Anyone Tried Dellortos or FCR MX carbs on Long Manifolds?

[koko64]

So this with the 37'simages (1) by Tony Kokonis, on Flickr

Vs

This with the 39's

images (2) by Tony Kokonis, on Flickr

It will save me JB welding or epoxying the cast version and porting to get the shape I want for air flow and filter compatibility.

[koko64]

 I scored two of these FCR MX 39's after making low ebay bids to test the waters, so I'm committed now
images (2) by Tony Kokonis, on Flickr
20200129_121203 by Tony Kokonis, on Flickr

Setting up for manifold mods to suit 2 x FCR MX 39's. I'll get Powerbarn to make me a 2 into 1 throttle kit and I'll start measuring for the cut 'n shut of manifolds. I have to decide which way to point the front cyl carb based on clearance to the battery box. I note that 900 manifolds are a little shorter with a nicer radius  so I may go modified 750 manifold on the Vert cyl and 900 on the Hor cyl. If I point the Hor cyl carb back to the motor it may not need a cut n shut with the angle of the front cyl being tilted upwards. I can decide which is the greater pita, relocating the battery box to behind the steering head or cut 'n shutting the front/Hor cyl manifold. The longer, straighter 750 manifold will serve well on the Vert cyl to allow the carb to clear the frame crossmember.  We'll see after real world mock up stage.

[koko64]

Regarding jetting. I usually use fattter than ideal slow jets for the FCR's without a choke, but won't have to make that compromise with these carbs. I can jet down for economy and smoothness and with 39's have good base line settings to try. Being able to remove the breather pods, carb breather hoses, extra carb heating oil lines and tap will really clean up access for roadside trouble shooting on this analogue bike. I'm really excited about this little project.

[pepeducat]

there are also the very good Mikuni TMR 41 from KTM and other
😉

[koko64]

  merci

[koko64]

This will be handy.
Mikuni-45-degree-rubber-sleeve by Tony Kokonis, on Flickr

[Speeddog]

That's a cute biscuit, where do they come from?

[koko64]

Mikunioz, our local importer/distributor.
https://www.mikunioz.com/shop/mikuni-rubber-45-degree-mounting-manifold-sleeve-for-40mm-spigot/?v=26e945ed8310

I'll test it on the Hor Cyl manifold to bring it around before cut n shut'n it. Then both carbs will face forward and be sidedraft. I've enquired with Powerbarn about the 2 into 1 cables they sell with split FCR's, but if they can't help me I'll modify the local Mikuni 2 into 1 throttle to suit. The Vert manifold will be cut at its straight end and machined to take a stock donut. This should be long enough to clear the main cross member and high enough to clear the front, angled strut (from my measurements). The manifolds will no longer be similar lengths, but I'll test it first before chopping both. I dont mind the long manifolds for the "scrambler" application. I can leave the battery/ignition box alone if this works. My goal is simplicity, less plumbing, no carb freezing, flatslide response (with a choke), and ease of maintenance.

[koko64]

Gotta say, I'm looking forward to removing the still-air chambers, choke cable, extra hoses, vacuum lines and baffles, and the float bowl to oil cooler plumbing to really clean up the area around the carbs.

[koko64]

This will be handy.
Mikuni-45-degree-rubber-sleeve by Tony Kokonis, on Flickr

It's a tight fit with 38mm inners and may require a trim.

[koko64]

Since the question was resolved, I'll log the progress of the MX FCR Project in a new thread.

Thanks for everyones contributions and advice, it really helps to have a sound board to sort out ones ideas. I feel I can now proceed with a clear direction and plan.
Cheers.