I don't know what you mean. what gear ratios weren't available last year? Also I was talking more about performance than gear ratios.
Harbor Freight Greyhound 79cc engine
- Thread starter KilroyCD
- Start date
Hi Jay,
Guess several weren't informed about our testing & research over the last 2 YEARS.
We didn't tell them we tested the Q-Matic on many 4-stroke motors and tested ratios from 5.99 X 1 to 22 X 1. We tested MBs that could climb the side of a building and some that could amaze many with top speeds above 50 MPH.
The Q-matic is in full production [shipping is lagging by approx 3 to 4 days] and will work on a large selection of 4-stroke motors including the larger [illegal as a motored bicycle in
most states]displacement motors.
Considering this post is about the HF 79 CC motor it is important to note that our tests have shown the motors to not be consistant, some run really good, and some don't. Our tests have shown the Honda & HS motors to be very consistant, and more often than not the HS will produce more top end than the Honda, but a little less low end torque.
As an X motorcycle racer I found that "bigger is better" to be an incorrect statement, in fact the real truth is, motor design is always the winner, not CCs or C.I.
However all is mute, and I wouldn't try to convince anyone that using a "certain" motor is better than others.
At the moment this post contains a lot of untested comments, and I am excited to see where it all ends up.
Currenty I hold the majority of the motorbike speed records on the east coast, not talk, just fact, and I will gladly race anyone at the upcomming event in Dawson Springs, KY in May. There will be a "Roller Road" [speed dyno] and the dirt drags if anyone wants to upset my 5 year winning streak. The current 49 CC 4-stroke speed record [top MPH] is currently held by Ron Dow from Texas on a [you guessed it] EZ Motorbike with the HS motor and Max Torque clutch. I current hold the dirt track record on my EZ prototype with the "Silent Power" drive system.
While the HF motor is not legal as a MB in many states, we understand the lure of the cheap price, but is the difference from $109. [plus tax] to $175. worth all the effort needed to mount the HF motor in a bike [many bikes won't accept the longer motor profile].
I guess the item that is of greatest concern [to me] is the exhaust. Hopefully someone will take the time to make a manifold that exits the motor at a better angle and side steps the possibilty of personal injury [burns]. We also hope for safety's sake that the location of the exhaust in relation to the fuel supply will also be re-considerd, as I am sure may wouldn't like the potential of a fire or explosion.
Have fun,
Guess several weren't informed about our testing & research over the last 2 YEARS.
We didn't tell them we tested the Q-Matic on many 4-stroke motors and tested ratios from 5.99 X 1 to 22 X 1. We tested MBs that could climb the side of a building and some that could amaze many with top speeds above 50 MPH.
The Q-matic is in full production [shipping is lagging by approx 3 to 4 days] and will work on a large selection of 4-stroke motors including the larger [illegal as a motored bicycle in
most states]displacement motors.
Considering this post is about the HF 79 CC motor it is important to note that our tests have shown the motors to not be consistant, some run really good, and some don't. Our tests have shown the Honda & HS motors to be very consistant, and more often than not the HS will produce more top end than the Honda, but a little less low end torque.
As an X motorcycle racer I found that "bigger is better" to be an incorrect statement, in fact the real truth is, motor design is always the winner, not CCs or C.I.
However all is mute, and I wouldn't try to convince anyone that using a "certain" motor is better than others.
At the moment this post contains a lot of untested comments, and I am excited to see where it all ends up.
Currenty I hold the majority of the motorbike speed records on the east coast, not talk, just fact, and I will gladly race anyone at the upcomming event in Dawson Springs, KY in May. There will be a "Roller Road" [speed dyno] and the dirt drags if anyone wants to upset my 5 year winning streak. The current 49 CC 4-stroke speed record [top MPH] is currently held by Ron Dow from Texas on a [you guessed it] EZ Motorbike with the HS motor and Max Torque clutch. I current hold the dirt track record on my EZ prototype with the "Silent Power" drive system.
While the HF motor is not legal as a MB in many states, we understand the lure of the cheap price, but is the difference from $109. [plus tax] to $175. worth all the effort needed to mount the HF motor in a bike [many bikes won't accept the longer motor profile].
I guess the item that is of greatest concern [to me] is the exhaust. Hopefully someone will take the time to make a manifold that exits the motor at a better angle and side steps the possibilty of personal injury [burns]. We also hope for safety's sake that the location of the exhaust in relation to the fuel supply will also be re-considerd, as I am sure may wouldn't like the potential of a fire or explosion.
Have fun,
2 years of reasearch and data WOW!!! I would love to see a spread sheet on those #'s. All my numbers are are calculated on paper so they are only theoretical numbers. Theorretically all one needs to do to go faster is get a smaller rear sprocket, you lose torque but gain top end speed. I know that there is a point where you don't have the torque to accelerate any more.
