Mikuni VM 32 petrol connection

rob carter · Oct 10, 2018

I have a 1971 750 norton commando with a Mikuni VM 32 carb.
The problem is I recently changed tanks (to a metal one) and i am having trouble connecting the fuel lines.I have a "T" piece which i am using to connect both fuel lines.
the problem is the height of the tank is only just above the petrol inlet to the carb and I was wondering if there was a kit out there that would do the job.

850commando · Oct 10, 2018

see this fuel line setup by Old Brit.

https://www.oldbritts.com/13_065192m.html

rob carter · Oct 10, 2018

Thanks for that.I went on line and they have discontinued this product.Maybe because of residual fuel left in the pipes.
I may have to do my own one.

seattle##gs · Oct 11, 2018

This is always a big headache. With a single Mikuni I use the right angle fittings for the petcocks, then a T fitting between them. What works well is to get some copper tubing that will just push into 1/4 fuel line. Thin wall plastic tubing is the best, I have some very good stuff which fits tightly enough that you don't need hose clamps. I can send you some if you like. It can be stretched over the large Mikuni brass tube if you heat it with a heat gun. Never needs hose clamps. The piece of copper tubing is about 2 1/2" - 3" long, is bent 90 degrees, and slips inside the tubing so it can make a tight bend over the carburetor. When you want to remove the tank it is best to unscrew the fuel fittings rather than trying to slide the hose on and off. If you have the stock blade type of petcock I made a holding tool for them so it is easy to remove the nut without loosening the petcock.

SteveA · Oct 11, 2018

rob carter said:
Thanks for that.I went on line and they have discontinued this product.Maybe because of residual fuel left in the pipes.
I may have to do my own one.

According to your link the black rubber type is still available!

I make up my own twin Mikuni fuel feed set up.

I use standard Tygon fuel pipe, crimped O clips on the unions, but a Japanese bike style wire sprung clip is all that is needed at the carb union, quick release with pliers. Use a longer pipe section from the T to the carb and you could do a tank drain without disconnecting the tank unions!

I have no problem with residual fuel because I drain the tank after use/races!

To be honest, if you are not riding for a while with ethanol fuels you should too....

rob carter · Oct 11, 2018

seattle##gs said:
This is always a big headache. With a single Mikuni I use the right angle fittings for the petcocks, then a T fitting between them. What works well is to get some copper tubing that will just push into 1/4 fuel line. Thin wall plastic tubing is the best, I have some very good stuff which fits tightly enough that you don't need hose clamps. I can send you some if you like. It can be stretched over the large Mikuni brass tube if you heat it with a heat gun. Never needs hose clamps. The piece of copper tubing is about 2 1/2" - 3" long, is bent 90 degrees, and slips inside the tubing so it can make a tight bend over the carburetor. When you want to remove the tank it is best to unscrew the fuel fittings rather than trying to slide the hose on and off. If you have the stock blade type of petcock I made a holding tool for them so it is easy to remove the nut without loosening the petcock.

Thanks for that.I have made up a right angled tube and it seems to work ok.

rob carter · Oct 11, 2018

SteveA said:
According to your link the black rubber type is still available!

I make up my own twin Mikuni fuel feed set up.

I use standard Tygon fuel pipe, crimped O clips on the unions, but a Japanese bike style wire sprung clip is all that is needed at the carb union, quick release with pliers. Use a longer pipe section from the T to the carb and you could do a tank drain without disconnecting the tank unions!

I have no problem with residual fuel because I drain the tank after use/races!

To be honest, if you are not riding for a while with ethanol fuels you should too....

Great.Thanks for that

rob carter · Oct 11, 2018

seattle##gs said:
This is always a big headache. With a single Mikuni I use the right angle fittings for the petcocks, then a T fitting between them. What works well is to get some copper tubing that will just push into 1/4 fuel line. Thin wall plastic tubing is the best, I have some very good stuff which fits tightly enough that you don't need hose clamps. I can send you some if you like. It can be stretched over the large Mikuni brass tube if you heat it with a heat gun. Never needs hose clamps. The piece of copper tubing is about 2 1/2" - 3" long, is bent 90 degrees, and slips inside the tubing so it can make a tight bend over the carburetor. When you want to remove the tank it is best to unscrew the fuel fittings rather than trying to slide the hose on and off. If you have the stock blade type of petcock I made a holding tool for them so it is easy to remove the nut without loosening the petcock.

Thank you for your reply.I have sorted this out by making up my own tubing.

850commando · Oct 12, 2018

as a follow up comment / i made up the hoses as shown by Old Brit and since i was without the crimp ferrules i used regular hose clamps , the entire assembly made access to the left side panel duz fastener impossible . so i rejoined them on the right side of the carb with a "T" which then leads over the top to the vm inlet.

Mikuni VM 32 petrol connection

Similar threads