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. :tup:

[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]

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.. :hehe: :lmao:

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]

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 !

:lmao: 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. :hehe:

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. :hmm:

[OneLeggedRider]

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]

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]

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

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

[Wild Dog]

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


This ↑↑↑
Same thing happens here, in the south of country hundreds and hundreds of miles without a soul or sometimes phone signal... In those area people just ditch small cc bikes for something more powerful or medium sized engines.

[Hawkrider91]

if i can just get my bike ride comfortably at 60 ill be fine.

[OneLeggedRider]

if i can just get my bike ride comfortably at 60 ill be fine.

Not enough information. Is the bike broke in (about 500 miles on it)? Mine topped out at 56mph when new and at about 180 miles it suddenly (as I was riding home) would do 64mph and I had to turn the idle screw down.

After that I drilled the stock pilot to .45mm, added a 3rd washer to the needle and a 110 main jet (performs flawlessly up to 80° temps) and then it would do 66mph with the 12/33 (16/45 = 2.8) ratio. Now with the 13/33 (2.5) ratio it cruises along happily at 60mph and you can actually wind the first 3 gears some before having to shift up.

Being that Florida is so flat you can probably get best results from 17/43 (2.5 ratio) or even go to 17/40 (2.35 ratio).

[JerryHawk250]

No, we didn't include any oddballs or fanatics.. :hehe: :lmao:
Oddballs??? Fanatics??? Wait! I resemble that remark! :wtf: lol


My Hawk in stock form with tuned stock PZ30 carb (40 pilot/115 main), gutted cat and 17/40 sprockets would top out at 72mph. But only after I had put 500-600 mile on it. before that it struggled to do 60mph.

[OneLeggedRider]

The Hawk class gear ratio average is 2.83

The TBR7/Magician class gear ratio average is 2.68

I think everyone will agree that the 2.5 ratio is the sweet spot for for these bikes as far as comfort and speed. This also tells me that the average Hawk class owner in the group is geared too low, which skews the top speed number a bit.

And being that the TBR7/Magician class owners are closer to the sweet spot could also somewhat account for their higher top speed average. And as MegaDan mentioned the sweet spot for the TBR7/Magician class is probably lower (2.3 - 2.4) because of the smaller tire diameter. So basically the entire group is geared too low for accurate top speed numbers. :hmm:

Back to the drawing board I guess. :hi:

[OneLeggedRider]

Oddballs??? Fanatics??? Wait! I resemble that remark! :wtf: lol


My Hawk in stock form with tuned stock carb, gutted cat and 17/40 sprockets would top out at 72mph. But only after I had put 500-600 mile on it. before that it struggled to do 60mph.

Wow, that's an impressive number and I'm not sure how much you weigh but from your videos it looks like pretty flat terrain and says alot for the 2.35 ratio.

Oddballs and fanatics.. :lmao: You and Dan are at the forefront of our sport and always pushing the envelope, which I have to applaud and the rest of us appreciate.

There was one owner in the study that did a mild port and polish without decking the head and his top speed was 71mph, but the average Hawk owner isn't gonna go that far.

[JerryHawk250]

Wow, that's an impressive number and I'm not sure how much you weigh but from your videos it looks like pretty flat terrain and says alot for the 2.35 ratio.

Oddballs and fanatics.. :lmao: You and Dan are at the forefront of our sport and always pushing the envelope, which I have to applaud and the rest of us appreciate.

There was one owner in the study that did a mild port and polish without decking the head and his top speed was 71mph, but the average Hawk owner isn't gonna go that far.
I'm on the Jay end of the spectrum at 175 lbs. lol The only hills we have around here levies, bridges and overpasses.

[JerryHawk250]

One thing to understand is that P&P and decking the head doesn't really increase the top speed by a whole lot but it really wake up the mid to upper rpm range to where when running 60-70mph you don't have to twist the throttle wide open to do it. Finally got some nice weather here. I started Friday after work till yesterday riding. :D I put a few hundred miles over the Labor Day weekend cruising anywhere from 60 -70 mph and never thought twice about doing it. One of the best mods you can do on these bikes.

