MK3 Restomod

lcrken · Jun 19, 2022

mdt-son said:
Ken,
Sorry for diving into history again. Did Kenny Dreer use CAD and other design/calculation software for his evolutionary work? Building physical bikes to test out new models and concepts must have cost him dearly. Today a small manufacturer like Kenny would and should rely on a "digital twin" to perform developments. It saves a great deal of time and money.

- Knut

Sorry for the late reply, Knut. I don't know how much modern digital design technology Kenny's team used. For sure they used CAD for most of their parts drawings, but I don't know if they used any FEA or other modern analysis tools. Stu Garner told me that the drawings he got with his purchase of Norton America were in a variety of formats, not all compatible, and that he had to have them all redone, but I don't know how accurate his description was.

Ken

lcrken · Jun 19, 2022

Still making progress, but slowly. I've finished the wiring, except for installing and timing the Trispark ignition module. I've tested everything I can at this stage, lights, turn indicators, ignition switch, horn, and starter solenoid, and they all work. The M-Unit controller has a lot of options to play with, but I'll do that later. For now its just programmed for classic operation. But I'm looking forward to using some of the features, particularly the automatic turn signal cancelling, as soon as it's running. At the moment, the harness is still just zip-tied together. I still want to tidy up a few little details before taping it. All that is left before I can fire it up is fitting the ignition module, making throttle cables and fuel lines, and adding gas and oil. After that, I still have to get the seat covered, weld in a mounting bracket for the left side cover, and fit some sort of air filter, before I can test ride it. But I can now see the light at the end of the tunnel.

I'm planning to use the Yamaha front fender to make a pattern for a carbon fiber front fender, but for now, the bike will be fine without it. I'm not planning any rainy day riding with it yet.

In hindsight, I'm not sure I would have gone with the M-Unit if I was starting over. It has some really nice features, but is more complicated than a standard system, and does add a lot of wire to the harness. But It does save me from having to install relays for the lights and such. Guess I'll have to wait for some experience with it to decide how much I like it.

Ken

lcrken · Jul 6, 2022

Another little bit of progress. Installed and static timed the Tri-Spark ignition, made fuel lines, and extended the length of the center stand. After almost dropping the bike a while back, I decided I re ally needed a working center stand. I'm using longer shocks at the rear than stock, as well as a larger diameter tire, and the stock center stand was too short to keep the bike stable, much less raise the rear wheel off the ground, I cut the legs and inserted 1" spacers, and now it the rear wheel just barely clears the ground.

This is my method of raising the rear of the bike while on the lift, so I could easily insert wood strips under the center stand till I got the rear wheel to the right height, and then measure how much to extend the stand. I'd been working on the bike by putting stacked pieces of wood under the bike and then putting the center stand down. That worked well until a few weeks ago, when one leg of the stand slipped off the boards while the lift was at full height, and I almost dropped the bike.

This is the stand after cutting the legs, along with the 1" spacers I turned on the lathe.

And the finished stand after painting.

And finally, the bike on the stand. I still need to install the spring, but the stand works well, doesn't seem any harder to lift the bike onto than the stock length, and still clears everything. I later shortened the foot assist on the left side of the stand to bring it back closer to the muffler. Mostly for appearance, but it will also give me some more road clearance at full lean, not that I'm likely to ever need it.

Getting really close to firing it up for the first time.

Ken

Jerry Doe · Jul 6, 2022

lcrken said:
Another little bit of progress. Installed and static timed the Tri-Spark ignition, made fuel lines, and extended the length of the center stand. After almost dropping the bike a while back, I decided I re ally needed a working center stand. I'm using longer shocks at the rear than stock, as well as a larger diameter tire, and the stock center stand was too short to keep the bike stable, much less raise the rear wheel off the ground, I cut the legs and inserted 1" spacers, and now it the rear wheel just barely clears the ground.

This is my method of raising the rear of the bike while on the lift, so I could easily insert wood strips under the center stand till I got the rear wheel to the right height, and then measure how much to extend the stand. I'd been working on the bike by putting stacked pieces of wood under the bike and then putting the center stand down. That worked well until a few weeks ago, when one leg of the stand slipped off the boards while the lift was at full height, and I almost dropped the bike.

View attachment 96476

This is the stand after cutting the legs, along with the 1" spacers I turned on the lathe.

View attachment 96477

And the finished stand after painting.

View attachment 96478

And finally, the bike on the stand. I still need to install the spring, but the stand works well, doesn't seem any harder to lift the bike onto than the stock length, and still clears everything. I later shortened the foot assist on the left side of the stand to bring it back closer to the muffler. Mostly for appearance, but it will also give me some more road clearance at full lean, not that I'm likely to ever need it.

