top speed please.

these chinese engines are not built for speed... However I am going to be doing a gearing system with my 70cc then soon upgrading to a 135cc engine. I should be able to pull somewhere around 40mph tops even with the big engine... I do not want to go faster :eek: :eek:
 
Re: speed

philcred said:
Joe that's good speed for a stock engine.
I am only doing 10 mph more and I have changed everything.

A stock scooter (moped) Peugeot speed fight 49cc will do 50mph + and they weigh a hell of a lot more they my bike.

Yeah, that was down a very slight hill and with a tailwind.....the engine was SCREAMING and I did it once. I can see 30-31 mph regularly on the flat with no wind and the engine sounds as if it might last for awhile like that....so that's a more realistic top speed for the Happy Time engine.

The Speedfight will go that fast because it has a much higher redline and a CVT transmission.

Ours are "stuck in 3rd gear" and have around 6000rpm redline.
 
no one beleives me, I dont expect them to. I got my engine used witha few modifications done to it, when installed on my mountain bike frame it pulled 45 easy, not screaming. for many streets at a time.

Now, its topping out at 30

I got an exhuast crammed up with carbon, a dirty fuel and air filter, and worn down clutch pads that barely grip anymore

actually, after the last 25 miles i put on the bike today, the last 3 it was topping out at 20, this is all my clutch. cant wait for my new one.
 
I think not disengaging the engine on steep downhills and pulling high RPMs where the engine is at max thottle going 34 MPH and actually keeping the bike slower than it wants to go was the downfall of my upper arm bearing and caused it to go out. When I get my bike going again, I am going to start pulling the clutch in and coasting down the steeper hills. I had a Power King 80 with a 44 tooth sprocket and I was able to cruise at 28 to 29 MPH easy. Max throttle gave me about 32 MPH. With under 300 Miles on my engine, the upper bearing shredded on me and tore up the upper half. Piston, cylinder, rings all bad. I have since put a 36 Tooth sprocket on and have switched to a Dax 70 (the dax 70 piston is even a tad bit bigger than my PK80 cylinder!!). Thatsdax is sending me a good cylinder for a used engine he just sent me. It's interesting to see the differences between the 2 engines. I would love to cruise at 30 with lower RPMs. (The reason for the 36T sprocket).

Dan
 
Bike #1 Cruiser style with DAX 70 will do about 32mph any day, and will occasionally wind up to about 38 mph...has 44 tooth sprocket...engine is well broken in and completely stock

Bike #2 Same set as above except with Power King 80 not yet broken in...I've had it going about 28mph or so for short bursts, but haven't held it open long enough to really know what it'll do because it is still new. However, it does not feel quite as spunky as my Dax 70 did when it was new.

Bike #3 Same bike exactly as Bike 2....not fully broken in yet...not sure if it ever will be cause it's a gutless wonder...I've tried everything I can think of and I can't get it to pull 22mpg on the level...and the slightest uphills require me to pedal.

Bike #4 Chopper style with 20" wheels, Dax 70, 44 tooth sprocket....lots and lots of low end grunt because of the small wheels...will top out about 25 mph, but vibrates a fair bit at anything above 19 mph...not the engines fault at all, it's just geared too low and wants to overrev because of it. It would probably be perfect if I installed a smaller rear sprocket

Bike #5 Sekine 10 speed road bike with Power King 80....very similar performance to bike #1
 
Ok, who fed the steroids to my Dax 70? I took it out today and it was totally nuts. I had the speedo showing well over 40mph. I even passed a gray haired lady in a Ford Focus. I stopped to check the engine over....thinking that I may have developed an airleak at the intake or head resulting in a lean condition (they always run best just before they blow). Checked the plug color and it was a nice light brown, so I kept riding it. I put over 35 miles on it and it never missed a beat and the newfound power remained. Must have just been ideal air temperature and pressure today, I guess?

Pete
 
My Dax 70cc topped out a 34mph downhill. I cannot get it to go faster than that. Well yet anyway :) Once I get the jackshaft done it should be able to hit 40mph.

I am having issues I killed my metal drillbit so that sucks but other than that I will get it done.
 
got my chinese 48cc up to 50kph (31.068miles) along the a flat section of road. Still a little room for inprovment.
 
Bog standard 48 cc Howell. now nicely run in 34mph slight downgrade, 30/31 on the flat. Minus point, big fat bloke on the saddle. Haven't calculated the CdA of my beerbelly, can't get through the door of my local wind tunnel center.
 
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