EFI Norton walkaround

Thanks Jim. You have a lot of good mods on that bike. All the best. Dereck

Incredibly interesting, we have seen a few mods before in your vids and pics, but this was awesome. I wonder a bit about the engine mounts, you say the front mount is empty inside but has a tube insert. Does that mean it´s bolted rigid to the frame? Have you done the same with the rear mount? Head mount?
Tommy

fiatfan said:

Incredibly interesting, we have seen a few mods before in your vids and pics, but this was awesome. I wonder a bit about the engine mounts, you say the front mount is empty inside but has a tube insert. Does that mean it´s bolted rigid to the frame? Have you done the same with the rear mount? Head mount?
Tommy

Click to expand...

No.
The front of the engine is supported only by the spring and the side play is controlled by the linkage. The front iso is no longer used. The spacer through the iso tube is only there to tie the front downtubes together.

The rear iso is still used but it is augmented by the linkage. It also has extra rubber donuts inside to help control the for and aft movement of the cradle caused by the cantilever shocks.

The head is controlled by one of the linkage type headsteadies I make. Jim

comnoz said:

fiatfan said:

Incredibly interesting, we have seen a few mods before in your vids and pics, but this was awesome. I wonder a bit about the engine mounts, you say the front mount is empty inside but has a tube insert. Does that mean it´s bolted rigid to the frame? Have you done the same with the rear mount? Head mount?
Tommy

Click to expand...

No.
The front of the engine is supported only by the spring and the side play is controlled by the linkage. The front iso is no longer used. The spacer through the iso tube is only there to tie the front downtubes together.

The rear iso is still used but it is augmented by the linkage. It also has extra rubber donuts inside to help control the for and aft movement of the cradle caused by the cantilever shocks.

The head is controlled by one of the linkage type headsteadies I make. Jim

Click to expand...

Ok, thanks, had to watch the vid again, think I got it :? This is a Mk III (well it was anyway 8) ) if I understand it correctly, but no electric starter?
Tommy

fiatfan said:

Ok, thanks, had to watch the vid again, think I got it :? This is a Mk III (well it was anyway 8) ) if I understand it correctly, but no electric starter?
Tommy

Click to expand...

When I built it 36 years ago I didn't need no stinkin' electric starter.
I may have done it different if I were building it today.
Actually it starts so easily with the EFI that I don't miss it -much....

Jim - I recently read a post of yours from 5-6 yrs ago bout Glisten from Por 15. Did you use it on your bike and if so, is it holding up well and would you use again?

gortnipper said:

Jim - I recently read a post of yours from 5-6 yrs ago bout Glisten from Por 15. Did you use it on your bike and if so, is it holding up well and would you use again?

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Yes it has done very well. It has stayed solid on the polished aluminum and even magnesium although the polished magnesium that I coated turned dark under the Glisten after several years.

I wish I had used it on my fairing and tank since the PPG clearcoat that is on it is suffering from a lot of rock chips.

I used Glisten on my front fender and it shows no pits.

comnoz said:

When I built it 36 years ago I didn't need no stinkin' electric starter

Click to expand...

Ha! I'm still hanging on to that one too Jim. Although its only a matter of time before Matt gets 'the call'!

Great walk around Jim. Great technical interest but also great to hear about you history with the bike too.

How about a 'walk around' of the engine? I know you can't walk us around the inside physically, but you get what I mean...?

Fast Eddie said:

comnoz said:

When I built it 36 years ago I didn't need no stinkin' electric starter

Click to expand...

Ha! I'm still hanging on to that one too Jim. Although its only a matter of time before Matt gets 'the call'!

Great walk around Jim. Great technical interest but also great to hear about you history with the bike too.

How about a 'walk around' of the engine? I know you can't walk us around the inside physically, but you get what I mean...?

Click to expand...

+1 ... so cool I second that motion. 8) ... thanks for posting such a great Comstock Norton video

The Engine

Starting with the crank. It is a stock MK3 crank that has been reworked with a heavy nodular iron flywheel



Improved radius on the PTO shafts and 6.250 Carrillo rods





A pin that is bolted through the big ends to help make up for the loss of strength due to the large offset grind to increase the stroke by 3mm.



Mk3 cases modded with a quick change cam running on needle bearings with inner races.



Sleeved barrels with 80mm bore.



312A grind Webcam modified for oil delivery to the lobes.



4 inch radius ground lifters. DLC coated pins



Vertex pistons with a cup, designed with low compression for a future turbo.



Hydraulic cam chain tensioner With HD chain. Plugged holes between timing chest and crankcase. Lower oil return hole drilled.



Fullauto head with re-angle guides and 3mm over intake valves, grooved for silicone o-rings and copper compression rings, no head gasket. Inserts for 10mm plugs- NGK #MAR10AJ, waisted head bolts.



The valve train consists of lightened rockers, Maney steel pushrods, Black Diamond valves and conical valve springs with Ti retainers.

Showerhead injectors mounted through rear air filter cover.






This winters projects include replacing the crank and cases with SBR billet cases and my billet crank.
Same specs- just strong enough to handle a power-aid.

