Scooter intake risers . By ncredleg (Read 865 times)

[ncredleg]

I am building a new intake riser to lift and clock my carb so that it faces front and I have a question about the 2 nipples on the stock intake. What purpose do they serve and do I need to transfer them to the new riser to keep them close to the engine block or can I leave them on the stock intake and use it as an elbow?If left on the stock intake they will be about 4 inches above their original location.

[ncredleg]

Has anyone installed their carbs facing front? What issues have you had with it? I was told by a company that I could not use the stock manifold because it would tilt the fuel bowl incorrectly and starve the carb. Does anyone know if this is the case? I really need to know ,this is holding me up. Thanks in advance,Russ

[Bashan]

If you're talking about these guys:

They're vacuum nipples and can supply vacuum to a fuel valve, fuel pump, or pollution devices. They either have to be connected to something or closed off. They do not need to be near the head but they do need to be between the head and the carb for the vacuum.

I turned my carb around for a while. I didn't use a flange on the manifold although that was my initial plan. I ended up using a high rise manifold bolted to a chrome "performance" manifold, with a short radiator hose to the carb. In reference to your previous question, the vac nipple on this setup was all the way up at the bend of the performance manifold:

It worked quite well but I ended up going back to the standard GY6 configuration eventually.

I did also turn it around once without compensating for the tilt and it did cause some float bowl issues although it did run. I wouldn't recommend doing that and expect it to perform adequately.

When you mentioned clocking flange I remembered where I'd heard that term before. Steven at MonsterGY6 does some pretty radical mods with scooters. Here's a thread from a while back where he turns a carb around and mentions a clocking flange. In fact, he states that he sells them if you wanted to contact him. In any event I'll be really interested in what you come up with. I'd really like to find a way to get the carb out of the traditional trash pit. I had also looked into the idea of a downdraft verticle carb but couldn't find anything that came close to fitting. Rich