OzVMX Forum

Marque Remarks => KTM => Topic started by: Roostin440 on March 20, 2011, 08:17:19 am

Title: Help with KTM id
Post by: Roostin440 on March 20, 2011, 08:17:19 am

Hi,
A friend brought his new to him KTM over for me to restore for him. I need a little help with the id. The numbers are..
Frame. 00820548 I think is 1980?
Motor.  5503348  I think is 400 ?
The plastic has been changed to who knows what, but all in all it is a good project bike.
(http://img.photobucket.com/albums/v440/mjf454/DSC01166.jpg)
(http://img.photobucket.com/albums/v440/mjf454/DSC01167.jpg)

Title: Re: Help with KTM id
Post by: Slakewell on March 20, 2011, 09:41:48 am

My guess would be an 81 model 390 the frame made in 1980. If you friend dosen't like it let me know I would take it off his hands.

Title: Re: Help with KTM id
Post by: Roostin440 on March 23, 2011, 02:21:59 am

I ran the numbers by Al Buehner and it turns out it is a 1980 420. I found a 1981 125 gas tank to replace the monstrosity that was on it. I have not found a source for a air boot from the carb to the airbox. Most everything else seems to be available.

Title: Re: Help with KTM id
Post by: Slakewell on March 23, 2011, 08:07:47 am

Brad Lewis makes repro air boots. Most 420's are MX models with the 390 being enduro.

Title: Re: Help with KTM id
Post by: Roostin440 on March 23, 2011, 12:23:33 pm

I'll yank the head and measure the piston. The motor has wiring for lights so maybe it is a 420 lower and a 390 top end?

Title: Re: Help with KTM id
Post by: Slakewell on March 23, 2011, 12:29:11 pm

The 420 is a rare bike in Aus as most imports were 390's and the 420 were for only 2 models before going to 495. Could be a 390 with a 420 top end? You can build a very nice MX bike from what you have there. If you wish to talk to Mr KTM aka Brad Lewis PM me and Ill pass on details.

Title: Re: Help with KTM id
Post by: bigk on March 23, 2011, 08:08:47 pm

You can't put a 420 piston on a 390 rod, the top bearing is a different size. Consequently I have a new genuine KTM 420 piston kit doing nothing! Don't think it's standard size, can't remember. It's availabale if anyone can use it.
Cheer,
K

Title: Re: Help with KTM id
Post by: ozktm on March 25, 2011, 10:40:25 pm

From '81 motor Parts book both 390 and 495 have the same Rod Kit Part number 560.30.015.044
There only difference is the piston/liitle end bearing /pin.
Is this true?

Title: Re: Help with KTM id
Post by: Tossa on March 25, 2011, 11:28:34 pm

I may be totally wrong, but then again it's a regular occurrence but triple tree top looks like an 80 model,

Title: Re: Help with KTM id
Post by: Roostin440 on March 26, 2011, 12:30:17 pm

I pulled the head and the 82mm piston makes it a 390. Tried to fire it up with the bing. With a new slide and a rebuild kit it leaked all over the place. Upon trying to figure out what was wrong the float crumbled in my hands. So a new 38mm Mikuni is on the way. I am guessing the carb to airbox boot will be a problem with the mikuni.

We decided to just restore the bike instead of trying to start it first. It is all tore down now and a load of parts are on the way.