KTM 640 Winter Project

[CSF]

Low594 - I wish I could justify the Ranzaco, but it just wasn't in the budget right now. The Seat Concepts seems to get great reviews. The other option I was looking at was a Gutts Racing seat cover. If you're happy with your foam then its another good option, although they do sell new foam too.


juames - Thanks! I think I may have made the rear of the seat a bit too tight. I think there is a bit of settling that needs to happen.

Yours looks great on the bike! Nice to hear another positive review on them.

[biensur22]

Good choice on the seat. I went up to Hemet a few weeks ago and ha them mount up new foam and cover on mine. While I must admit its a little low in the saddle, the foam and shape is still a night and day improvement over stock.

[CSF]

I went and picked up my carb parts tonight. I didn't have time to get into putting the carb back together, but I did snap a few shots of the new parts vs. the old:




(I wonder if the 4 dots there might be wear indicators?)



These are the most telling pics, the jet needle sits in this hole. Check out how far off the hole is now.
New:


Old:



Heres how the slide is supposed to sit:


Here is how it was sitting:


I didn't bother posting pics of the emulsion tube or jet needle, but the wear is obvious in them as well. I can't imagine that there won't be a noticeable difference in how the carb operates.

If anyone is actually still running a BST, I would really suggest having a good look at it!

[wrk2surf]

its funny when you negelect em... they loose perfomance slowly.. after a rebuild you think you have a new bike again!! Derek at Motolab is the go to guy for carbs.. especially the trusty bst's...

[CSF]

I put the carb back together with a 155 main jet and a 47.5 idle jet. I still need to put it back on the bike and see how it works but it looked super clean. Sorry I didn't take pics...

[gunnerbuck]

Originally Posted by CSF

I went and picked up my carb parts tonight. I didn't have time to get into putting the carb back together, but I did snap a few shots of the new parts vs. the old:




(I wonder if the 4 dots there might be wear indicators?)



These are the most telling pics, the jet needle sits in this hole. Check out how far off the hole is now.

I didn't bother posting pics of the emulsion tube or jet needle, but the wear is obvious in them as well. I can't imagine that there won't be a noticeable difference in how the carb operates.

If anyone is actually still running a BST, I would really suggest having a good look at it!

I have bought a couple BST 40s off of guys who just can't get the bike to run right with that carb and opted for a FCR instead... In both cases when I stripped down the carbs they showed the parts wear similar to what yours had... With the parts in that condition there is no way the bike will run right and it will use way more fuel to boot...

I have tried a 47.5 pilot in both bikes and always end up going back to the 45... The 47.5 seems just too rich down low and I live at sea level...

[CSF]

gunnerbuck -

Very interesting about the carbs you've bought. I sort of suspect alot of people opt to buy FCRs instead of rebuilding their BSTs, after seeing what a proper BST rebuild costs I can see why. Since I've only ridden my new to me 640 for about 3 hours I wanted to give the BST a shot, there must be a reason KTM had it as the stock part. I wouldn't call myself a fast rider, I'd prefer fuel economy, simplicity and reliablity. I'm not sure that sticking with the BST gives me those things... I'll have to see.

"I have tried a 47.5 pilot in both bikes and always end up going back to the 45... The 47.5 seems just too rich down low and I live at sea level..."

Do you have an after market exhaust installed? I ask because the manufacturer of mine recommends the 47.5, but If I find a rich condition I'll switch it back to the 45. I live around sea level as well so that's good info.

Thanks

[gunnerbuck]

Originally Posted by CSF

gunnerbuck -

Very interesting about the carbs you've bought. I sort of suspect alot of people opt to buy FCRs instead of rebuilding their BSTs, after seeing what a proper BST rebuild costs I can see why. Since I've only ridden my new to me 640 for about 3 hours I wanted to give the BST a shot, there must be a reason KTM had it as the stock part. I wouldn't call myself a fast rider, I'd prefer fuel economy, simplicity and reliablity. I'm not sure that sticking with the BST gives me those things... I'll have to see.

"I have tried a 47.5 pilot in both bikes and always end up going back to the 45... The 47.5 seems just too rich down low and I live at sea level..."

Do you have an after market exhaust installed? I ask because the manufacturer of mine recommends the 47.5, but If I find a rich condition I'll switch it back to the 45. I live around sea level as well so that's good info.

