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MK3 Restomod

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MK3 Restomod

Postby lcrken » Sat Jan 23, 2016 8:56 pm

This is a thread about rebuilding and modifying my 1975 Commando MK3. It was my street bike for many years, and I've finally got around to building it into my idea of the perfect Commando. I posted some details on straightening and modifying the frame here

commando-frame-straigtening-t23185.html

and I'm now in the process of mocking things up to see how my ideas are going to work out, and to get some measurements for machining parts.

These two pictures show the frame and swingarm with empty crankcases installed. That let me check the steering head angle and swingarm droop angle with the lower frame tubes horizontal. In that configuration, the rake is 26 degrees, and the swingarm has 7 degrees of droop. Those are the numbers I expected, but it's nice to be sure before I start machining the fork yokes. I'm planning get 3.75 to 3 " of trail, still not sure exactly what I want. I'm using a set of Ohlins (conventional) Superbike forks, which have 43 mm diameter stanchions, and require wider separation that the stock Norton forks. Because I steepened the steering head angle, I'll need less offset in the yokes, and I'll also need them a bit wider because of the diameter of the sliders. I'm still not decided whether to make new yokes, or weld inserts into some Yamaha yokes, and re-drill the stem holes for more offset. The latter would be quicker and easier, so I'll probably go with that.

commando-frame-straigtening-t23185.html



These are pictures with the Quaife 5-speed gearbox and electric starter bits (Old Brits kit) in place. Because I'm using Maney cases for the 1007 cc engine I'm building, and a crankshaft with pre-MK3 configuration, I'll have to do some machining on the cases to fit a MK II style alternator, and probably a modified MK 11 primary cover. Preliminary measurements indicate that I will be able to move the gearbox over a bit to the left, and still make the Old Brits starter work. On my old PR race bike, I moved the gearbox over almost 1/4", which gave me clearance for a wider tire. In this case, I don't think I can go that far, but it does look like I can still move it over a significant amount. On the PR, I had room for a really wide rear tire, but for this street bike, I'm only looking for a little more room.





That's it for now. Next step is to machine cases and then check everything with the belt drive installed. Then it all comes apart for final painting and assembly.

Oh yeah, before someone catches it, yes, I do have the shocks installed on the wrong sides. The pre-load adjustment knobs will be on the outside, not the inside.

Ken
Last edited by lcrken on Fri Sep 01, 2017 10:28 am, edited 1 time in total.
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Re: MK3 Restomod

Postby worntorn » Sat Jan 23, 2016 10:26 pm

Ken, I think there are quite a few of us here who also consider this to be the dream Commando. I'll be tuned into this one, thanks for sharing.

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Re: MK3 Restomod

Postby trident sam » Sun Jan 24, 2016 4:06 am

Yes I agree, the bike is looking great. I wish I had the skills to do something like that !
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Re: MK3 Restomod

Postby Chris » Sun Jan 24, 2016 4:35 am

Hi Ken

Lots of ways to customise a Commando & everytime I look at modernising I come up on the same areas.
Swinging arm, engine plates. Your neat box section I love. Ludwigs alloy swinging arm & engine plates are just exceptional & are on my dream/wish list.
OIl tank or lack off. I like Jeans tope tube conversion but there is a lot of work to it,ie filler neck, altering the petrol tank etc.
Front end I have decided 43mm BMW forks with one off yokes, modern but not over the top.
Light weight wheels & discs I keep coming back to spoked wheels.
Engine I believe the bigger the better, drive is what it is all about.
Thats the thing about Commandos. What you can do to them is endless & stock bikes are lovely as well.
Great work Ken keep it up.

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Re: MK3 Restomod

Postby Paddy_SP » Sun Jan 24, 2016 5:39 am

Great stuff - I look forward to seeing more! :)

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Re: MK3 Restomod

Postby trident sam » Sun Jan 24, 2016 6:03 am

Ken,
How does the QPD starter system work, I take it there is no engine sprocket sprag ala stock Mk 3 ?
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Re: MK3 Restomod

Postby dennisgb » Sun Jan 24, 2016 7:06 am

trident sam wrote:Ken,
How does the QPD starter system work, I take it there is no engine sprocket sprag ala stock Mk 3 ?
sam


Yes, I'm interested in this also. I've never seen this one. Do you have to cut the cover to fit around it?

