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M20 brake plate bolt

i just got a set of brake shoes for my 44 M20 from Drags so now can put the front wheel back on but... on the right girder there is a large screw to anchor the brake plate, a large flat blade screwdriver fits it nicely but it screws in too far and tries to pull the brake plate toward the fork and will bend it, is there a spacer or ??? missing?
thanks guys

email (option): taybrig@shaw.ca

Re: M20 brake plate bolt

Kevin that screw should only be done up so far, so that the brake plate is not pulled over and then locked on the outside with a nut. Once set properly, you need not undo it again as the brake arm has a keyhole slot for lifting the wheel in and out. Ron

M20-252

M20-249

email (option): ronpier@talk21.com

Re: M20 brake plate bolt

Is that the correct way, adjust the bolt?? I screw the bolt solid up to the fork and bend the ear of the brakeplate if needed....

BR, Michiel

Re: M20 brake plate bolt

Yes, that's the way I see it as well. The bolt has a shoulder on the back and to my mind this should be slightly deeper than the material gauge thickness of the brake plate...So, when the bolt is fully tightened against the shoulder the brake plate will still 'slide'...The nut on the back then serves as the lock nut for the bolt...

This does sometimes require a 'tweak' of the brake plate arm to achieve correct operation but not in every case I have found...

It will work in the way described by Ron though, so I guess it's just a question of details..
However, it is noticeable in the photo that the bolt does not extend fully into the nut, which it might if the alternative method was used....Ian

email (option): ian@wright52.plus.com

Re: M20 brake plate bolt

Yes without taking mine off for a proper look, I thought there was a shoulder to allow the brake plate to slide up through the keyhole. What Kevin describes sound threaded all the way? I've never had to undo the brake anchor screw on any M20 that I've worked on to remove the wheel.

Better that there is more clearance than less so as not to distort the brake plate, and never heard of bending the brake anchor to suit??

Ron

email (option): ronpier@talk21.com

Re: M20 brake plate bolt

I'm glad that Norton just used a substantially slotted plate and a welded pin...

A torque anchor should surely always be in the same plane as the brake plate ?

It's quite difficult to guess on this type of query if the OP doesn't post a photo but it does sound as if the screw is lacking a shoulder.

Re: M20 brake plate bolt

Don't think so, Nathan. The KM's had the speedo in the brakeplate in combination with this keyhole arrangement. Think the splaying of the fork was only on the lefthand side, indeed to accommodate the new speedodrive.

Looking at the earlier construction from where this derived from I really think the brake arm should be up and touching the forkleg. In the earlier models the brakearm had just a plain hole. A threaded fixing bolt came in from the other side of the forkleg and a nut was used to lock it up. So the brakearm was firmly clamped up to the forkleg.

Late '30's this keyhole system came, might be a bit quicker to remove the wheel but also prone to wear and this play can result in a annoying tick when moving up the bike.

The arm will bend quite easily sideways so there is a great chance it is deformed if not touching the fork. Best to make sure the arm not being forced one or the other way when locking up the wheelnuts as this will also force the brakeplate from it's correct position.

Cheers, Michiel

Re: M20 brake plate bolt

That drawing is not very accurate, to say at least :smiley:

I believe the late '30 forklegs were not parallel in the first place but they were symmetrical. There was a light angle to the outside so the bottomlegs had to be placed parallel to eachother of course.

When the separate speedodrive on the left came BSA just splayed the leftleg, so they could leave the rightside unaltered. I assumed they placed the leftside bottomlug parallel again.

Re: M20 brake plate bolt

I understand what you're getting at Nathan. I've never given it much thought, but I guess they could have increased the wheel spindle slot on the right side upwards by a small calculated amount to bring the axle level? (thanks for the pic BTW)

I also get Michiel's point about the ticking from the non bolted down anchor, but to my mind it's how it's meant to be as well as several other makes that rely on a slot or stud that can also tick. Ron

email (option): ronpier@talk21.com

Re: M20 brake plate bolt

thanks everyone, mine had been assembled wrong at some point so my disassembly pics had a nut and washer as well as the spacer between the fork and brake plate and thus the anchor bolt didnt protrude through the fork so a nut could go on
cheers

email (option): taybrig@shaw.ca

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