Very nice, JIm. Love to see all those details.

Ken

what a superb machine i wish i had a fraction of your talent very inspiring cheers baz

Thanks for all the compliments.

It's what my wife likes to call "The Knack"

[video]https://www.youtube.com/watch?v=60P1xG32Feo[/video]

Heres to engineers.

Fantastic, and interesting as usual. +1 on the Dilbert video :lol: Sums it up pretty well I guess.
Tommy

There has been some very good work gone into that bike. Have you ever built one which was minimalist/functional (racer ?)
I'm interested in your EFI. Have you made your own engine management system or is it based on an aftermarket produced elsewhere ? A friend of mine, started a company known as Motec - his EMS is used in Porsches and Ferraris - his workers are mainly highly paid computer people. I think it might be difficult to go down a similar path and make your own EMS. In my own situation, I no longer have easy software from which I can produce the tables necessary for setting up an advance curve - I've found Python Language, but it is just another struggle. Many years ago I had access to a very versatile computer which was used in a scientific field - made things much easier. I find modern PCs are just too smart - to do the same things I used to do in the old days, can be a real mind-bender.

acotrel said:

There has been some very good work gone into that bike. Have you ever built one which was minimalist/functional (racer ?)
I'm interested in your EFI. Have you made your own engine management system or is it based on an aftermarket produced elsewhere ? A friend of mine, started a company known as Motec - his EMS is used in Porsches and Ferraris - his workers are mainly highly paid computer people. I think it might be difficult to go down a similar path and make your own EMS. In my own situation, I no longer have easy software from which I can produce the tables necessary for setting up an advance curve - I've found Python Language, but it is just another struggle. Many years ago I had access to a very versatile computer which was used in a scientific field - made things much easier. I find modern PCs are just too smart - to do the same things I used to do in the old days, can be a real mind-bender.

Click to expand...

Yes, I have built several Norton racebikes, both for use in vintage and modern classes. All gone now due to fire.

The ECM is my own build. It is based on a Microsquirt but has added circuitry with a second ignition system and crank pickup to make kick starting possible.
I use custom firmware designed by Al Grippo [of Megasquirt] and myself. I use Tunerstudio to tune it. Jim

I have always been interested in your use of panhard bars and the novel front iso modification to the spring set up. I cannot get my feeble mind around how the spring is working to dampen vibrations as it has to be working in the vertical plane primarily as the panhard limits the side play. Does your set up improve/ reduce vibration or is it more to make things more rigid and precise. Could you explain your set up a little more esp all three points of control and the outcomes. No ,actually 5 points of control with the panhards. PS Being a product of the 50's I take great delight in your Fuel Injection and flag emblems. First factory V8 engine to produce 1hp per cubic inch, 283 Chevy.

aceaceca said:

I have always been interested in your use of panhard bars and the novel front iso modification to the spring set up. I cannot get my feeble mind around how the spring is working to dampen vibrations as it has to be working in the vertical plane primarily as the panhard limits the side play. Does your set up improve/ reduce vibration or is it more to make things more rigid and precise. Could you explain your set up a little more esp all three points of control and the outcomes. No ,actually 5 points of control with the panhards. PS Being a product of the 50's I take great delight in your Fuel Injection and flag emblems. First factory V8 engine to produce 1hp per cubic inch, 283 Chevy.

Click to expand...

With a 360 degree twin the motion from vibration is on a plane perpendicular to the crankshaft. IE -no rocking couple.

The rod end linkages do the same thing as the washers that were in the original isolastics but they do not need clearance like the washers and they don't need regular adjustments to keep the clearance in check. That keeps the handling tight.

With a low balance factor [54%] the dominant motion from vibration is in line with the piston travel. IE- up and down.

With a spring or a large rubber isolastic near the engine the engine is allowed to move up and down easily and the engine tends to pivot on the small rear isolastic mount. The fact that the engine can move easily in this direction keeps the vibration from being transferred into the frame.

The spring is no better than a fresh and perfectly designed rubber isolastic mount. The problem being that isolastic mounts with the correct "spring" rate seem to be hard to come by any more. That plus rubber tends to sack and loose it's isolating capability soon.

The change in direction of the dominant motion is why an isolastic bike tends to vibrate more when the balance factor is raised.
When the engine and cradle are being forced to move for and aft because the dominant motion has been changed by the higher balance factor, then that motion is transferred into the frame by the small rear isolastic.

This is completely different than a solid mounted engine [Atlas] where less vibration is likely to be transferred to the rider if the dominant motion is for and aft. That is why solid mount bikes tend to work best with higher balance factors. Jim

'Yes, I have built several Norton racebikes, both for use in vintage and modern classes. All gone now due to fire.'

Looking at your video, I suggest most privateer race bikes are not built by people with your capabilities and competence. I'd have liked to have seen those bikes that were burned - what a tragedy ? I think that what you have done with your road bike proves the 'law of diminishing returns'. A lot of it is what the Commando always should have been. Can you imagine trying to set up a production line to reproduce it ? It is more a work of art than a feat of engineering.