175 head- on center vs. off center comb chmber?

[Doug Bridges]

I am trying to gain some knowledge on what types of heads were used on the 175 KTM motors. My parts catalouge shows two different heads available for the 72-73 motor and the 74-75 motor.
#52-30-006-200 with off center combustion chamber
#52-30-006-100 with on center combution chamber
I would like to know why there was two different types and if either head could be used on any motor and what difference it would make on how the motor would run.
I have a 79 175 motor (similar to 77 I beleive) that I am trying to get into running condition and it needs a new head. I beleive that the head it came with may not be the original head as it has some fins cut off of it to acomadate the 79 tourqe style expansion chamber. It has part #52-30-006-200 cast on it which should be off center chamber, but it is on center. My 79 book shows part #520.30.006.500. The bottom line is that I need to find out what year and what style head will work on this 79 motor as there doesn't seem to be too many 79 parts around. I would also like to know what year the 6 fin cylinder was first used. Was it 76 or 77.
Thanks, Doug

Doug Bridges
73 Jackpiner
74 Jackpiner/FrankenPenton project

[Merlin]

Forget the offset head, it will run cooler, make more power and be much less fussy about jetting and fuel quality with the concentric chamber. When you get to the carburetor use the Bing and be sure to use a "40-404" vaporizer. I put jetting specs in a post here, I'll see if I can find them and put them here.
 Here they are for a 30mm bing:...........KJ,the needle jet is as you describe probably one size too big,the ideal needle jet will allow you to put the needle back to the center groove as well as allow you to use the proper main jet. Be careful not to change the main jet as some may do masking the too large needle jet...............my 72 Jackpiner runs clean as a spoon with the following,#1 slide,#1 needle,#150 main jet,#2.80 needle jet,#35 pilot. Also if the carb is new current production it should have the new type vaporizor #40-404 with the single small hole and a half shrould with the cut side facing the engine..................this jetting is with a Twin-Air air filter and the airbox snorkle removed(non high breather)......................

Quote: Thomas Jefferson, We are all born ignorant, some work to remain that way.
 Quote:Peter Villacaro, "it is impossible to teach those that wish not to be taught".

[Doug Bridges]

Thanks for the info on the head Merlin. As far as carburation for the 79 motor, it sports a 36mm carb so that will be another can of worms to deal with. I will keep the carb settings for the 30 Bing in my notes as I have one on my 73 Jackpiner.
I am still looking for any aditional info I can get on the 175 heads.
Thanks

Doug Bridges
73 Jackpiner
74 Jackpiner/FrankenPenton project

[G Ellis]

Doug If you have a 1979 175 it should have 6 fins on the cylinder. This uses a differnt head than the 73-76  175 motors. Also the x factor, to the top of the ring is different. If you need some help give me a call 217 260 0237  Later Gary