750cc Norton Commando Salt Flats Build

worntorn said:
Going for records, which = high rpm, certainly higher than a Commando likes, I think you are very wise to deep six all of the original Commando stuff in favour of strengthened parts.
These race classes must allow all new engines?
I ask because Alp built and ran a Vincent at Bonneville awhile ago in a class that required original crankcases be used. The engine was burning Nitro and he managed to go past 190 mph if memory serves. That was quite a feat with original cases and very risky to life and limb!

Glen
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I think the Vincent falls into the vintage class which has a lot different restrictions from modified production class that I'm going for. Modified production rules in the SCTA book states "the engine must be from the same from the same manufacturer as the frame". My take on that is you can't put say a Honda engine in a Norton frame. Doesn't state about replacing parts. NOW, I might be totally wrong on that. I plan to send in the build plans to have the machine pre-registered/appoved.
 
Zachary Brown said:
I think the Vincent falls into the vintage class which has a lot different restrictions from modified production class that I'm going for. Modified production rules in the SCTA book states "the engine must be from the same from the same manufacturer as the frame". My take on that is you can't put say a Honda engine in a Norton frame. Doesn't state about replacing parts. NOW, I might be totally wrong on that. I plan to send in the build plans to have the machine pre-registered/appoved.
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Zach, if you look in the rule book under the engine classes section, specifically paragraph 7.J.9, "CLASS PUSH ROD FUEL - PF AND PUSH ROD GAS -PG", you will see "any motorcycle engine with push rod operated valves." The only limitation in terms of replacement parts is that the cylinder head has to have the same number of valves as the engine was originally produced with. Only the production class engines are limited to OEM cylinders, heads, and crankcases. That is not a requirement for the modified classes. As you pointed out, the only engine limitation for them is that the engine must be from the same manufacturer as the frame.

I can assure you from several years of taking my featherbed/Commando bike through SCTA tech, that no one ever questioned the Maney crankcases (and sometimes Maney cylinders) on my engines. And that's not because they didn't know the difference.

As long as you're running in the Modified Production classes, not the Production classes, you should be fine with the aftermarket engine parts.

Ken
 
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Thanks Ken! I figured that was the case. Just didn't want to 100% trust my interpretation of the rule book. Should've quoted the PF and PG engine rules as well. I've got the book right next to me at all times these days haha.
 
Alright. It's been too long and here's a little update on the project. Sadly my fabricator had some health issues come up so the new gearbox cradle is a little delayed. All should be in by the end of next month though. In the meantime I've been working on the wheels.

Started off by replacing every hub bearing with new units and packing them with fresh grease. Once all reassembled it was time to measure the hub offsets before cutting out the old junk spokes. After freeing the hubs from the old rims I spent a little elbow grease on a bit of cleaning and polishing. Not going for a show polish but just enough to satisfy the eye.

As for the wheels, I ordered 18" Excel rims and stainless spokes from Buchanan's. They arrived last week and I've just gotten around to lacing them up. Waiting for the correct spoke torque wrench adapter to arrive before putting the final touches on everything. Looked for the appropriate torque for the spokes and the forum provided again! Gonna do it in 2-3 steps starting at 30in-lbs and ending at 55in-lbs.

750cc Norton Commando Salt Flats Build
750cc Norton Commando Salt Flats Build


And as I was typing this the UPS fairy just delivered aluminum bar stock needed to start fabricating the rear footrests. Gonna be a busy weekend at the drawing board and drill press!
 
Good to see you're making progress, Zach. I'm still hoping to at least get some runs in at El Mirage this year with my Norton. Been some big changes in my life, so I'm not sure about making it to Bonneville again, but it is still a possibility.

Ken
 
Zachary Brown said:
Alright. It's been too long and here's a little update on the project. Sadly my fabricator had some health issues come up so the new gearbox cradle is a little delayed. All should be in by the end of next month though. In the meantime I've been working on the wheels.

Started off by replacing every hub bearing with new units and packing them with fresh grease. Once all reassembled it was time to measure the hub offsets before cutting out the old junk spokes. After freeing the hubs from the old rims I spent a little elbow grease on a bit of cleaning and polishing. Not going for a show polish but just enough to satisfy the eye.

As for the wheels, I ordered 18" Excel rims and stainless spokes from Buchanan's. They arrived last week and I've just gotten around to lacing them up. Waiting for the correct spoke torque wrench adapter to arrive before putting the final touches on everything. Looked for the appropriate torque for the spokes and the forum provided again! Gonna do it in 2-3 steps starting at 30in-lbs and ending at 55in-lbs.

View attachment 112865View attachment 112866

And as I was typing this the UPS fairy just delivered aluminum bar stock needed to start fabricating the rear footrests. Gonna be a busy weekend at the drawing board and drill press!
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Nice truing stand. Who makes that?
 
