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Newbie Alert first pre 65 trials bike


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Hi All,

Hope you are all keeping well, I am struggling to attain  a few bits for my DMW MK15 trials bike which i am currently restoring. Would someone be able to guide me where I could post on the forum. As I am in need of a set of steering head bearings. No originals were found as the bike was in bits when I received it and was not then able to get measurements or part number. And I am looking for a complete exhaust for the bike.  The frame bore for the bearing is 46mm outer and then chamfered to a depth of 12mm, Then inner bore of the bearing needs to be 32mm. 

I have been struggling for a few months now but after a show i have been to have been advised to pop up on here.

look forward to hearing from all


Kind Regards 



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Sounds to me, that you've still got the outer race still in the headstock. If so, the bearing you require would be 46mm OD  x  32mm ID Timkin type. . The inner race would probably sit proud of the 12mm chamfer so's depth of bearing somewhere between 15....20mm probably... see what's available.

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  • Andy changed the title to Newbie Alert first pre 65 trials bike

Ensure that all of the bearings inner and outer tracks are out of the headstock (frame). Measure accurately so that you have the following dimensions:

Top headstock inner diameter inside of O

Outer diameter of fork steering shaft 

Ditto for the lower bearing

It is usual for the top bearing to be smaller than the bottom as it is the lower that takes most of the load. 

Now give Simply Bearings (google for address etc) a call and they will be able to help, or you can use their guide to select what you need. It is obviously essential that what ever you use must be correct. You can also select seals for these bearings. As suzuki250 says the originals may have been ball bearings with cup and cone tracks. 

You might also try other bearing suppliers as not all do the slim type of taper roller bearings needed for the headstock. Sometimes you can strike it lucky and a car rear wheel hub bearing kit can fit. 

Ask greeves has identified that you might have taper roller bearing outer tracks still in the frame. These can be drifted out and you may find the bearing information that you need stamped into the track outer face, once you have that your part way to sorting it.

As for the exhaust you will need to research. From what I gather your Mk15 would have originally been a 200 (197) Villiers engined bike of about 1957ish year or there about. You will probably end up having to get an exhaust made or use parts from various suppliers, most of the then Trials bikes all used similar systems. Villiers Services might be able to shed more light on this for you?Pictures would be good too!?Oops you posted while I was typing...looks as though you still have an outer track in the headstock!

By the look of the paint it could be a nice bike you have got yourself?

Oh and welcome ? 

Edited by section swept
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Hi All,

going to remove the outer races tomorrow and measure up. I had a quick chat with Phil from vintage bearings. If they cant be sourced then a set can be made. So all is looking positive. After rebuilding the 32A villiers engine. And put onto a test rig this morning all is looking good there. So hopefully will be ready for a few shows next year.

Really appreciate all your responses :D


Have a good weekend all 

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DMW Mk 15 IAN there’s a nice big photo of your bike or rather what it should look like with good view of the exhaust. Go to google type in DMW Mk15 Trials and hey presto on images and there she is, tried to lift it to TC but no go. Hope that gives you all you need for replacements. I think the footrest position may be altered, what do you think???There you go...did it!?



Edited by section swept
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Morning All,

I managed to get both the inner and outer cups out, the yoke cup after making a slide hammer up and putting a edge lip on a threaded rod to try grip the outer ring edge had no luck. so carefully ground one side of the cup and all is well.

The DMW both inner and outer cups are the same and they are the following specs:


TIMKEN   07100 S   Inner Cup


TIMKEN  07210 x   Outer Cup


Bearing King had these on there website so all is looking positive. 


Thanks Section Swept for the photo  :)



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There is a better picture in Roy Bacons Villiers book showing the correct 'silencer' I remember my Dad trying to buy one for his DMW collection about 20 odd years ago from the factory. They let him have a later ex works bike (which was awful) but the Mk15 was promised to someone else.

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