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Bultaco 250 1971 Problems


mrmoog
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Can any of you guys help me out here, I've got the above bike and the problem I've got is when i go to kick it over the kick start goes throught the motion but it does not engage and turn the engine, the return spring has gone put that wouldn't stop the engine from turning over would it? any help you guys could offer would be a great help. Regards Paul H (paul@paulherbert.demon.co.uk)

Sorry.... i first posted this in maybe the wrong forum

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iirc, a slipping clutch can cause the above problem. Or the kickstart pawl is not working correctly. The kickstart stop (a J-shaped bolt) on one of my bikes was worn and caused problems too.

I have not been able to successfully replace that spring without splitting the cases, but I have heard of it being done.

When I've tried I've bent the spring up too much.

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iirc, a slipping clutch can cause the above problem. Or the kickstart pawl is not working correctly. The kickstart stop (a J-shaped bolt) on one of my bikes was worn and caused problems too.

I have not been able to successfully replace that spring without splitting the cases, but I have heard of it being done.

When I've tried I've bent the spring up too much.

Any of the things mentioned above but also your bike may have the clutch bub located on the gear shaft by a woodruff key, some older models do. If that has sheared you'll have no drive to the clutch through the kickstart, it'll just turn the gearshaft and spin it inside the clutch hub. Check the clutch for slipping/woodruff key first, if it is neither of those the problem lies inside and you'll need to split the cases. Bults are the easiest engines to work on but you'd be amazed at how they can be codged up when reassembled by some people.

Broken spring won't cause the problem of non-engagement

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Further possibilities are:

The drive key for the crankshaft sprocket has sheared.

The person asking has never before started a bike with non-primary kickstart and is pulling in the clutch lever when kicking.

That second one is a distinct possibility.

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okay i checked the clutch and found that it is the problem, I think? I adjusted the clutch and the problem disapeared....okay....Then I was told about how the ends of the clutch push rod sometime wear giving problems, i took the casing off, pulled out the rod and the ends looked fine, what i did notice is that the ball bearing that is inside the hollow shaft was missing, this explains the slack in the lever, does anyone know what the dia of the ball is, I guessed at 5/32 (way to big, casing does not sit flush) it was the only spare ball bearing i had.

Your right you know i tried pulling in the clutch while kicking it over and its the same symptoms, I never new that

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As you all have guessed i'm new to T/shocks the 250 T is my first, it was mis-treated by a Yorksire man in it's youth, I've got hold of her now and i'm breathing some life back into her.

Model 49? (Sorry)

The engine number is B 9101086

Edited by mrmoog
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As you all have guessed i'm new to T/shocks the 250 T is my first, it was mis-treated buy a Yorksire man in it's youth, I've got hold of her now and i'm breathing some life back into her.

Model 49? (Sorry)

The engine number is B 9101086

Model 91

As it is I just picked up a M91-92 Parts book...

Part Number 159-010

From what I can tell a 5.5mm ball bearing. If you don't want to go to a Bultaco dealer any bearing supplier should be able to help you.

I just got done putting my M92 (the 350cc version of the same bike) so if you have any questions it's pretty fresh in my mind. I didn't tear apart the engine but have mental scars from the last Bultaco engine I was in.

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5.5mm is about 7/32" i tried this size (sorry i did say 5/32) if you say it should be 7/32 then there is a ball already stuck up the tube, strange as there seems to be a lot of free play before the vertical arm that pushes the rod actually come into contact with the ball.

Many thanks for all the help you guys are giving :)

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5.5mm is about 7/32" i tried this size (sorry i did say 5/32) if you say it should be 7/32 then there is a ball already stuck up the tube, strange as there seems to be a lot of free play before the vertical arm that pushes the rod actually come into contact with the ball.

Many thanks for all the help you guys are giving :)

Once the pushrod is out and you have a clear angle, you can look all the way through to make sure nothing is up there.

5.5mm is what the parts book said, if you can wait a few days I'll be pulling the primary drive side apart on my M92 and can give you an exact measurement of the associated parts.

I'll take pictures of all the parts and you can compare.

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That would be great if you could do that, could you measure the length of the rod aswell, also how can you tell by looking that the clutch needs replacing, if i'm gong to be around that area i'd like to check

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