'99 KTM 640Adventure-R rebuild time

[Low594]

I tried a search here and google, I have also been working through the LC4 Index and cant find any info on a comparison of the heads. I gather that my '99 has the smallest valves, then it seems around '01 they changed the valve size, then there is the Hi Flow head. Has anyone else found or know info on this?

[Seikkailu_R]

Originally Posted by Low594

I tried a search here and google, I have also been working through the LC4 Index and cant find any info on a comparison of the heads. I gather that my '99 has the smallest valves, then it seems around '01 they changed the valve size, then there is the Hi Flow head. Has anyone else found or know info on this?

Here...

Intake valve 36mm, from 1994 350 SUPER-COMP to 2007 660 RALLYE FACTORY REPLICA

Exhaust 30 mm, from 1994 350 SUPER-COMP to 2002 640 LC4-E Super-Moto

Exhaust 32mm, from 2001 660 RALLYE to 2007 660 RALLYE FACTORY REPLICA

Something like this...

[Low594]

Originally Posted by Seikkailu_R

Here...

Intake valve 36mm, from 1994 350 SUPER-COMP to 2007 660 RALLYE FACTORY REPLICA

Exhaust 30 mm, from 1994 350 SUPER-COMP to 2002 640 LC4-E Super-Moto

Exhaust 32mm, from 2001 660 RALLYE to 2007 660 RALLYE FACTORY REPLICA

Something like this...

Thank you!

[wrk2surf]

the rallye valves and springs are used on ALL 03 and later 625 and 640s.

people have been known to go larger...

[Low594]

I am working with Moto Lab and with his previous work on a 2000 640A he found that with these early motors are restricted via the exhaust, valves all the way out to the pipes. What I am wondering about now is what "Hi Flow" means on these. Is it just larger valves or larger valves and improved exhaust runners? Has anyone done a side by side comparison?

[wrk2surf]

at least get a 03 or newer exhaust with a sxc can.. then a new muffler like a FMF.. unless you want to make some rally down pipes..

the old pipes have a pre muffler and then a crap muffler usually a supercrap

there is a thread going on with the exhaust valves going larger on the newer bikes and the head has been reasonably cleaned up in the ports on the 03 and up..

[Low594]

Originally Posted by wrk2surf

at least get a 03 or newer exhaust with a sxc can.. then a new muffler like a FMF.. unless you want to make some rally down pipes..

the old pipes have a pre muffler and then a crap muffler usually a supercrap

The bike has the sxc muffler and pre muffler on it currently. It will be getting a larger diameter set of primarys and be in a 2into2 with a collector/splitter.

there is a thread going on with the exhaust valves going larger on the newer bikes and the head has been reasonably cleaned up in the ports on the 03 and up..

Is it in the index? I did a search and didn't see it and also scanned the first 10 pages (I believe) of the index. Probably missed it!

[Low594]

Does anyone know of a BST40 that has a Throttle Position Sensor on it? If so, what bike model and year?


I am investigating a cam for this and need some specs. I have the '98-99 Repair Manual, which has the following info:
640- IO 13* BTDC IC 51* ABDC
EO 53* BBDC EC 11* ATDC

400- IO 22* BTDC IC 47* ATDC
EO 60* BBDC EC 4* ATDC

Can someone with a later book check for different numbers for a comparison? Thank you!

[Seikkailu_R]

Originally Posted by Low594

Does anyone know of a BST40 that has a Throttle Position Sensor on it? If so, what bike model and year?

From 2003-> ?
All LC4 models with BST-40 ?

[wrk2surf]

have mine unplugged..

[Low594]

Originally Posted by wrk2surf

have mine unplugged..

Interested in getting rid of it?

[wrk2surf]

Ok lets see a photo of that bike.. good price BTW

[Low594]

Well, I've made a bit of progress lately.
-I found a crank/con-rod set in excellent shape from an 04 Duke (6500 miles!) and it showed up a couple of days ago, $150 shipped off of Ebay.
-Also, Moto Lab is getting a programmable Ignition Module to replace the CDI unit. This will allow me to load specific maps for performance/economy/low alt/hi alt/bad fuel or whatever! But it is also requiring me to get a new coil (on order as well and a carb with a TPS (Throttle Position Sensor). Thanks to Work2Surf, I now know that PartShark sells them new for around $330!
-Looks like the gasket set will be ordered on Monday, if its not a holiday.
-Later today I will disassemble the bottom end of the motor. So I should be finding out how the tranny looks and will know if the mainshaft has the newer bearing.
-On another note, I found a shorter SuperMotard style front fender that I will be running unless I am in the dirt and a matching rear underfender with a clear LED taillight. It should give the bike a more updated appearance, while replacing the faded blue front fender and it will give me the Euro style vertical license plate mount. But these will wait til she moves under her own power!



*If anyone has a BST40 w/TPS on it that they are not planning to use, I would be interested in purchase or some level of trade with my non-TPS unit!

[Low594]

Originally Posted by wrk2surf

Ok lets see a photo of that bike.. good price BTW

Well, currently it's in Superlight mode! But sure I'll get a couple.

[Low594]

BTW, the BST40 w/TPS is found on 2003 and later 640s. Does anyone who has upgraded to an FCR, have one laying around? Here's a pic of what the TPS looks like on the carb


The reason I want one for my '99 is that the new Ignition Module, which will replace the CDI unit, will be able to keep a closer eye on the throttle position and thus be more accurate with the Advance Curve at said throttle postion.