420 KTM

[242]

I'm rebuilding my 1979 420 KTM and having trouble with the deck high setting. I'm using a double ring Wiseco Piston without a L-ring so the deck hight in the KTM manual will not work. The manual says I need about .040 -.044 clearance for the MC motor and about .060-.065 for the GS. I now have .044 clearance between the top outer edge of piston and head using solder as a gauge. Will this be OK or do I need more? I would like to set the 420 to GS specks. L8er Dave

[dirtbike]

That is close to 1.1 millimeter and will be just about perfect.

[242]

Thanks, I though I was right-on. I'm going to try and add a .006 gaskit and see how that comes up. I'm not planning on racing the 420 just some mild trail riding, about all my Doctor will let me do. I'm also going to try and put on a smaller carb after I get the bike lined out. I have a Bing 38mm off a 1982 Maico with a lever type chock, I'm going to rejet and try. The 420 has a 54/40/1102 Bing and the Maico Bing is a 54/38/111, I thing this will work and will start out with the 420 jetting. Thanks again, Dave