The Pocket Bike Engine and Your Opinion...

[conradcliff]

Ok, so I've been posting bits and pieces of questions and info about these 47cc pocket bike engines all over the place and I thought I would wrap it all up into one dedicated thread.

Just as a precursor, and although I appreciate the concern, I've pretty much got the mounting and gearing all figured out. I plan on rack mounting the engine and running it to a jackshaft just like the SBP kit and then to a freewheel crank just like the SBP kit and then back to my hub gears just like the SBP kit.
What I'm hoping we can do with this thread is lay down some solid experiences with these pocket bike motors and determine what kind of reliability one can epect from them.

Some of the advantages to these engines is that they are cheap, have incredible parts availability, can be upgraded like crazy and they look cool to boot.
Some disadvantages, well, I don't really know. That's what I'm trying to figure out. I pretty sure this engine in particular does not have a cast iron sleeve like the GXH50 (which is my other option) so it probably wouldn't last quite as long, but I wouldn't be suprised if you could find an upgraded cylinder with a sleeve considering how many parts are available for these things.

In summary, what do you think? Have you owned one either on a pocket bike, a motorized bike or anything else for that matter? What can you say about the characteristics of these engines, are they powerful, are they reliable or are they just plain finicky pieces of junk?

It's waiting on your opinion that keeps me up at night, so please drop a line if you've got some time..hey that was almost a rhyme!

Thanks for any help, you guys are great!

 

[fastboy9]

The pocket bike engine is surprisingly powerful and will beat a happy time easily! You can buy big bore upgrade kits too which will give you a CNC machined cylinder that will make the engine last a lot longer. As long as you look after it well then the advantages definetely outweigh the disadvantages. Go for it!

Fastboy

 

[conradcliff]

Freakin sweet! Thank you so much for the reply! Yeah, according to the description the one I'm planning on purchasing already comes with the 44mm big bore upgrade and some other things. I think you've pretty much just pushed me over the edge!

Thanks again!

 

[fastboy9]

No problem! that bike is going to be a screamer! cant wait to hear more, the list of upgrades is crazy, 11hp is pretty easily obtainable and the parts are so cheap for what you are actually getting. I think the record top speed on here is by a guy called kawasaki 999, he has a GP460 engine which is usually for go-peds, these engines are only 4.2bhp and his goes 55mph!!! so a fully modified engine up to 8hp, wow that would just be amazing, that plus gears omg.

Fastboy

 

[nathanl]

That is tempting. Not a whole lot of information on the page though. Can't see the mounts, do they mount in a similar way to the happytime? I guess not since you're going with a rackmount? Also, what sold me on the happytime was the built in gear reduction, anything like that on this engine? The page doesn't say much about it!

Edit: I got curious and found haggard's thread on it, looks like you need external gear reduction and no easy frame mount options. I'm terrified of fabricating a jackshaft so I'll stick with the happytime, but go for it if that's something you can handle! That will be an awesome bike!!!

 

[conradcliff]

I can't wait to see what happens! It wont be long now, I'll have the bike by next week and once I give it a looking over and make sure everything is going to fit I'll be ordering the parts. This is gonna be fun!

 

[Mountainman]

I am also wondering about the outcome for you with this engine

thinking about a fast MB THING for my next build

ride that thing

 

[conradcliff]

I can't wait to get started on it. I'll be making a detailed thread of the venture with plenty of pictures once I get underway..

 

[ocscully]

In case you haven't already seen this thread here is another member who used a similar inexpensive pocket bike motor and reduction gearbox on a home made rack mount http://www.motoredbikes.com/showthread.php?t=12836

ocscully

 

[nathanl]

This was probably answered before, but I am being shoed off the computer, Would the pocketbike engine be able to mount to a grubee 4 stroke style frame plate? (Anything is possible I guess, but without severe modifications?)