Info on long runner manifold.

[datzenmike]

Thanks.

 

... or trolls

[2wheel-lee]

On 2/5/2019 at 8:59 AM, Stoffregen Motorsports said:

Last time I visited Rebello Racing, Dave told me about a manifold they are using now in lieu of the Mikuni intake. It is a short runner intake that is available new and is relatively inexpensive. I can't remember the brand, but if you call them, I'm sure they could sell you one.

 

He also told me that they work better than the Mikuni intake, so win-win.

 

I wonder if that's the OER manifold. Some of the pictures I've seen of it for the 4-cyl L engine, the OER manifold looked similar to the long comp / Cannon / Redline / Harada manifold. 

 

I'd really like to find a Mikuni or other short manifold for my 620. I got one of those gooseneck Cannons, but would definitely prefer a Mikuni if I can find one. 

[2wheel-lee]

On 2/5/2019 at 8:59 AM, Stoffregen Motorsports said:

Last time I visited Rebello Racing, Dave told me about a manifold they are using now in lieu of the Mikuni intake. It is a short runner intake that is available new and is relatively inexpensive. I can't remember the brand, but if you call them, I'm sure they could sell you one.

 

He also told me that they work better than the Mikuni intake, so win-win.

 

I wonder if that's the OER manifold. Some of the pictures I've seen of it for the 4-cyl L engine, the OER manifold looked similar to the long comp / Cannon / Redline / Harada manifold. 

 

I'd really like to find a Mikuni or other short manifold for my 620. I got one of those gooseneck Cannons, but would definitely prefer a Mikuni if I can find one. 

[Stoffregen Motorsports]

I think Rebello is actually using a 6 cyl Cannon intake and cutting it down to fit the 4 cyl. I do know whatever they are using, Dave told me they are available new.

[2wheel-lee]

I was wondering if the front and rear pairs of the 6 cyl engine would essentially bolt up to a twin. Is the bolt pattern and port location the same?

[Stoffregen Motorsports]

Yes.

[G-Duax]

Yup, done it myself several times when I picked up a 'broken' L6 manifold out of Japan.

Think I still have a center section around here somewhere.

[2wheel-lee]

When you do this 'conversion' do you reweld the two sections together or mount them independently? If welded together, do you do it at both the head flange and the carb flange, or just one or the other? I'm thinking about doing this with a Mikuni triple to a dual setup. I'm thinking with center linkage, at the very least, the carb flange would need to be joined to ensure vibrations wouldn't cause the carbs to have any movement from each other to disrupt the linkage. On the other hand, I'd hope there isn't much movement in the first place! 

[G-Duax]

Mount them independently.

Never had an issue with linkage, as many L6 manifolds have linkage shaft mounts on the front & rear pairs.

[2wheel-lee]

After I posted that, I thought if I were really compelled to tie the carb ends together I could simply make a heat shield (bent piece of thin aluminum) that could sandwich between the carbs and the manifold - with a gasket on one side and isolators on the other.  

[Stoffregen Motorsports]

19 hours ago, 2wheel-lee said:

After I posted that, I thought if I were really compelled to tie the carb ends together I could simply make a heat shield (bent piece of thin aluminum) that could sandwich between the carbs and the manifold - with a gasket on one side and isolators on the other.  

That is what I was going to suggest. The heat shield could also be an air cleaner backing plate. If you make one, don't forget to have holes for the float bowl vents.

 

Here is one that I just built for a friend. It does not include an air filter.

 

 

 

 

Here's one that does incorporate an air filter.

 

 

 

And another.