[OneLeggedRider]

One thing to understand is that P&P and decking the head doesn't really increase the top speed by a whole lot but it really wake up the mid to upper rpm range to where when running 60-70mph you don't have to twist the throttle wide open to do it. Finally got some nice weather here. I started Friday after work till yesterday riding. :D I put a few hundred miles over the Labor Day weekend cruising anywhere from 60 -70 mph and never thought twice about doing it. One of the best mods you can do on these bikes.

I'm thinking about just doing the port and polish without decking. The reason behind this is we only have 2 local gas stations out here in the boonies and they only sell 87 octane and diesel. I'd have to drive 30 minutes to get higher octane and that would be a pain, having to remember to fuel up before coming home or keeping a couple jugs full at the house.

It's already a pain keeping a jug of 2-stroke mix around for the very thirsty Scrambler.

[JerryHawk250]

I'm thinking about just doing the port and polish without decking. The reason behind this is we only have 2 local gas stations out here in the boonies and they only sell 87 octane and diesel. I'd have to drive 30 minutes to get higher octane and that would be a pain, having to remember to fuel up before coming home or keeping a couple jugs full at the house.
Understand. I think the P&P alone will make a big difference IMO. But you know me, I had the head off and it was like "Might as well do it" at the time. lol I'd like to see what results you have once done.

[Hawkrider91]

Not enough information. Is the bike broke in (about 500 miles on it)? Mine topped out at 56mph when new and at about 180 miles it suddenly (as I was riding home) would do 64mph and I had to turn the idle screw down.

After that I drilled the stock pilot to .45mm, added a 3rd washer to the needle and a 110 main jet (performs flawlessly up to 80° temps) and then it would do 66mph with the 12/33 (16/45 = 2.8) ratio. Now with the 13/33 (2.5) ratio it cruises along happily at 60mph and you can actually wind the first 3 gears some before having to shift up.

Being that Florida is so flat you can probably get best results from 17/43 (2.5 ratio) or even go to 17/40 (2.35 ratio).


i have 180 miles on it. so once i hit 500 it should perform better? i have done jets except the pilot jet. i dont where to get it.

[OneLeggedRider]

i have 180 miles on it. so once i hit 500 it should perform better? i have done jets except the pilot jet. i dont where to get it.

Yes it will definitely perform better at 500 miles and will keep improving all the way up to 1000. Drill the pilot to.45mm or order Tako's sprocket and jet kit.

[Azhule]

i have done jets except the pilot jet. i dont where to get it.

I sense a can of Spam with a ebay link coming in shortly :lmao:

[NzBrakelathes]

i have 180 miles on it. so once i hit 500 it should perform better? i have done jets except the pilot jet. i dont where to get it.

https://clevelandspeedshop.com/collections/heist/products/pilot-jet-heist-misfit

[OneLeggedRider]

Well after much debate, a few fistfights, and some heartfelt apologies at the last Bored Member meeting it has been decided that a 2.5 gear ratio is NOT infact the "sweet spot" for these little China bikes.

A broad consensus of our riders who weigh 175+lbs and don't live in the flatlands feel that a 2.6 ratio is more to our liking and J. Money concurs (not sure why but Jay's hoping that moniker will stick). Even at his meager 140lbs he says the 2.3 ratio felt like power assisted coasting and is really pleased with his current 2.6 ratio.

Justin, another member of the study has been playing with different ratios before upgrading to the 520 setup. He tried the 2.5 per my recommendation (he's currently 2.86) and there was no speed increase and a significant power loss in 4th and 5th, so he wants to go to a 2.75 which I strongly disagree with because that was my last ratio and it was a pinch too low.

I currently am at 2.53 with 13/33 sprockets (which J. Money loves), but if I'm not happy with it I'm gonna go to 13/34 which is a 2.61 ratio.

