ET: Engine (Twin) Mikuni carbs

[Les Thomson]

Going to try a different direction with 30mm VM Mikuni carbs. Has anyone done this to a Norvin with 2 front heads & front carb manifold to clear top frame rail ( wide line ) Not a lot of room to play with. If it has been done a photo of front manifold would be a great help
Thanks Les Thomson

 

[Chris Launders]

I have 34's on mine and scalloped the inside half of the top frame rail away and welded a flat plate on to clear the front carb, don't forget you have to get the petrol pipe in as well, my manifold therefore is sort of "standard"
Chris.

 

[Les Thomson]

Thank Chris but i don't fancy cutting & welding the frame. Might have to make a manifold short enough just to use the rubber Mikuni connector. I would have liked the carbs at the same angle front & rear
Les Thomson

 

[stu spalding]

Hi Les, I had a lot of trouble with the standard Mikuni rubber connectors, yet another example of 'petrol proof' rubber that isn't. I found that a piece of radiator hose was much better. Cheers, Stu.

 

[Robert Watson]

I had trouble with the Mikuni rubbers, however I know some that have been on for a long time. I think it maybe more to do with being a little weak mechanically when mounted to a big V twin and not a smoother modern bike. I replaced mine with Rad hose and in 2010 when on our big EU tour had one fall apart near Portsmouth, in the rain. managed to sneak a corner under a canopy in a Freshco (?) petrol station forecourt. I took it off and turned it front to back and it seemed to be OK. In Lubeck Germany it completely disintegrated as we pulled into the Hotel parking lot. The late Andreas Wagner came to my rescue and an industrial supply house had some non wire reinforced fuel and oil hose that was the perfect size, so I bought the minimum order of 1 metre but having very little spare room, asked them to cut only enough to make 4 new rubbers. They have been there ever since. Many people blamed the fuel for the deterioration, so I pointed out that this was radiator water hose, had been handling an air/fuel mixture for something like 15 years and really didn't owe me anything!

 

[Pushrod Twin]

I use 28mm Dellortos and rubbers off a Guzzi V50 on my Rapide. The rubbers fit over 36mm stubs, havent had issues with either rubbers or carbs. However, in this country we are spared the ignominy of ethanol fuel, on the other hand, the Italians have plenty ethanol, dont hear of issues from them.
Will the Guzzi rubbers fit your Mikunis?

 

[BigEd]

Hi Les, I had a lot of trouble with the standard Mikuni rubber connectors, yet another example of 'petrol proof' rubber that isn't. I found that a piece of radiator hose was much better. Cheers, Stu.

Les,
Never tried the Mikuni rubbers. Like Stu and others here I have used radiator hose on my Rapide with 28 mm Mikuni carbs. The same two bits of hose for 50,000 miles since 2008, no problems. Cheap to try, available almost anywhere, what's not to like?

 

[Les Thomson]

Thanks for all the feed back. To get the carbs to fit will have to do away with the Mikuni rubbers ( too long )
Will post a photo of manifolds when i make them. They will be very short.

 

[Les Thomson]

I use 28mm Dellortos and rubbers off a Guzzi V50 on my Rapide. The rubbers fit over 36mm stubs, havent had issues with either rubbers or carbs. However, in this country we are spared the ignominy of ethanol fuel, on the other hand, the Italians have plenty ethanol, dont hear of issues from them.
Will the Guzzi rubbers fit your Mikunis?

I followed your postings years back when you were grafting gearbox to motor. Very interesting what you done

 

[vibrac]

I used samco silicone hose that Ben uses on the k100 fitted for 2 years no problems if oil gets on the internal rubber connections you can even get the situation where doing the clip up too tight squeezes the carb off!
On the other hand the rubber connection on my 34mm on the Egli Comet is fine .