Project bike: 2007 KTM LC4 640 Adventure

I got a few jobs done over the weekend and hoped to do a lot more on the bike, but got called into work to help rewire and rebuild a server room.

I did manage to clean and reassemble the carb, I couldn't find anything obviously damaged or worn internally. However I did find that the handguard was dragging on the throttle and delaying the return. I unbolted the hand guard and now the throttle snaps closed nice and cleanly. I haven't had a chance to test it yet but I think that may have been the cause of my overrun problems. I also found the TPS was adjusted to it's most extremely advanced position. I returned that to centre, and will see what that does.

I emptied the radiators and refilled them with glycol/antifreeze, but need to run the engine so I can top it up.

I swapped the microswitches under the sprocket cover... that was a messy job.. (no one told me it would piss oil all over my shoes.. :huh) I got the first one out and it was dumping oil everywhere, I thought oh crap.. and pushed the bike on it's left side and kept working. The 2 angled switches are coveniently placed where you can't get a socket on them, and you can only get a spanner about 1/8th of a turn. The bottom switch was really tight, and felt like it was stripping, but instead it had some white thread sealant or locktite stuff on it. I undid the bash plate which didn't help, and then the brake lever and oil filter cover... eventually I got it out and swapped the switches over. Thankfully they back in easier than they came out, and now I have a working neutral light again and I should be able to start the bike without pulling in the clutch.

I also removed the EPC and SAS rubbish, but as my parts haven't arrived I couldn't finish the job off properly. So I have temporarily blanked pieces off using bolts as plugs held in place with hose clamps. I also removed the remains of the scott oiler kit. I'd like to refit it one day, but for now I'll remove it so it can't cause any problems.

I haven't had a chance to start it yet, but will try and fire her up tonight. After all my pottering and half done jobs my "to do list" now looks like this:

Thought I might do some reading about TPS settings and found this handy post:

Gotta luv this place. Clever people everywhere.

Well I bolted it all back together and took her for a ride around town last night.

I had to jump start it again so it looks like i'm in for a new battery.

I noticed that it started with little or no choke so maybe I didn't set the pilot jet correctly and it's a bit richer than before. (I might be out 1/8th of turn) It certainly started easier and idles smoother.

It ran well, but it felt to me like it had less oomph, so maybe retarding the TPS adjustment has affected that. It feels a bit rough pulling through about 1/3rd throttle/revs.

As for fixing the throttle overrun, hard to say, the bike does decelerate, but still not enough for my liking. It drops tp about 3000 rpm and then slowly decelerates, but it's still trundling along at 20-30+kph in 2nd gear (I'll check that tonight.)

It feels like you're engine braking into a corner and you're 1 gear too high.

I tried a few half hearted attempts at a wheelie but she wasn't interested. That was easier before I pulled the EPC and SAS crap off. I haven't drilled the slide yet, so that might help a little.

Does sound like something's not quite right. Should drop straight to idle speed. Book spec is 14-1500rpm but they do like a bit more, 16-1650, just lets them spin up a bit easier and resists stalling better.

High idle on the overrun/not returning to idle can be caused by an intake air leak, IIRC.

I set my idle down pretty low, a bit below 1500rpm IIRC.

Hmmmm I'm pretty confident it's not around the manifold. It was doing this before and after removing/reinstalling the carb.

Although to be fair i didn't pull the rubber doofer off and inspect it, so maybe there is a fine crack/split hole in it somewhere.

A quick test is to spray the manifold with the engine running. Can't remember if you use water which slows the engine if there's a leak, or something combustible which speeds it up. Maybe a search here will find something - or one of the gurus in the bst40 thread might know.

I was just throwing it out there as something to check.

Another thing to check would be the vac to the fuel pump, maybe cap it off & fill the tank so the carb gravity feeds & try it out.

Cheers
Clint

I was talking to an ex bike mechanic today, and was telling him about the over-run. He suggested it might be running too rich on the fuel/air screw.

When I stripped the carb, mine was 2 3/4 turns out.

