Has anyone ever used the Honda GX31 and transmission from a harmony garden tiller to power a bike? I just got the tiller free and have the bike. Would like to see some pics if someone had done one.
Honda GX31 with a tiller transmission?
- Thread starter Recycler
- Start date
We'd like to see some pics and some specs on the engine and transmission. Oh and I use a 33cc 4 stroke and have a shifter bike with the widest reduction range in forum history (66.79-16.25\1). We don't have to have to used it; to tell you what to do with it.
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Since you didn't provide any viable information about the tiller; I looked up the information.
The engine produces 1 hp at 7000 rpm. The idle speed is around 3100 rpm. The transmission has 1 forward gear and a 32\1 reduction.
If you don't alter the total reduction ratio, then these are the level ground speeds you can expect for the following tire sizes:
24"~15.6 mph
26"~17 mph
27.5"~18 mph
29"~19 mph
The engine produces 1 hp at 7000 rpm. The idle speed is around 3100 rpm. The transmission has 1 forward gear and a 32\1 reduction.
If you don't alter the total reduction ratio, then these are the level ground speeds you can expect for the following tire sizes:
24"~15.6 mph
26"~17 mph
27.5"~18 mph
29"~19 mph
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The problem with a tiller transmission is 2 fold... There not snycronized for shifting other than from a stop and there very close to each other... At best you would have a hi and low gear that would crawl to speed or top out quickly... A TAV is what you want for a tiller engine and it gives it a variable speed depending on the weights and springs to adjust to your weight and power...
Jerry's sidewinder with little power and many gears works for him but would be over powered with a larger 200cc engine... He's got more range of rpm also... The more gears the better chance of finding a gear for the situation your in... Where a tiller engine sort of limits the ability to use the gears I imagine you would be shifting a lot of times to keep it in the narrow 2500-3000rpm or whatever it's governor allowed where the TAV does this constantly with a belt and clutchs it robs power so the TAV won't work with something small... A tiller with 5 HP can afford to lose a few or half it's power on the TAV...
You can hot rod a tiller engine but you risk the engine and flywheel coming apart above the governor RPM and there are parts available for this... But you loose reliability ... What Jerry has is ultra reliability with the Robin Subaru engines and quality bicycle gearing...
Just study up on the builds there's a lot of ways to do it some of the quality parts aren't available anymore like the sick bikes shifter and grubee kits... There's a lot of trash out there that appears to be similar but lack the quality of the parts... I'm going the route of the 79cc predator that's bored and stroked to 98cc with a 30series TAV for the above reasons and it's small size... After working out everything is the best route for me... Only because all the parts are available... I have everything except a spare engine and the comet 30seris tav1 which is steel backing plate and a Colman metal cover that I can weld and modify easier than an aluminum Chinese one... With a 7" driven pulley to help the 79 take off from a stop... Rather than a 6"... A juggernaut driving it on the engine for the high Rpm it's going to have... Along with some spares and kit to adjust the thing... A clamp for automatic transmission clutch for a Chevy 350 to put it back together... And I expect several adjustment before I get it right... I'm a 2 stroke guy so 4 stroke is something I'm still trying to figure out... I don't think it will pedal so it's not a bicycle at that point and with the power involved I think it may be dangerous to have a pedal chain that could cause problems and I'm not a fan of wide pedals wanting to dig into the pavement turning and the okwardness of it... Or short cranks that clear the ground that are useless to pedal something heavy like a 4 stroke tiller engine... Moped rims hubs and tires get expensive... I'm just doing the wheels for everything I plan on building this summer... Some for the bicycles some for 2stroke some for the 4 stroke... 12 sets of wheels... 2for each build... That way I'll have an inventory to use as I go and have little to get specific to each build... Also for consistency and compatibly and once I know the parts it's going to help with problems that come up in the future... Or I can just canablize one for another while getting a replacement... I'm taking it way too far for most that are into this just focused on parts taking a chance that someday I'll be using everything I have for something... It comes from building hot rods from parts from specific years of cars where each year had something like a good year for the engine and another for the suspension and another for the brakes and another for the body style... From junkyard picking from back when from a sea of junk you would search for the jems hidden there... A lot of it was pre emission control to later emission control systems... Where the engine had lost most of it's power to that... Now they call it off road use only... And there's an art to making off road to appear factory... With the bikes it's more of an insurance that if they stopped selling the parts I like it wouldn't matter because I have enough of them it wouldn't effect me... Then as they go out of business I can look to gather up the last few remaining which is basically what I'm doing now... So building from a standpoint of using the most commonly available stuff first and saving for later the hard to find stuff and using the best lubricant for those to get the most life out of it... The parts that I have that came damaged and got replacement for are the first on something... First to experiment with etc...
