montynormand
Member
can anyone tell me why the SR292 has two pulse lines on the case? Perhaps the twin sr433 or sr643 ran dual fuel pumps with seperate pulse lines? - but then why the 292?
RJH
New member
Huh – that’s interesting.
Is it two complete holes or a tee?
My guess would be someone installed a 2nd pulse line to run an independent Mikuni pump for pumping juice to the sliders.

Is it two complete holes or a tee?
My guess would be someone installed a 2nd pulse line to run an independent Mikuni pump for pumping juice to the sliders.
montynormand
Member
RJH
New member
What does it show in the parts book about the carb. Are there 2 to the carb?
It was pumper stock - right?

It was pumper stock - right?
montynormand
Member
RJH
New member
Where do you find this junk
It does have two diaphrams.
Years ago my buddy built a flat track bike using a SR292. Next time I see him I'll ask.
He has evolved to a Yamaha 540 (+/-) sled engine with CVT in his street bike. Nothing touches it in 1/4 mile.
The parts books must show some direction of the lines.

It does have two diaphrams.
Years ago my buddy built a flat track bike using a SR292. Next time I see him I'll ask.
He has evolved to a Yamaha 540 (+/-) sled engine with CVT in his street bike. Nothing touches it in 1/4 mile.

The parts books must show some direction of the lines.
montynormand
Member
finding odd ball stuff can be fun.... have never seen a dual pumper like these so thought I would take a look at them. just something different!!!!!
its the only explination I can see for the two pulse lines. However these are not the original carbs for the sled. any idea what they were originally for?
based on this diagram, do i see a pulse line to the carb, and another to a pump?
its the only explination I can see for the two pulse lines. However these are not the original carbs for the sled. any idea what they were originally for?
based on this diagram, do i see a pulse line to the carb, and another to a pump?
Attachments
RJH
New member
The early Doo’s and Hirths had some type of return line going back to the tank. That could account for the mess of lines – but neither had 2 pulse pipes in the crankcase.
But wait…..you may have hit on something – yes I think you nailed it…..
Like you observed – maybe one went an independent diaphragm pump and the other went to the diaphragm pump on carb – ya – that makes sense.
Maybe the old stock Mikuni’s didn’t have the poop to suck enough fuel to satisfy that big bore engine – or so they assumed. The chassis mounted pump acted as a supplement.
The proof would be if the stock sled came with a chassis mounted diaphragm pump cause for sure it came with a diaphragm carb. If it had the pump – thus the two required pulse lines.
Next?

But wait…..you may have hit on something – yes I think you nailed it…..

Like you observed – maybe one went an independent diaphragm pump and the other went to the diaphragm pump on carb – ya – that makes sense.

Maybe the old stock Mikuni’s didn’t have the poop to suck enough fuel to satisfy that big bore engine – or so they assumed. The chassis mounted pump acted as a supplement.
The proof would be if the stock sled came with a chassis mounted diaphragm pump cause for sure it came with a diaphragm carb. If it had the pump – thus the two required pulse lines.
Next?

GP292Racer
New member
Double pulse lines are for a double pumper carb when running alcohol (or fuel as old racers call it). My 1971 blizzard 292 was set up this way.
montynormand
Member
thanks for the input, no one has been able to give me a straight answer