MK3 Restomod

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Whilst my workshop isn't as well equipped as yours Ken, I do have the same high quality yoghurt parts containers .
 

lcrken

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Fast Eddie said:
Looks pretty awesome Ken!

So, we'll soon see / here it running shall we...?
I certainly hope so!

Next major bit is making some fork yokes. At that point I should at least have a roller. The other touchy fabrication will be a secondary plate to fit the stator, similar to the one on a MK3. That will let me use a larger front pulley for a better primary ratio to ease the load on the clutch and gearbox. After that, making up some footrests to accommodate a left side master cylinder and right side shifter, which shouldn't be too difficult. And so on.

Ken
 

lcrken

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triumph2 said:
Whilst my workshop isn't as well equipped as yours Ken, I do have the same high quality yoghurt parts containers .
They are handy, aren't they? My wife goes through a lot of that particular Trader Joe yogurt, so I have a ready supply of the containers.

Ken
 
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If you are changing the yoke offset and the rake, when you first ride the bike take care and be sensitive to how the bike is behaving when entering and leaving corners. If it stands up when braking into corner - that is really bad. If it self-steers and tightens it's line when powering out of corners, that can be good if you ride in a way that can use it to advantage, but might not be good on a road bike - neutral steering might be better. In any case the handling should inspire confidence, not destroy it. The difference between good handling and bad handling is very small when you are making fork yokes.
I noticed in that photo of the rear brake you will be using, that the end of the stay for the calliper is attached to the swing arm - attached to the engine plate at the rear of the gearbox with a rose joints might be better. That way it might tend to lower the rear end of the bike when you use it.
 
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Many racers, given the choice, will take a front end that dives during braking and doesn't extend too quickly with the power screwed on. The dive promotes quicker steering going in and the slow rebound keeps the machine from running too wide coming out. Soft rear springing will cause a wide exit also as weight is transferred from front to rear. Girder-type (Hossack) front suspensions with lots of anti-dive dialed into the adjustable geometry give mixed signals and this is the primary reason the telescopic fork still even exists.
 

lcrken

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acotrel said:
If you are changing the yoke offset and the rake, when you first ride the bike take care and be sensitive to how the bike is behaving when entering and leaving corners. If it stands up when braking into corner - that is really bad. If it self-steers and tightens it's line when powering out of corners, that can be good if you ride in a way that can use it to advantage, but might not be good on a road bike - neutral steering might be better. In any case the handling should inspire confidence, not destroy it. The difference between good handling and bad handling is very small when you are making fork yokes.
I noticed in that photo of the rear brake you will be using, that the end of the stay for the calliper is attached to the swing arm - attached to the engine plate at the rear of the gearbox with a rose joints might be better. That way it might tend to lower the rear end of the bike when you use it.
I rarely use the rear brake on the street, Alan, so I think it will probably be fine with the brake stay on the swing arm. I agree that you can change it's effect on the bike under braking by moving the attachment point around on the frame, but the theoretical benefit just doesn't look worth the effort for a street bike. There are a lot of production bikes and race bikes with the caliper mounted to the swing arm with no problems. Besides, I used this same setup on my race Commando for many years, so I know it works fine.

I've already mentioned this in another post, so I'll keep it brief. The critical parameter at the front end for proper handling is trail. Rake and yoke offset are only really significant for their effect on trail, with a secondary impact on wheelbase and front/rear weight ratio. Within the normal range of rake you might try on a Commando, say 24 to 28 degrees, as long as you choose a yoke offset to give a reasonable trail with the tire size you are using, the bike will handle well. A little too much trail will give a bike that is solid in high speed sweepers, but needs a bit more force to start the turn-in, and needs a bit more effort on the bars to hold a line while accelerating out of the corner. But it really isn't that sensitive to a little extra trail. A little less trail makes it really easy to turn in, but not quite as stable feeling in sweepers, and too little can make it quite scary. I raced the same Commando PR for almost two decades, and tried a lot of things that affect trail, including 19, 18, and 17 inch tires, longer rear shocks, raising and lowering the front forks, cutting and welding the steering head for less rake, but most significantly a set of adjustable front yokes (from Spondon). I tried three different offsets on the yokes, and settled on one that gave 45 mm offset. That's a lot less than a stock Commando, but I had jacked up the rear a bit, lowered the front, and was running 18" slicks. The end result was slightly more trail that the stock Commando. Contrary to your concerns, I didn't really find handling to be sensitive to small changes. Larger ones, yes, but still not in terms of life threatening handling quirks. I ended up with a setup that gave me very neutral handling, which I preferred, and that's what I'm planning for this bike.

From what you've said before on the forum, it sounds to me like you've formed your opinions on bike setup from smaller, lighter weight, shorter wheelbase bikes like the Seeley, which are more sensitive to changes than the Commando. I've also raced bikes of that sort, and they are nowhere near as forgiving as the Commando is, and much more sensitive to changes. Getting the rake and yoke offset right for a street Commando is nowhere near as difficult as you seem to think.

