New updates:

Bought a 2004 YZ250 rear wheel complete with hub,sprocket and rotor but told the seller to cut off the rim+tire and spokes because they were in bad shape and to save a few bucks on shipping....it cost me 68USD with shipping! ;)

ALSO: Bought a Mikuni BST40 single carb from a KTM 620 LC4 for 21quid +shipping!
It's the same carb as the Suzuki DR650...

It's the mod some guys have posted out there that works with a 2-1 carb joint from a Rhino or grizzly ATV ;)

Will need that joint and mod my throttle assy or get a twist throttle ofor one of those ATV's ;)


Vando :innocent:

a 2-1 carb joint from a Rhino or grizzly ATV is in a straight line so won't allow that carb to fit properly it will be too tight against the rear shock to fit any air filter on it, that mod will only work on the early xt's where the shock mount is further back.
unless you modify it to angle the carb and even then you will still have some clearance issues.
xt's have a push pull throtle cable so you will need to swap the twist grip to that single cable type.

Thanks for the heads up wolf!

I was thinking of the 2002 grizzly's carb joint. which is shorter! but it has a two problems.

Look at the pictures attached..

It is straight forward but the mounts are a little different.
The top screw holes are pointing inside whilst they should be pointing both to the left and both bottom should be pointing right

The second picture is a carb spacer. On the raptor660 that gives her about +2 HP so a similar one would do great I think..

I guess that making a plate that let's me fix this situation will be enough..

The second problem is the grizzly joint is somewhat weird... but give me ideas please..

The rear shock doesn't scare me much because since I might fit an YZ/WR rear shock, I'll have to weld the top mount a little behind on the frame about 8centimeters... but that mod will be after this summer...maybe in September or October or just in the Christmas..

But I do want to put the carb before that suspension mod..

Mayday Mayday Mayday! :rofl:

Vando :innocent:

This is the carb: http://i.ebayimg.com/19/!BSVfbJgB2k~$(KGrHgoOKkYEjlLmY4pPBKCsIjkU3g~~_1.JP G

With shipping to Portugal it is 35.65quid ;)

awesome deal!

Vando :innocent:

raptor inlet is for the 5valve head also the shorter grizlzy manifold will affect fueling too, the ports won't be long enough to give good mixture so the head will need porting to give a better mixture hence the spacer on the raptor giving better performance.

hummm would it give a too rich or too poor mixture?
What is the main difference for the 5valves?

It is currently jetted for the KTM620 so if the lengtht would make it poor, it should compensate I guess.. but that will be one of the problems..jetting...

I'll also be getting either an airbox from either the raptor or the DR650 or at least get the measures so I can make a custom one in fiberglass for my XT..

Vando :)

5 valve head has 3 inlet valves and is water cooled so no it won't fit :rofl:

I've just checked and the 2000 raptor 600 has a 4-valve engine

the part number is 4H7-11133-10-00 superseeded by 4H7-11133-11-00
which are the same as the XT...

The carb joint is the metal one, the one that appears to be the longest of the pics I've posted..

Lol, forgot to post the pictures xD

here they are...

They don't appear to be that much longer than the grizzly's 660 one..

its longer than stock when you include the carb mounting stub, plus its slap bang in the middle which means it has clearance issues with the top of the carb it will be in line with the spine of the frame :(

Hey guys!

Does anyone have BST40 have a choke plunger laying around?
The carb I bought doesn't have one so I need to get one..

I know the LTZ has a Mikuni BSR38mm and I've found one choke plunger that looks exactly what I'm looking for but dunno if it'll fit... it's on flebay for 15bucks..
Do you guys know/think it'll fit on the BST40?

My other problem is... throttle cables! this carb came from a KTM640 SM but will the throttle cables from a DR650 work with it, are the cables exactly the same?
what other bikes have this same carb?

@ wolf I've also been posting on advrider and one of the guys mentioned some KTM linkless swingarm

Those KTM swingarms, the shock mount points are offset to the right and will probably help out with this carb setup, what do you think?

They also mention that KTM rear shocks have a large veriaty of shock spring rates but I'm concerned about the possible height change :S

I guess that since I already have most parts of the YZ rear end I'll just try to see what I can come up with... if it doesn't work on the XT I'll try the parts on my 2002 DT125R or just end up selling the whole thing...


Ideas?

Vando :innocent:

your bargain carb doesn't sound much of a bargain i'd hazard a guess that it has a cable choke so thats why its missing so maybe you need all the ktm throttle and choke controls.
the spring rates will be the least of your worries if you move the top mounting back you wont be able to use the air box which actually holds the battery in place too.
linkages are a pantograph allowing more movement with less linear travel as i have said before the linkage will have an affect on rate of spring required or lack of linkage in the case of the ktm.

I'm all forward to getting rid of my stock airbox! It's a huge pile of nothing! lol
It has actually been one of the things I wanted to get rid off and just put two of those conical airfilters untill I found out it would mess up the jetting..

I've asked here or on advrider and one of the guys said he could send me some internal measures and drawings/pictures of his DR650 airbox so I can make own in fiberglass that fits way better and holds everything nice and clean as Yamaha should've done in the first place..


The choke parts are actually cheap on BikeBandit and the throttle, I will try to use my XT's with a little adapter or something like that....If that doesn't work I'll just wait around patiently I will find one on flebay sooner or later..


Could you explain me a bit more how exactly the linkage and suspension actually works?
This is something really interesting!

Vando :innocent:

air boxes are actually quite important they allow the induction system to draw the correct volume of still air through the venturi of the carb to give a proper mixture.
read up on suspension for yourself its too complicated to put in a forum post read this one first then research from the info given on that

Car Bibles: Motorbike suspension types and how they work.

Hey there..

@Wolf
I've read the website you postedf and now I understand the principles of the linkage..

Do you think an early XT longer rear shock will give me the little extra height I'm looking for to "match" the front forks?

OR

I guess that would allow me to mount the fork a little behind on the frame to give me more space for the carb, no?


Updates:

1. - Got my carb a couple of days ago! it looks great!
2. - Bought that Y-carb joint boot for 18.99USD with shipping (the same here in Portugal is almost 170€ with taxes and shipping)

For the carb I still need:

• The small rubber boot that links the Y-joint to the carb..

• will buy the throttle grip with cables from a KTM LC4 640 just in case the XT's cables won't work with the carb

• And the choke plunger is still missing

I know that the 1990 DR650 carb (also a Mikuni BST40) had the choke plunger I'm looking for but I'm afraid that Mikuni might have changed something since 1990???

I also know the choke plunger off the DR350 will fit the DR650 carb but I have yet to find out what differences the Mikuni BST40 has from make to make (mine is Mikuni BST40 but from a KTM LC4 640)

HELP!! :rofl:

Vando :innocent: