Big Engine Bicycle 79cc 4-stroke

[cspaur13]

i hope it sounds good. i might just weld a pipe to the back and put the regular exhaust on it or idk. might try both. i'll let you guys know.
i just got the muffler off and it sits nice and snug and my frame. if it was 2 much bigger i'd be screwed.
i think znsanerider ddi it but i dont know how. i'l have to ask him.
yea they matched internet price for me. i hope you all purchase this engine and try a frame mount build.
thanks,cody

 

[cspaur13]

Rgvkid

about he de-govenering. all you do it open up the crank case. then the gear is in the back its plastic. you pul the center cap off with needle nose plyiers, my center cap was metal but it might be plastic. might take along time. then you have to pull really hard for the gear to come off. i thikn u have to twist it to the left alittle while your pulling. then make sure you get the washer off behinde it. then your good. then you can take the arm that went to the top of the engine for your throttle. cut it and take it out. seal up the hole with w/e then your done. you can go to my thread posted in general dicussions about it. 79cc frame mount build.
good luck,
cody

 

[macarollo]

on my 196cc HF motor and I assume the 79cc one is the same.... the gear is held on by a small ring clip. I used a screw driver and hammer to wedge the screwdriver under the ring and then it came loose eventually. I found this to be easier than brute force ripping the gear off.

 

[Rgvkid]

Thanks Cody and Mac for the DeGov info. Im starting my build this week. I'll post the progress.

Thanks Znsane for the hub info on the larger tire. Greatly appreciated.

 

[cspaur13]

macarollo
that dose sound like a good idea. but i dont think you can do that on the 79cc cause its a tight fit in there. you can try. but idk if it will work

Rgvkid
urwelcome. have fun building it. is it gonna be frame mounted, rack mounted or a push trailer.

 

[ZnsaneRyder]

I know you are supposed to remove the internal governor, but I've not had any problem with leaving it in there, and going straight to the throttle. However, since you folks seem to have had little trouble with removing the gov gear, and lever, I'm going to do that on both my 6.5 and my bro's 2.5. Less unnecessary stuff in the crankcase.

I can't wait to see one of those HF 2.5s mounted on a bicycle! It's a heck of a task, but it's worth it in the end when you are flying down the road!

 

[cspaur13]

you might have better luck. i think you have way more room in 6.5 crankcase. so it should be alittle easier.

yea. it will still be cheaper than a 2 stoke kit and it will be more reliable and less fixing/repairing things.

 

[ZnsaneRyder]

Have you figured out what rear wheel sprocket to get for your bicycle? Once you get that figured out, then you can calculate the rest.

I figured if you get close to a 9:1 ratio with your 26 inch wheel, you get 36mph @ 4200RPM. Just come up with a combination of sprockets with your jackshaft to get close to that ratio, and you should have good power.

Have you downloaded the Gear Ratio Calculator? It will help you determine your teeth needed for your jackshaft and wheel sprockets.

I'd recommend going not real big on the wheel sprocket, so you have some more chain clearance. You can reduce gearing a lot with the larger jackshaft sprocket, so it makes it easy to have a low enough gear ratio. Jackshafts are great because they multiply the two ratios. No gearbox needed with a Jackshaft, just keep the chains tight, and figure a way to adjust them when they stretch.

 

[cspaur13]

no. stll playing around with the gear ratio calculator to get the right numbers. i wish the clutches could have 8 or 9 tooth sprockets on them.
for the jacshaft will the gear ratio calculator work for it.

 

[ZnsaneRyder]

The gear ratio calculator works for up to two jackshafts. Makes it much easier to calculate ratio.

Since the Clutches have more teeth than 8 or 9, just add more teeth to the jackshaft sprocket to have a lower ratio.

If you figure out what sprocket you are mounting to your back wheel, I'll help you with the ratios. Do you already have a sprocket from a bike kit or something to mount to your rear wheel?

Here's an example with the gear ratio program, assuming a common 44T rear sprocket: