adapting cast wheels to commando

heres a front (not mine)

http://www.ebay.com/itm/yamaha-sr500-fr ... 1854850756

Jimbo, Thanks for posting that pic. Is the rear wheel that you posted a pic of, a drum brake hub? So many of the pictures of wheels that I have found in my searching which are for sale are stripped down and I can't tell by the pictures if they are drum brake rear hubs. It's been pretty frustrating hunting down the parts that I want...

As I said, there seems to be a lot of front wheels that will work (I have a single disc front end even though my bike is originally a drum brake front end) It's the cush drive hub 18" rear with a drum brake that's eluding me. Thanks for you help

Well, the donor parts are in the house! I am pretty psyched to get started. I'll take a few pictures as I go and post them when I am done. (IF I'm successful) My donor wheels came from a 82 yamaha XJ seca 550. the front wheel is 19 x 1.85, and the rear is 18 x 2.15. The existing tires are good enough for the mock up since I will be buying new tires after the modification prove successful. The existing rear tire is 120 - 90 - 18, and I think on a 2.15 wide rim that tire profile might actually work in a norton swing arm. If I can't make it work, I'll just buy the 110 width tire as it's replacement.

The front wheel has a speedo drive who's cable end looks exactly like the norton one, so I may have an easy swap there from the 19" norton rear wheel speedometer drive to the 19" front wheel speedo drive. 19, and 19, how far off could it be??

The cush drive is massive on the yamaha. I'll be ditching the un-cushed rear wheel that was stock on my '70 commando too.

here's the donor wheels. I'm gonna make sure they will work before I paint them.

Rear,


Front


One interesting thing was that the height of the 19" front tire is exactly the same diameter as the tire of the 18" back wheel, so as far as I can see I can't fathom how it wouldn't handle as well as a pair of 19" wheels, since their heights would be identical... anyone???

Did I mention that I'm pretty psyched yet?... ok, never mind...

Well,..... good news and bad news.

The good news is the cast wheels work fine. Here's some pictures... for posterity.

primary side view:


timing side view:


front wheel:


rear wheel:


The bad news is that it would have cost about the same price to simply buy madass's cush hub, and mount alloy rims to end up with a similar set up, with lighter weight wheels and cush drive hub. Machine work costs killed me. I spent $700. on machine work to make things fit perfectly. Without calculating my time, I'd say I spent in the neighborhood of $1,000. give or take a few hundred... on machine work and parts.

In the rear, I bought and enlarged a used norton swingarm's axle slots to use the larger diameter yamaha axle, since I needed a new axle for the yamaha rear wheel anyway. The change from norton to yamaha is at the enlarged axle slots in the norton swing arm and it allowed me to keep the rear wheel bearings stock. I also moved the brake cable holder to the opposite leg of the swingarm and added a tab on that swingarm leg to mount the drum brake torsion arm. After centering the hub with various spacers, I still had to have .250" machined off the sprocket carrier to align the rear sprocket. I bought an aluminum sprocket in the stock norton 42 tooth made to fit the yamaha hub, which made my ratio remain the same as it was previously.

In the front, I changed the 15mm yamaha wheel bearings to 17mm diameter bearings so I could use the 17mm norton axle. I adjusted the wheel hub to the center with axle spacers, and then had to shimm the brake rotor out .134" to get it to fit in to the caliper slot. I had the machinist make an offset bracket for the norton caliper for the larger diameter yamaha rotor. It moves the caliper another 5/8ths away from the wheel center.

Today is the first day I've had it all together and I've just taken my first test ride. It's all working well enough. The steering feels lighter, but I don't trust the old front tire that came with the wheels, since it feels hard so I am not really laying over hard yet.

My advise to anyone wanting to modify cast wheels is that it's not a less expensive route than just buying the high performance stuff that is already adapted to work on a commando. There was someone here who had his commando painted british racing green and he painted his cast wheels gold, just like the lettering on his bike and that combo looked outstanding. I'm not sure if I like the look of my cast wheel set up as well as I liked the spokes look. Maybe it will grow on me eventually. I can always switch back to spokes and sell this set up if I don't like it.

At least you did it and now you know. And everybody else does by your sharing. Never die wondering. Good job.

That looks quite sharp.

After all that work, NOW you decide you don't like the mag look !!
They look like guzzi wheels.
What color would you paint them, they look quite good in natural alloy.

Its not only the tire height that affects the steering, its the tire width.
Most folks go smaller wheels to get wider tires.
When you lean it over and the rolling contact of each wheel is different sizes, the steering gets different.
Nortons settled on same size wheels front and back, just by good ole trial-and-error and what feels best.

Fullauto said:

At least you did it and now you know. And everybody else does by your sharing. Never die wondering. Good job.

