Well, now that it looks like everyone has lost interest in this bike, I have finally produced a few real parts that are almost ready to be installed.

I've had the CNC mill for about four months now and though I've been playing around cutting out swing arms in MDF, these are the first aluminum parts I've made.

I've attached a few pictures, but since this is my first time attaching pics here, they might not show up.

If they do, the first is of the adapter to mount a TT rear sprocket to the rear wheel. I still need to finish drilling and tapping the four 3mm holes to attach the sproket to the adapter

The other two pics are of my front sprocket. I started off using a TT front sprocket as well, but decided to make an entirely new sproket to fit in place of the stock front pulley. It came out nice on the first try. The pictures are of my prototype part in machinable wax - I'll be cutting an aluminum version tomorrow night.


Hopefully once I get these parts finalized and get a working aluminum swingarm interest in this bike will pick up again. If only I had a little more free time to work on these things...

Dave.

Nice piece of machining Dave,
I wish I could have cnc mill too . Shouldn't be better if that front sprocket would be made of steel (I think this because it's more strained) and rear sprocket made of alu?
Good luck.

Cool i have 2 of these bikes always looking for improvements!
Great work!
A ? for you do you need that heavy gyro in the rear wheel for this bike to work?
it feels way heavy...i do go off road with the bikes?

I just got my hands on a Ricky Carmichael (very heavy) and decided to put in my novak brushless system in. The problem i'm having is the teeth on the spur gear do not match any of my pinion gears I have laying around. Should I replace the spur gear or pinion gear and where would i buy one to fit.

I've got one as well. They are fun. Kinda slow, but can still roost in loose dirt! I'd be interested in any parts to beef up the drive train as well, cause I know that's probably what will go first.

STeve B in NC

Thanks aveox. The CNC mill is definitely nice. I wish I had more time to play with it, but work, my three little girls, and a new house keep me pretty busy. I hope to be able to produce an entire off-road bike one of these days and follow your lead.

I see that CNR sells an aluminum front sprocket so I hope it won't be a problem. I started cutting one last night, but only got through the first side. Hopefully I can finish it tonight.

As far as the gyro goes, if you do a search here on Carmichael bike you will find a thread from earlier this year that goes on for many pages. I believe there is someone (Signats?) that ran without his gyro, but said it was pretty unstable off-road. Last I heard he had sanded his down a bit to lighten it up a bit.

He was also running a brushless motor (Novak or Hacker I think) on that bike and was having problems with the gears inside the rear wheel melting! There is a little planetary gear transmission set up so the gyro spins much faster than the wheel. I'm wondering how the stability would suffer if the gyro only spun as fast as the wheel - thinking of using a one-way bearing to drive a lighter gyro wheel maybe...

I have a 19 turn spec motor that I've been meaning to put in mine, but haven't had the time. I know that other thread mentions the pitch of the pinion gear though so check it out.

I recently picked up a spare bike on ebay that I'm going to be stripping down to see what else I could do to it.

the whole off road bike sounds awsome to me, tell me more...

Ok, here's the link to the other discussion about the bike.

Unfortunately Ebay is about the only place you can get one now...

http://www.rcgroups.com/forums/showthread.php?t=187142


Oh, and here's the front sprocket in aluminum. I need to clean it up a bit, but overall it came out pretty nice - and it fits nicely. I also need to put the new stepper motors on my mill so I can take more aggressive cuts.

Now on to the swing arm! By the way, I've decide to make it a one piece and just cut the axle slot all the way through to the back. Can anyone see a problem with that?

Thanks,
Dave.

Nice work Dave. Are you going to make the swingarm the same shape as the plastic one? The only problem I see possibly with the axle slot open at the ends, is making sure there is some way to secure the axle bolts. They are pretty flimsy on the stock rear wheel, but they are just in a hole thru the plastic swingarm with no way to adjust their position. If the axle on your swingarm can be adjusted for the chain tension, you may want put holes for pinch bolts to go thru the top and bottom arms of your axle cutouts to cinch down on the axle when it's installed (just like on a 1/1 bike).

My 0.02. You may have fingured out a better way already.

STeve B in NC

Really nice piece of work Dave,
About sprockets - maybe I'm wrong with that steel sprocket. I have industrial chain drive on my bike so both sprockets are made of steel (they are designed for higher loads). And about gyro. I used full wheels until they were lightened and I have to say that bike is now significantly less stable. I don't mean leaning speed while cornering but stability on bumps or small stones on the road. It behaves like it would be much lighter and more easily falls when riding over bumps.
Look at http://www.rcgroups.com/forums/showt...9&page=1&pp=15

How about the gyro with constant angular velocity mounted on bike frame instead of having double speed gyro on rear wheel? You wouldn't need to accelerate gyro while speeding up the bike so I think it would save some energy. But disadvantage is using of another motor for gyro.
And another tip - why not to make steel wheels. They would have high gyroscopical moment.
And last issue, could you specify "follow your lead"? I'm not very skilled in english and in dirt bikes.

I too own one (ricky carmichael dirtbike) and it was soooooo slow I had no choice but to fix it. I gutted the beast and installed a novak discovery II esc, an ofna servo (50 oz), and a traxxas receiver. I replaced the shock with an old traxxas shock. Lastly, I soder the motor that came in the beast to this new setup. The reason i had to use the stock motor is due to the spur gear and pinon gear, really weird stuff. Now this thing flies and my battery life has tripple. It is now 3/4 lb's lighter.

Ya, it is slow, and it has a slow steering response. I used mine today. Not a Ricky Carmicheal, but this other dirtbike that is blue. Really slow. Around 7-20 mph. It looks cooler without the guy on. I took mine off after jumping it off little jumps about 1 foot high.

Steve, I'm planning to keep the swing arm pretty much the same shape as the plastic one. I was going to go with a two piece setup, but decided that would just add more machining work and removing the rear wheel would still be a pain... I'm still working out exactly how to lock the axle in position - so are you suggesting something like this? A vertical bolt to pull the top and bottom together? I must admit the last time I worked on a 1:1 bike was a 1974 (I think) Honda SL70!

Aveox, I think the frame mounted gyro has been done before. I'd like to stick with something in the rear wheel, but will have to see how it goes... Oh, by "follow your lead" I just meant that one day I'd like to do what you have and make an entire bike from scratch!

And finally, Balact Man, what all did you strip from your bike? Are you saying you made it .75 lbs lighter or 3 to 4 lbs lighter? I haven't picked out a new radio for the bike yet, but I do have a 19 turn Epic motor that I am going to put in - hope it runs with the stock ESC. I stopped at the local hobby shop yesterday and picked up a 32 pitch 13 tooth pinion - it matches the stock one exactly...

Originally Posted by dmincin

Steve, I'm planning to keep the swing arm pretty much the same shape as the plastic one. I was going to go with a two piece setup, but decided that would just add more machining work and removing the rear wheel would still be a pain... I'm still working out exactly how to lock the axle in position - so are you suggesting something like this? A vertical bolt to pull the top and bottom together? I must admit the last time I worked on a 1:1 bike was a 1974 (I think) Honda SL70!

...

The pic is exactly what I had in mind.

Hi dmincin,
I think it there may be a problem to clamp the top and bottom arms when axle will be adjusted to the left side on your picture (closer to pivot). You will need high force on bolt to clamp top and bottom arm and those may be deformed. I use this on my rear arm and it needs M4 bolt to clamp securely rear arm (shown on picture). I don't want to dicourage you from this system and it may work in reality. Try it and you will see.
Goooood luck.