KTM Thumper Discussion

[Coolhand]

Popped the sub-frame and yanked the carb tonight... intake side was gritty and dirty. Top of the carb where the slide goes looked like mud up there... can't believe the bike ran as well as it did

[_RG_]

Great report on the race! Thanks for taking us along.

Justin, tear that carb down to the itty bitty pieces and clean it. These fcr carbs are a miracle when well and a real pain when they ain't. If it takes an entire can of carb cleaner to blow out all the crud then so be it. Exploded diagrams are all over the web for them and the cleaning part is way easier than getting the dang carb off the bike. Just be sure the text on your pump diaphram is pointing out when you go back together with it (don't ask how I know this is important).

Whatever got into the valves and cylinder probably got blown out. All that grit sticking to the greasy inside walls on the manifold tube (tween the carb and head) is what bothers me. It'll just keep feeding grit to the engine if left there. Pulling it with the carb already out of the way should be easy (don't know - I've never done it). Let us know how it goes.

[greeneggs&ham]

Perhaps something like a gun cleaning rod. A tee shirt on a cloths hanger, some type of liquid cleaner, and some gentle scubbing. Just not sure how much the rings and valves may have ingested already. But if it is not smoking or the valve adjustment has not changed, maybe it has been caught before any damage. If there is that much in the carb, I would pull the valve cover and check in there.
Sorry to be such a downer after your ride weekend.
But it was a great report, and I wish I had been with you. You made it sound like a great event. Sam

[weekend_warrior]

That is a pretty common problem with the FCR.... I believe slavens has a cure for it. A little filter box that has mulitple ins and outs.

http://slavensracing.com/products/ca...filter-by-7602

Just did the piston on mine (450exc with 350 hrs on it). Nothing in the valve cover. If anything it would go strait to the cyclinder.

[Coolhand]

Originally Posted by weekend_warrior

That is a pretty common problem with the FCR.... I believe slavens has a cure for it. A little filter box that has mulitple ins and outs.

http://slavensracing.com/products/ca...filter-by-7602

Just did the piston on mine (450exc with 350 hrs on it). Nothing in the valve cover. If anything it would go strait to the cyclinder.

Interesting, but that filter cover is designed for the vent lines, much smaller diameter than the valve cover breather and kind of in the wrong location.

So in other news, have any of you guys seen a replacement for these (#3 and #4). They will be the death of me...

[greeneggs&ham]

No and I have never noticed them. Does something bolt into them? I could go out to the garage and look but since you asked... Have you lost them before?

And as for the Slavens thing, your problem was not with dust going up the hoses, it was a major hose was left off. Which, in turn, left you hosed! Sam

p.s. I am on the way to the garage to look.

[Coolhand]

Originally Posted by greeneggs&ham

No and I have never noticed them. Does something bolt into them? I could go out to the garage and look but since you asked... Have you lost them before?

And as for the Slavens thing, your problem was not with dust going up the hoses, it was a major hose was left off. Which, in turn, left you hosed! Sam

p.s. I am on the way to the garage to look.

Yeah my subfender attaches to them with #33...


They're little molded rubber thingy's with a metallic insert, into which you screw this strange drywall looking screw (#33). A crappy design, very little "feel" for when it's tight, and the screw eventually (at least in my case) tears up the insert and can bind or gall itself solid with the darned thing.

[Coolhand]

I have met the enemy and the enemy is mine.... RTV'd in two 6 mm 316 SS nylock nuts and they worked like a charm.

[greeneggs&ham]

I went out to the garage and still could not see them. What happens to them, missing or stripped? Sam

[poser]

KTM gurus. While riding today (did the MX school) the bike was getting harder to start the later it got.
Is it time for rings and valve check?
AFAIK it's on the original wings and two years ago the vales were in spec.

[RollingJ]

I want a bike with wings. I would fly around the vale.

[Coolhand]

Originally Posted by greeneggs&ham

I went out to the garage and still could not see them. What happens to them, missing or stripped? Sam

Sam, since the screws that go in are nominally self-threading screws, they eventually gall/strip everything out.

Got the front wheel bearings and seals in this afternoon, walked around Ace Hardware with a pair of dial calipers until I found a PVC fitting that had the perfect diameter to press them in. Only a little drama with one bearing that didn't want to fully seat. So KTM is finally alive and running well but man what a struggle. Forgot to mention, the first thing I did when gaining access to the carb was pop the subframe loose and lift it... and the first 8mm screw I backed out basically jammed up with Loctite and trashed the threads in the hole. GRRRR.... had to go buy a tap and chase them. Second thing I did was tie the subframe out of the way with bungie cords up over my garage door track. Of course 30 minutes later I'm coming in from outside and pop the garage door only to watch it rip the bike off the stand and dump it on the floor (the front wheel was off as well). I couldn't win for losin.

J

[Coolhand]

Originally Posted by poser

KTM gurus. While riding today (did the MX school) the bike was getting harder to start the later it got.
Is it time for rings and valve check?
AFAIK it's on the original wings and two years ago the vales were in spec.

I'm far from a guru, but the things that pop into mind are A) is it desmogged? and B) valves.

J

[poser]

It never was smogged its a 250sxf.
Though I did recently put a can with a spark arrester in it.
I'll do the valves in the next week or so.

[ekms377]

I would bet the valves are in spec. They hardly ever go out. However, they may not be sealing. Do a leak down. Air filter clean?

[poser]

Originally Posted by ekms377

I would bet the valves are in spec. They hardly ever go out. However, they may not be sealing. Do a leak down. Air filter clean?

You know it was really dry and dusty, and I neglected cleaning the air filter before, hopefully that's it.
I'll borrow a compression tester and do a leak down.

[greeneggs&ham]

Originally Posted by Coolhand

Second thing I did was tie the subframe out of the way with bungie cords up over my garage door track. Of course 30 minutes later I'm coming in from outside and pop the garage door only to watch it rip the bike off the stand and dump it on the floor (the front wheel was off as well). I couldn't win for losin.

J

I trying not to laugh but before I finished the sentence I knew what was going to happen. Been there, but I won't admit it.
I have been tieing the bungie to the handlebars.
Glad to here you got it going again.

[greeneggs&ham]

Originally Posted by poser

You know it was really dry and dusty, and I neglected cleaning the air filter before, hopefully that's it.
I'll borrow a compression tester and do a leak down.

Check the plug, with the warmer weather it may be getting rich. If so move the pilot down 1 step. If better, but still a little rich, adjust with the needle. Sam

[Coolhand]

Originally Posted by greeneggs&ham

Check the plug, with the warmer weather...

Warmer weather? What's that?

[poser]

Originally Posted by greeneggs&ham

Check the plug, with the warmer weather it may be getting rich. If so move the pilot down 1 step. If better, but still a little rich, adjust with the needle. Sam

So I think I may have found the source of my angst.



I'm not sure I know what you mean by "move the pilot down one step"