What I've been doing for the past week...

[ScOoTeR]

So, I couldn't get my KTM jetted properly - either is ran good and fouled plugs or I could make it run leaner but I ran into knock.

Here's what the inside of my exhaust pipe looked like:

Plug:


Basically, I was pulling trans oil into the crankcase and fouling everything out. I had replaced the seals, but it still leaked. When that happens, it's time to change your crank bearings. While I had everything apart, I sent the crank out for a rebuild - good thing, here's a shot of the big end "pin" where the bearing rides:

note the ridge at the top and the spots where the rollers micro-welded themselves to the pin. This damage was only on 1/2 of the pin and probably contributed to the failure of my crank bearings (excessive vibrations).

Here's a few shots of the cases going back together:








I'll throw it back in the bike tomorrow. Hopefully I have fixed my problem.

[Chip Wheeler]

Sweet pics of the plug and pipe!

Hopefully everything works out!

[curt1656]

Don't forget to put a "hot cam" in it.

[ScOoTeR]

Originally Posted by curt1656

Don't forget to put a "hot cam" in it.

Is that what the holes in the crankshaft are for???

[curt1656]

There's 2 holes in the crank. The one in the rear is for the "buttsecks''.

[ScOoTeR]

Update. Found a crack in my swingarm - upon further inspection and messing with it, it is now broken.

Found a used one and hopefully it'll get here fast.

[curt1656]

Bummer.

[luvitmyjeep]

Originally Posted by curt1656

Bummer.

x2

[ScOoTeR]

Update:

KTM is back together with another swingarm from Arizona and the engine and everything else is buttoned back up. Changed out the silencer packing and finally mounted a tool bag to the rear fender. Went back to a 36mm carby (stock size) after farting around for a couple of years with a 38mm - besides, the cylinder and head work I had done made it near impossible to keep the front tire from lofting anywhere over 1/2 throttle. Fired up first kick and purred - can't wait to test it out next weekend.

My old reliable (and recently rebuilt) 98 XR280 (77mm bore XR250) is now leak free and the brakes are 100% again. I now have a "buddy bike"! That damn bike started second kick on two year-old gas after sitting for just as long (I haven't touched it since I bought the KTM :tonka: )

Tomorrow I'll refit the bike shoe in the trailer to fit a full sized bike, add a cabinet and then barbecue a couple of baby backs to take to the inlaws.

[Motor Slut]

it's always nice when a motor runs right after a complete teardown

[Mike Hancho]

Originally Posted by Motor Slut

it's always nice when a motor runs right after a complete teardown

I wouldn't say it was nice, I'd say it was done right...how it should be..

[ScOoTeR]

Originally Posted by Motor Slut

it's always nice when a motor runs right after a complete teardown

Originally Posted by Mike Hancho

I wouldn't say it was nice, I'd say it was done right...how it should be..

It was nice this time because of one thing: the carb situation.

The bike should have a 36mm Keihin PWK stock - mine came (bought used) with a 38mm PWM. The PWM has a horrible idle / off idle circuit - I could jet it to run clean at low throttle openings, but it would lean out when I went over 1/4 throttle. I had to compromise and let the jetting be rich enough for larger throttle openings and let the low RPM / throttle riding load up and foul the plug.

I switched to a 38mm PWK airstryker and the difference was night and day (better), but my deteriorating crank bearings made me pull trans oil into the crankcase. The result was trans-oil fouled plugs when the bike was jetted right. I just rebuilt the whole engine and replaced all the bearings and seals, rebuilt the crank and put it back together with a "stock" 36mm PWK.

Over the winter, I sent the head and cylinder out to Slavens and had the base decked and the head welded and re-machined to get better squish characteristics. With the 38mm PWK, when the powervalve opened, the front end would loft almost uncontrollably. The 36mm should give me a bit more low end and keep the top end manageable in the trees.

I'm all geeked right now because this weekend we're meeting a coworker and his family up north and they are going to start trail riding for the very first time. He has a son that is 9 that he bought a TTR90 from here for. I'm looking forward to 4 solid days of zipping through the trees.

[Skooter_Built]

[quote=ScOoTeR;1097553]
Here's what the inside of my exhaust pipe looked like:

QUOTE]

for a lover of teh Buttsecks, your "tail pipe" does not look clean/inviting. They make shower kits to remedy that

[Mclovin]

Damn wish i knew how to do these.. my 400EX needs an engine i dont know the 1st thing about tearing on of these apart to rebuild it.. Wana make some money??

[stevelknievel]

Originally Posted by Mclovin

Damn wish i knew how to do these.. my 400EX needs an engine i dont know the 1st thing about tearing on of these apart to rebuild it.. Wana make some money??

those motors are fairly easy to work on. what do you want to do to it.

and glad the ktm fired right up!

[ScOoTeR]

Originally Posted by Mclovin

Damn wish i knew how to do these.. my 400EX needs an engine i dont know the 1st thing about tearing on of these apart to rebuild it.. Wana make some money??

Not too bad to do. Give me a pm if you're serious.

[ScOoTeR]

UP riding over the holiday weekend.

[curt1656]

Drummond?

[ScOoTeR]

Originally Posted by curt1656

Drummond?

I wish! I tried to talk my wife into going back, but she wanted to try some other trails. The pic was taken on the north end of the Brevoort loop - we rode some other trails that were as rocky, if not rockier than Drummond but I had forgotten my camera.

[95geo]

sometime this season we need to get together and ride some trails, I have a few buddies that would go too. now I just have to find some free time.