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...... Mikuni 38mm flatslides

Posted: Wed Jan 06, 2010 7:53 pm
by brook
...... If there is anyone in the group, that has alot of experience with Mikuni F/S... Please reply
Thanks Jeff

Posted: Thu Jan 07, 2010 7:55 am
by Wrider
I have some experience with them... Buzzz probably has more... What's your question on them?

Posted: Thu Jan 07, 2010 11:19 am
by BuzZz
I have just enough experience with them to love my EFI. :lol:

Flatslides on what bike? A single cyl. or a rack of 4 on a multi?

Posted: Thu Jan 07, 2010 12:01 pm
by brook
..... The question is,.. How can I stop the throttle, from sticking wide open??
.. With the gas tank off, and the motor running, and working the throttle.
the RPM's do not drop..... and the slides are down.
.. I put my hand on the back of the carbs. and there is a great amount of vaccum.
What can I do??

Posted: Thu Jan 07, 2010 12:11 pm
by BuzZz
The slides are down? and it's still revving high?

Either the slides are not fully closed (sticking slides are a common issue with high vacuum 4-strokes, so they invented CV's) or you could have an air leak in the intake tract.

Does it idle at start-up then free-rev after opening the throttle?

How big is the engine? CC-wise.

Posted: Thu Jan 07, 2010 12:12 pm
by brook
..... My mistake, they are on a FJ1200.
.. I am trying to uplaod a pic, not having any luck.
.. It's a FJ, but I have a R1 nose, R6 tail, Fz1 wheels, brakes and forks and a YZF1000 swingarm. and alot more mods.


Can someone help, with uploading[/list]

Posted: Thu Jan 07, 2010 2:09 pm
by BuzZz
I'm no help with anything computer/pic related, but I got a rack of stock FJ CV's I could sell ya. :wink:
J/K... I need 'em, cause I ain't gonna try retrofit a set of 'slides on mine.

You must have had to cut about 60 lbs of steel off that frame to fit those plastics, eh? The bike definitely does need a diet....

Personally, I wouldn't bother trying to fit a set of flatslides on the bike. Mostly for ridability issues, they are a blitch to tune (worse if you took off the airbox, and I bet you had to in order fit the swingarm and tail) and the only power benefit would be at full throttle, you probably lose that nice, fat lowend and midrange.

I just had a thunk. The stock CV's do have a flat-ish slide and are made by Mikuni, a true 'flatslide' Mikuni racing carb is a very different animal. If you have the stockers, then I would check the diaphrams on top of the slides for holes, separation or rips.

Whatever the case, I want to see this bike, get a pic up, Dude. :wink:

Posted: Sun Jan 31, 2010 9:46 pm
by brook
........ I have been working on the F/S's, and ready to be put back on.

.. But, I need to know first, If the boots need to be hone-out, to match the intake ports, before going on
Thanks Jeff

Posted: Sun Jan 31, 2010 10:28 pm
by BuzZz
Well, you are really the only one who will be able to answer that. Mikuni made/makes flatslides in a variety of different sizes, you have never said what size you have. The dimension they give when stating size will be the inside throat diameter BTW, and only useful as a guideline when determining the outside diameter of the intake boot mount.

Take a pair of calipers and measure the area of the carbs the boot will mount onto, then measure the inside of the intake boots. If the boots are a larger inside diameter than the carbs, a good seal will be hard to achieve, if they are too small, than you won't get the carbs into the boots. A little smaller is O.K., the boots are rubber and will stretch. Use some lube to get them over the carbs if you have too.

And I still want some pictures of your bike, Man.