Shift kits

[avery schroeder]

I've seen them smaller.

I agree that a shift kit is a waste of time compared to a good pipe and a good port job, but I don't agree that a stock skyhawk does 43 with a 28t. you'd be lucky to even get it off the line with that gearing, let alone get any speed out of it. overgearing is a thing.

I'm telling you what I did with my brand new Skyhawk. Why don't you buy one and test it

 

[avery schroeder]

I have to call BS on that.... A stock skyhawk barely has enough power to turn a 44 tooth let alone a 28 tooth, I've run a 32 on one before and it was maxing out at about 25mph because of overgearing..... And second thing, where are you finding 28 tooth sprockets???? Lol I've never seen one that small

Mzpartsmiami on eBay store has a lot of motorbike stuff other websites do not

 

[Steve Best]

Call what you want but a stock Skyhawk does 43 I have tested and proven all I did was port the jug and skirt the piston and it does 56 now

Once you have a pipe, porting, aftermarket head and carb, it is getting hard to call it "stock".

I believe you. My stock Skyhawk did high 30s with no mods at all. Was easy to get to 45 kph with very little work.
I don't even have a tuned pipe on it (like you show in your picture) and I am over 60 kph now, with the stock 44t sprocket.

Problem with a 28t sprocket is starting away, or making it up a steep hill or slow speed trail riding in sand. Even the 44t has trouble in deep sand.

Nice bikes Avery, what are you using for pipes?

Steve

 

[Ttt]

Once you have a pipe, porting, aftermarket head and carb, it is getting hard to call it "stock".

I believe you. My stock Skyhawk did high 30s with no mods at all. Was easy to get to 45 kph with very little work.
I don't even have a tuned pipe on it (like you show in your picture) and I am over 60 kph now, with the stock 44t sprocket.

Problem with a 28t sprocket is starting away, or making it up a steep hill or slow speed trail riding in sand. Even the 44t has trouble in deep sand.

Nice bikes Avery, what are you using for pipes?

Steve

I'm talking in mph Steve, and your right I did forget to mention it did not have a stock carb or pipe but that is all that was not stock. I litterly took it out of the box and put the carb on and put a banana pipe on it. And I'm using a cr125 pipe a kx85 and kx 65. I didn't have the head or anything on when I did the "stock" runs. But I assure you it was the same jug and piston that came from the factory and a 28 tooth sprocket and got 40+Mph every time

 

[KCvale]

I agree with KC. A shift kit might not make you faster, but it sure helps to keep it in the sweet spot, and helps to keep you from thrashing the engine at high rpm all the time.

Actually they do go faster, the upper gears are overdrive.

Having said that, they do add a lot of complexity, and require more up-keep on the drive train itself.

That is true for 2-stroke shift kits, they are finicky and hard to install, and yet another reason I have moved to 4-strokes and electrics.
My 4-stroke shifting system is more reliable and easy to maintain than most any direct drive.

Welded on engine base with attached adjustable bearing tensioner wheel.
Imagine, no tensioner issues ;-}
Quality SBP freewheel crank assembly.
Internal 5-speed SA disc hub in perfect alignment with it's pedal sprocket.
Nice & quite #410 HD Z-chain for both chains.

A 50cc engine doesn't put out much power compared to a tuned 66cc 2-stroke, but I can run with them, and in city driving getting from point A to point B the fastest because of gears!

When you can get to 20mph from a dead stop in like 3 seconds and up-shift to change the 'sweet spot' it's a glorious feeling ;-}

 

[Steve Best]

Hey, just completed my first shifter!
48cc Grubee motor, and a very rough jackshaft setup with a freewheel on the pedal.
I am getting the "kick" of "lift the rear wheel by the seat" starting. Takes some getting used too.
Using a lever cable shift as a thumb throttle.
Tried a dual cable brake, not enough leverage, back to dual levers.
Bike is a test bed. Steel jackshaft, 41 chain and frame are heavy. Version II will be aluminum and 1/8th chain.

More testing to come. Motor is completely stock.

Other news, I have a cast iron 49cc reed fed cylinder off a motoscooter that will fit on the larger China Motor.
Ports are larger and I suspect double the HP should be possible. Cost is about $100. Have not tested yet. Riding!

Steve

 

[KCvale]

Cool Steve ;-}

 

[HeadSmess]

*twiddles thumbs and waits for a video, filmed from a moving car with speedo shots as well as GPS shots whilst holding steady alongside*

56mph. just shy of 100km/h?

good one

 

[Andy Birch]

View attachment 72791

Are those expansion chambers off a CR80 motocross bike?

 

[CrazyDan]

If you read everything he did say it was a cr125 pipe.