Frame painting and electrical connections (pics)

[Jerry Birky]

I would like to mention here another important and overlooked part of an ignition ground path.
An Ignition stator ground begins (or ends) at the frame of the stator.
A painted engine case or oxidized stator adaptor plate will disrupt the ground path.
This will cause weak or no spark at all. make sure all mounting surfaces are free of paint/oxidation between backside of stator and engine case.

[G Ellis]

Rain Man I have them for HPI ignitions. I am a dealer here in the states for their product.

[AndyL]

Thanks Jerry, and I am on it.  
Gary also pointed out the importance of a good case ground on the ignition, so I will be installing a separate ground wire from the stator plate to the coil mount, stopping at a head fin along the way.

Andy
#14u
MOVMX, AMA, AHRMA

[Rain Man]

Anybody own a Fluke?  
Thanks Gary, I've been wondering if they have that specific ignition for Jackpiners too?



Raymond
 Down East Pentons

[G Ellis]

They are the same for all KTM Penton motors. I have them in stock.

[Pistonhead]

She is looking great Andy keep up the good work and I can't wait see her competed. I am getting some inspiration for mine through your build so thanks for the motivation.

Ron Sherfy,Ohio                        1974 Penton Berkshire 100   1994 ATK 406                        1976 Honda mr175             1974 Honda mt250

[AndyL]

Thanks for all the questions/comments, I do appreciate it.
I have made a bit of progress this last week, here are a few more pics and some of my own comments and a question.

I went with a 520 chain. The chain guide/slider will need some adjustment as it isnt centered.

I did the Mikuni conversion. I know, Bing is the Thing on Penton, but I have 4 other vintage MX/HS bikes and they all have Mikuni carbs. Given my history/knowledge base/spares, I went with the conversion.

I had to do some fiberglass repair on the side panel and tank, but I drain the fiberglass tank on the other bike after each ride, so I think it will be OK with this tank.

I am guessing that the 250 exhaust spring length is around 95mm. All of my spare exhaust springs are for Hodaka's and an American Eagle Geronimo, and are shorter.
The Curnutt shocks are getting a rebuild.
First start up was pretty easy, 4 or 5 kicks, so far it has started after that with one kick (4 short heat cycles, low rpm in first across flat ground). The motor rebuild seems excellent.

I am not sure I like the extra flywheel weight on the HPI ignition.  I will pull it off and do a few more heat cycles to the motor, just to see the difference.
I have added a separate ground wire (ignition case, head, coil mount, all verified with a Fluke).
I need to work on the cable routing a bit to free things up and secure them from tree snagging.

Last one is a question:
How does the end cap come off the pipe on this bike?  I dont see a fastener anyplace; is it crimped on?




Andy
#14u
MOVMX, AMA, AHRMA

[Toolsurfer]

Build looks good. Just checking out those fork boots. Are they new and where did you acquire them. I am in need of a pair for my Hare scrambler. William

[454MRW]

Some of the end caps were retained with a spring but I believe that one is tack welded in place, as were some others originally. Careful grinding at the seam, and possibly around where the perforated tube sticks through the center portion of the cap will be required. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Penton
1976 MC5 400
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM's
1976-78 125-400 RM's
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R

[AndyL]

OK, thanks Mike.  I will take a closer look at the silencer this weekend.

William: I got the fork boots from Al Buehner.  http://www.pentonpartsusa.com

Al also has a ton of parts that don't show up on his web page, so call and ask.

Andy
#14u
MOVMX, AMA, AHRMA

[Toolsurfer]

Thanks Andy and looks like it coming together for you. Those  air cooled two fifty's are thoroughbreds. Good luck William

[AndyL]

Ok, so now I have a question for the POG collective:
I put the Bing back on the 73 250 HS and it seems to run great.  

But while gathering parts, I ended up with a few Bing 84's (and a 74/75 MX1 250 Can-AM).

Anyway, a couple of the Bing 84's have some sort of choke or other mechanism screwed on to the carb body.  Can someone explain to me, or tell me where to find, what it is and how it works?



Andy
#14u
MOVMX, AMA, AHRMA