MX FCR Project (Monster 750).

[Pinion]

Awesome thread

[koko64]

20200330_113319 by Tony Kokonis, on Flickr

20200330_113012 by Tony Kokonis, on Flickr

Long stack on the shorter manifold and short stack on the long manifold with 45 deg boot. An attempt to balance the manifold lengths re intake tuning. The short, straight manifold on the rear cylinder will be 40-50mm back allowing space for the longer stack and filter.

[koko64]

After hours of testing combinations of manifolds, boots and carb positions, I can report that I cannot get the carbs to fit. The carbs foul each other, even with the custom manifolds. I believe that Mikuni TM carbs will fit as they are 25mm and 46mm slimmer than the slant body carbs and the MX carbs respectively. The TM 36 and 38mm carbs also have their components like the choke and throttle cable in different locations giving easier clearance. They do not have accelerator pumps. There are other TM pumper carbs, but they are more expensive.
The Supersport is a better candidate for the FCR carbs.

Talk about "Sunk Costs". Should have got the Mikunis.

[Von Eisen]

 
Bummer   ... So its a no go fitting those two slant bodies side by side, with the OEM manifolds and  45 degree elbows either ? or do they still want to  clash ?

[koko64]

Its very tight that way too when the carbs have chokes, but just possible. I can squeeze them in, but the lhs carb choke knob and fuel pipe boss foul unless you angle the boots outwards. Your manifold boots give more clearance from the struts and there are no choke knobs. Im concerned about the angle of the boots you're using, but if they work without float level issues, then they could be the solution for my set up.

The Supersport frame gives more options to fit the carbs in relation to each other without snagging frame spars. I might grab my mates Superlight before we go into full lockdown.

It's over to you bro and I'll be watching closely.

[koko64]

If I lived around the corner from Buzzer or Pinion, I would have cut n shut rewelded manifolds and all would be well. It's doable, but requires on site fabrication, TIG welding, etc that will have to wait until after the pandemic.
Doable, but not in a quick 'n dirty way.
The Mikuni TM's otoh, have their protrusions facing upward where there's plenty of room as the fuel inlet, choke and cable all exit vertically saving room between the carbs. The carb's cast bodies are narrower too and quite uniform in shape. On an unmodidied 750 I would run the little 36mm carbs as there's no accelerator pump.

[Von Eisen]

Cable arrived today, so spent a little time on the carb project

fcr8 by simon lane, on Flickr

[Von Eisen]

Decided to lock the carbs together, thought they would be more stable that way.  Looked through my off cuts, found some 9mm and a  piece of 8mm bar. A couple of threads cut and a little filing and they are together.

fcr2 by simon lane, on Flickr

fcr1 by simon lane, on Flickr

[Von Eisen]

They sit in there nicely ...

fcr3 by simon lane, on Flickr

fcr4 by simon lane, on Flickr

fcr5 by simon lane, on Flickr

fcr6 by simon lane, on Flickr

[koko64]

Very tidy

[Von Eisen]

 The cable was a task, getting it so the carbs synched correctly took ages. Return cable is now obsolete, as the return springs are way strong  .  K&Ns are going to have to under go a little surgery, cant quiet shoe horn them in, as they are, on the long stacks ... All going to plan will drop back on it tomorrow and see how he runs.

fcr9 by simon lane, on Flickr

[koko64]

Got a straight side on shot to see the angle of the carbs with those boots?

[Von Eisen]

 I was just about to say to you about that ... I did take a pic for you but when I came in and started uploading them I realised it was crap. Will snap another for you tomorrow, there is heaps of clearance there  

The bowls are at a slight angle, but I don't think its going to cause any stress ... We will find out 

[koko64]

Those boots may be the solution, however your carbs have easy clearance from each other compared to mine. They each appear about 20mm slimmer in the body and without the protruding choke knobs. The fuel pipe boss on each carb also protrudes less. You have room to spare.

[koko64]

VE, what is the width of each carb at its widest point? If I can use your boots then I may be able to salvage this project. I have four carbs to use so that's something. For me, it depends on how your bike runs going up steep hills