Thread: What am I Thinking? Long Story w/pics

Thanks Guys!

Does anyone have a suggestion for sprockets?

I'm too lazy to look through the whole thread again.

Sprockets depend on a number of variables.

1. Gearbox Ratio in each gear
2. Primary Gear Ratio
3. Horsepower
4. Tire Size
5. State of Tune.

You need to figure out the above variables and then plug them into my speed calculator:

7.5 HP is capable of 55mph.

Honda50.com Gear Ratio - Speed Calculator

You'll notice I only have Honda and Japanese combinations from the pulldown menu. There is a 100% chance we will not ad any of the chinese "flavor of the day" gearboxes/engines because they change too fast, and we have no interest in them. However, you can get the ratios and plug them in manually.

One of my old combinations was as follows:

Honda Monkey 4 speed gearbox with a 1.043 4th Gear Ratio
67/18 Primary Ratio
88CC BBK, Race Head, 20mm Carb, Good exhaust - Around 7.5HP
3.5X10" tires
I ran a 35T rear sprocket, and a 15T front sprocket, but did run a 16T on occasion. I liked the 15T better with the 4 speed.

on any of the chinese motors, I expect them to run out of steam before 10,000 rpms.

The more horsepower you have, the taller gearing you can run. If the bike falls flat in top gear, either your front sprocket is too big, or your rear is too small.

Alot of sprocket choice is personal riding preference. Just my 2 cents.

With a stock 72cc I'd run a 38 tooth rear and a 15 or 16 front. I don't know what the finale drive ratio is in a 72cc lifan but if its the same as a early KO that would put you in the ball park, guessing your new tires are a little larger in Dia. then the knobbies. A good running 88cc 4 speed will run 50 to 53 mph with a 38 rear and a 17 front but the 72cc won't pull that gear in high very well.

PS, I see Dan posted an answer If you were going for more flat land speed and or your going to put in a larger engine sometime latter, his suggestion of a 35 rear sprocket would be better so you don't have to change the rear latter (and save some $'s) just run a 14 or 15 counter sprocket. MHO.

Thanks Dan!...That will be a good starting point...and it might just be right on the money!!

Thanks Grant, I appreciate it!! I'll get a couple different counter sprockets and play around with them.

Karen,
That's what I do. I have 14, 15, 16 counter sprockets and 30, 31, 33, 34 and another one I can't recall what it is. Really does make alot of difference and fun to mess around with.

what sprockets are on it now?38T rear seems to be popular with clones.like Grant said 15- 38 and a 88kit 19mm carb hits 52mph.not so good for off road hills though.thats what i have also.for tires,dont laugh the dr atv why not tires for 18.99 each are real nice.cheng chin,they grip real well in the turns and i ride it hard.tthey are directional also.stopping grip excellent too.you know when some a-hole pulls out in front of you.3.50-10inch.speedo is not affected by much with these.cheng chin tires have come a long way since we were kids.for shocks i just ordered yasusu 330mm on ebay.2 pairs.i will let ya all know how they are.i want to ditch my ''trailbuddy style'' shocks too.i bought them in 06 on e bay from ''baysao''.

Karen ,
You may want to ride it first , and see how much power you have . My dobber had a 14f & a 42r sprockets . I wheelied in 3 gears . I changed them to 16f & 36r . Made a huge difference . Remember though , mine is a 107cc . Claimed 7hp , which is 40% more then yours .

I bought one of these and was on a ride in PA and that " missing nut ", well It found its way into the spring or..?? and bent the valve. just thought you might want to know.

---------- Post added at 10:41 PM ---------- Previous post was at 10:24 PM ----------

what are the honda style footpegs off of??

Originally Posted by kmcrab

I've made a few changes to the Dobber...

I broke out the Roto Zip and got rid of that back mudflap. You can see in the 2nd to last pic how much I took off. The license plate bracket that came with this bike will only work if you have slots instead of holes in the plate unless you drill for them, which is possible with this bracket. The vintage 1968 Kansas plate would not fit, but the 1981 Iowa did.

I removed the Dirt Dobber decals from the frame and the "Super" decals from the front shocks. I haven't decided yet what to replace the frame and indent decals with.

I changed out the 2.5" foot pegs...Check out the difference! Stock is 4". Wow they were small.

I put an original KO seat on it just to see how it looks...I like it, but the clone pan is not the same as Honda and the way the wiring is on this bike the seat pan will cause damage to the wiring and connectors, so if I want the KO look it will have to be a KO cover over the clone foam using that pan.

What are you guys opinions on the seat...Keep it like it came? Add chrome studs along the bottom of the stock clone seat? Change it to a KO cover and studs? You can compare the seat that came with this bike in my first post. Thanks.

Any new pics?