Jerry's sidewinder with little power and many gears works for him but would be over powered with a larger 200cc engine... He's got more range of rpm also... The more gears the better chance of finding a gear for the situation your in... Where a tiller engine sort of limits the ability to use the gears I imagine you would be shifting a lot of times to keep it in the narrow 2500-3000rpm or whatever it's governor allowed where the TAV does this constantly with a belt and clutchs it robs power so the TAV won't work with something small... A tiller with 5 HP can afford to lose a few or half it's power on the TAV...
You can hot rod a tiller engine but you risk the engine and flywheel coming apart above the governor RPM and there are parts available for this... But you loose reliability ... What Jerry has is ultra reliability with the Robin Subaru engines and quality bicycle gearing...
Just study up on the builds there's a lot of ways to do it some of the quality parts aren't available anymore like the sick bikes shifter and grubee kits... There's a lot of trash out there that appears to be similar but lack the quality of the parts... I'm going the route of the 79cc predator that's bored and stroked to 98cc with a 30series TAV for the above reasons and it's small size... After working out everything is the best route for me... Only because all the parts are available... I have everything except a spare engine and the comet 30seris tav1 which is steel backing plate and a Colman metal cover that I can weld and modify easier than an aluminum Chinese one... With a 7" driven pulley to help the 79 take off from a stop... Rather than a 6"... A juggernaut driving it on the engine for the high Rpm it's going to have... Along with some spares and kit to adjust the thing... A clamp for automatic transmission clutch for a Chevy 350 to put it back together... And I expect several adjustment before I get it right... I'm a 2 stroke guy so 4 stroke is something I'm still trying to figure out... I don't think it will pedal so it's not a bicycle at that point and with the power involved I think it may be dangerous to have a pedal chain that could cause problems and I'm not a fan of wide pedals wanting to dig into the pavement turning and the okwardness of it... Or short cranks that clear the ground that are useless to pedal something heavy like a 4 stroke tiller engine... Moped rims hubs and tires get expensive... I'm just doing the wheels for everything I plan on building this summer... Some for the bicycles some for 2stroke some for the 4 stroke... 12 sets of wheels... 2for each build... That way I'll have an inventory to use as I go and have little to get specific to each build... Also for consistency and compatibly and once I know the parts it's going to help with problems that come up in the future... Or I can just canablize one for another while getting a replacement... I'm taking it way too far for most that are into this just focused on parts taking a chance that someday I'll be using everything I have for something... It comes from building hot rods from parts from specific years of cars where each year had something like a good year for the engine and another for the suspension and another for the brakes and another for the body style... From junkyard picking from back when from a sea of junk you would search for the jems hidden there... A lot of it was pre emission control to later emission control systems... Where the engine had lost most of it's power to that... Now they call it off road use only... And there's an art to making off road to appear factory... With the bikes it's more of an insurance that if they stopped selling the parts I like it wouldn't matter because I have enough of them it wouldn't effect me... Then as they go out of business I can look to gather up the last few remaining which is basically what I'm doing now... So building from a standpoint of using the most commonly available stuff first and saving for later the hard to find stuff and using the best lubricant for those to get the most life out of it... The parts that I have that came damaged and got replacement for are the first on something... First to experiment with etc...
I looked up the specs on the Honda 31cc engine and tiller. It only has 1 hp. It's blade rotation is 194 at 6200 rpm; that's a 32\1 reduction. So in this case you're dealing with an assist engine.
Right... And it's probably a lot of work to get it to mate up with anything to be worth it... Or compete with a garden hoe for tilling for that matter
Given the 1hp has enough torque to hold the speed... I'm guessing with all the areospace technology in the world would still be a dud... Maybe some little green men from Voltron could help design it for a zero gravity no atmosphere cruzer for the moon... Here on earth 3+ HP is where I'm at...
The Robin Subaru 35 only has 1.6 hp. Yet I can do level ground speeds around 30 mph. If Recycler isn't a large person and/or have steep hills to contend with, this little engine and transmission is good for 15-19 mph depending on what size tires he's using. Many of us are happy with those kind of speeds.