Click to expand...

thanks, I am a little OCD. I really had to try it. I couldn't just buy new alloy rims to lace up to my "non-cush" early commando hub, and I didn't want to bite the bullet for one of madass's beautiful new cush drive hubs. I thought that I could modify cast wheels for less than $500. but I was wrong. I wanted to share my project information so other people thinking of modifying cast wheels will know that it isn't easy, nor less expensive than the already "manufactured to fit the commando" options.

Rohan said:

That looks quite sharp.

After all that work, NOW you decide you don't like the mag look !!
They look like guzzi wheels.
What color would you paint them, they look quite good in natural alloy.

Its not only the tire height that affects the steering, its the tire width.
Most folks go smaller wheels to get wider tires.
When you lean it over and the rolling contact of each wheel is different sizes, the steering gets different.
Nortons settled on same size wheels front and back, just by good ole trial-and-error and what feels best.

Click to expand...

Thanks, I don't hate the look. I'm just underwhelmed. I can't find the picture of the green commando with the gold cast wheels which really looked amazing, but no matter. Maybe I'll paint them silver someday or repaint the bike british racing green and the wheels gold... It's not as important as how they work. The back tire is still somewhat soft, but the front is pretty hardened up and needs to go. I actually rode the bike with only the back cast wheel installed with the front spoke wheel still on it and it handled better than ever. The crappy old front tire is now on the bike with the new cast front wheel and it's definately a lighter feel, but I didn't like the handling as much.

I'm going to go with new avons AM 26's, front 100/90/19 and rear 110/90/18 and hope for the best. The 120 tire on there now is very forgiving, but also doesn't give a very precise feel. I'm hoping that going for the 110 width tightens up the handling a bit. (I'm in the trial and error vortex now...)

jimbo said:

good job! keep an eye out for front brake pad wear as the Yamaha discs are thinner than Norton's , you wouldn't want your pads to fall out! :shock:

Also I found the brake pads offered for Norton calipers eat Japanese discs

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Thanks, I noticed the thinner disc and will keep my eye on that. My front braking capacity has increased. The brakes really grab hard now if I squeeze with a greater amount of force with no loss of feel at less forceful useage.

Thanks for all the help, advise, and comments... now I know...

o0norton0o said:

Thanks, I don't hate the look. I'm just underwhelmed. I can't find the picture of the green commando with the gold cast wheels which really looked amazing, but no matter. Maybe I'll paint them silver someday or repaint the bike british racing green and the wheels gold... It's not as important as how they work. ...

Click to expand...

I've a green Commando with gold cast wheels:



I think what you've done is great and I've done similar things to vehicles that will never provide anything in the way of return-on-investment, but that's not the point for me, it's doing it myself to the best of my abilities. And at the end of the day, I do it to only please myself - and I'm a tough judge!

quote;Thanks, I noticed the thinner disc and will keep my eye on that. My front braking capacity has increased. The brakes really grab hard now if I squeeze with a greater amount of force with no loss of feel at less forceful useage.

Thanks for all the help, advise, and comments... now I know...

Notice in my posted photo, I have sourced an aftermarket EBC floating disc that bolts up to the made for Honda Lester. its much thicker ,and made of better material that the pads are not chewing up . You might be able to source that type with your set up .

o0norton0o said:

My front braking capacity has increased. The brakes really grab hard now if I squeeze with a greater amount of force with no loss of feel at less forceful useage.

Click to expand...

'Probably a function of having moved the caliper out an additional 5/8" away from the axle, or, in other words, closer to the contact patch of the tire to the ground. That's arguably a better way to achieve improved braking as compared to a smaller master cylinder. Greater rotor diameter leads to increased rotor speed/less pad pressure required for a given braking force, a-la Buell:


I do like the look of those Yammy wheels! Good on you for soldiering through.

Nathan

Davamb, your bike looks great. It's one of the bikes that convinced me to try to adapt a cast wheel to my bike.

Jimbo, I checked out those aftermarket brake rotors. Hopefully I won't burn this yamaha rotor up too fast because I really went over budget getting my project to where it is now, but the new front brake set up as it stands now is a huge improvement so I'm pretty psyched with it.

Thanks nate, The look of the cast wheels is growing on me more and more every day. Like Rohan said, I could probably paint them silver and they would blend right in.

So,.......today I added the last key piece to the puzzle on this modification oddessy gone wild . My Avon tires arrived UPS, and I mounted them... HOLY SHIT, The bike handles better than it ever did. I took the bike on my test loop and tennatively laid it into the first few corners and everything was right. The bike felt solid enough for me to hit the left lane on the hiway and do 90mph comfortably back home.

The only thing left unfinished is the speedometer, which I am in no hurry to work out. I may get a bicycle GPS speedo for $15. and tape it to the face of the smiths. I sure would like to adapt a gearbox to my front wheel for that stock smiths....

.... oh, and I'd love to thermoform a taller windscreen for my fairing since I am tall and don't like ducking down to get out of the wind....