Engine mods I may try.

I reviewed one once, its not really suitable for a MB. Very Low on power @ .9 hp and no hot rod potential.It is compact and light, but you wouldn't be happy with it on a MB.
 
I have some experiance hot rodding small block Chevys and a 410 Edsel beastie I put in a '55 Ford tudor as well as several motorcycles, but there's not much in the way of hop up parts available for the Robin. I will have to wing it I guess.
 
The problem is that you can only do some much before you need to work on cam timing and compression. Compression might be able to be increased using a techinque I developed for the Honda GX31.Although you can only increase compression on the stock engine a small amount because its too easy to push cylinder pressure to high and end up losing power.The rule of thumb is to have trapped CR not over 9:1.
Then the next thing is the cam. The unilobe cam can be modified to a certain degree although to maintain valve train geometry and increase overlap, you have to add material at the top of the lobe, the trick of reducing base circle does not give enough of increase in lift or overlap to really make it effective.
You could try it though, and just make new pushrods from drill blanks to bring geometry back.Unfortuntly the cam lobe is a sintered metal part molded in the cam gear, it would need to be ground, but this could be setup on rotary table on a bridgeport with the appropiate shank mounted grinding wheel.
 
Mr Mike

Any Progress?
I love your new bike it's great.
When you get all the tuning done let me know.

If you get bored over the winter i would love to build one for my wife.
But thus far i have no experiences with the rack mounts.

I'm sure you would be a great help.
 
Helping to build a rack mount for your wife would be fun. Have you thought about what system you will go with? Friction drive is cheap, light, and simple, if hard on the tire. Staton's 18.5 to 1 gear box/chain drive is strong, bullet proof, and very high quality, but fairly heavy. The GEBE belt drive system is light and smooth with a nice choice of 4 final drive ratios, but the price seems a little high for what is included. I've built bikes using all 3 and the GEBE may be the best compromise between weight and ease of use.

I haven't even started yet. Money will be very tight untill after the holidays. I've decided to go with a one size larger Walbro carb of the same series as stock, porting the intake/gasket to match the carb, and building a freeer flow exhaust. I want to keep the reliability, long life, and fiddle free running of the engine. The only difficulty these mods could cause is over revving the little mill. If I add a tach the revs will be my responsibility and I will have to learn to exercise some control over my exuberance.
 
I hear it my spending is cut back till next year.
The bike you brought over was a Subaru?
I think a bike just like that would be perfect for her.
If something breaks down she would be stuck till i went to get her.

Plus she wants the full suspension.

And a Pink Motor with pretty flowers painted on it. LOL
 
Ha ha ha ha ha! The engine is a Subaru Robin EHO35, 33.5cc, 1.6hp, and uses a Golden Eagle Bike Engines (GEBE) belt drive system. My bike is a Maelstrom. Full suspension = plush ride. Any full suspension bike will work, but mine has a rear disc brake and that made mounting the GEBE system a pain and voided the warranty. A rear disc is not recommended. You could certainly paint the engine cover pink with pretty flowers on it. It has a cover because it is fan cooled and the cover directs the air flow evenly over the engine. Let her paint it herself.
 
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