Two things sold me on the HF 2.5 one was the price of $76.74 (tax included) the other was the low end torque. So I know I got the correct engine.
I can't wait to see the outcome of all this.
Two things sold me on the HF 2.5 one was the price of $76.74 (tax included) the other was the low end torque. So I know I got the correct engine.
I can't wait to see the outcome of all this.
Felton: Exactly, with twice the torque as the honda/HS you can do what Evan is doing and have an overall ratio of 9 to 1 or less to the tire and take the cake in top end and 0 to 40 mph.
What is the length of the motor mount for the hf 79cc from inside to inside of the frame on the top side of the mount? At what angle (if any) is the mount intended to be positioned in the frame?
Here is a link to the post that describes how I mounted the engine.
http://motorbicycling.com/f6/my-heavy-duty-4-stroke-engine-11745.html
I don't remember the length of the plate but I measured the bike and fabricated the mount to fit the bike. This shows how I compensated for the different angles of the frame.
Hope this helps.
Jim
Thanks Quenton for helping shed some light on ratios and their connection and importance concerning performance. Maybe sharing this info (2 yrs worth of data) w/ your dealers will help them better represent your product. Also I'd like to complement you and whoever else helped you design such a versatile transmission; It's nice to finally see it! I've referred a couple of folks in your direction and I hope all is well!
So running a 9.688:1 reduction ratio my bike pulls easilly to 35mph w/o winding out (still breaking it in) and pulls hills better than any motor that I've previously tried. I will be trying the other 2 ratios that I presented and posting results shortly including video. So far my math confirms Kilroys estimates of engine speed and my ratio estimates.
Also an ex m/c racer I agree w/ Quenton on some other points. Motor design is hugely important in performance outcome of any engine and bigger is not necessarilly better. To some extent it should be noted that different motor designs provide better performance for different applications. However torque and hp rate the amount of work a motor can do (Hp = torque x time); more hp and torque = more work and less stress on the motor for a given job. There are benefits and drawbacks to all of these motors and every gain represents a sacrifice (trade off). Evan
So running a 9.688:1 reduction ratio my bike pulls easilly to 35mph w/o winding out (still breaking it in) and pulls hills better than any motor that I've previously tried. I will be trying the other 2 ratios that I presented and posting results shortly including video. So far my math confirms Kilroys estimates of engine speed and my ratio estimates.
Also an ex m/c racer I agree w/ Quenton on some other points. Motor design is hugely important in performance outcome of any engine and bigger is not necessarilly better. To some extent it should be noted that different motor designs provide better performance for different applications. However torque and hp rate the amount of work a motor can do (Hp = torque x time); more hp and torque = more work and less stress on the motor for a given job. There are benefits and drawbacks to all of these motors and every gain represents a sacrifice (trade off). Evan
Fossil that airfilter looks nice!
Bearbattered, we've found an average in the area of 10" from center of front tube to center of seat tube on cantilever frames. And the mount should be level. FireBelly offers 4 stroke mounts in any length you need! Thanks, Evan.
Bearbattered, we've found an average in the area of 10" from center of front tube to center of seat tube on cantilever frames. And the mount should be level. FireBelly offers 4 stroke mounts in any length you need! Thanks, Evan.
Benn thinking about buying a harbor freight motor 79cc just to play around with there on sale again for $89 + 20% off tax and everything $77. Its been about 5 months since the last post anybody figured a cheaper way for a trans? Im sure the q matic is good and all but come on $275+shipping for a trans for a $77 engine wont the same crap that fits on a hs or honda fit on the hf? I think the bolt holes are the same there has got to be a better way. The output shaft is 5/8 same as honda and hs. Thanks
Hi Eldo,
Sorry but the cheap drives won't fit the HF motor. The low quality, low price drive system has a different bolt pattern and I don't think it is wide enough to fit. However I am sure you could make an adapter. The think the shaft is also shorter on the HF motor.
The Q-Matic has been used on several HF motors [BTW it is $259.75] and has managed to produce higher top end speeds than most and still allow take-off without pedal assist.
One major advantage of the Q-Matic on the HF motor is the use of an optional adjustable front drive pulley. By using the adjustable drive pulley it is possible to dial it in to fit the riders needs.
Sorry the Q-Matic is pricey, but it is the best and is made with American labor.
BTW if you want to buy some [new] junk drive systems and give it a try, I will gladly sell you one for $25.00 plus shipping [NO WARRANTY, NONE, ZERO, NADA]. We have a small supply that we used for initial testing and even some that have never been used. They include the clutch, gears, cover, housing, and I would even throw in a bunch of Chinese bolts used to mount them. If you want quanity I would even reduce the price, maybe buy 2 and get 1 free [3 for the price of one and still less than you spend for the motor]. BTW buying several might be a good idea as they aren't known to stay together for a long period of time, and the HF motor with additional HP & Torque might be too much for them.