All I can say to sidewinder and mossy is WOW !!! I am quite impressed with what you have done. There was a lot of equipment listed that I am not familiar with; I’m just piddling around retasking parts I either have or come across. In Texas, if a motorized bike is over 1 hp and/or travels faster than 20 mph, it requires a registration to be used on city streets. Thanks for all the info; I’ll let you know how things come out,
Actually you can build a motor-assisted scooter and are allowed to go up to 35 mph.
Texas law.
SUBCHAPTER E. MOTOR-ASSISTED SCOOTERS
Sec. 551.351. DEFINITIONS. In this subchapter:
(1) "Motor-assisted scooter":
(A) means a self-propelled device with:
(i) at least two wheels in contact with the ground during operation;
(ii) a braking system capable of stopping the device under typical operating conditions;
(iii) a gas or electric motor not exceeding 40 cubic centimeters;
(iv) a deck designed to allow a person to stand or sit while operating the device; and
(v) the ability to be propelled by human power alone; and
(B) does not include a pocket bike or a minimotorbike.
(2) "Pocket bike or minimotorbike" means a self-propelled vehicle that is equipped with an electric motor or internal combustion engine having a piston displacement of less than 50 cubic centimeters, is designed to propel itself with not more than two wheels in contact with the ground, has a seat or saddle for the use of the operator, is not designed for use on a highway, and is ineligible for a certificate of title under Chapter 501. The term does not include:
(A) a moped or motorcycle;
(B) an electric bicycle;
(C) a motorized mobility device, as defined by Section 552A.0101;
(D) an electric personal assistive mobility device, as defined by Section 551.201; or
(E) a neighborhood electric vehicle, as defined by Section 551.301.
Added by Acts 2005, 79th Leg., Ch. 1242 (H.B. 1596), Sec. 3, eff. June 18, 2005.
Amended by:
Acts 2011, 82nd Leg., R.S., Ch. 91 (S.B. 1303), Sec. 24.015, eff. September 1, 2011.
Acts 2019, 86th Leg., R.S., Ch. 612 (S.B. 969), Sec. 5, eff. June 10, 2019.
Acts 2019, 86th Leg., R.S., Ch. 882 (H.B. 3171), Sec. 2.18, eff. September 1, 2019.
Sec. 551.352. OPERATION ON ROADWAYS OR SIDEWALKS. (a) A motor-assisted scooter may be operated only on a street or highway for which the posted speed limit is 35 miles per hour or less. The motor-assisted scooter may cross a road or street at an intersection where the road or street has a posted speed limit of more than 35 miles per hour.
(b) A county or municipality may prohibit the operation of a motor-assisted scooter on a street, highway, or sidewalk if the governing body of the county or municipality determines that the prohibition is necessary in the interest of safety.
The department may prohibit the operation of a motor-assisted scooter on a highway if it determines that the prohibition is necessary in the interest of safety.(d) A person may operate a motor-assisted scooter on a path set aside for the exclusive operation of bicycles or on a sidewalk. Except as otherwise provided by this section, a provision of this title applicable to the operation of a bicycle applies to the operation of a motor-assisted scooter.
(e) A provision of this title applicable to a motor vehicle does not apply to a motor-assisted scooter.
Texas has another statute that states a moped has to be on a certified manufacturer's list which gets updated every 90 days. It also states this doesn't include a motor-assisted scooter.
What that means is you can't operate a self built moped on the roadways in Texas but you can operate a self built motor-assisted scooter on the public roadways.
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Notice the statute says it has to be capable of being propelled by human power alone. That means either kick propelled or pedal propelled. There are seated scooters with pedals. Knowing the state of Texas they aren't going to give you a hard time for using a bicycle if you stay under 35 mph, avoid streets with speeds posted higher than 35 mph, and obey the traffic laws.
You have to go by each state rules, they are different. Like your bike here would be illegal, no manual shifting, all automatic, 20 mph tops according to the books. ....................Curt
My bike would be illegal in most places, due to being a manual shifter. However, my area is very lenient on enforcing the automatic transmission clause. It was for legal reasons I built the LandRider which shifted 7 gears automatically.
Here in Tennessee their main concern is you obey the traffic laws and stay under 30 mph on level ground and climbing hills. Going down hill you can go the posted speed limit.
I'm not required to have a Speedometer, mirrors, communication lighting, or a horn. Yet I have all these things for my safety. All Tennessee requires is a headlight for night riding and a red rear reflector.
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