View attachment 96479

Getting really close to firing it up for the first time.

Ken

It’s looking very good…

gortnipper · Jul 7, 2022

Been there, done that with the ply strips under the stand on a lift. Not fun. Luckily it was lowered and I was just perched getting it up on there .

lcrken · Sep 5, 2022

So now its time for the typical good news/bad news post. On the good side, the bike fired up perfectly. The starter system works very well, the engine starts, idles, and sounds really fierce. Then the bad news. It has oil leaks at the crankshaft main seal, the oil feed line, and the reed valve breather. The main seal and the oil line should be pretty simple to fix, but not so the leak from the reed valve block. I made it to fit at the rear of the crankcase, as on some of the earlier 750s, using a design mostly copied from Jim Comstock's work. It's a bit difficult to see exactly, but it looks like the oil is dripping down from the joint where the reed valve is sandwiched between two alloy plates. The screws holding it together and attached to the case are not accessible with the gearbox in place, and it can't be removed with the engine in place, due to interference with the reed valve. Catch 22 personified. So the engine is going to have to come out yet again. Kind of a bummer, but not much choice left. My goal is still to be riding the bike at the Hanson Dam ralley in November, so I need to get started. But definitely not today. Temps outside and in the shop are over 100 degrees F. To much for this octogenarian.

Ken

lcrken · Sep 5, 2022

Couldn't wait. The engine is out.

And on the bench.

Turns out the main seal leak is a bit more than a bad seal. The back of the drive sprocket wore against the crankcase, and pushed a bit of swarf in between the seal lip and the crankshaft. I've cleaned it up, and think a new seal will fix it, but I'm going to have to do some machining to get clearance for the pulley. When I originally fitted the pulley, it had clearance. I suspect that when I torqued the alternator nut, it expanded the taper in the aluminum pulley enough that there was interference. Wish I could find the same pulley in steel. In any case, I'll sort it out eventually. I'm hoping that I can just relieve the back of the pulley enough to get clearance. If not, I'll have to go with a brass shim on the taper. I've done that in the past with good success, but it still seems kind of tacky.

And then there's the leaky reed valve that forced the removal of the engine in the first place. It does appear to have been leaking where the valve is clamped between the two aluminum blocks, but I don't know why. I used a thin smear of sealer on each side of the valve plate, but that doesn't seem to have been enough. I'm also a bit unhappy with the need to remove the engine to pull the gearbox, so I think I'll block of the back of the crankcase, and go with a different location for the reed valve breather.

It is Labor Day here, and I've certainly been laboring. Time for a rest and a bit of whiskey while contemplating the next steps.

Ken

Ken

gortnipper · Sep 6, 2022

lcrken said:
And then there's the leaky reed valve that forced the removal of the engine in the first place. It does appear to have been leaking where the valve is clamped between the two aluminum blocks, but I don't know why. I used a thin smear of sealer on each side of the valve plate, but that doesn't seem to have been enough. I'm also a bit unhappy with the need to remove the engine to pull the gearbox, so I think I'll block of the back of the crankcase, and go with a different location for the reed valve breather.

Can you transplant it to a donor sump plug?

Happy end of summer.

In celebration of Spring coming to NZ, we got an Antarctic blast and about 75% of the country is below freezing tonight.

KiwiShane · Sep 6, 2022

gortnipper said:
Can you transplant it to a donor sump plug?

Happy end of summer.

In celebration of Spring coming to NZ, we got an Antarctic blast and about 75% of the country is below freezing tonight.

The top of the gorge on the way back from Gisborne was covered in snow today

gortnipper · Sep 6, 2022

KiwiShane said:
The top of the gorge on the way back from Gisborne was covered in snow today

Our place will have frost in the am.

KiwiShane · Sep 6, 2022

gortnipper said:
Our place will have frost in the am.

I won't be rushing off to work in the morning ...that for sure

Fast Eddie · Sep 6, 2022

Ken,
I had to relieve material from the seal area of my Maney cases.
With mine, the seal sat in deep, so there was plenty of scope to relieve material from there.

I also blanked off the crank case breather and use a sump plug breather (the Comnoz / NYC version) which fits and works perfectly.

lcrken · Sep 6, 2022

Fast Eddie said:
Ken,
I had to relieve material from the seal area of my Maney cases.
With mine, the seal sat in deep, so there was plenty of scope to relieve material from there.

I also blanked off the crank case breather and use a sump plug breather (the Comnoz / NYC version) which fits and works perfectly.

