18MM Mikuni Carb

[jlebh1]

I bought the mikuni looking carb of warren its great heres the link to my review - http://www.motoredbikes.com/showthread.php?t=16900 if you read it I took the intake manifold to a muffler shop (my dads friend owns it) and they cut the manifold put it out sideways and welded it back up.

 

[Fletch]

misteright1_99,

Where did you find jets for the 18mm? I only see main jets offered on Nichecycle.com for that model. They have pilot jets of all types but the 18mm isn't listed for them. Here is the page I'm looking at: http://www.nichecycle.com/Items.aspx?code=MIKUNIPILOT&key=cat

Thanks

 

[schulze 123]

misteright1_99,

Where did you find jets for the 18mm? I only see main jets offered on Nichecycle.com for that model. They have pilot jets of all types but the 18mm isn't listed for them. Here is the page I'm looking at: http://www.nichecycle.com/Items.aspx?code=MIKUNIPILOT&key=cat

Thanks

Hi,
The 18mm carby uses the VM22/210 series pilot jet.

Cheers BJ

 

[Fletch]

Thanks BJ, I figured it out and ordered some after I posted. Are you running this carb? I ordered an 80 and 85 main, and 20, 22.5, 25, pilot.

 

[schulze 123]

Hi Fletch,
The carby I'm using is the 'Speed' type as supplied by Rock Solid Engines, but I'm working on fitting a Walbro unit and reeded intake as found in the following thread.

Cheers BJ

http://www.motoredbikes.com/showthread.php?t=30364

 

[Fletch]

The plastic manifold clamp/spacer that came with my VM 18 was too large for the CNS manic mechanic intake, and too small for the stock intake. I'm wondering how Misteright_199 got his to fit the stock intake, but I don't think he's still following this thread. One of his posts said that he had broken the clamp on the carb.

So I sanded the spacer down to maybe 1.5mm with a dremmel (unevenly of course) to fit over the CNS intake because the CNS intake fits nicely into the rubber gasket inside the carb. The stock manifold would be too narrow to do this. This really thin spacer was working well until I broke it yesterday by opening it up too far.

Now I'm at a crossroads and don't know what to do to get this carb mounted properly. I tried using some gasket material and I thought that would work, but it is too flexible and the carb ended up rotating around after a short ride. Anyone know who can make a custom manifold for me? I know Jim might be willing, but he is really busy. I might use some permatex gasket shellac on both sides of the gasket material, but I really think that the clamp needs something hard like plastic to clamp down on.

If anyone has this carb and any ideas, I'd really appreciate them. I may take it to a local machine shop and see how much they would charge for a custom intake. My guess is too much The main problem I've had with these HT engines is the carbs.

 

[ocscully]

Mikuni Manifold?

I was trying to get one of these Mikuni VM18's to fit onto my Honda 4-stroke and came across a aftermarket manifold from an outfit in Canada. I remember it as having been pretty pricey and so I tried making my own version, then came to the realization that the 18mm throat opening was 2mm+ larger than the opening on the motor and the project came to a abrupt halt. Maybe all you would need is to have an adapter sleeve made to fit the MM or stock manifold?

ocscully

 

[Dave C]

The plastic manifold clamp/spacer that came with my VM 18 was too large for the CNS manic mechanic intake, and too small for the stock intake. I'm wondering how Misteright_199 got his to fit the stock intake, but I don't think he's still following this thread. One of his posts said that he had broken the clamp on the carb.

So I sanded the spacer down to maybe 1.5mm with a dremmel (unevenly of course) to fit over the CNS intake because the CNS intake fits nicely into the rubber gasket inside the carb. The stock manifold would be too narrow to do this. This really thin spacer was working well until I broke it yesterday by opening it up too far.

Now I'm at a crossroads and don't know what to do to get this carb mounted properly. I tried using some gasket material and I thought that would work, but it is too flexible and the carb ended up rotating around after a short ride. Anyone know who can make a custom manifold for me? I know Jim might be willing, but he is really busy. I might use some permatex gasket shellac on both sides of the gasket material, but I really think that the clamp needs something hard like plastic to clamp down on.

If anyone has this carb and any ideas, I'd really appreciate them. I may take it to a local machine shop and see how much they would charge for a custom intake. My guess is too much The main problem I've had with these HT engines is the carbs.

If your local High School still has a shop class you can try there. The one here has made parts for my rockets on occasion. The instructeors love it because it simulates real world shop conditions, the kids get to try their skills and I KNOW you will have them interested just because it's for a motorized bike

 

[Fletch]

I appreciate the tips...

oscully, Do you remember specifically where that manifold was sold? I'm having no luck really finding any manifolds that resemble the ones on these HT's. Maybe I'm not entering the correct search words? Mikuni's I guess are made for snowmobiles so I get a lot of results for manifolds that are L shaped... They would stick straight up or down. What do you think about a spigot version with a flange mount (rubber)? Wouldn't that melt? I don't really understand how those work or hold up. Having the carb bolted directly to the jug would be ideal, except I don't know about blow back?

For now I secured the carb with some gasket material that is "glued" on the manifold with Permatex Indian Head Shellac, and then I sealed the carb to the gasket material with more of it (so 2 layers). It looks ugly as **** but I think it will hold. I realized my jet needle was bent, and I didn't know how soft and pliable these are compared to the brass ones. So I'm waiting on a new needle before I can test out my new mount. I also ordered another spacer/adapter because the first one that I sanded down real thin was working until I flexed it open too far and it snapped.

BTW- If I took an intro to welding class, would I be able to make a manifold, or is it more difficult?

 

[ocscully]

minimobracing.com

Fletch,

Here is a link to the page at minimobracing http://www.minimobracing.com/store/KITACO/c60/index.html?page=2

Also if you do a google images search for Mikuni VM18 manifold you will get lots of photos of setups using this carb. click on the photos and once they come up close them and you will be taken to the site that they are from, could be a vendor or just someone who has posted their solution somewhere on the web.

ocscully