73 175 Jackpiner crankshaft assembly

[Ed Peterson]

My 12 year old son has talked me into restoring my 73 175 jackpiner. Where do I find a good crank? Also new bearings, seals, gaskets? Need help!

Ed Peterson

[tlanders]

Ed,

When I rebuilt my Piner, I bought the gasket set from Al Buehner (216) 651-6559 (you could also get it from Larry Perkins (417)865-8884), the bearings and seals from my local bearing house (Brocaw Bearing (417) 257-7566) and the conrod from Stan at my local bike shop D&S Cycle (417) 256-2793 who got it from Eurorods. Is the crank bad or just the conrod?

Teddy

 

[Ed Peterson]

Teddy,
Thanks for the info on the gaskets, seals and bearings. With my limited knowledge of motorcycle cranks I can only explain it this way. The shaft on the magneto side of the engine is broke completely off. My question is what caused it to break? The bike was repaired by a local shop in 1976. It only ran for a week or two afterwards and has been sitting in my dads garage for 25 years. I hope someone out there can find one.
Thanks for the reply.
Ed

Ed Peterson

[Rocket]

Ed
In 73, I bought a new Jackpiner and the crank broke on the mag side after a few months of riding.  Penton repaired under warranty because they were having failures quite often.  I am kind of going on memory for the sizes but here goes.  The original crank had 19mm, (3/4") journals and the new was 25mm, (1").  Maybe your crank never had a problem before and is the small diameter.  You will have to know this to get the proper main bearings.  Hope this does not confuse you to much.  A crank from a newer 175 should work with no problem.
Rocket

 

[Ed Peterson]

Rocket
Thanks for the information.
I checked the diameter of the shaft and it is 3/4". I am assuming that if I find a new crank with the 1" diameter shaft, then I get a diferent size inner race and bearings, it will work? Will any 175 KTM crank work from 1974 up to 197_?
Thanks again,
Ed

Ed Peterson

[Rocket]

Ed
You should be able to use a crank from a newer 175, (74-76) with no problem.  You just need to get the right main bearings and crank seals, just ask for bearings and crank seals for the newer motors and everthing should work out fine.  Do you have the manual that explains how to shim for side clearance on the mains?
Rocket

 

[john durrill]

Ed,
I am going through the same thing you are now with my sons 175 Jackpiner. The small journal crank is 20 mm the large is 25 mm.
You just order a different bearing. The small journal bearing is a "M 20 R 40 DIN 615".
The large journal is a "L 25 din 615".
The only differance is the inner race diameter. 20 verses 25 mm.
Either crank will work.
Rocket, what type of rideing were you doing when the crank you had in 73 broke? we sold several  small journal 175's and had no problems. They were only used in enduros though. Did the factory just have a bad run of cranks or was it they would'nt take motocross or some other type of rideing?
Just would like to know as I may only be able to find a small journal crank to relpace  the one in my sons bike.
Ed hope this was a help,
John D.

 

[Rocket]

John
I was racing scrambles at the time.  I rode Penton's from 73 thru 77 and only had 2 DNF's in all that time, one broken crank and one carb needle breaking.  Very reliable M/C.
Rocket

 

[john durrill]

Rocket,
then you were doing the same kind of rideing my guys were. Maybe some of the orignal Penton guys could shed some light on this . Doug, Anybody.
Was their a weakness in the crank design or did a bad batch come through and all the other small journal cranks are ok?
It would be good to know the root cause.
John D.

 

[Ed Peterson]

Rocket,
I have the original manual that came with the bike when it was new. I received an e-mail from Dr.2Stroke who has a crank from a 74 that may work. How much should I expect to pay for a used crank? Is there a reliable shop that can rebuild the crank for me? I'm a do it myself type guy but don't mind help when i'm out of my league.

John D.,
Will any bearing and seal supplier have access to the parts I need or is there a supplier that specializes in parts for KTM/Penton?
Thanks Gentlemen,
I appreciate the info and as you can probably tell, I am quite ignorant on this subject but I am learning more every time I logon. With help from this forum, I should be in Ohio in July riding my Piner. Only problem is I'll need another bike for my son Thomas. Anyone got one for sale?
Thanks again
Ed

Ed Peterson

[Rocket]

Ed
I really don't know what a good price would be for a crank assembly.  If it is in excellent condition, I would imagine $125 or so.  Al Buehner would probably be a better person to ask or Larry perkins.  Most any motorcycle shop should be able to rebuild the crank with no problem, I have done many of them with no real problems.  With a new crank assembly, the bearings will have to be shimmed to achieve proper side clearance.
Rocket

John
I don't know how many of the cranks broke back then.  Penton replaced the assembly for no charge and said that some of them had been breaking and the update was the large journal crank.  
Rocket

 

[DKWRACER]

Ed, I may have a reasonable used crank, (total motor) for sale....send me your email address,
[email protected]

 

[john durrill]

Ed,
The main bearings are not a common bearing. It would depend on you local bearings house as to getting them . Larry and Al can get them for you if you cant find them in town. The seals you can get from local bearings house also . Its the same deal. I live in a very small town and have not been able to get them in town.
We just got an engine overhaul kit ( gaskets and seals ) from Al so i know he has them.
Larry and Al can help with most Parts.  POG members can sometimes help with the things that are hard to find.
If you need something just post and someone will try and help.
John

 

[john durrill]

Ed,
Just recieved an 175 engine overhaul seal and gasket set from Al.
I would  recomend it to any one rebuilding a 175. It had every o ring seal and fiber washer one would need to rebuild an engine. Enought base gaskets to do a proper job setting deck height and all the other gaskets  needed . It saved me a great deal of time and effort. ( some of the fiber washers and O rings would have never found)
Just a heads up,
John



Edited by - John Durrill on 12/11/2001  8:59:39 PM