Last 2 weeks have been busy, but there has been some progress. Like I mentioned in the last update I finally got the aluminum bar stock in to make my footrests. I don't have a full machining setup to work with but a drill press, saw, and some files can work wonders with a little elbow grease.

Decided to keep it simple and functional. No complex curves or angles. Got out the dykem and scribe and got to work. Started with the pegs. Used 5/8" dia. stock for the toe pegs and 1" for the heel pegs. Drilled and tapped one side each for attaching to the main beam before back clearing the rest of the way through. Got out some long bolts and cut off the heads so I can chuck up the pegs in the drill press to put a decent finish on the pegs. Started with 80 grit paper and finished with 320 grit.

Next was the main beam. Marked center of the stock, spaced out the heel and toe pegs at 5.5", and decided to throw in a few holes in between for a little weight saving. Once all the drilling got done, I marked up the main beam to cut off some of the excess and taper from the larger rear to the front. After a lot of time with a handsaw and a vice both parts were roughed in.
750cc Norton Commando Salt Flats Build


Next came the backing plates to attach the linkages. Transferred the holes from the main beams, then drilled and tapped. Que another long session in the vice with the handsaw and all major components were roughed in. Still have come finishing work to do (grinding off excess from screws, final sanding, and shaping the toe end of the main beam) but I think the end result will work just fine. May have to redo the backing plates to allow for a better angle latter but for now its one more thing off the checklist!

750cc Norton Commando Salt Flats Build
750cc Norton Commando Salt Flats Build
 
Schwany said:
Thanks

Yeah, I understand what the D reversion dam in the exit floor does, just wondered if that smaller exit hole really would be that useful for making maximum HP at WOT for 3 miles or whatever the length of that run is. Kind of a reality versus on paper question.

I'm working on a spare early Commando head and thought it might be interesting to build up the exhaust ports more like a D for the street. Probably won't though. I don't have a flow bench to test anything. Nor do I know what that port looks like on the inside.

I do unfortunately get what I think is significant reversion in my combustion chamber from exhaust ports that are matched to the ID of my 1.5" exhaust. I have never put the engine on a dyno to see how bad it actually is, but it makes my FCR slides rattle at idle.
Schwany said:
Thanks

Yeah, I understand what the D reversion dam in the exit floor does, just wondered if that smaller exit hole really would be that useful for making maximum HP at WOT for 3 miles or whatever the length of that run is. Kind of a reality versus on paper question.

I'm working on a spare early Commando head and thought it might be interesting to build up the exhaust ports more like a D for the street. Probably won't though. I don't have a flow bench to test anything. Nor do I know what that port looks like on the inside.

I do unfortunately get what I think is significant reversion in my combustion chamber from exhaust ports that are matched to the ID of my 1.5" exhaust. I have never put the engine on a dyno to see how bad it actually is, but it makes my FCR slides rattle at idle. :)
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Could a reversion dam be made by welding in a small piece of sheet metal into the exhaust pipe to simulate the floor of the Full auto head?
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I will try to find a useable set of pipes this month (two events are coming up) and I'll give it a try. Any opinions on where the dam should be welded in? I'm assuming very close to the exhaust port. Near the bend?
 
After many months of waiting the gearbox cradle is done! Huge thanks to Michael at Music City Metalcraft for getting this done.
750cc Norton Commando Salt Flats Build
750cc Norton Commando Salt Flats Build


Here's a comparison of the original vs. new.
750cc Norton Commando Salt Flats Build
750cc Norton Commando Salt Flats Build


Tomorrow I'm hoping to get enough time to start dry fitting all the frame pieces together before sending everything to sandblasting.
 
lcrken said:
This is a picture of Tom's bike as he ran it in the 750-MPS-PG class. He ran the same bike, but with the front fairing removed, to set the record in the 750-M-PG class. You can see the advantage he got from the massive rear streamled tail section.

View attachment 109569
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I got to see that bike at Miller's (Salt Lake City) in 2008. Cool stuff.
 
Zachary Brown said:
After many months of waiting the gearbox cradle is done! Huge thanks to Michael at Music City Metalcraft for getting this done.
View attachment 113383

Tomorrow I'm hoping to get enough time to start dry fitting all the frame pieces together before sending everything to sandblasting.
Click to expand...
Zach, I am really enjoying following your project thread. It's nice to have ample funds and a well-equipped shop to go along with mechanical/engineering skills. "The Sky's the Limit" as I've heard it said.

Certainly you are not cutting corners, I can hardly wait to hear the news once you'd had a few productive test sessions. Keep up the GREAT work!
 
I have been wondering about which type of motor I would use if I was doing a land speed record. In racing, there are two common types one gets its power at lower revs than the other. I cannot get my head around whether it might be better to accelerate up to high speed quickly, and winde-up for the rest. Or would it be better to have a motor which pulls harder and windes-up more slowly at first, but continues at a faster rate.
The light crank in the photos might suffer in a head-wind.
 
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