switching from Keihin to Mikuni

700modsled · Oct 30, 2009

Any of you 700 owners put the Mikuni flat slide carbs on? I heard they were better performing compared to the Keihin 38mms that come stock. I have a set I can get for free was considering on converting if it will boost performance. Anyone do this?

retiredpop · Oct 31, 2009

You won't get an increase in performance with the Mikunis but it will be easier to tune.

rmkboxer · Oct 31, 2009

what year ar the keihins off of, I would be interested in them, mikunis are easier to tune for sure

retiredpop · Oct 31, 2009

I'm not trying to be picky but the Keihin D slides are 39mm.

700modsled · Oct 31, 2009

retiredpop said:
You won't get an increase in performance with the Mikunis but it will be easier to tune.

How are the Mikunis easier to tune??

retiredpop · Oct 31, 2009

It just seems there are a lot more parts available for Mikuni carbs. Keihin was only used for 4 years by Polaris so there are not the quantity of tuning parts out there. Needle jets are not replaceable on Keihin so you are stuck with what they come with. Even the jet needles are not easy to find anymore. Other than that I really don't mind the Keihins. They seem to give good performance.

785RMK · Nov 1, 2009

I made the swap and wouldn't go back. My Keihins would make the sled bog every once and a while. (Keihins) When the needle and seat go bad, and a new needle doesn't fix it. You have to buy a new carb. The Keihins also had to be cleaned thoroughly especially the pilot jet. You can spray carb cleaner through it and it won't come clean. You have to use a torch tip cleaner ( or a small object) to run through it (not boring) to get the jet clean, or else you will have a lean pop at idle. Don't get me wrong they are still a good carb. The Mikunis flat sides have replaceable needle and seats, and are very responsive. Like everyone else has said everyone has parts.

700modsled · Nov 1, 2009

Thanks, thats good to know. I got the set of mikunis going to put them in. In the process of a full engine overhaul at the moment. Taking the oil injection out. Was wondering where I can buy one of those aftermarket billet throttle housing with non of the plastic polaris crap and kill switch? cant seem to find them anywhere online and I seen a few sleds that have them. Look nice.

785RMK · Nov 1, 2009

you mean something like this

http://http://www.cpcracing.com/site/256083/product/CP-003-0006

or this

http://www.powermadd.com/products/powerblock.html

rmkboxer · Nov 1, 2009

fastrax has a nice billet throttle that you can put your kill switch on

700modsled · Nov 1, 2009

thanks, thats what i was lookin for. i think ill go with the CP racing one its alot cheaper. Its hard to find online vendors for aftermarket sled parts.

jsledder · Nov 1, 2009

I made the switch on a couple 97 700's and am very happy. Spent a whole season trying to tune the Keihins and could not get past the low end bog with the Keihin's, went with the Mikuni's and jetted like SLP said to and all is well. Parts are easier to get too, I have a whole bag of needles for Keihin's and bought 1 set for the Mikuni's and they work just fine.

SnowXTC · Nov 11, 2009

We made the switch on my daughter's 2000 600 and would never go back. You cannot switch fast enough. Not a huge performance boost, but a huge reliability increase and tuning which in turn will boost performance.

Snowman87 · Nov 16, 2009

If I have a 98 600 which Mikuni's would work?

off road rider · Nov 16, 2009

Jetting info??

what jetting are you guys running on the 700.. Im also doing this.. mostly ride from 4000 to 8000 ft Thanks

SAUER_POWER · Nov 19, 2009

Im Running a 98 600 mod and I'm planing the swap to a set of 40mm. Can anyone that has done this give me a base point as far as main and needles.

Thanks guys

rmkrazi · Nov 21, 2009

off road rider said:
what jetting are you guys running on the 700.. Im also doing this.. mostly ride from 4000 to 8000 ft Thanks

I second that...:beer;

freak58trio · Nov 21, 2009

In one of my sled's I run a SLP single pipe 370 main, needle in the 2nd position at 3000-6500 with a twin I would probably start at 410 main and the needle in the 3rd position .

jsledder · Nov 22, 2009

When looking for a set of racks to use, make sure the center distance is the same. I bought a set from a Ski-Doo and they are different, so the rest I looked at I made sure the center to center was the same.

As far as jetting, SLP told me to use the jetting from the same model sled with the same size motor that used those carbs. I had a 97 700 RMK and used the jetting from a newer 700 RMK with Mikuni's, I also have the SLP pipe and their instructions have that jetting/clutching info listed. I don't remember right off hand what I jetted at, but I did it once and the plugs look like it's real close.

Here's the sheet I used, notice it has one chart for Keihin equipped motors and one for Mikuni..... You'll want to get a good read on the plugs and look at the wash if your familiar with that, or even EGT's if so equipped, to make sure your good.

785RMK · Nov 22, 2009

I used the jetting off a 2001 700 rmk that had Mikuni's, it worked.

switching from Keihin to Mikuni

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