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carl_g 05-15-2008 08:42 AM

KTM rebuild
 
I know it is not a sportbike, but nonetheless it is my bike and 2 weekends ago I blew up the bottom end during a race.
I need to split the cases and replace the crank. I will also replace the piston and rings while I have it all apart.
Here is my progress so far of taking off the top end.

Head (needs to be cleaned up)
http://www.ism409.com/images/ktmrebuild/rebuild_1.jpg

Engine
http://www.ism409.com/images/ktmrebuild/rebuild_2.jpg

Cylinder & top of piston
http://www.ism409.com/images/ktmrebuild/rebuild_3.jpg

Power valve actuating arm
http://www.ism409.com/images/ktmrebuild/rebuild_4.jpg

Cylinder - doesn't look bad at all!
http://www.ism409.com/images/ktmrebuild/rebuild_5.jpg

Another cylinder shot.
http://www.ism409.com/images/ktmrebuild/rebuild_6.jpg

This weekend I will split the cases so stay tuned for more..
oh yeah wish me luck :LOL:

ronin_01r1 05-15-2008 08:55 AM

take lots of pics! GL.

NYCSTRIPES 05-15-2008 11:14 AM

What controls the power valve?

The head gasket design is very similar to the TZ50 I have. Personally I wish it was something more substantal than these little o-rings.

bondo 05-16-2008 08:39 AM

1 Attachment(s)
Looks good Carl.
I guess you could consider it a little "unplanned maintenance"
There's a lot of hours on that bottom end and a fresh engine will be nice to have next time you are 20-30miles into the woods.

I think I might start carrying a buddy tow rope too. :ride:

The guy who parked next to us at the Curly Fern was the owner of powerseal. They did my cylinder.

Behold :nod2: :roflmao:

bondo 05-16-2008 08:44 AM

1 Attachment(s)
Quote:

Originally Posted by NYCSTRIPES (Post 85989)
What controls the power valve?

The head gasket design is very similar to the TZ50 I have. Personally I wish it was something more substantal than these little o-rings.


Hey Ken,
Centrifugal force and 3 different springs with a screw adjuster. You can adjust the power/exhaust valve to operate any way you'd like. Tune the power so it's just right.

O-rings are simple and it's all you need with relatively low cylinder pressure/heat. I like 'em! If it was a turbo I-4 drag bike, then some nice copper/bronze head gaskets with metal o-rings machined into the block are necessary.

NYCSTRIPES 05-16-2008 01:43 PM

Quote:

Originally Posted by bondo (Post 86016)
Looks good Carl.
I guess you could consider it a little "unplanned maintenance"
There's a lot of hours on that bottom end and a fresh engine will be nice to have next time you are 20-30miles into the woods.

I think I might start carrying a buddy tow rope too. :ride:

The guy who parked next to us at the Curly Fern was the owner of powerseal. They did my cylinder.

Behold :nod2: :roflmao:

Powerseal does nice work. They replated the barrels on my TZ250 this spring. I am pretty happy with the quality of the work.
Ken

Ant 05-19-2008 10:06 PM

Yeah Carl!

carl_g 06-06-2008 08:44 AM

I have been sort of lagging on this project while waiting for parts to come.
I made some good progress last night.

Here you can see I took off the main clutch case cover and took apart my autoclutch.

http://www.ism409.com/images/ktmrebuild/rebuild_8.jpg

I also pulled the flywheel and stator off..

http://www.ism409.com/images/ktmrebuild/rebuild_9.jpg

I will have an impact wrench tonight to get the primary gear off and then I will finally be able to split the cases and send out the crank to be rebuilt.
Thank god for friends having extra bikes with the willingness to let you beat on them :lol: :ride:

NYCSTRIPES 06-06-2008 11:30 AM

who's rebuilding your crank? Local?

With the TZ250, all you need to do is wedge a penny into the primary gear and you can use standard tools to loosen the nut. From the angle of the picture I can't tell if that's possible with your bike.


Ken

carl_g 06-07-2008 12:37 AM

Quote:

Originally Posted by NYCSTRIPES (Post 86743)
who's rebuilding your crank? Local?

With the TZ250, all you need to do is wedge a penny into the primary gear and you can use standard tools to loosen the nut. From the angle of the picture I can't tell if that's possible with your bike.


Ken

The crank is getting sent out to this guy in KY. He goes by the name of Mr Crankshaft and he has been super helpful and there has been excellent communication.

Here are some pics of my progress tonight.. finally the cases are split!

Engine out of the frame..
http://www.ism409.com/images/ktmrebuild/rebuild_10.jpg

another engine pic...
http://www.ism409.com/images/ktmrebuild/rebuild_11.jpg

Make sure you read the shop manual :lol:
http://www.ism409.com/images/ktmrebuild/rebuild_12.jpg

BAM! Split cases.
http://www.ism409.com/images/ktmrebuild/rebuild_13.jpg

Inside of left half of engine.
http://www.ism409.com/images/ktmrebuild/rebuild_14.jpg

The reason for all this work..bad crank.
http://www.ism409.com/images/ktmrebuild/rebuild_17.jpg

Inside of the right half of engine.
http://www.ism409.com/images/ktmrebuild/rebuild_18.jpg

NYCSTRIPES 06-07-2008 10:39 AM

looks like you're on your way. the mr. crankshaft website claims a quick turn around...hopefully you'll be back in business quickly. Question..the green stuff on the engine case...is that a rubberized or paper gasket ? or is that silicone?

Ken

carl_g 06-07-2008 10:58 AM

Quote:

Originally Posted by NYCSTRIPES (Post 86784)
looks like you're on your way. the mr. crankshaft website claims a quick turn around...hopefully you'll be back in business quickly. Question..the green stuff on the engine case...is that a rubberized or paper gasket ? or is that silicone?

Ken

paper gasket..

John712 06-07-2008 10:52 PM

oh man, and i though my bike was in pieces!

Ant 06-09-2008 09:49 PM

why are the rear cylinder bolts corroded?

NYCSTRIPES 06-09-2008 09:54 PM

probably from a coolant leak..just a guess.
Ken


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