The BST bible: http://www.advrider.com/forums/showthread.php?t=347184 says 2 1/4 - 2 3/4 turns

This thread on thumper talk: http://www.thumpertalk.com/forum/archive/index.php/t-392117.html says 1 1/2 - 2 1/4 turns.

I'm curious what other people settings are.

So, how many turns out is yours? Clint? Colin?

Mine's about 2.25 but who knows exactly, I've got the adjustable one and it gets a tweak now and then (especially summer vs winter). I'd expect it would have to be a heckuva long way out to cause grief though, like +/- 1 turn from 2.25.

However if you have an adjustable screw then it's only going to be a few minutes to test ride every half- or quarter-turn from 1.5 to 3.0.

Just saw your post, so went and checked mine. Still have the carb as it was removed from putting in the FCR. Mine was about 2 3/4 out. From memory, I needed to adjust it at times as well, (much like warewolf by the sounds) but it was always at the "further out limit" of what was recommended.

I just used to adjust it and ride for 10 minutes at each setting, looking for best pull from just above idle. I always had the suspicion that it may have been moving due to vibes because it was so far out. I never moved it more than about 1/4 of a turn from memory, so may have been compensating for wear on reflection??? But the needle and jets etc all look fine to my fading eyes now, but I have not looked as closely as I feel I could. Would need to dig out my loupe, and I think it's at work.

Hope this helps.

I think mine is around the 2.5 mark, not sure exactly. I set it for best idle then checked the pull from idle which seemed pretty good, a 1/4 turn either way didn't make it any better accelerating off idle for me so that's where it stayed.

It's a bit of a bastard to adjust without the bling screw, I found a screwdriver bit in a 1/4 sq drive bit adapter on a 1/4-3/8 sq drive adapter made a perfectly sized tool. To get a good setting turn the idle down as far as you can without the decomp kicking in, adjust for best idle, turn the idle down again as far as possible then fine tune.

Cheers
Clint

My latest bits finally arrived today.

An assortment of missing nuts and bolts, the little plug to blank off the SAS hole in the head and a new battery.

I haven't had a close look yet, but what keeps the SAS plug in place? Do you need some kind of sealant/locktite?

Sorry Roger I don't think I replied to your post. Thanks for your info and experience. Very handy.

I can see myself heading down the same route as yourself as time and money allows. I'll probably start with an "Auspuff" and see how things progress from there.

Cheers

You might need a new copper washer underneath it, and it's held in place by the exhaust manifolds.

Sweet, i got the washer also.

I just thought it might need something to gum it up a bit.

I stripped the bike down again and started gremlin hunting.

I adjusted the pilot jet so that it is now 2 turns out. I couldn't really tell how much tension was on the choke so I backed it right off.

I replaced the vacuum line to the petrol pump as it had a join in it, from connecting to the SAS gear as well as when Mike added the scott-oiler. I thought it was air tight but could blow through it gently. I don't know if you should be able to blow through petrol pump normally so maybe the hose had a leak.

I fit the nice little cap to blank off the EPC vent hole in the top of the carb and then thought, well... since I already have the tank off, i might as well have a go at removing the SAS pipe... ye gods.. what a sod of a job. Trying to undo the manifold flanges without removing the radiators...

The problem is that the middle flange bolts are hidden between headers and behind the frame. You can't get a socket or ratchet or spanner directly on to it. I got there in the end after buying an assortment of tools from repco & supercheap that didn't actually help...

I had a mate drop in, so work stopped for a few hours, and I didn't get back out to the shed until 6pm.

Once i finally had the SAS pipe out and blank plug in, I started to reassemble it all, i used allen screws instead of the original hex head bolts because I have allen keys with a ball joint on one end, which allowed me just enough of an angle to get the screws in, and 95% of the way tightened. Much better. It took to 2-3 hours to get the orginal bolts out but only 2-3 minutes to put the new ones in. (including a dab of locktite.)

Last of all I fit my new motobatt battery.. I'm a bit dissappointed with it because it doesn't come with terminals and screws which are a slightly odd size, plus it doesn't have the indent like the original battery and it's about 15mm taller... So the bracket that holds the CDI has to be mangled and no longer lines up with the original bolt holes and isn't secured. So the tight squeeze under the seat for the wiring is now even tighter and the only thing holding the battery in place is the seat.