Let me know if interested, as I would love to have more space in the parts room.
And if anyone else wants to try the Chinese gear drives, PLEASE contact me as I would love to get rid of them.
Have fun,
Sorry but the cheap drives won't fit the HF motor. The low quality, low price drive system has a different bolt pattern and I don't think it is wide enough to fit. However I am sure you could make an adapter. The think the shaft is also shorter on the HF motor.
The Q-Matic has been used on several HF motors [BTW it is $259.75] and has managed to produce higher top end speeds than most and still allow take-off without pedal assist.
One major advantage of the Q-Matic on the HF motor is the use of an optional adjustable front drive pulley. By using the adjustable drive pulley it is possible to dial it in to fit the riders needs.
Sorry the Q-Matic is pricey, but it is the best and is made with American labor.
BTW if you want to buy some [new] junk drive systems and give it a try, I will gladly sell you one for $25.00 plus shipping [NO WARRANTY, NONE, ZERO, NADA]. We have a small supply that we used for initial testing and even some that have never been used. They include the clutch, gears, cover, housing, and I would even throw in a bunch of Chinese bolts used to mount them. If you want quanity I would even reduce the price, maybe buy 2 and get 1 free [3 for the price of one and still less than you spend for the motor]. BTW buying several might be a good idea as they aren't known to stay together for a long period of time, and the HF motor with additional HP & Torque might be too much for them.
Let me know if interested, as I would love to have more space in the parts room.
And if anyone else wants to try the Chinese gear drives, PLEASE contact me as I would love to get rid of them.
Have fun,
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I found a gearbox that works well with this HF engine. Here's the link:
Mini Bike minibike jackshaft Backplate Go Kart Cart - eBay (item 190400162425 end time Jun-02-10 13:44:12 PDT)
This bolts up to the engine and along with a cent. clutch provides a 2 to 1 reduction. I use a 60 thooth rear sprocket for a total of 12 to 1 reduction. There are many different gear ratio options. So far the 12 to 1 seems to work well.
Tom
Mini Bike minibike jackshaft Backplate Go Kart Cart - eBay (item 190400162425 end time Jun-02-10 13:44:12 PDT)
This bolts up to the engine and along with a cent. clutch provides a 2 to 1 reduction. I use a 60 thooth rear sprocket for a total of 12 to 1 reduction. There are many different gear ratio options. So far the 12 to 1 seems to work well.
Tom
Hi,
As Evan pointed out they use different ratios because of the higher revving Honda & HS motors, but it is possible to weaken the clutch spring to allow clutch engagement and use a smaller sprocket on the rear to use the torque of the HF motor.
Have fun,
As Evan pointed out they use different ratios because of the higher revving Honda & HS motors, but it is possible to weaken the clutch spring to allow clutch engagement and use a smaller sprocket on the rear to use the torque of the HF motor.
Have fun,
Quenton Think you ought to get your nose out thew air before some one knocks it out and thats not a threat its real made in USA.If I wanted to build a rocket I wouldnt use a HF motor. Just want to put a cheap motor on a $25 bike and make it work. Sorry if that doesnt work for you. Larry
Hi Larry,
I totally understand what you are trying to do, and I think your best option might be the jackshaft on ebay and a less expensive cent. clutch. This would give you a good option and not invest a lot at the same time. Good prices on stock 5/8" clutches http://www.gokartsupply.com/clutches.htm
I checked the bolt pattern on the side of the Honda motor and found the site with information on the HF. The Honda pattern appears to be 75 MM center to center.
The HF is listed at 65 MM center to center.
here is the site on the HF information
http://manuals.harborfreight.com/manuals/97000-97999/97964.pdf
Hope this information helps.
Have fun,
I totally understand what you are trying to do, and I think your best option might be the jackshaft on ebay and a less expensive cent. clutch. This would give you a good option and not invest a lot at the same time. Good prices on stock 5/8" clutches http://www.gokartsupply.com/clutches.htm
I checked the bolt pattern on the side of the Honda motor and found the site with information on the HF. The Honda pattern appears to be 75 MM center to center.
The HF is listed at 65 MM center to center.
here is the site on the HF information
http://manuals.harborfreight.com/manuals/97000-97999/97964.pdf
Hope this information helps.
Have fun,
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Awesome TS. I teer my hair out trying to do that. Could draw the circle with a compass and a sqr on it and would have a perfect pattern. Big time, thanks.
Dan
I Have Bought From Him. He May Have More. That Item Has Been Listed For A Yr Or Two. " Bid Like Your B Gates" Lol. Ron
I Have Bought From Him. He May Have More. That Item Has Been Listed For A Yr Or Two. " Bid Like Your B Gates" Lol. Ron