**Also if you go to the 520 do not go bigger than a 12 tooth front sprocket. I had to cut out a significant portion of the sprocket cover to make clearance for the beefier chain. :tup:

[Megadan]

My big butt likes the 2.6x range as well, and it works good for a mix of flat land and moderate hills.

As far as the 520 and the 13t front sprocket. Results may vary. Mine fit just fine.

[China Rider 27]

I have a stock HAWK meaning I only have the air box and carburetor tuning modifications. I have a 520 chain and had the 13t 35t ( 2.6X ratio) installed for a short while and I will say a great ratio no doubt. The first time I shifted from 1st to 2nd I thought wow you can wind out 1st gear and 2nd is sweet on rpm too, but I live in mountain country and the flatland quickly becomes hilly and then mountainous so power up a grade is important. What I found navigating up some fair sized hills compared to other ratios was a greater loss in power and speed with the 13t and I weigh 180 lbs. I have an 11t installed now (courtesy of Dan's research) which figures 3.1X and I can run almost the same WOT top speed of 60-62 mph AND it maintains greater speed up the hills than the 13t apparently better utilizing the stock engine band power output.

[OneLeggedRider]

My big butt likes the 2.6x range as well, and it works good for a mix of flat land and moderate hills.

As far as the 520 and the 13t front sprocket. Results may vary. Mine fit just fine.

I think its the Uni-Bear chain. Mine was ever so slightly rubbing the cover with the 12 tooth on it, and it definitely wasn't going on with the 13 tooth.

[China Rider 27]

13t can also be solved with the 520 13t reverse keeper installation which requires grinding the sprocket cover. I found it runs great that way and I install all my sprockets in reverse keeper to get good clearance from the case. 13t is too good of a ratio to let the issues stop you in my opinion.

[Tashka]

on stock bike with stock sprockets, my hawk would top out at 60 whether alone or 2 up. now it tops out at about 75 with myself and 65 2 up, at a much nicer rpm. I weigh 165 lbs. I currently have it at 17/44,

[OneLeggedRider]

13t can also be solved with the 520 13t reverse keeper installation which requires grinding the sprocket cover. I found it runs great that way and I install all my sprockets in reverse keeper to get good clearance from the case. 13t is too good of a ratio to let the issues stop you in my opinion.

Nah, the way mine was rubbing on the inside front of the sprocket cover there were 2 distinct lines with the 12 tooth. Flipping the sprocket wouldn't have helped. That being said the Uni-Bear chain is bigger and bulkier than the expensive 520 chains I've got on my quads.

[Hawkrider91]

if anyone can help please. tried to pull out the screw to see top dead center and i guess it was too tight idk it stripped out. any ideas to get it off? reason im doing it is because there is a quite a bit of ticking coming from valves. how much tick is too much?

[OneLeggedRider]

if anyone can help please. tried to pull out the screw to see top dead center and i guess it was too tight idk it stripped out. any ideas to get it off? reason im doing it is because there is a quite a bit of ticking coming from valves. how much tick is too much?

Uhmm.. :hmm: This thread has nothing to do with valve adjustment. Please use the search function and if you can't find an answer we will gladly assist you on an appropriate thread. Or start a new thread, that will probably get you quicker results. :tup:

[Megadan]

That being said the Uni-Bear chain is bigger and bulkier than the expensive 520 chains I've got on my quads.

Makes sense. Two ways to get strength. The cheap way, which is more of lower grade material. The more expensive way, less of a higher grade material.

[NzBrakelathes]

Uni Bear chain is a fine choice and good bang for buck on China cheapo bikes.

I personally suggest that over say a fancy big brand 428, so I suggest a mid level 520 chain n sprockets

[ChipToothy]

You can add another Bashan to the Hawk class at max 64 mph. 17/46 is the gearing. Rider is 200lbs with 30 pounds of TKC80 100/120 knobby wide tires.