MZ/MuZ Riders

It may take me a while yet to get all of the paint and powder coat work done that I want to do to the bike, as well as attain about $3000 worth of wheels, calipers, carbs, custom welding and assorted goodies, but it has finally begun. I know it's cheesy but I'm calling it Cafe Rocket 686. I was never good at being creative with words. Too modern to be a cafe racer and too naked to be a crotch rocket, this 686cc thumper will be one sweet custom MZ. The motor is out now and needs a good cleaning before too much engine work can proceed. If the bike ends up looking half as good in reality as it does in my head, I'll be very happy.

All the best mate , Sounds like you got a plan , keep us all updated with photos ,
If theres any advise i can give you it would be this----$$$$$ Keep an eye on what your spending $$$$$

That's funny. Almost everyone that's heard how much money I will end up spending by the time my project is over has asked me if I really want to spend that much on my bike. Answer? Yes. By the time it's finished, you'll have to pay me about $10,000 to talk me out of it. Plus, it's a hobby. Not many hobbies return a profit and are more about accomplishing a goal while spending quality time with someone/something you love. I will post updates and pics as often as possible and will likely be back on the road by end of summer.

It sounds like a good plan to me! When you're drip feeding cash into a project it doesn't seem to feel so bad.
I spotted this one recently while browsing and some more pics here :
http://vicente-design.com/one-off-motor ... er-rocket/

Chalks wrote:It sound like a good plan to me! When you're drip feeding cash into a project it doesn't seem to feel so bad.
I spotted this one recently while browsing and some more pics here :
http://vicente-design.com/one-off-motor ... er-rocket/

cache_2415333278.jpg

You've discovered the bike that inspired me. I actually got in touch with the person who designed that bike to find out what tank he used. It's off of a '93 Suzuki RG125. After many months of searching, I finally found a guy in England who would ship one to me in the US. My bike will have a similar tail on it but will be a little different, since I'm shaping it by hand, and both the tail and tank will be white with MZ logos. No fairing up front, just a big round headlamp with a Scitsu tach. Frame and swing arm, as well as the rims on the spoked wheels will be black. Hubs will probably end up being silver unless the gold anodizing on them is close enough to match gold Brembo calipers. New oil tank and subframe will be aluminum and will be set up similar to the custom bike in the photo. I'm shooting for under 320 lbs and 60 Dynojet hp at the rear wheel.

Here are some pics of the RG125 tank so you can see the shape of it more clearly. I never liked the shape of the stock tank, even when it had all of the body panels in place.

The engine is almost as disassembled as it's going to get for this rebuild. Flywheel and balancer drive gear still need to come off but so far, everything that isn't getting rebuilt or replaced looks good for quite a few more miles. It looks like the head had been off because there was black silicon everywhere, but considering the engine has around 40k miles, I'm pretty happy with the condition. The cylinder still has hone marks around all but a small section where the stock piston skirt was rubbing. You can't feel any grooves or ridges. I was even pondering reusing the OEM cylinder with stock bore hi perf piston instead of the 686cc aftermarket cylinder and Weisco piston that I already have. The aftermarket casting isn't nearly as nice as the OEM casting and I think I remember someone saying that boring this engine really doesn't do you much good until you stroke it too(edit:dont' listen to me about the stroke). Decisions, decisions!

The head is getting sent off for port, polish and valve job to a guy who comes highly recommended on the Raptor forums. He's been doing porting for over 20 years, seems like a real nice character on the phone, and will do the whole head for $350 plus any valves or other parts that need to be replaced. If memory doesn't deceive me here either, oversized valves and/or upgraded spring/retainer system aren't necessary for Stage 1 modifications.

If you could help us out from a previous topic-"check it before it goes bang"-
Will you let us know wether the nut on the balancer drive wheel is loose and only held in via the retainer washer,Also ,did you find the sprung drive gear,how was it , word it it comes loose and damages the keyway,,Ive bought a solid one from a raptor to replace mine just in case,

I already opened up the retainer washer and gave an initial try to break the nut, but I didn't get to put that much force on it without having a friend to hold the engine down. It isn't reverse thread is it? And are any of the other shafts inside the engine reverse thread? I will post info on the gear when I can get it off. Thanks

Here are some pics in case they help anyone. I also have some questions about the condition of the combustion chamber. The plug was a light tan so I was expecting to see a chamber that looked pretty good. Instead I found this build up that looked almost like mineral scale on both sides of the exhaust valves, as well as the usual carbon build up. The photo of the cylinder shows the only vertical wear marks to speak of.

by your pics,it seems almost normal...perhaps the exhaust valves were running too tight...you said head had been off before, may have been running rich for awhile too..
since you're sending the head out anyway,see what your machinist says.....
Good luck on the build...love that cafe skorp in the pic....
You still into EDF? Just built an F22

No, I was just getting into them when I bought my first computer and the screen name stuck with me. Now my focus is on large scale gliders, over 3 meters, and aerotowing them up to soaring altitude. Unfortunately, it's such a small area of interest in the community that there are very few people to fly with. I'm just acquiring tow planes and gliders slowly and hoping the scene in central Texas explodes. Eflite just released what is supposed to be a "best bang for the buck" 4.2 meter Red Bull schemed scale glider so they must see an emerging market. Fingers crossed.

basser23 wrote:l...perhaps the exhaust valves were running too tight...

The exhaust valves had some gap because I could move them @TDC. The intakes were all 0 gap. What will that do to your performance?

No valve clearance is bad! It can contribute to premature cam wear, burnt out valves and seat, poor performance, bad starting, etc etc. It's bad maintainance if they're out, it's an hour's job tops to keep them within tolerance.

You'll need the clutch drum off to check the nut on the balance shaft, on my spare motor it was as slack as piss! The gear itself was a bitch to pull from the balance shaft probably due to early stages of a keyway being pummled! The sprung gear that causes the balance shaft damage is on the crank shaft.

It may be a good idea, if we change the the sprung gears on our cranks, to pull the balance shaft gear fron the shaft and check the keyways just incase it's too late. I haven't had time to replace mine yet but the bike is parked up far away from the salt that's being sprayed on the queens highway.