So after all that, I bolted it back together and took it for a run down the road at about 11pm in freezing soupy fog... And you know what... I reckon I might have fixed it

When you rev the motor it now drops straight back to 1500rpm. and on the road it will continue to cleanly decelerate. She definitely and clearly decelerates below 3000 rpm, although I still don't feel it has a lot of engine braking, it's clearly better than it was.

I'll take it for a bit of a ride tomorrow and see how it behaves, and might do a bit more fine tuning of the pilot jet if needed.

Good news Peet!

Yes the SAS bore is a PITA. I removed mine while the head was off, after eye-balling it often in the frame and thinking hmmm... But I installed it after I re-fitted the head and yeah

I'd pick the vacuum hose as the likely culprit for an air leak, if not in the length of hose then maybe at the end fitting.

Sounds like now it's time to enjoy the beastie... stop posting, get out there and ride

Yep, hoping to do some more of that, next weekend in fact...

I took the bike for short ride today. It feels good, but not sure if its 100%... but that's quite possibly just paranoia on my part. I think it takes a while till get used to a bike, and i'm still learning about this one. It's quite a different beastie to the 950's... all the rattles, grumbles and groans are in different places.

This week I'll sort out the carrier and handguard properly.

I'll give you a useful tip: they don't like to be nanna'd or ridden on motorways. Twisting the throttle makes them handle.

I had really been looking forward to the MMM ride this weekend... and even made it to the start line... but sadly couldn't join the ride.

On the way from Gisborne down to the start line in Rangitaiki, I noticed the gear changes were getting stiffer... by the time I had got to Wairoa, I had no clutch at all.

I stopped at a garage and found the clutch reservoir empty, so we topped it up and bled the clutch. All good and so I carry on...

By the time I got to Napier... same problem... but this time the reservoir isn't empty

I topped up and got a small bottle of oil to top up again if needed. (it takes mineral oil not typical brake/clutch fluid.) 90k's later I grind to a crunchy halt at Rangitaiki... no clutch.... nothing, nada...



Clint had a lookie and confirmed, it "Yep, there's no clutch". We think the piston seal on the slave cylinder is shot and each time I pull the lever it pumps air into the line instead of oil.

We decided to try the trick of cable-tie-ing the lever back so that hopefully it would let the air bubbles out overnight... and then retired to the bar... to do important... beer... stuff...



This morning as we all geared up, I topped up the reservoir again and tried it out, and... I only had half a clutch...



After the riders brief we all set off down the road, but within the first kilometre or so off the tar i was back to having zero clutch again.

As I couldn't stop the bike or get it started again without a running start I didn't like the idea of the upcoming creek crossing and greasy steep bits.. through the forest. Then I thought... hmm no clutch, little or no engine braking, tall gearing and tight windy roads around the lake with crunchy downshifts... not a good idea... So I decided to pull out of the ride, turn around and head back to the road and head home..

I took it pretty easy, trying to be gentle of the gearbox and minimise the number of changes. And so about 4 hours later after 300 k's of riding with no clutch in patchy rain, I was back home in Gizboring...

Other than the clutch packing up, and the bike developing a miss at at about 5000rpm, it's also getting crappy fuel economy. It used 32.8 litre's in 490k's, that's 6.6 litres/100k's instead of the expected 5 litres/100k's.

That doesn't sound like much, but if you look at another way, I should be getting about 500k's from a 25 litre tank... but with my current fuel consumption I'll be empty in less than 380k's. About 120k's (25%) short of normal... (which is very long way if you're walking or pushing a motorbike..)

Sorry to hear of your dramas. Sounds like you must have been a VERY bad boy, in this life or the last, to deserve all this!

Can I just say one thing: don't ride the fcuker until you sort that clutch! When the slave leaks it usually puts the clutch's mineral oil into the crankcase and the bottom end does not like it. Read up on here, lots of info.