This looks like an awesome build. Keep the info coming.
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Re: MK3 Restomod

Postby hankmarx » Sun Jan 24, 2016 8:23 am

Holy moly that's good looking! Looking forward to the build.
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Re: MK3 Restomod

Postby lcrken » Sun Jan 24, 2016 10:09 am

dennisgb wrote:
trident sam wrote:Ken,
How does the QPD starter system work, I take it there is no engine sprocket sprag ala stock Mk 3 ?
sam


Yes, I'm interested in this also. I've never seen this one. Do you have to cut the cover to fit around it?

This looks like an awesome build. Keep the info coming.


Hi Sam,

it's an Old Brits starter, not QPD. Very similar, and clearly derived from the original QPD and later Kenny Dreer designs, but a little better engineered. More info here

http://www.oldbritts.com/starter.html

The Sportster starter has a Bendix drive, which engages a ring gear on the back of the clutch drum. No sprags, etc. I'll eventually post some pictures that show the details. It does require cutting the primary covers to fit around it, but since it uses a belt drive, that's not much of an issue. I would have considered keeping the MK3 starter system with a Dynodave starter motor, which I've been using on the bike for quite a while, but can't do that with the Maney 1007 crankshaft, which doesn't have the MK3 style extended mainshaft. I'm also not really sure the stock sprag would hold up as well with the larger engine. I kind of like the idea of getting rid of the sprag.

Ken


In my case, since the original bike is a MK3, I've got to sort some things out still. I'd like to use the heavy duty Quaife 5-speed, but it's set up for a right side shifter. That means I have to decide whether to find a good way to convert to left side shift as on the standard MK3, or go back to the earlier right side shifter. I've become used to the left side shift on all my street bikes, with only the race bikes still having right side shift. If I go back to the stock Norton gearbox instead, it's pretty straightforward to adapt the earlier primary cover to the stock MK3 crossover shaft for the left side shifter. It would also be pretty simple to do the same with a custom primary cover, if I go that direction. If I go with the right side shift, then I have to fab some brackets and linkage on the left side for the rear brake system. Decisions, decisions.
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Re: MK3 Restomod

Postby trident sam » Sun Jan 24, 2016 11:51 am

Thanks for info Ken.
As an aside, there was a Commando for sale on evilbay UK recently, an import from the US that was fitted with a QPD starter and belt. The bike was semi choppered but was up for a good price of GB£5000, it had obviously had a lot of money spent on it, and really wouldn't have taken that much to sort it out, of course I didn't have the 5 grand :roll:
Good luck with the rest of the build, I'm looking forward to seeing the finished article.
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Re: MK3 Restomod

Postby Jerry Doe » Sun Jan 24, 2016 1:27 pm

Very cool. I think getting rid of the sprag is a huge step in the right direction. Terrible design in my opinion.. Cant wait to see more about your project Ken, cheers
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Re: MK3 Restomod

Postby cjandme » Sat Jan 30, 2016 12:20 am

worntorn wrote:Ken, I think there are quite a few of us here who also consider this to be the dream Commando. I'll be tuned into this one, thanks for sharing.......Glen

+1 lookin' good Ken and I will also "tune in" next week for more of your "regularly scheduled" posts :mrgreen:
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Re: MK3 Restomod

Postby Craig » Sat Jan 30, 2016 10:33 am

I mean no offense to others here with on going builds .... but this one is way cool .... go for it Ken .... lots of interest for sure... a real beauty so far ...
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Re: MK3 Restomod

Postby pete.v » Sat Jan 30, 2016 11:03 am

A stand out attribute of these electric starters is the gearbox output support as with the Maney outrigger. And of course, no god awful spragg. A real bonus! The installation seem a bit exhaustive though.

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Re: MK3 Restomod

Postby acotrel » Sat Jan 30, 2016 11:56 am

I'd be interested to know how the combination of your new steering geometry with the isolastics makes the bike handle. Are you using 18 inch wheels ? I've often thought of playing with a standard commando and the slight disconnect between the handle bars and the pivot puts me off.
Looks like an excellent build - keep up the good work.
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