Hi All,
After crank shaft overhaul and replacement of all bearings of my 1973 Penton Hare Scrambler I have started to put the engine back together but ran into a problem: I don't seem to be able to install the transmission and shifter mechanism correctly.
After putting the engine halves together I can't work the gear shifter correctly. It is hard to engage the gears and I feel no reset spring force on the shift lever when working it. It is kind of sluggish. Do these symptoms ring a bell with anybody? Is there some obvious assembly mistake leading to these symptoms? The engine manual talks about setting the gear dogs in the right place through the three openings at the top of the engine. I tried that but probably don't even understand what it is they are talking about. I can only see gears 1, 2, and 6. Would you have some advice to offer?
Thanks for any advice people might be able to offer
Andreas
Have to see it to fix it but you can check to see if your shift forks/rods are in the proper locations in the transmission gears when installing them as a unit. Kind of tricky trying to hold the Layshaft and Mainshaft clusters and the three shifting rods all at once. Check to see if the shift return spring is properly located on the left case. May have the shift shaft shimmed too tight,some were shimmed, some wern't. I spin the CS without installing the clutch on a bare bottom as soon as I close the cases to see if all six gears engauge up and down. Then finish the bottom. Good Luck
you may have installed the shifting drum so that its pinching the drum detent lever down between the drum and case. you have to make sure that its back out of the way when you install the drum chi jer
Hi all,
Here some technical details that might be important for my current problem.
The bottom part is the original shifter shaft of my 1973 KTM 250 engine. The top part is a second shifter shaft I got out of a 1976 scrap engine:
http://s1341.photobucket.com/user/andreas_g_piepke/media/Penton/100_3697_zps7be05808.jpg.html?sort=3&o=1
As on can see the 1973 part allows to install the shift lever on both left and right sides, the 1976 does not. What one can also see is that the large spring has a tight axial fit on the 1976 part (top) while it is axially loose on the 1973 part (bottom). On the 1976 part the claw is shoved right against the spring body while on the 1973 part there is a lot of play between spring and claw.
The next picture shows the orthogonal view of the same parts:
http://s1341.photobucket.com/user/andreas_g_piepke/media/Penton/100_3699_zps8f65a3ea.jpg.html?sort=3&o=0
The left part is from the original 1973 engine, the right part is from my 1976 engine. As one can see the large spring has a tight fit around the little pin on the 1976 sifter claw while the 1973 spring is bent and has a very loose fit around the pedestal. Furthermore, the 1973 spring has a lot of radial play on the shaft, while the 1976 spring fits tightly on the shaft.
Would people be able to comment on this? Does my 1973 part have the correct components? Perhaps someone can shed some light on this difference for me.
Thanks!
Andreas
It turned out that there was a simple solution to the problem I reported earlier. The image below shows the shifter claw of my 1973 Penton (left) and that of a scrap engine (right).
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_3699_zps8f65a3ea.jpg)
The problem with the shifting came from the spring. Jerry Birky of Penton Racing Products pointed out by email that the spring needs to be tensioned. That fixed the problem and cost nothing! I guess that was simply a case of "know how".
Andreas