Ken
 

lcrken

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Some more progress. I've had the head on and off so many times now I've lost track of the count. Finally got the pushrod lengths right. I also turned the head bolts down and polished them.



Interesting thing about the 1007 is how little head gasket surface there is around the pushrod tunnels. These shots show how little surface there is.







Steve leaves the sleeve lip something like .005" proud, which should help with combustion chamber seal, but the sleeve lip is pretty narrow, and I expect that I'll eventually see it flush with the casting. If that causes a problem, I'll cut a groove in the lip for a copper o-ring. I'm hoping that because this is a low compression street motor I won't have sealing problems. I'm using a .020" copper head gasket from Jim Schmidt, and an .005" copper wire in the sealant on the gasket around the pushrod tunnels, and we'll have to wait and see how that one works out too. This is the first 1007 I've done, so I'm still learning what works.

I also shortened the three studs in the head, and the two 5/16" studs in the cylinder, and that helps with installing the head.

This is a picture of the engine with the head finally installed.



I stll need to install the timing and rocker covers, and make a fitting for the oil drain from the head. Next step is doing mount for the alternator, plus some sort of degree scale for timing, and then it goes into the chassis.

Progress is slow, but at least it is progress.

Ken
 

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Lookin' good Ken, thanks for posting these recent pics! Are you going to be using inch & a half pipes on your exhaust system?
 

lcrken

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That's my plan at the moment. I considered 1 5/8", but think I'll stick with 1 1/2".

Ken
 

lcrken

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Another little bit of progress. I've finished the reed valve breather and installed it.



This is the second one I've done, and I was originally inspired by Jim Comstock's more elegant design. But I enjoy making as much as possible myself. I do have one of Jim's reed valve breather assemblies that replaces the stock drain plug for my other MKIII, because it's way more complex to make than anything I would try to make. But the Maney cases are already machined for the early style crankcase breather, so this was a pretty simple project to do in my home shop. This is a shot of the breather bits.



Ken
 

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grandpaul

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Nice bit of kit.

You should whip up a dozen and help offset your engine build cost.
 

lcrken

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grandpaul said:
Nice bit of kit.

You should whip up a dozen and help offset your engine build cost.
It might seem so, but it's not really feasible for me. Doing them on a manual mill and lathe is pretty slow. Jim can produce them for CNW on his CNC way faster, and better looking too. His design is also more compact because he uses a different reed valve. Besides, I'm just copying his idea, so it doesn't seem right to try to sell them. I just enjoy making things myself. At 74 years of age, I still get excited about learning new skills in the shop, and making something different. If you don't count my labor, it cost me only $35 or so to make it. Of course if you count my labor at any reasonable rate, it was unbelievably expensive.

Ken
 

lcrken

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So, the alternator mount is finished. I may still space the rotor a little further out, to center it in the stator better. I'll be replacing the 32 tooth front pulley with a larger one before finishing the bike. Not sure if it will be 37, 38, or 39 tooth. Depends on the availability of the right length belt. I'd prefer 38, but might not be able to manage that. I modified the stock MKIII support to bring the stator as close as possible to the pulley.







Ken
 

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lcrken said:
........So, the alternator mount is finished. I modified the stock MKIII support to bring the stator as close as possible to the pulley. Ken
Super Fine! It even looks Bad Azz just sittin' there on the bench. :)
 

lcrken

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cjandme said:
Super Fine! It even looks Bad Azz just sittin' there on the bench. :)
Thanks. Now I just need to get it off the bench and into the bike!

Ken
 
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Looks good Ken

Will this primary setup require a custom made primary cover?

Did the crank extend out to the outboard face of the rotor or did you use some sort of deep nut to pick up threads?

Glen
 

lcrken

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Son of Siredward said:
Looking good Ken!
Did you end up purchasing the mag wheels? Pretty good deal.
Yep. Should be here Tuesday.

Ken
 

lcrken

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worntorn said:
Looks good Ken

Will this primary setup require a custom made primary cover?

Did the crank extend out to the outboard face of the rotor or did you use some sort of deep nut to pick up threads?

Glen
It will require a custom primary cover. It would have anyhow because of the starter brackets.

I used the stock Commando sleeve nut for the rotor. The rotor is approximately the same distance out on the mainshaft as stock, but because the stator is further out, I am looking at whether I can space the rotor out a bit more to match. I think the alternator will still work adequately as is, but if I can line up the rotor and stator better, I will.

If I had been willing to keep the 32 tooth front sprocket that comes with the starter kit, this wouldn't have been quite as complicated. But I really think I'm going to need the taller primary ratio to stay within the clutch's torque capacity.

Ken
 

grandpaul

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Once you are certain what width you need for the pulley, you can maybe shave the alternator stator stand-offs down a bit, THEN space out the rotor. The more bite you have with the rotor nut, the better.
 
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