I think you will find that there is a pivot bar that the float actuates the needle with but that the float actually goes up and down on the two guides.
ET: Engine (Twin) Mikuni carbs
- Thread starter Ian Savage
- Start date
Fuel leak
Ahhh So why do I remember floats hanging up on little rods, maybe that's my flat slides??
as per Robert's comment, the guide pins that the floats go up and down on were what I was referring to. But of course the pivot pin on the float tang is another possible problem area.
Pulled my rear carb yesterday which still had signs of silt in the bowl and that's with new fuel lines, in line filters and Caswell liner. That stuff is pernicious, where does it hide away,
To cap it all the front carb' rubber manifold seems to be losing integrity and not holding carb' firmly. Winter lay ups are bad enough, add a forced lock down and the term 'use it or lose it' becomes more widely relevant.
Pulled my rear carb yesterday which still had signs of silt in the bowl and that's with new fuel lines, in line filters and Caswell liner. That stuff is pernicious, where does it hide away,
To cap it all the front carb' rubber manifold seems to be losing integrity and not holding carb' firmly. Winter lay ups are bad enough, add a forced lock down and the term 'use it or lose it' becomes more widely relevant.
Can we see some photos of yours Brian, On another thread, Looks interesting, Cheers Bill.
So out this morning with some small drills etc
As to the manifold I gave up with the standard moulded sleeve if it got lubricated doing the clip up tightly could squeeze the carb off.
I used a piece of Ben's custom blue (other coulors are available)
radiator hose he uses on the k100 it's not plain rubber now that's been ok for 2 years
As to the manifold I gave up with the standard moulded sleeve if it got lubricated doing the clip up tightly could squeeze the carb off.
I used a piece of Ben's custom blue (other coulors are available)
radiator hose he uses on the k100 it's not plain rubber now that's been ok for 2 years
Sticking floats, can in these carbs also be due to lack in design:
The little pin on the float, actuating on the fork,
Is causing a side ways thrust, when the pin it not on same height as the forks pivot.
Hence the float rubs on the side of the bowl. Made from zamak.
Maybe polish inside a bit.
Or use oiled petrol.....
Have to say, a concentic A. Is better here. Thats all the advantage on them over the M's
The little pin on the float, actuating on the fork,
Is causing a side ways thrust, when the pin it not on same height as the forks pivot.
Hence the float rubs on the side of the bowl. Made from zamak.
Maybe polish inside a bit.
Or use oiled petrol.....
Have to say, a concentic A. Is better here. Thats all the advantage on them over the M's
I gave up with Mikuni rubbers years ago, a piece of radiator hose works fine. Cheers, Stu.
Well this is a rouge unit I have now examined the needle under a glass, checked the float height (15mm from gasket top face (where gasket would sit) to lever tip (28mm VM)
checked the lever pivot hole and the pivot pin, no binding, cleaned out the float holes, checked the pins lifted them up an down either with a light touch and then with a flick they always drop down
Held carb in hand turned on petrol it leaks in a steady stream from 10 degrees each side way and twenty odd front to back.as well as its normal horizontal level
filled up bowl with petrol floats bob up like it was a fishing day on a smooth lake
petrol is Esso premium this months.fitted a filter but its all as clean as can be.not much of a head in the tank
I am a bit lost now, I have a 34mm somewhere I will see if I can replace the immaculate valve assembly I already have with another immaculate one!
This is the first time I have had any problems with a Mikuni (and I have had a lot) and this one has been on for two years I remember it worked straight from the box
I have now examined the needle under a glass, checked the float height (15mm from gasket top face (where gasket would sit) to lever tip (28mm VM)checked the lever pivot hole and the pivot pin, no binding, cleaned out the float holes, checked the pins lifted them up an down either with a light touch and then with a flick they always drop down
Held carb in hand turned on petrol it leaks in a steady stream from 10 degrees each side way and twenty odd front to back.as well as its normal horizontal level
filled up bowl with petrol floats bob up like it was a fishing day on a smooth lake
petrol is Esso premium this months.fitted a filter but its all as clean as can be.not much of a head in the tank
I am a bit lost now, I have a 34mm somewhere I will see if I can replace the immaculate valve assembly I already have with another immaculate one!
This is the first time I have had any problems with a Mikuni (and I have had a lot) and this one has been on for two years I remember it worked straight from the box
Well I posed the question to Allens the Mikuni Gurus lets see what they say I would like to use the Mikuni if I can its my first choice.. as light as a feather to use and its carburation is superb....
I of course have some fall back there is a perfectly operating 34mm Mikuni but its a bit large
My second choice would be an old 276 I dont have a good one at the moment and a new one is silly money.
There are the two Monoblocks off the Alphabet twin that raced at Cadwell thats now sporting two 1-1/4 GP's we havent taken on the brake yet so these were back up, but after buying the GPs I cant see us going back.
so that makes Monoblocks my No three choice
Finally there is my stash of TT carbs but they need close inspection to find the unworn combinations and I would have to butcher a slide to get a tickover
I will struggle on with the Mikuni first to try and find the problem it is very strange I seem to have exhausted all the normal causes and I have not encountered the problem before
I of course have some fall back there is a perfectly operating 34mm Mikuni but its a bit large
My second choice would be an old 276 I dont have a good one at the moment and a new one is silly money.
There are the two Monoblocks off the Alphabet twin that raced at Cadwell thats now sporting two 1-1/4 GP's we havent taken on the brake yet so these were back up, but after buying the GPs I cant see us going back.
so that makes Monoblocks my No three choice
Finally there is my stash of TT carbs but they need close inspection to find the unworn combinations and I would have to butcher a slide to get a tickover
I will struggle on with the Mikuni first to try and find the problem it is very strange I seem to have exhausted all the normal causes and I have not encountered the problem before