640a help, please

[johnnyg 0]

hi all,

i have an '03 640adv with almost 30k mi on it. on my last ride, my hydraulic clutch began fading as my ride went on (of course it started when i was the furthest from home). at first it seemed to happen only at higher speeds (>50mph), and would feel normal after i slowed -- but then the fade returned, eventually at any speed. i got onto i-8w from s-2, to get myself home with the fewest number of shifts possible, and near the top of the climb my motor cut out and my rear wheel locked up. at 70mph. i pulled the clutch lever, but to no avail. i skidded over to the breakdown lane (it's an impressive distance, btw -- look for the skid mark if you get out that way), checked my shorts, and got the bike into neutral and... it wouldn't start. turned over fine, but wouldn't catch. pushed it the last bit uphill and over to coast down to the jacumba exit where i waited for my wife to pick me up.

i inspected the bike at home and took note of a few things:

-- oil on the motor around where the clutch cable enters the gearbox (rh side, above sprocket);

-- oil under the crank case, along the seam, just enough to hold dirt;

-- oil weeping around the shift lever/kick start shaft where it enters the gearbox;

-- when i cycle the kick starter a few times (slowly), i'm not sure i'm getting enough resistance (compression), though i believe i can feel when it's at the compression stroke. i'm not certain b/c i never use the kick start and haven't developed an accurate feel for it. i suppose i could compare cycling the kickstart with the decomp lever pulled vs not pulled (will try that tomorrow).

my initial thoughts are that gearbox trouble and engine trouble are two separate issues... but i'm new to this and wouldn't be surprised if i'm overlooking something. i would like to repair the bike myself, if possible, but am stumped at exactly where to begin the engine diagnosis. i know i need to check for spark and fuel delivery, but after that... what? is it possible i ruined my motor? when it turns over, i don't hear any new noises joining the usual racket that happens with an lc4, but as i mentioned, my experience is limited... does anyone out there have any insights they can offer regarding these bikes, with this mileage, and these symptoms (or any combination thereof)?

i sure hope i didn't kill my bike -- i'm kinda worried!

thanks in advance,

johnnyg

[paulmbowers 236]

Hmm.

Tell us about the clutch "fading". Does that mean slipping? A rise in engine rpm without an increase in forward speed?

All that oil- was the crankcase possibly over-full?

The rear locked up *even with the clutch pulled in* but you could then push the bike- presumably in neutral, correct? At that point, would the motor turn over with the starter?

Trying to determine if the motor seized or if maybe the clutch bolts backed out or something.

[CalNub 0]

Hey Johnny. Glad you managed to pull out of a serious tailspin and land safely. Id suggest posting this question on ktm-talk as well.

[johnnyg 0]

thanks for the quick response pmb and cal... i appreciate the time.

so, when i referred to the clutch "fade", i meant that the hydraulic lever actuation fades, like when air is in a brake line. the clutch wouldn't disengage when i pulled the lever in my skid. sorry my terminology was off... technical writing is harder than i thought!

on the freeway, i think that the gearbox jammed and forced the motor to quit. with the bike stopped, i got it into neutral and the motor turned over, but wouldn't catch. there are no new rattles that my semi-deaf ears can discern, so i'm hopeful i didn't break something inside the motor.

the oil isn't pooling or anything, a small amount (enough to hold dirt, but not dripping) is collected around where the hydraulic line goes into the gearbox from the lever -- i think the oil is from the line/gearbox junction weeping. i'll attend to the weeping there and at the shifter/kickstart shaft when i open the gearbox.

i really appreciate any insights...

regards,

johnnyg

[Desertrunner 0]

I'm not familiar with the 640, but I'll throw out some suggestions. I would treat the engine and transmission issues separately. You should check the compression, ignition, and fuel for the engine. If it turns over in neutral, you know you didn't lock it up. Seeping oil would not cause an engine to fail, unless you ran it too low. As for the clutch, if the fade developed progressively, perhaps there is a leak in the hydraulic line? Are you able to drain the oil and check the line with a vacuum pump? If all checks out okay, pull the clutch apart and inspect it. The plates and springs themselves might be worn out.

If the gearbox actually did jam as you describe, something would have had to break to jam it. I find that unlikely if the bike was in good running order with no known problems. Start small and eliminate possible issues. Somebody with more 640 experience should hopefully be able to throw more suggestions your way.

[johnnyg 0]

hi runner,

i'm thinking the engine and trans trouble are 2 different issues also. i believe the fluid on the motor, at the hydraulic line junction with the gearbox, is leaking from that junction (i probably should have used the term "fluid" rather than "oil" -- again, that technical writing biting me in the caboose). i don't know if the trans causing the motor to stop suddenly could do any damage to the connecting internals. i'm going to post this on ktmtalk, per cal (thanks for the suggestion) and see if anyone responds.

again, i appreciate any/all input.

regards,

johnnyg

[AATA 0]

I would start with draining the oil and see if you find any metal pieces. Easy and if you find anything significant, you know it has to come apart.

Glad you were able to save it and not crash!

[johnnyg 0]

thanks aata, tomorrow i'll be draining the oil and will post results...