I want to build one from scratch!

[the neighbor]

We've got over an acre of yard, and another acre-or-so of fairly rough mowing. I know we should be looking at a commercial-type unit, but, unfortunately, for a miriad of reasons, we're stuck in the $300-500 bracket. After 20 years, the dead and wounded have piled up. Its ridiculous! I started building one a few years ago, using 2x3 tubing for a frame, an ANCIENT simplicity transaxle and a '74 Honda 750 four for power. Really. But about the time I was ready to pull the bike apart, I came to my senses, and traded off the bike... However, the idea remains... There are a lot of issues to be faced when adapting a motorcycle engine to a lawnmower application, but there is great potential. Plus, the prices are decent. Visit a motorcycle wrecking yard. I'm thinking electric. If you, for instance, were to couple a 450 Honda twin to a D.C. generator, then the mower deck could be run direct-drive from individual electric motors... What belts? Tractor drive could be by variable speed D.C. motor. The engine would have to gain some shrouding and a fan, but, don't forget, the engine has its own charging system, so the fan, lighting, and maybe the deck lift are taken care of... OR, I could go all-hydraulic! And easy on the low-rider jokes. OK. Anybody got any input?

 

[redneckfromhell123]

if your going to use a honda motor use a 1980s hondamatic motor theyre two speed with no clutch they are very reliable and they are both kick and electric start so if the battery dies it fires over within one or two trys i would put a solid axle on the rear like a four wheeler run the chain to it and get a ragb that runs off the chain to a mowing deck or what ever you decide to use . i will say that it will be a fast machine so get some good brakes those motors run to 90 or more mph ! so you might have to gear it down the motors are oil cooled and also air cooled so theres no fan issues. and i think these motors run dc current so youll be set on that

 

[demhustler]

We've got over an acre of yard, and another acre-or-so of fairly rough mowing. I know we should be looking at a commercial-type unit, but, unfortunately, for a miriad of reasons, we're stuck in the $300-500 bracket. After 20 years, the dead and wounded have piled up. Its ridiculous! I started building one a few years ago, using 2x3 tubing for a frame, an ANCIENT simplicity transaxle and a '74 Honda 750 four for power. Really. But about the time I was ready to pull the bike apart, I came to my senses, and traded off the bike... However, the idea remains... There are a lot of issues to be faced when adapting a motorcycle engine to a lawnmower application, but there is great potential. Plus, the prices are decent. Visit a motorcycle wrecking yard. I'm thinking electric. If you, for instance, were to couple a 450 Honda twin to a D.C. generator, then the mower deck could be run direct-drive from individual electric motors... What belts? Tractor drive could be by variable speed D.C. motor. The engine would have to gain some shrouding and a fan, but, don't forget, the engine has its own charging system, so the fan, lighting, and maybe the deck lift are taken care of... OR, I could go all-hydraulic! And easy on the low-rider jokes. OK. Anybody got any input?

ok, here's input:
4 example - genset Honda Power Equipment - EG4000

8.5 HP (6.3 kW) from 270cc 55 lb (25 kg) ICE - input
4kw (5.36hp), 155 lbs genset - output

to deliver it to the wheels you need same motor as generator in genset (4kw) - not speaking of batteries bank in-between (parallel or series hybrid)

 

[Tommy]

then the mower deck could be run direct-drive from individual electric motors...

It'll be interesting to see how that works out for you, I'm heading in the gear motor direction because
I'm not happy with all the noise I get from the motors running at 10000RPM(as much if not more then gas engine)
at 2000RPM I don't seem to have that issue(can't even hear the motors running).

Tommy

 

[demhustler]

if direct drive - better to have spindle - reinforcement between motor and blade: guy replaced ICE on his push-mower with el.motor, hit simple flashlite, hiding in the grass, and banded shaft; replaced motor - and soon again hit some dog toy - banded shaft again
blade tip speed normally 18,000 -20,000 ft/min (200 mph); engine run in 3600 rpm; if your el. motor has weaker shaft than 3-5 kw ICE - it must be spindle and/or coupling (in many small mowers you can disengage blades) - or motor shaft won't survive impacts