Hawk, TBR7 and Magician top speed averages.

[OneLeggedRider]

Let me first state it wasn't my idea to compile the group data, that honor goes to a bright young fella named Aaron P. All I did was crunch the numbers. He's going to map out a more detailed chart that includes gear ratios when enough folks have reported in.

The parameters included the general mods, sprockets jetting pipe etc. and bike model. All speeds have to be GPS confirmed on flat ground sitting up and not drafting an automobile.

With 25 members reporting in, 19 Hawk which included 1 Bashan Storm, and 6 TBR7 and Magician (I lumped them together because those 2 put out nearly identical numbers and didn't seem to be affected as much by rider weight), here's what I came up with.

The Hawk class top speed average is 62.26 mph (which didn't surprise me).

The TBR7/Magician class average is 68.66mph (guess those smaller diameter tires do make a difference).

The average American China rider weighs 221lbs. Now this did surprise me, these after all are little 229cc bikes so I figured the average owner would be about 180lbs.

I haven't done any speed runs since I went up to the 13/33 ratio but it seems the 66mph I got with the 12/33 was very respectable.

[Megadan]

This is including bikes with only bolt ons and no advanced work? Jerry and I can both hit about 75, but we both have bigger carbs and aggressive head work.

[OneLeggedRider]

Originally Posted by Megadan

This is including bikes with only bolt ons and no advanced work? Jerry and I can both hit about 75, but we both have bigger carbs and aggressive head work.

No, we didn't include any oddballs or fanatics..

I'll crunch the numbers for the gear ratios tomorrow but I'm guessing the average to achieve these speeds is about 2.5 or 2.6.

[RedCrowRides]

Damn , i guess I better start eating if I order that DB47 i am lusting after, i am seriously shy of the 221 average lol !

[NzBrakelathes]

Beyond 6000 RPM is detrimental for this type of engine for long periods as per local advise.

I fail to see the benefit in TOP SPEED on wee bikes, cruising speed is more usefull and should be about 6000 RPM.

[OneLeggedRider]

Originally Posted by RedCrowRides

Damn , i guess I better start eating if I order that DB47 i am lusting after, i am seriously shy of the 221 average lol !

You'd have to talk to cousin Jay about the risks of riding these mean machines without proper ballast.. I'm 40lbs over the average and I think I can hear a slight groan when I climb aboard.

But yeah, 4 of the 25 were 300+ and possibly a 5th that chose to not to answer that question. So these little CG engines must be pretty hardy. MtnManPoe says our beer bellies make us more aerodynamic but I haven't tested that theory.

[OneLeggedRider]

Originally Posted by NzBrakelathes

Beyond 6000 RPM is detrimental for this type of engine for long periods as per local advise.

I fail to see the benefit in TOP SPEED on wee bikes, cruising speed is more usefull and should be about 6000 RPM.

Just a friendly way of testing our bikes performance without the benefit of a dyno. And the reason I went up to the 13/33 ratio was so I could comfortably cruise along at 55mph without feeling like the engine was coming apart.

[wedooit]

I am the average of weight you mentioned above. I have had the BMScrp at about 60 mph. I don't know what the rpms are. I really never look at the speedo, just check to make sure i don't get a ticky, and that comes from riding sleds.

[OneLeggedRider]

What's interesting is most of these bikes have the bolt on mods as Dan mentioned and are "broke in". Without a dyno or drag strip you can't really tell if the mods improve acceleration (I'd say they do) but the most common Hawk number reported was 63mph, even on the few stock bikes. The same for the TBR7/Magician class, most were 68mph which Jay achieved without the pipe. This confirms that unless you take drastic measures like Dan and Jerry the CG just cannot breathe well enough to make any power on the top end no matter what you bolt on.

[Frag2]

Right on, for mine Magician ive added front sprocket an carb so far, myne a little bit faster but not much

[Megadan]

Originally Posted by NzBrakelathes

Beyond 6000 RPM is detrimental for this type of engine for long periods as per local advise.

I fail to see the benefit in TOP SPEED on wee bikes, cruising speed is more usefull and should be about 6000 RPM.

Top speed matters a lot more to those of us that live in the U.S. outside of the big cities, which is about 80% or more of the land mass that comprises our country. In the Central U.S. where I live there are large swaths of nothing for hundreds of miles, and this means most of the highways here are 60-65mph with people going much faster than that simply because they can easily get away with it. It's hard to police thousands of miles of highway with a low population density surrounding it. That isn't even including major State highways (65-70mph) or interstate (75-80mph).

As far as beyond 6000 being detrimental, I would argue that. Myself and many others have put thousands of miles on our bikes, many of which were on highways with the engine singing along at 6500-7000 the whole time.

[Megadan]

Originally Posted by OneLeggedRider

No, we didn't include any oddballs or fanatics..

I'll crunch the numbers for the gear ratios tomorrow but I'm guessing the average to achieve these speeds is about 2.5 or 2.6.

You should break down the gear ratio in relation to tire/wheel size. A 2.7 (17/45) on a 110/100-18 rear tire will have a different final drive to that of a 2.7 on a 110/90-17.

As a whole a 2.6-2.7 sprocket ratio on a 18" rear wheel bike with a properly jetted carb at lower altitude (sub 4k ft) and tire pressures pumped up for road use will usually have a top speed right around 65-67mph with full bolt ons, but has an "ideal" max cruise speed of around 50-55mph - aka, not wide open.

The same bike with a 2.5 ratio is capable of topping out at about 70, but can maintain a 60mph max cruise speed with greater ease and less throttle.

[Hawkrider91]

i have a 17/45 setup and a 115 main with stock pilot jet that comes in the mukuni carb. also did the air box mod. my top speed is only 60. i weigh 225. any way i can get it higher? i'll be riding on roads with 55 speed limits here in florida.

[Tashka]

my top speed is 75 but the bike can creep to 70 anytime. 17/44 on a 428 chain

[Hawkrider91]

should i lower my rear sprocket? to a 40 that is or a 43? its 2019 hawk 250 if that helps