That's my plan too, as well as relieving the back of the pulley.

Ken

worntorn · Sep 6, 2022

Frustrating!

Glen

Schwany · Sep 6, 2022

lcrken said:
So now its time for the typical good news/bad news post. On the good side, the bike fired up perfectly. The starter system works very well, the engine starts, idles, and sounds really fierce. Then the bad news. It has oil leaks at the crankshaft main seal, the oil feed line, and the reed valve breather. The main seal and the oil line should be pretty simple to fix, but not so the leak from the reed valve block. I made it to fit at the rear of the crankcase, as on some of the earlier 750s, using a design mostly copied from Jim Comstock's work. It's a bit difficult to see exactly, but it looks like the oil is dripping down from the joint where the reed valve is sandwiched between two alloy plates. The screws holding it together and attached to the case are not accessible with the gearbox in place, and it can't be removed with the engine in place, due to interference with the reed valve. Catch 22 personified. So the engine is going to have to come out yet again. Kind of a bummer, but not much choice left. My goal is still to be riding the bike at the Hanson Dam ralley in November, so I need to get started. But definitely not today. Temps outside and in the shop are over 100 degrees F. To much for this octogenarian.

Ken

Wasn't expecting that report. Poop!

That reed valve issue is exactly why I did not do the machine work to install the cNw (Comstock) reed breather on the back of my 750 case when the motor was apart. No way to access the fasteners once the motor and gearbox are in the frame. I wanted to be able to service it.

The JSM sump breather would fit slightly better on my motor and frame. Unfortunately, I'm putting off installing one until my 2 into 1 exhaust headers that run center under the motor start to rust through.

You'll have it all sorted soon enough. Looking forward to a better report on your project next time.

mean gene · Sep 6, 2022

WOW! Sorry I haven't read this Post before. Wonderful work and bike!

cjandme · Sep 6, 2022

Truly unfortunate, but better to discover these things now instead of when your out and about, right. Anyway that bike your building is really super fantastic, as always thanks for taking the time to post the progress up here...definitely a source of inspiration seeing it all coming together. Cj

lcrken · Sep 7, 2022

Things are a little worse than I thought. Turns out the chunks of aluminum got forced past the seal, and broke the lip in the case at the bottom of the seal cavity, and some of the debris might have migrated into the main bearing rollers. In any case, the drive side half of the crankcase needs some repair, so the engine has to come completely apart. Oh well. Pulled the cylinder head and cylinder today, and at least that all looks good. I expect to either have to weld the case a little and re-machine the seal area, or machine the case for an insert. I'll sort that out when I get it the rest of the way apart. Pictures to come when I get it completely disassembled. Never a boring moment in the life of a Norton owner.

Ken

Schwany · Sep 8, 2022

Never a dull moment with aftermarket performance parts.

Barnyard mechanic observation: Shouldn't there be some taper meat on the crank showing behind the woodruff key notch just in front of the main seal lip? More taper diameter close to the case may have prevented the situation. So the raised section on the seal pocket is too high, too far toward the drive side? Is that what youz guys determined? Only other explanation would be the crank shrank or was shimmed to far toward the timing side. If it was shimmed at all.

Is that a Maney crank as well?

lcrken · Sep 8, 2022

Schwany said:
Never a dull moment with aftermarket performance parts.

Barnyard mechanic observation: Shouldn't there be some taper meat on the crank showing behind the woodruff key notch just in front of the main seal lip? More taper diameter close to the case may have prevented the situation. So the raised section on the seal pocket is too high, too far toward the drive side? Is that what youz guys determined? Only other explanation would be the crank shrank or was shimmed to far toward the timing side. If it was shimmed at all.

Is that a Maney crank as well?

There was small bit of of the shaft showing between the seal and the woodruff key, but not much, and it didn't show up so well in the pictures. I'll be checking the dimensions when I repair the seal pocket, and if it is possible to seat the seal any deeper, I will do so. I doubt that there is much room for improvement. The 1007 crankshaft is wider than the stock crank, to allow moving the bores apart for the 83 mm bore size. That means the main bearings are also further apart in the cases, meaning less space between the main bearings and the seal.

The main bearings are shimmed .005" on the drive side and .010" on the timing side, to get .010" end play.

It is a Maney 93 mm stroke crankshaft.

I have the head and cylinder off, and should have the engine completely apart in a few days. At that point, it should be obvious what I can, or can't do to improve the situation. Worst case would be a new set of cases, but I'm pretty sure I can avoid that.

Ken

MK3 Restomod

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