[alrobyn3]

Hi folks-
I need a wiring diagram for the headlight on my vintage 1970 scrambler,is there a PDF file?

 

[Derek]

Probably the nearest your going to get is for the 250/350/450 Mk3 off Bevelheaven

 

[alrobyn3]

Thanks I appreciate your help...
One other question if you can help....
My bike was running great then one day the speedometer cable came out while it was running " the holding collar must have been loose" ...the gear that it connects to jumped up and and was chipped so I took it out to replace it. Then I noticed it wouldn't start and I lost about half my compression which prior to this was fine. It seems like the valves are not closing in sync during the compression stroke. ANY SUGGESTIONS? CAN I RESET THE TIMING MYSELF?

 

[Derek]

I would if I could understand your problem. The speedometer cable is connected to the drive on the front wheel and has no connection to the engine whatsoever.
If you mean the tachometer (which I don't think the Scrambler has), it is driven from the bevel drive cover on the cylinder head but has an oldham coupling to the bevel gear which comes away with the cover without disturbing the bevel. So I have no idea what you have done.

 

[alrobyn3]

It must be the Oldham coupling that spun loose when the cable came out....why should that change compression?​

 

[alrobyn3]

Sorry bout that,it is the tach and the bevel gear,not the speed cable. After the cable came out ,I took the cover off and saw that that gear was damaged.........so I tried to start the engine ( serial # 09941)* without that small gear and thats when I noticed I had lost some compression......so I thought now the timing must have changed ,like the valves not closing correctly.
Not sure exactly why I had it running great one minute and not at all the next.

​

 

[Derek]

This a picture (not a very good one) of the bevel gears at the cylinder head.

The tacho drive is mounted in the outer cover (not shown) and engages with the slot on the end of the camshaft. The bevels on the camshaft and vertical shaft have timing dots on them. You can see the dot on the vertical shaft bevel in the picture. The timing is correct when the dots on both are lined up and the engine is at TDC with both valves closed at the end of the compression stroke.
You can also download a manual off the Bevelheaven site. It sounds like you could use one.

 

[alrobyn3]

This a picture (not a very good one) of the bevel gears at the cylinder head.

The tacho drive is mounted in the outer cover (not shown) and engages with the slot on the end of the camshaft. The bevels on the camshaft and vertical shaft have timing dots on them. You can see the dot on the vertical shaft bevel in the picture. The timing is correct when the dots on both are lined up and the engine is at TDC with both valves closed at the end of the compression stroke.
You can also download a manual off the Bevelheaven site. It sounds like you could use one.

bevel. So I have no idea what you have done.[/QUOTE]

Sorry bout that,it is the tach and the bevel gear,not the speed cable. After the cable came out ,I took the cover off and saw that that gear was damaged.........so I tried to start the engine ( serial # 09941)* without that small gear and thats when I noticed I had lost some compression......so I thought now the timing must have changed ,like the valves not closing correctly.
Not sure exactly why I had it running great one minute and not at all the next.

​

This a picture (not a very good one) of the bevel gears at the cylinder head.

The tacho drive is mounted in the outer cover (not shown) and engages with the slot on the end of the camshaft. The bevels on the camshaft and vertical shaft have timing dots on them. You can see the dot on the vertical shaft bevel in the picture. The timing is correct when the dots on both are lined up and the engine is at TDC with both valves closed at the end of the compression stroke.
You can also download a manual off the Bevelheaven site. It sounds like you could use one.

This a picture (not a very good one) of the bevel gears at the cylinder head.

The tacho drive is mounted in the outer cover (not shown) and engages with the slot on the end of the camshaft. The bevels on the camshaft and vertical shaft have timing dots on them. You can see the dot on the vertical shaft bevel in the picture. The timing is correct when the dots on both are lined up and the engine is at TDC with both valves closed at the end of the compression stroke.
You can also download a manual off the Bevelheaven site. It sounds like you could use one.

This a picture (not a very good one) of the bevel gears at the cylinder head.

The tacho drive is mounted in the outer cover (not shown) and engages with the slot on the end of the camshaft. The bevels on the camshaft and vertical shaft have timing dots on them. You can see the dot on the vertical shaft bevel in the picture. The timing is correct when the dots on both are lined up and the engine is at TDC with both valves closed at the end of the compression stroke.
You can also download a manual off the Bevelheaven site. It sounds like you could use one.

 

[alrobyn3]

Thanks for your help... I think that's exactly the place I need to check.....how do I put the timing back correctly?
Thanks again
Al
Hi I just checked....found both timing marks on both gears....put piston at TDC and they DO NOT MATCH UP!......where should I correct this?, with the TOP GEAR THAT HAS A HOLDING NUT ON IT?

 

[Derek]

What did you take apart in there? You're going to have to reverse whatever you did.

 

[alrobyn3]

Hi

Thanks for your help... I think that's exactly the place I need to check.....how do I put the timing back correctly?
Thanks again
Al
Hi I just checked....found both timing marks on both gears....put piston at TDC and they DO NOT MATCH UP!......where should I correct this?, with the TOP GEAR THAT HAS A HOLDING NUT ON IT?

 

[alrobyn3]

Derek
I havn't done anything,yet
I was waiting to find out how to time those two gears.
What should I do time it above on that cyl head or open the crankcase n
Tnx for your help
Al

 

[Derek]

Did you undo the nut holding the bevel gear on the end of the crankshaft? If not the timing cannot be changed.
The dots will only line up on every 2nd revolution at TDC at the end of the compression stroke Turn the engine through 360º and have another look.
This picture is the best I can come up with to illustrate the cam timing. I wouldn't advise taking the crankcase cover off unless you really have to, you could end up with the ignition timing wrong as well.

 

[alrobyn3]

Thanks I'll check all the timing marks then check compression