1973 850 Mono shock / showa forks.
- Thread starter bwolfie
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Bob Patton is being shy about his rear link. I'm not as I'm besides myself how well it tames about everything complained of or breaks in exceeding normal Commando handling. In Spades.
When ya get any bike leaned way over under hi power, the power pulses on tire reaction becomes a scary issue. I really like the way isolastics allow better hook up, if the chassis can take it to find out what I'm talking about. In Peel's case I'd be pensive a fixed swing arm in tire thrust axls would act like other bikes I've pressed too far. They were mono adjustable shocks, BFD to me now.
Anywho a chain tension-er might solve the slight chain length/tension changes of swing arm mounted separate from isolastic power unit drive sprocket.
Peel may have to use one d/t the 5+ inches of rear travel expected.
Tie rear of frame tubes together and along with the mono swing arm itself may work just fine to endure the loads.
Cradle in 6061 TS alloy needs to be ~1/16 thicker than the steel cradle. Don't know it 7075 TS would allow less meat but would weigh more than 6061 if mass is the goal. Consider SS bushes for stuff like say center stand or maybe all mount holes too to get away with thinner plate in weak spots.
When ya get any bike leaned way over under hi power, the power pulses on tire reaction becomes a scary issue. I really like the way isolastics allow better hook up, if the chassis can take it to find out what I'm talking about. In Peel's case I'd be pensive a fixed swing arm in tire thrust axls would act like other bikes I've pressed too far. They were mono adjustable shocks, BFD to me now.
Anywho a chain tension-er might solve the slight chain length/tension changes of swing arm mounted separate from isolastic power unit drive sprocket.
Peel may have to use one d/t the 5+ inches of rear travel expected.
Tie rear of frame tubes together and along with the mono swing arm itself may work just fine to endure the loads.
Cradle in 6061 TS alloy needs to be ~1/16 thicker than the steel cradle. Don't know it 7075 TS would allow less meat but would weigh more than 6061 if mass is the goal. Consider SS bushes for stuff like say center stand or maybe all mount holes too to get away with thinner plate in weak spots.
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I tried using a rod with hard rubber ends to keep the cradle up on my bike. Vibration was a serious problem that I never overcame.
Now if you were to make the leaf springs longer so they acted on the swingarm near the rear of the arm- about where the shocks connected originally it could work. No rod would be needed.
Now if you were to make the leaf springs longer so they acted on the swingarm near the rear of the arm- about where the shocks connected originally it could work. No rod would be needed.
Why does a Sportster (or any HD) with very moveable rubber mounts work by having only the engine/transmission move and it would not on a Norton? Instead of having the pivot for the swing arm on the engine cradle, it could be attached to the frame, probably concentric to the output sprocket and then just let the engine and transmission shake all they want.
I think the guys who built the "Featherlastic" ( http://www.ntnoa.org/bobcox.htm ) did it that way.
Jean
I think the guys who built the "Featherlastic" ( http://www.ntnoa.org/bobcox.htm ) did it that way.
Jean
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You can do it that way. It would probably work better with a rear belt drive and tensioner arrangement. I found the extra slack in the chain to be somewhat disconcerting.
Easiest would be stick with twin shocks. Spend the money on good shocks and they can work as well as any monoshock. Jim
Easiest would be stick with twin shocks. Spend the money on good shocks and they can work as well as any monoshock. Jim
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Normally all John Player Nortons had isolastics. I wonder how this one behaved...
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Main reason mono shocks came on the scene is two fold, and none really apply to road racing - one to get more range than dual shocks could w/o a linkage and two to get balanced response in dampening rather than the effort to match shocks. A 3rd reason is less motion of shock meant lower temps so easier to keep in dampening zone. Likely sports makers jumped on it as more sexy and less items to stock and handle. Its not the strongest way to go if 5 inches of travel is enough in rear, but mono does allow lower bike for extra travel - a real boon for the racers going off track. Here's more what I'd do for a Commando mono
http://www.ultimatemotorcycling.com/MotoCzysz_C1_Review
I picked up my box of bearings and my aluminum today. Got started on the forward mount and trans cradle. I have some MK3 Iso's coming next week, so I should be able to get the engine cases and mounts in for mockup in the next week or two. I have to turn down the GSXR's triple tree a little to fit my new bearings. If I can sell a few more items (mainly my snowblower) I'll have the money for my RGM order. Then I can really get going. I'm thinking of switching from a 19" rim on the front to a 18". I have to lace up a wheel either way, i'll just sell mine as an assembly.
As a side note, I will have one Aluminum front engine mount for sale in a week or two. I had enough material to make two. If anyone is interested let me know. I'll make it as a MK2 style, it can easily be made to fit a MK3.
As a side note, I will have one Aluminum front engine mount for sale in a week or two. I had enough material to make two. If anyone is interested let me know. I'll make it as a MK2 style, it can easily be made to fit a MK3.
bwolfie
if you are going to buy a belt drive now is the time to go with an over driven ratio. it has a few advantages over the stock ratio. less torque into the gearbox, you can run a smaller final drive sprocket so less strain on the gearbox output and if you like to run a 21 tooth with stock primary it will get you away from the 2 -1 final drive and make it a hunting ratio on the chain and sprockets.
if you are going to buy a belt drive now is the time to go with an over driven ratio. it has a few advantages over the stock ratio. less torque into the gearbox, you can run a smaller final drive sprocket so less strain on the gearbox output and if you like to run a 21 tooth with stock primary it will get you away from the 2 -1 final drive and make it a hunting ratio on the chain and sprockets.
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bill said:
I think the RGM unit he mentioned is already overdrive.
you can check with RGM on what ratio's they offer. I know norvile offer engine pulley's with 32,34,35 and 36 teeth and clutch drums with 68,69,70 and 72 teeth. the standard norville is 2.187 ALMOST the same as stock and they offer an over drive as much as 1.97 and that is the one I would use. the std norvile with a 21 counter shaft works out to 4.374 which is approx 4200 RPM at 70 MPH and the norvile 1.97 and a 19 works out 4.35 and that is where I would start. if you want to slow down the motor more a 20 tooth works to 4.137 and and a 21 is 3.94
I scored a 40mm belt drive setup NIB off of ebay. came with 2 commando belts and 2 atlas belts. I'll sell the atlas belts. It's a Norvil unit. I'm going to order a Alloy center hub and alloy pressure plate from RGM. All much lighter than stock. I'm excited. I started machining my mount and cradle last night. I'm hoping to finish up the front mount tonight.
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