Penton 125 Pipes from Circle F

[namgar]

I just got the pics of my new pipe from Kevin at Circle F yesterday. It will be available soon for the CMF framed Pentons both without the silencer installed so you can add the parts from Al B. or with the Circle F silencer installed (The bitchin' cool MX race version!). A friend of mine is buying a prototype of the model without the silencer and is going to be the Guinea pig for test fitting the parts from Al B. I expect we will have to go through some tweaking with the mounting brackets, or possible airbox clearance. Hopefully it should fit fine since it was made from a original pipe in very good condition

He will be shipping it to me this week for test fitting.

The pics are available at:

http://f1.pg.photos.yahoo.com/ph/wrgahrma/my_photos

in the folder "Penton Six Days"

I will add more pics when I get it mounted. Please let me know what you think. There are some obvious differences such as you lose the ridge and shaping from the original in the headpipe area. I believe the volume is pretty close to the original, as are the cone dimensions so I expect the power charecteristics to be similar but I asked him to tune it towards a little more low end and mid. Full testing will obviously have to wait until I get some wheels built.




William R Gahrmann

[imported_n/a]

William,

This is really cool!  Let us know how the pipe performs and when they become available for sale and at what price.

I forgot to ask:  Does Kevin already have fixtures for 250 or 400 pipes?

Glenn

[Gavin Housh]

Nice looking pipe! Bogus looking mounting brackets! Looks like they are simply sawn off pieces of heavy angle iron. Do you recall how that when you install or remove the stock pipe you have to twist and turn the pipe to get it off the bike. Remember how the mounting braket barely clears the carb an cylinder head. Those big cobby monstrosities don't look like they'll fit. Check out the stock mounts. Notice how minimal they are. They made them that way for a reason. So you could get the pipe on and off. If I was to buy one of these pipes I'd order it without mounting brackets, and fabricate my own. Just my two cents. Still looks like a great product.

[rd400pi]

Namgar,
  Awesome pipe!  Thanks for doing the leg work to get a pipe off the ground.  I'm sure the bracket issue will work itself out.  Count me in for one (if it will fit my 74!).  

Mike Husted
72&74 SixDays
76 MC5 250

[namgar]

The brackets are a little large but keep in mind that this is the prototype.  I don't remember the brackets on his other pipes being inordinately large.  I'll have a look when I test fit it, it's possible that once we have the bracket itself marked for the bolt location he can work to reduce the size.

Tolerance is a funny thing, you don't want too much or too little!



William R Gahrmann

[namgar]

The pipe is here and on the bike!!!  

It is going to take some adjusting since the silencer hits the reservoir on my old beat up Works shocks (the top is slightly bigger than the stock ones).  It slid into place easy as could be, right through the airbox, past the carb - rotate and slide the manifold onto the bolts.  All went well until I tried to snug the manifold bolts back into the final place and that's when I realized it was hitting the shock.  I tried flipping the shock but it still touches.  Also the silencer needs to be tweaked out a bit at the tip so it parallels the frame loop for that cool straight back look.

Please ignore the background clutter and the fact that my bike is a big old hunk of crud, I know I should stick to mopeds...

Got some preliminary pics up on my Yahoo! Photos at

http://f1.pg.photos.yahoo.com/ph/wrgahrma/my_photos

in the "Penton Six Days" folder

Let me know what you think.  After a year this project is finally coming together.



William R Gahrmann

[imported_n/a]

William,

Thanks for the update.

I also note that your bike is a +-'74 model.  The '72-'73 frames have the mount for the pipe at an angle away from the ground, so the pipe you're working on now will not bolt right up to the older CMFs.

Glenn

[Steve Minor]

Sweet looking pipe.......Any idea how it will perform? Also, is there a plan to put this pipe (or maybe other models) into production?

[namgar]

It occurs to me that I might have the rubber spacers on the pipe brackets wrong which is pushing the pipe to one side.  It's been over a year since I took this bike apart, can anyone tell if they are right?  Otherwise I'm gonna have to start looking at the book....

Will

William R Gahrmann

[namgar]

Glenn,
I'd have to check my frame number to verify but I don't think my bike is a '74, I believe it is a '73 but I have parts on it from several different bikes so don't judge by what you "see".  I THINK (and that's always scary) that all you would need to do to adapt between the two would be get the pipe from Circle F without the brackets welded on and tack them into place yourself.  I don't know a lot about Pentons though so I could easily be wrong.

and yes Steve, Kevin at Circle F will be producing this pipe either as you see it (with his silencer) or without the silencer so you can put Al B's repop Penton silencer parts on it.  As a matter of fact the very next pipe that he makes is going to be without the silencer so we can do a test fit on my bike with Al's parts.

William R Gahrmann

[imported_n/a]

William,

If Kevin can just leave the rear bracket off, but include it with the pipe, that would work for me.  Thanks for the update.

Glenn

[Gavin Housh]

William, The pipe looks sano enough. My 72 has the outer bazooka cover cut off so all I have is the 7/8" outside diameter stinger going back to a small silencer that is removable. After taking the silencer off and tilting the carb I don't have to remove the exhaust flange to get the pipe out. It seems that the copper crush washer behind the flange would need to be replaced after removal of the flange each time or some leakage might occur. I try to limit taking the flange off unless absolutely necessary so I don't need to keep ordering crush washers. Your rubber spacers look right to me.

[namgar]

Glenn, my frame is a late '72/early '73, frame number starts 211xxxx. so it should be the same as yours.

Gavin, The pipe I sent him as a model was exactly what you described, a regular Penton head pipe with the bazooka removed and a pickle on the end.  I usually leave the flange on too but it was removed for the engine rebuild and never replaced until now.

Looks like it's gonna have to go back for some professional "adjustment", the kind of thing I usually do myself with a torch and big ole hammer....

William R Gahrmann

[imported_n/a]

William,

I've got to run to the garage and look again in the daylight.

Glenn

[imported_n/a]

William,

Your frame and mine are the same.  Sorry for the confusion; but great that it will work.

Glenn