULIN Azz]

Ok,

This is my 7th banshee rebuild, I know Im vapor locked and overlooking something simple.

THE BIKE - 2002 YAMAHA BANSHEE

I just rebuilt this complete motor, new crank, bearings, seals, clutch, pistons, rings.

The cylinders are bored 2mm over(max bore on st.ock sleeve). I have the Pro-Design Cool Head with 20cc domes. I have 280 mains, stock 25 pilots and clip on 3rd pos. boost bottle, The reeds are boysen rad valves and are in fair condition, appear ok to run. K&N air filter and FMF Fatty pipes.

THE PROBLEM

Upon start-up it only runs the right cylinder. It will run the left intermedietley with no paticular pattern. When it runs it runs strong. it's just dead, at any RPM.

I have switched spark plug caps and the problem stays with the left cylinder, i have switched reed cages and no change. Fuel flows seems ok, double checked cool head seals and compression test revealed 152 psi, i have the tors blocked off and spark is healthy. Left pipe will load up with raw gas. I have gone through the carbs and all seems to flow ok, I have the equilizer tube in place, manifolds are all sealed and crack free, boost bottle is sealed.

I am hoping somebody will have some suggestions and that I m just over looking something simple. Any help is greatly appreciated.

[chevrolet banshee]

you mite of bumped your mag and is only poting out half power but if that then it shold run on one fore a wile then the other ore week spark one both

[BansheeDan]

Ok,

This is my 7th banshee rebuild, I know Im vapor locked and overlooking something simple.

THE BIKE - 2002 YAMAHA BANSHEE

I just rebuilt this complete motor, new crank, bearings, seals, clutch, pistons, rings.

The cylinders are bored 2mm over(max bore on st.ock sleeve). I have the Pro-Design Cool Head with 20cc domes. I have 280 mains, stock 25 pilots and clip on 3rd pos. boost bottle, The reeds are boysen rad valves and are in fair condition, appear ok to run. K&N air filter and FMF Fatty pipes.

THE PROBLEM

Upon start-up it only runs the right cylinder. It will run the left intermedietley with no paticular pattern. When it runs it runs strong. it's just dead, at any RPM.

I have switched spark plug caps and the problem stays with the left cylinder, i have switched reed cages and no change. Fuel flows seems ok, double checked cool head seals and compression test revealed 152 psi, i have the tors blocked off and spark is healthy. Left pipe will load up with raw gas. I have gone through the carbs and all seems to flow ok, I have the equilizer tube in place, manifolds are all sealed and crack free, boost bottle is sealed.

I am hoping somebody will have some suggestions and that I m just over looking something simple. Any help is greatly appreciated.

 

 

make sure the slides are in sync....i just fired up my motor built by dan @ a&s and i had the same problem on the same side(left)

as mine was running i brought the left idle up untill i heard it start hitting on the left side...

shut it off and pulled the air filter and the slides at that point were real close so i got them as even as i could by eye and it runs pretty well.....i havent rode it yet cuz im waiting on my shocks still

so im sure i still have some fine tuning to do myself.....

 

but i would start by like i said making sure the slides are in sync

and also make sure there not in backwards.....half moon shape or cut away should be facing the airbox side....

 

 

Dan

[chevrolet banshee]

hey bansheedan thats a sweet banshee :thumbsup: :thumbsup: :thumbsup:

[GOIN FAST AND HAULIN Azz]

Thanks I will try that, i never did check the actual sync of the slides.

[Banchetta]

You also might have a stuck float so its flooding out one cylinder....make sure you have fresh plugs as well.

[ohiobanshee]

Do a leakdown test. A friend put in a 4mm crank, upon starting it ran on only 1 cyl. He did a leakdown test and found out he left a crankseal out.

[Banchetta]

Do a leakdown test. A friend put in a 4mm crank, upon starting it ran on only 1 cyl. He did a leakdown test and found out he left a crankseal out.

Now that you said that, it reminds me of when I put my stroker back in my frame. My builder stuffed a rag in my left exhaust. Took me an hour to figure out why I only got exhaust from one cylinder. Didn't I feel a little sheepish..... ::

[BansheeDan]

hey bansheedan thats a sweet banshee :thumbsup: :thumbsup: :thumbsup:

thanx man....just finished up the frame up re-build

cant wait to ride her.....