XT600E with MIKUNI single carb doable!

**bacardi23** · #1 11 Sep 2009

Hi all. A few of you might've read that I'm fitting a Mikuni BST40 carb on my 1990 XT600E..

Here is the deal.
IT is doable, BUT.. (HOLD your breath)

Parts needed:

Mikuni BST40 carburetor
Grizzly 600 2-1intake manifold. part number: 4WV-13586-00-00 (superseeded by 4WV-13586-01-00
TWO O-rings part number: 93210-36769-00 OR you can use your stock XT's stock manifolds O-rings that fit nicely.
Grizzly 660 JOINT, CARBURETOR part number: 5KM-13596-00-00
Two clamps to lock and hold the rubber boot in place.

Now you can stop holding your breath. lol

Rear shock has to be moved a little back about 40-50mm, a mount has to be made.
For the carb to fit in its place you have to CUT some metal on where I'll be pointing on the pictures give or take a little metal lol

Tomorrow a friend welder is comming here to do the work and advise me on what has to be and can be done and what has to be "reinforced"..

Vando

**Tenere Tom** · #2 12 Sep 2009

I've been waiting for you to do this!!!

Full details please!!!!!!!!!!

Tom

**bacardi23** · #3 12 Sep 2009

Lol

hey

Notice at the shock location... it is exactly 55mm (center to center screws) towards the back of the frame on the small gap where the top of the air box holds onto the frame (two holes on a strip of metal that is welded onto both sides of the frame).

The shock, with my YZ250 front forks, is spot on with me on the bike lol! the seat height increases a bit matching the 5cm increase on the front and I like it lol

The kickstand will have to be increased by about 15cm guesstimate..I didn't actually measure it... or get a MX one with similar needed length that can be fitted..

Stock air box: I got to check if there is enough clearance for the rear shock but for now I can only say that it has to go back about 5cm from the top mounting holes...because of this the right seat plastic panel looses it's mounting hole..

Since I want to make a fiberglass airbox-battery-CDI (or TCI?) holder and a LowerMudguard-taillight/license plate holder I'm not really worried about the stock airbox..

The "worst" part of all this I guess will probably be finding the correct carb settings..

Vando

**bacardi23** · #4 14 Sep 2009

Found a simple, easy to do, short-term solution for the carb-to-airbox air duct.

As the name says, It is a very flexible Air Duct in aluminum type of foil but is not the most apropriate because it isn't smooth on the inside of this tube, it is "wrinkled" which will probably cause some air turbulence from the airbox to the carb.

I will try to either fit some high quality aluminum duct tape on the inside of the air duct OR will be making something somewhat more difficult but also interesting thing which is.........liquid resin or epoxy glue on the inside just enough to make it SMOOOOOTH

BTW, for the most curious, I will have the rear shock fitted and welded into the new position later tonight I hope!

Vando

**bacardi23** · #5 14 Sep 2009

Also, this is a thread on another forum that I sometimes post some things...

This one link is for the new shock mount position
XT600 faux-rally(e) (disturbing content) - Page 16 - ADVrider

I hope it is not against to forum rules posting this link here, if any of the admins nag about it I'll delete it or something..

Vando

**bacardi23** · #6 15 Sep 2009

Hi all

well...today the rear shock got its new mount!

thing is... I am not that satisfied with it because it was welded a bit further back and the bike STILL with the engine off i too f

g high...

I'm gonna put the engine on the frame right after I finish this reply sooo yeah.. wish me luck!

Vando

**G600** · #7 16 Sep 2009

Vando, very interesting.

What is the purpose of this mod? Why/how is this carb better than the stock one?

**bacardi23** · #8 16 Sep 2009

New technology versus old technology

and more power lol

plus...I needed to gain 2inches on the rear of my bike because I fitted some front forks off a 2002 YZ250 which gave me 2 inches height on the front...

Vando

**bacardi23** · #9 16 Sep 2009

humm... I thing I've just

t he cap of the carb... it had a vent on top side which most BST40's do not have.

Since that vent had already been closed-covered it from the top and inside AND since the Grizzly carb doesn't have it, I went and cut the top vent!

Now I got a 6.5mm hole on the top of the carb cap which I have to "close" it

Any ideas on how to fix this besides getting a new cap? it's about 45USD plus shipping

Vando

**Pigford** · #10 16 Sep 2009

The carb slide mod was often done in conjunction with a Dyno Jet kit.

Can you not use some metal putty stuff to plug the hole?

If I was upgrading the carb I'd defo go for a plain "flatslide" carb - not CV, as a f/slide is easier to tune.

Good luck anyhow!

**bacardi23** · #11 17 Sep 2009

yes I know about the carb mod... I've read quite a few regarding jetting and tuning...that's why I need to check all the jetting..

as for that metal putty...It might just work!!

As a last resort... new cap, no bugger..

**cyberzar** · #12 17 Sep 2009

don't know how thick is the metal you have the hole in, maybe you can use a screw to close it...

**bacardi23** · #13 17 Sep 2009

It's not a metal cap... it's some type of plastic coumpound that isn't really a plastic?!

**bacardi23** · #14 18 Sep 2009

Pics:

**bacardi23** · #15 18 Sep 2009

Well.. I think I've fixed it! lol

I've put a stainless steel screw that was just slightly larger than the hole and gave it a couple of turns in so it was surface with the interior.
After that I cut the rest of the screw.

Vando