$7 Roadmaster MTB 4stroke Shifter.

cannonball2 · Jun 20, 2011

Have built all kinds of MBs, but never a shifter. A neighbor down the road bought a group of bikes from a local police dept auction, I bought 10 bikes for $70. Bunch of suspension MTBs and a few road bikes. In the lot was a rigid frame Roadmaster from 2000. The more I messed with it the better I liked it. Had a Grubee G4 I had pulled from another bike, figured Id use it. An email to SBP found out the dont make a kit for the one I had. Soo, out came the tools. I bought pretty much everthing I needed form SBP on Fri. and it was in the mailbox at 2:15 today. Thats service!! Any way got it pretty much finished today, a fairly simple build, most of the work was in the bearing hangers cut from 3/16 sheet. Basically down to hardware, paint, tank and details.

rustycase · Jun 20, 2011

That's a very nice jackshaft bracket you made!
I like it!
Tnx for posting the pics.
rc

cannonball2 · Jun 20, 2011

Thanks RC! That is where most of the work as been so far. When you DIY stuff like mounts you have to real careful not to back yourself into a corner so to speak. I think I missed the re-engineering opprotunities this time.

NEAT TIMES · Jun 20, 2011

Cannonball2

Very neat and clean. When you weld the jackshaft plate`s to the motor angles it will really stabilize the jack plate`s and finish it off.

To be honest, I think it is too simple, basic and fully functional !! Lol

But like I say; Parts left out never break!!

Thanks for sharing. You are a "whizz" ! Pun intended.

Ron

rustycase · Jun 21, 2011

CB2... Seems like I've spent most my life getting out of that corner!

Myself, I'd probably be happy with 20-25mph for the distances I need to travel here about town... small town, and there ain't nuthin' here anyway!
So I'll probably gear lower than the 44 and be good to go.
(But I'm having fun considering using a SA 3spd hub as a jackshaft)

What I would like to do is mount my HT engine low. Move the BB forward.
Which means there's plenty of those corners I can back myself into!

Have you seen a Ducati Cucciolo ?
Really interesting 4cycle clamp-on!

Your integrated mount design could be worthy of production!

Best
rc

cannonball2 · Jun 21, 2011

Thanks for the kind words guys. NT, the bearing plates will remain bolt on. There is a thick wall seat post driven down into the seat tube to reinforce it, therefore I can tighten the bolts to their max without the seat tube deforming. Being under the motor mount angles there is a great deal of clampimg force to keep them in place. Will slot them slightly for chain adjustment

RC, cool idea on the 3 spd as a jackshaft, I got a really unusual Specialized bike with the lot that has some sort of multi speed hub. As I remember its a bunch of speeds. Have to take a look at it I have one engine left! I almost used a 48T but after figuring the ratios felt it might be too low. This is strictly going to be a road bike, so really low mountain trail ratios wouldnt be used much. I figured a low overall ratio of around 29:1 and a high of around 13:1. When the G4 was a single speed it overall was 17.6:1 and it did real well but got pretty buzzy at 30mph. Calculated top with the shifter is around3 38, dont really need to go that fast(especially until I upgrade brakes) but hope the cruise in the 30mph range will be more relaxed. If the works out as hoped, I really plan to upgrade this bike, the entry level price was right!

NEAT TIMES · Jun 21, 2011

cannonball2

That is thinking out side of the box, driving heavy wall tube into seat post !! The bearing holes in the jack shaft plates appear very precise. I mite pm a question.

Again, amazingly clean build.

Looks like it came from a "Cannon" factory!

Ron

silverbear · Jun 21, 2011

Pretty slick!
SB

cannonball2 · Jun 21, 2011

Thanks NT & SB! Well got it finished and running, shoulda done one of these a long time ago! Rides great, and the normally buzzy HS is smooth and quiet in the top gears. Had no real issues, with the exception of a miss matched 8 speed thumb and paddle shifter which requires a hunt for the gears(6speed). I have a 6 speed grip shift on the way. Was wondering about putting it on the left. All I can see it does is invert the shifting, something I can get used to. Any other problems? My right thumb is just about used up. Now its time to refine it a bit($$$)!

cannonball2 · Jun 21, 2011

Wow, some how it dumped the pics. Try again.

ocscully · Jun 21, 2011

I'm curious about which BB you are using?, The one from SBP or the one that came with the 4G Motor kit.

ocscully

cannonball2 · Jun 21, 2011

Had the 4G on hand so just modified it. It was a few thou over 5/8 so I turned it to size then had a friend down the road cut a keyway.

cannonball2 · Jun 23, 2011

Have to say I REALLY like this thing! You shifter guys know this already. Almost got the hang of shifting it with a friction lever. My indexed shifter should be here today. I envision myself shifting through the gears like a MC-yeah right. The HS engine is much more enjoyable with this set up. It amazes me how it will pull the top gears once up to speed, I figured the last gear might be unuseable. It pulls along easily on the flats and slight inclines. Looking in to upgrading the bike and came to the conclusion its cheaper to buy a complete bike and remove the parts. By the time you price wheels, tires/tubes, brakes, chain etc., you can get a whole bike and have a bunch of other stuff, like seat shifter, brake handle etc., plus a frame for another project, just what I need!

BTW Neat Times thanks for the prop in the seat post in the seat tube, but that came from SBP website, cant take the credit.

benutne · Jun 23, 2011

Man, phenomenal job. I love the way it bolts directly into the frame. Have you had a chance to try it out?

cannonball2 · Jun 23, 2011

benutne said:
Man, phenomenal job. I love the way it bolts directly into the frame. Have you had a chance to try it out?

Thanks! have ridden it a good bit. Literally waiting on the mail for my indexed shifter. Im all thumbs with the friction shifter(haha!). Once I can consistantly get the gears, this thing will be happening!

daRog · Jun 23, 2011

31,173 views of this thread? Awesome.

cannonball2 · Jun 23, 2011

daRog said:
31,173 views of this thread? Awesome.

Something aint right about that!

cannonball2 · Jun 23, 2011

OK, I am aware its not high end stuff, but its generally better than what I have. Im getting tires, tubes ,wheels, chain, upgrade brakes, derailuer, free wheel with the late style sprockets, shifter, brake handles, cables, grips, handlebars, front suspension(iffy maybe), and metal pedals(mostly). all for out $85 out the door. I will clean polish and assemble the old parts to make a farily decent some new/some old bike to donate at Christmas. Its as close to a win/win as I get.

cannonball2 · Jun 24, 2011

Transformation complete. Finally I have something that shifts with just a click! Used virtually every thing from the donor, except the pedals, they changed the thread size. Hokie front end works ok and was an easy way to get v brakes on the front. All in all I pleased with the way it turned out. Have $92 in the bike(dont ask about the Grubee stuff), with enough parts left to make a good looking donation bike. I realize this is low end stuff, but I am a road rider, thats real easy on his bikes.

NEAT TIMES · Jun 25, 2011

cannonball2

Gear`s make for bigger smile`s! Red white & blue! Looks great. Now the fun has started. Don`t forget us. Lol Super job.

Ron

$7 Roadmaster MTB 4stroke Shifter.

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