2 Stroke Mountain bike with shift kit build.

This is now my 4th bike build and I wanted to show everyone as I go to get feedback. I was unhappy with my results on my last 3 builds. Also, I've found this forum to be a really helpful, friendly and informative community, anyway here it goes. So in excitement, I impulsively purchased the HD 2 stroke shifter kit at sickbikeparts.com I know now I wasnt fully processing that this kit is not a "jackshaft" which is fine because ultimately I didn't want the "jackshaft kit", i was wanting a "shift kit" that idea is really awesome to me. Luckily, even though i misunderstood I got the right kit,(i think). I got my "shifter kit" in the mail today. This is my 4th bike build I'm starting. I've had a blast with the other 3 builds. Thank you all to anyone that has helped answer my questions. This is the bike that I'll be installing the shifter kit on along with a new motor kit I already had. I'm undecided about which of the two handlebars to put on it. Well thanks again everyone. I really value your feed back.

 

[xspade17x]

How would I put this intake manifold on my engine

 

[xspade17x]

I've only got two screw holes

 

[mark20]

id get a proper 2 stroke pipe first, then if you have a belt sander or just sandpaper and a glass table, you can shave the stock head and cylinder down for a compression increase (do about 1mm of the top of the cylinder, and a hair off the head, should give you a nice bump, go in baby steps, you can always remove more, but you cant put on more)

heres a really nice clone of my mz65 pipe (real ones are close to 150$ now, if you can get it that is)
https://www.bicycle-engines.com/zed...plica-for-2-stroke-motorized-bicycle-engines/
you can also cut off your stock exhuast baffle and clamp it on to the pipe to get it real quiet.

just some reccomendations.

and those reeds are for pocket bike motors hence the 4 bolt pattern

 

[Chainlube]

You're better off spending some money on a pipe than that little carb, it needs an adapter to fit plus a pocket full of jets to fine tune. End up being the same price as a pipe in the end. Plus, by the time you get the adapter and the intake and carb all stacked up in there, you're out of room for everything to fit. I'm putting a 2 stroke scooter pipe on my 4X build, but I have to complete rebuild the pipe to fit the bike and performance I want, but it's nothing radical. Just want to get up the hills with my fat arse on it.

 

[Street Ryderz]

Unfortunately true performance from the Chinese bicycle engine doesn't come from bolt on parts only slight improvements that cost you more else where as other problems arise.This engine requires alot of corrective work witch many are not setup to do when they first start out and get mislead by vendor and reveiw claims,as stated above your best bolt on gains will come from a good pipe but then being able to set it up and tune it is more important than just bolting it on.Do some research and read up on these things is your best bet!

 

[xspade17x]

So I ordered this before I read the reply from all of you..

Is it gonna be beneficial? Also would this exhaust pipe be any good

Thank you everyone for your input.
I know I'm going to have to rejet the carburetor that's why I got one with the jets.

 

[xspade17x]

I actually decided on getting this exhaust pipe

 

[xspade17x]

I wanted to post an update but I also need some advice. I have the shifter kit on it with a 17t sprocket in a 10t sprocket out and a 44t chainring on the cranks. With a 40t chainring that goes to the axle But also on the axle I have 10 speed cassette that goes all the way up to a 42t which I feel like it's not pushing the power it can with the current cassettes. I want to go smaller. I'm not sure if that will be better or not. But when I ride I know the bike has more power it just feels like it's being limited. Idk I need some feed back. Thanks.

 

[GreasyChris]

In my experience with the jackshaft a 44 and a 36 t chainring on the crank works best using a 28-14 5 speed freewheel on the back wheel. Every egg vine had a torque curve where it produces the optimal amount of power and torque if your gearing is off the engine will not be able to power thru that gear and is like trying to take off in your manual cart in 4th gear. If your gearing is the other way then the rpms go up but your don't go anywhere because the is way to much reduction. Using a 36t chainring and a 5 speed 28-14 freewheel my bike will pull from a dead stop without pedaling and shift thru all 5 gears and top at at 53mph. Hope that helps.
Heres a gear ratio calculator for ya.

Tire Size, RPM, Speed, and Differential Ratio Calculator

Describes the process for converting a gasoline powered car to electric power

www.advanced-ev.com

 

[5-7HEAVEN]

A

In my experience with the jackshaft a 44 and a 36 t chainring on the crank works best using a 28-14 5 speed freewheel on the back wheel. Every engine has a torque curve where it produces the optimal amount of power and torque if your gearing is off the engine will not be able to power thru that gear and is like trying to take off in your manual car in 4th gear. If your gearing is the other way then the rpms go up but your don't go anywhere because it's way too much reduction. Using a 36t chainring and a 5 speed 28-14 freewheel my bike will pull from a dead stop without pedaling and shift thru all 5 gears and top at at 53mph. Hope that helps.

The problem is your 40t chainring. A large denominator(40) results in high gear ratios in 7th-8th-9th-10th gear. It's like you have a 34 tooth sprocket in 7th gear, then 28t, 24t and 21t sprockets in 8th-9th-10th gears.
If you use a 24t chainring, then your final drive gear will be like a 34t rear wheel sprocket, and 9th-8th and 7th gear will accelerate.

If using a 24t here, the first few gears will be very low. You'll be able to climb stairs w/your bike!

When creating gear ratios for engines, consider what rpm they make maximum torque. Gear small high-winding engines very low(high numerically) and 79cc-212cc engines much higher(lower numerically).

How high and how low?

My 47cc Tanaka engine's geared at 43.64:1 First gear and 15:1 final drive. Like 113t and a 36t sprockets.
It's perfect for me.
OTOH, I'm gearing my governed 212cc engine at 10.9:1 First and 5.45:1 final drive.
We'll see how that works.