First Ride w/Shift kit tonight:(

[Mr Hydroseed]

So I've got some china import 4 stroke kit I got off of ebay, its actually pretty darn sweet. Being a single speed it starts off pretty slow and takes a little to get to top speed, the problem was It just never sounded like the engine was at optimal rpm's, like it was just geared too high.
Not to make anyone look bad, but I sent an email to sickbikes along with pictures of my kit that I bought and asked if the shift kit would work? They said NO. Reason: the motor and gear box are too wide and the pedals would never clear the gearbox and or the motor. I believed them for about 3 seconds then decided to order it anyways. Well they were wrong, before i had to pedal with my feet on the outer 1/2 of the pedals even with the extra long bottom bracket axle that came with the kit. The sickbikes crank axle was even longed and the included cranks angle out slightly as well giving me 100% clearance for pedaling with my feet all the way on the pedals. I was very impressed with the entire bottom bracket and crank assembly.

So, I was all excited to test out the shift kit after taking forever installing it tonight and things where a little noisy and rattly. Of course I forgot the jumpstop too.... I think i installed the shifting chain a bit too long also. I purchased a new 8spd twist shifter and in high gear it is no way the same or close to the same ratio as my original single speed. I thought there was something wrong with my engine because there was no power at all. I was all wrong in shifting at first, I kept hearing weird noises, oh thats it shifting. Sometimes it shifted really smooth and other times not so much. I tried finding the top speed in 8th gear and was like blahhhh, I dropped it down to 3rd then 4th and the engine was really winding up, it was letting it all out and it loved it! I was thinking the kit was worth it just to have it in 3rd or 4th gear it was flying! I'm funny in that everytime I see a car im like lala lala im just pedaling my bike here heehee. A car had passed me then stopped at a stop sign, it took off and I went after it, wait a minute i'm like keeping up with it? This is awesome!!! drive a few miles down the road in pitch darkness except for my Walmart bike light which actually works pretty good, when all of a sudden the chain goes kaplang kuput. The chain is now all wrapped around the small chainring, not so awesome! I get on the side of the bike and hold on to, obvious the muffler... sizzle... ahhhhh!!! After wrestling with a severely mangled chain for awhile some kids in a pickup offer me a ride, SWEET!!! I explained to them, just 2 days ago I saw some elderly guy with a cane pushing a broken office chair with his backpack on it going ever so slowly down the sidewalk, I turned around after picking my son from camp and he was laying flat on a bench and didn't look so good, I gave him a ride to the bus stop. I said to my son, see now I've got some good Karma points. One of these days I'll need a ride for some reason and now hopefully someone will help me out. Weird!
I can't wait to get a new correct length chain on it along with the jump stop and go riding again, close to home. I'm a little worried about letting other people ride it cause I think there just gonna power shift it to death. Oh, yeah. I'm not sure how much power shifting is allowed, but **** it is awesome! I'm still trying to figure out how to shift the best way and the only thing I may change is to lower the gearing a little bit on the jackshaft but otherwise I would recommend other in getting one of these shift kits. The End.

 

[professor]

Think about where the loads come in to your derailer before you powershift. I would not do it.

 

[5-7HEAVEN]

I have a Tanaka 47R racing engine with shift kit on my bike. It has taken MONTHS of almost daily riding to fine tune the engine/combination. Thankfully, the engine is super reliable, so I'm not having to troubleshoot engine, bicycle AND drivetrain.

I have a few suggestions. The first thing you need to do is to find your engine's "sweet spots". These are rpm ranges where maximum horsepower and maximum torque is realized. You don't need a tach; you will feel how your bike runs best.

You also need to find out what your gear ratios are in each gear. Eighth geat is rarely effective, unless your first and second gears are VERY low. Are you using 11t-32t rear cassette? How many teeth are in your bicycle chainring sprocket? How many teeth on your jackshaft and engine sprockets?

It takes a while to learn how to effectively use the engine rear cassette. The very first thing you need to do is to stop powershifting. In the beginning, I power shifted, which led to bent cassette sprockets, which contributed to chain jumping and other issues. Nowadays, I normally use first, third and fifth gears, sometimes sixth and seventh and rarely eight gear. I also slack off the gas, pedal three strokes, then get back on the throttle again. This places MUCH less strain on the chain and sprockets. Knock on wood, the chain has not jumped off and wedged itself between frame and sprocket bolts since I started pedalling.

I would also advise you to carry a spare chain, master link, hand cleaner and chain breaking tool. Besides the Jump Stop, I left the front derailleur on. This helps keep the chain aligned.

I would advise against powershifting. You will always end up short shifting, because you'll be thinking about missed shifts and broken chain and gears. When you pause between shifts, you can rev to the max, pedal to make sure the chain is engaged, then jump back on the throttle.

Hope this helps.