[slashedrider95]

Here's the problem. When I start it, it's pumping gas into the crankcase and will run fine when the hose from the crankcase is pulled off...if we hook the hose back up, it runs boggy. Does anyone possibly have a diagram on how to put a keihin fuel pump back together? It would be greatly appreciated.

 

[1973_ssx_440]

shouldnt be pumping fuel into the case?

it should be pumping fuel into carbs.
the line from the pump to the case should be for vac pressure to drive the pump....

i think you got some lines mixed possibly or you have a leaky diaphragm allowing fuel past the pump and thru the vac line into the case. in that case all you would need is a new vacuum diaphragm in your pump..

im not sure about snowmobile setups though as im going off of past motorcycle, dirtbike, enduro, and car experience.

i got my first sled this year and i was foolin around with the pump and figured the case line was vac just like my vintage enduro bikes so i pulled the line and the pump stopped and the sled ran off of the fuel in the float bowl for a min or two and died

 

[Yamaha440]

You would have a rip in the diagram. May also be jetted rich, for when you pull of the hose you are letting more air into the crankcase. Here are some diagrams, just find your Exciter.

Yamaha Parts, Yamaha Snowmobile Parts, Yamaha ATV Parts, Yamaha Motorcycle Parts, Yamaha Accessories at wholesale prices

I also have an '79 Exciter or two (one getting a top end). Welcome to the club.