Thanks

I have a SM exhaust on one of the 640s and the other has a cored out oem unit... If you use the bike for racing or technical trailriding then the FCR will be a better choice as the extra wheel lofting snap it provides will allow you to more easily bounce over obstacles... If you use the bike for travel then the BST is a much better choice as it provides a less jerky power characteristic, better fuel economy and is much less sensitive to elevation changes for the high mountain passes...

I picked up a FCR 37 to try as I figured it would give half of what the BST gives and half of what the FCR 39/41 gives... I played around tuning it for a couple of days but ran out of time on the project... Where I left off was good power made, good snap but a bog off the bottom when I really snapped the throttle open... I figure this could be solved with a bit of AP tuning, but that will have to wait till a later date, unless I sell the thing...

[bmwktmbill]

Originally Posted by gunnerbuck

I have a SM exhaust on one of the 640s and the other has a cored out oem unit... If you use the bike for racing or technical trailriding then the FCR will be a better choice as the extra wheel lofting snap it provides will allow you to more easily bounce over obstacles... If you use the bike for travel then the BST is a much better choice as it provides a less jerky power characteristic, better fuel economy and is much less sensitive to elevation changes for the high mountain passes...

Wise words.
bill

[motolab]

Originally Posted by CSF

(I wonder if the 4 dots there might be wear indicators?)

They are not, but the indentations in the bottom corners concentric to the bore can be considered as such. They are 0.020" (0.51mm) deep when new, and emulsion tube wear is guaranteed when they get to be .010" (0.25mm) or less deep.

How many miles were there on your carb? Were the slide lift holes enlarged?

Regards,

Derek

[CSF]

Hi Derek,

Thanks for the info, I'll keep an eye on the bottom corners for wear.

The bike reads about 25000KM, but the speed sensor was broken when I bought it so I'm guessing there are around 30000KM. I also have no idea if the carb is original to the bike, It could have been swapped out. The slide lift holes were not enlarged.

[CSF]

Its been a while. Life, work, family... all the usually distractions. Everyone knows the drill.

I've been doing little bits and pieces here and there. Tonight I got into more electrical stuff. I hate electrical. But it needs to be done so I want to simplify it as much as possible. I bought a relay and 6 fuse block that I'd like to run: HID high, HID Low, Grip warmers, twin horns and 2 accessory ports.

I started trying to figure out the best placement for the fuse block, I considered putting it in a water proof box, tucking it under the dash or even on top of the dash for easy access. I don't think theres enough room by the battery, not sure if its a great place for it either.







I think this might be the best place for the relay:


Thats going to take some more work, so I moved onto figuring out the HIDs. I cut the wires and made a hole in the back of the light cover for the new wires and rubber.



Once I got the lights in place I rigged up the ballasts to test everything out. Unfortunately my battery is still too dead to even fire both lights. I like the look of these HIDs though:







Theres still lots of work to do to get everything working, but its moving in the right direction. I'm swapping out a set of pro taper bars for my stock ones so I can start permanently mounting some of the cockpit stuff next week.

Thats it for now.

[biensur22]

you're running your HID's through a fuse block? ¿porque?

Also, can you post wher eyou got that hid kit? I'm curious for something like that on my own 640a.

[bmwktmbill]

I think your choice for placement of the relays is solid, I have two crammed in there, one for each light.

That has worked well. Be sure to tighten all the connectors. I had a problem with a loose one and got an intermittent failure.

It's been said many times that you need to run both beams on high to avoid the ballast warm up problem that is inevitable when you switch up to the high beam when the high beam ballast is cold.
bill

[CSF]

Originally Posted by biensur22

you're running your HID's through a fuse block? ¿porque?

Also, can you post wher eyou got that hid kit? I'm curious for something like that on my own 640a.

I'm running the lights that way in an effort to upgrade the wiring and make the system simpler and more reliable. I'm running a much heaver 10 gauge battery cable up to the cockpit to attach the fuse block and all of that will run through a single relay. I think it will simplify the mess of cables running up to the front of the bike, and make it easier to do side of the road trouble shooting if I ever have to.

I'm also basing my install off this write up: http://www.advrider.com/forums/showthread.php?t=197163

I bought my kit from ebay, I just bought the cheapest "G4 micro kit" I could. These kits are apparently have smaller ballast then the slim ballast kits and are "more" water proof. Not sure if I believe all that hype, but the kit was only a few $ more then a slim ballast kit.

bmwktmbill - Thanks for the input, that's where I'll mount the relay then. There doesn't seem like there is much room elsewhere anyway.