Jump to content

bent kickstart shaft


dr-alpina
 Share

Recommended Posts

 yesterday fixed ignition at my 199a .  I removed kickstarter and case. started engine without left case, to watch rotating flywheel with marks on it and use a flash gun. (never had a problem with that) several times kicked back. I have a new cylinder on it,so it really has compression... Then with right ignition try to assemble case, but kick start shaft was very hard to move and didn't come back. Without screws in the case kickstart shaft could be moved but you could see it was eccentric . I tried to bent it back a little, with heat. no way and didn't want to break the engine housing. I never thought this could happen. bent shaft? ...any ideas?

Link to comment
Share on other sites

 

The kickstarter shaft is much too long to be used without the support of ignition casing,
as it is now bent it is time to get the shaft out to get it straightened again,
there is sadly no other fix without overstressing the engine casings and bearings as I know.

  • Like 1
Link to comment
Share on other sites

 

Definitely bent shaft. Will need to split the cases to change it if you can't straighten it enough in-situ.

Normal practice when using a strobe on a Bultaco is to start the engine with the cover on then take the cover off. Same for Montesas.

Fully equipped workshop would start the motor on starter rollers driving the rear wheel.

I have no idea how you got away with starting it that way before, even with low compression.

Link to comment
Share on other sites

 

I did find a replacement shaft a couple of years back through Inmotion in the UK. Unfortunately, the shaft on a 199a is longer than the earlier models as I discovered when I finally tracked down the correct flywheel case which forced the change. As others have said, you will need to split the engine to change the shaft. 

Good luck.

Link to comment
Share on other sites

 
 

Kick start shaft will be slightly bent, check with a straight edge. Clearly mark the bend with a permanent marker pen and familiarise your self with the position. Obtain a length of angle iron, this will be your straightening guide/ jig. Obtain a short piece of flat mild steel bar or similar the same length as the kick start shaft. Set up either a G clamp or mole grips so that you can clamp the flat. This is your jig being readied. Use either ally sheet or mild steel to protect immediate surrounding area as you are going to have to heat the shaft with a gas blow torch or better still oxyacetylene torch. Heat to no more than red hot! Now place the jig on the shaft and clamp together. You may have to do this a few time before you get the shaft straight. This way you place no loading onto the crankcases etc. DO NOT cool the shaft rapidly, allow it to cool by itself in the air. You can clamp gently a pair of mole grips onto the shaft close to the crankcases for use as a heat sink while cooling. BE GENTLE so as not to mark the shaft. There you go kick start shaft straight and no engine strip needed ?? Next time you want to start the engine with the cover off try bump starting the beast. 

Edited by section swept
Additional material added
Link to comment
Share on other sites

 
 

The shaft more than likely will be bent where it changes to a smaller diameter just past the return spring. You could take measurements from the magneto case mounting bolts to the hole for the shaft [in the case, as this will be the ideal measurement] and compare them to what you have on the actual engine, this would give an idea of the extent of the bend and in which direction. If you plot it out on a piece of paper, the four measurements will give you a good visual of your problem. Another way would be to make a template out of ply or MDF that mimics the timing case holes. If you bolted this in place again it would show you the extent and direction of the bend, you would need holes/cutouts for the flywheel and sprocket and a larger hole for the kickstart shaft. You can use a try square against the shaft and template as you try to straighten it. However Its going to be a bit of a gamble trying to straighten it while still in the bike.

  • Like 1
Link to comment
Share on other sites

 
 
 

Hi had a bent K/Start shaft on my A no heat this will weaken it I used a tube and found where the bend was then gently use the tube to bend it straight worked for me and never had any problems. but if your not confident enough just split the Engine easy enough.

Link to comment
Share on other sites

 

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
  • Create New...