Ok so I'm not exactly new just lazy!!

cyclemotors said:
Mark, is that an alluminium frame or steel ?

Would you say its better to install on an alluminium or a steel one, what im tryin to say is would a steel frame produce less vibration than lets say an alluminium one.

Also you know how you mounted the front of the engine to the bottle holder slots with a steel custom mount, well does that affect the vibration too?

Id be really interested in finding out thanks...

Ok my frame is all alloy and very very light. In fact my motor weighs more than the bike!! I can't recommend it highly enough. Its all about power to weight. As far as vibration goes its important to be thinking right!! Sorry but you just asked a mechanical engineer a question that can't be answered with a yes or no. So its gona be a long answer!! First the frame transmits vibration the engine produces it. The lighter the frame and the firmer the mount the more vibration is transmitted. So in other words if you filled your frame with lead the mass of the out of balance crank would not be able to efficiently move the mass of the frame and you would hardly feel any vibration. You would also hardly be able to get the motor to pull you on flat ground but it would be smooth!!! So to have a bike that performs and dampen the vibration you have two things to work on. Firstly eliminate as much vibration as possible at the source and secondly introduce a buffer or dampening zone between the source and the frame. The vibration in these motors comes mainly from 2 sources. The standard front sprocket meshing and releasing from the chain and the poorly balanced crank. The front sprocket needs to be reworked to allow free mesh and release. Just look at a small push bike sprocket and compare the difference at the points of the teeth. File your drive sprocket like that and you will have less chain wear, stretching and vibration. Secondly balance your crank. This is simply done by placing your crank and con rod on a set of parallels with the con rod end supported and removing metal from the side that swings to the bottom. Don't get all hung up on crank case volume cos it will not have any effect on performance on these motors that you will ever notice but you will notice a big improvement not only in smoothness but in the way the motor spins up. Now my motor is mounted on 3mm thick pieces of aircraft ally. This is to allow it to flex a bit and reduce the strain on the crank case casting.

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As it comes out of the box the 80cc motor is a nasty piece of work but with a bit of carefully loving it will become a smooth powerful reliable power plant. !! Vroom vroom!!!!
 
etheric said:
Klahowya! I like the front light. I'd like to see some closeups of that light mount, and the intake too if ya feel like posting a topic in the picture section with some goodies for us.
This ghost ring may help if you've still got some tension problems. That stock roller is about as cool looking as the chainguard.

The light is just an old bike light screwed to the disk break caliper mount of my forks. Haven't wired it up yet but it needs to be there to be legal in Aus. The inlet manifold is just the stock one cut turned to an angle and welded back together!! Too easy!!
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Thank you so much for that detailed answer and picture illustrations, i have learnt so much..

Cant wait to get started on my new bike, will post some pictures when im done and you can let me know what you think.

really appreciate it man....
 
skaryfast, that WAS an xlent explaination 8)

my older HD-steel mtb frame does absorb a ton-o-vibration...
 
rear sprocket

Skaryfast, please give us more details and pics on how you attached the rear sprocket to the wheel. It looks like it is not bolted to the spokes.
 
Re: rear sprocket

Vongould said:
Skaryfast, please give us more details and pics on how you attached the rear sprocket to the wheel. It looks like it is not bolted to the spokes.

Not only that unless me eyes are deceiving me it looks to be 2 sprockets side by side :? :?

And speaking of Australia. I am curious if you know the legal grey area there on the use of those bikes? I know the coppers are pretty strict there about everything from chirping the tyres :) to tread depth to road cancer (rust).
 
hey Mark, I need to do a similar thing with my inlet as I have no room for an air filter.
 
i can't answer for QLD where skaryfast is from, but here in Victoria, if the bike puts out more than 200 watts it technically needs to be registered, which is nigh on impossible to do. i think 200 watts is put out be like a 20cc motor, so almost all are technically illigal.
 
balance the crank

Can you give us more detail on how to balance the crank. Pictures maybe?
 
please make sure to take the tech talk into the proper area, we don't wanna miss out on something good 8)
 
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