Measuring a Mikuni to figure out the size....how do you do it??

[71TXman]

I am curious to know how you figure out the mm in a Mikuni carb? Do you measure the inner diameter of the bell? Or do you measure the inner diameter of the carb where it would mount to the engine/rubber boot??

I have measured both.....the I.D. of the large bell is 2.5".......the I.D. of the carb where it mounts on the boot is 1.75".

The 2.5" comes out to be 63.5mm, so I doubt that is correct. The 1.75" comes out to be 44.45mm so I am assuming that is correct? That would mean I have 44mm carbs?

Next question....I wonder if one will be hard to find if I need it?

[ddub]

Justin,
Yes it is the inside diameter of the carb where it mounts towards the engine.

44mm are not real common but I also would not call them rare.  They were used on some Ski-Doo 670's but even most of those had 40mm.  I am not sure what other brands would have used them.

If you get in a pinch, I have a pair.  They are not for sale, but I could loan them out.

[71TXman]

Thanks for the info ddub & the offer!!!! If they are going to be a pain to find, I hope the one I fixed up works, or I will put on 3 38mm carbs as I was told these work great on a 795.

Luckily I have the day off today!!!! So I can make some calls & see what is out there!

Thanks for the info ddub!! Much appreciated!

[ddub]

3 44's on that bad boy?  that sounds like a lot of carb.  How is it on low end?

My late model 800 doo only has two 40mm and it has plenty of carb.

Good luck!

[71TXman]

Low end.....HOLY CRAP is all I gotta say. "When" I hammered the throttle to the bars a couple times on it, it was just instant & insane response. It also cruises around just great at 25mph also. It never hesitated or anything. I have 420 main jets, 30 primarys & 1.8 for the housing for the jet that lets fuel in/shuts it off......

These 44's also have powerjets in them that hang in the bell of the carb, but I closed those off......the 44's on here work fantastic though!! I would like to keep them on here if possible.

[78polarisrxl]

I bet a pair of 38mm bored to 39.5mm would be sweet on them.  3 44mm carbs maybe to much depending on the port job.  for just playing around the yard, i would go with the 39.5mm, if ur gonna drag race or speed run it id do the 44s. to much hassle for a trail sled. i have a set with the cables in ready to rock if u want to experiment with them.

[71TXman]

Thanks for the info RXL....I was told stock 38's with proper jettting would be perfect on this machine. Made some calls today and no luck finding another carb to replace my broken one. Hopefully the JB weld holds (explained in another thread)...so we will see!!

[78polarisrxl]

Theres an epoxy at Menards that i use for stuffing crank cases. its a 2 part deal, squirt it out mix it up and its resistant to gas, oil and good 4 high temps, plus its like 1.99 a tube.  i can get the name 4 u if ud like tonight.?

[Nico]

You can buy new 44 mm Mikuni roundslides, I've seen prices starting at around $125. In case your fix doesn't hold up and you do need another one :)

[JESS77CCCAT]

Old free airs should have tillys   Jess