Riser for 32mm carb from BIGE / Mcdonough

Posts: 139

Cool! I am going to stop by home depot on my way home from work today and p/u a 1 1/2 inch coupling and 1 1/2 piece of PVC pipe. I'll give Glade a call on Monday and order a K&N air filter and cover with a 1 1/2 inch opening.

This new MRP pumper carb does not want to idle smoothily. It surges up and down. Also, when I am at full throttle the engine starts to cut out and sputter.

Any suggestions?

Posts: 710

I would do your air intake mods first, then tune your carb.

Quite a few of us that have that 32mm pumper carb upgraded to a 1/4" or 5/16" fuel line. Depending upon your elevation, your main jet (after air filter mods) will need to be tweaked. I'm at about 800 feet above sea level and I'm using a 132.5 main jet. You'll need to adjust your air mixture as well. I think I'm about 2 1/4 turns out.

Posts: 139

Ron,

Good point. I will wait until I put the new air intake tube, coupler and K&N air filter on first. I suspect that the 1 inch diameter pipe and connecter I'm using now is restricting the air flow and possibly causing some unnecessary turbulance that is adversly effecting the idle and engine performance at full throttle. I spoke to Glade today. He is mailing me a 132.5 jet w/ the new 1.5 inch diameter K&N. I am at 800 ft above sea level too. So, we should be about the same settings. I appreciate your feedback and will let you know how it goes...

Later,

Andy

Posts: 139

I purchased the 1.5 inch coupler and 1.5 inch PVC pipe for the intake tube. If any of you plan on doing this, do not purchase a 1.5 inch coupler. It is too big for the 32mm carb opening and 1.5 inch PVC pipe. Purchase a 1.25 inch coupler and stretch it a little bit. You will have a much tighter and more secure fit.

In the meantime, I bought a vacuum gage at NAPA auto parts. Once I get the riser, performance manifold, carb, coupler, intake tube and K&N air filter back on I'll splice the vacuum line from the gas tank to the performance intake barb and adjust the carb to maximum vacuum to optimize the perfomance of the 32mm carb.

Posts: 2647

Andy, that is totally my fault!!!!! After reading your post, I just went outside to check my buggy, and you are absolutely right, it is 1-1/4... I am very sorry... I hope it did not inconveinience you. I feel awful now!!!

Sorry Andy!

John Embarassed

Posts: 139

No worries!

Posts: 4331

Andy, got the riser back today, wow that flange was bent up. the others were ok. hope it all works out for you

thanks
Eric

Posts: 139

Eric,

Glad you received the riser. The flange is not bent. The flange is flat. Set it on your desk top. It's just welded onto the tube at an angle. It made my carb sit at an agle and also prevented the intake tube from clearing the cross member with out pushing in the connector between the carb and intake tube.

If you are having those made for you I recommend you do some quality assurance after you receive them and before you sell them to the public.

I recommend you clearly make sure that before you sell them to a buyer that they clearly understand that it is not a simple bolt on part. They need to realize that there will need to be some shaping with a dremel tool or the like. Even on the new riser you sent me when you run your finger along the inside edge to tha flange and the tube there is a significant edge where the welder did not align the flange opening perfectly with the inside edge of the tube.

In my opinion, it is not worth $29 when you have to do all the extra work yourself to get it right before bolting on.

However, the challange is that there is no one producing these in bulk rate using high tech precision equipment. So, we don't have the flexibility of shopping around.

Posts: 4331

yes it was welded on wrong. I will have them made by a diffrent company and they will be better. thanks for your imput, I will note all of those things for the next production run.