hotrod chain saw build / buy

[stumpjumper83]

First off I'm building a commercial firewood processor, and the saw will be used exculsively for that and in a fixed carriage.

Now what I'm looking for is a bad a$$ 250cc dirtbike powered hotsaw, or simular or someone that can tell me how to mod a bike motor for driving sawchain. Hydraulically powering the saw is out due to cost of high flow pumps and all I need the high flow for is the saw. Any ideas?

 

[Meadow Beaver]

If you want a bikesaw contact Dennis Cahoon, bikesaws aren't cheap though.

 

[romeo]

Bad idea in my opinion.

 

[brokenbudget]

Bad idea in my opinion.

i agree. somebody needs to do some reading and learning.

 

[stumpjumper83]

i agree. somebody needs to do some reading and learning.

Glad I found someone that know more about what I want to do than me... Do you two want to share your wisdom? Or are you two just certified members of the naysayers club?

Again, because of the hyraulic requirements of the splitter ram, 60 gpm @ 3,000 psi & the need to keep my cycle times up, I cannot run a hydraulic slasher saw. So that means I have to go to something else, those 250cc hotsaws really get her done, and it isnt like I'm going to be carrying it all day.

 

[brokenbudget]

Glad I found someone that know more about what I want to do than me... Do you two want to share your wisdom? Or are you two just certified members of the naysayers club?

Again, because of the hyraulic requirements of the splitter ram, 60 gpm @ 3,000 psi & the need to keep my cycle times up, I cannot run a hydraulic slasher saw. So that means I have to go to something else, those 250cc hotsaws really get her done, and it isnt like I'm going to be carrying it all day.

re-read post #4. then follow advice.....

 

[radoutdoors]

Cant agree more, do some more research, these saws are running for seconds not hours, hotsaws that is. If I were you I would research chopsaws, and google firewood processors. Hotsaws are a blast to run but I would not feel safe running a gas motor for hours wide open.

 

[sps3172]

Glad I found someone that know more about what I want to do than me... Do you two want to share your wisdom? Or are you two just certified members of the naysayers club?

Again, because of the hyraulic requirements of the splitter ram, 60 gpm @ 3,000 psi & the need to keep my cycle times up, I cannot run a hydraulic slasher saw. So that means I have to go to something else, those 250cc hotsaws really get her done, and it isnt like I'm going to be carrying it all day.

I'll add a bit of detail......

As I understand it, despite being based on liquid cooled motocross engines, 'bikesaws' don't have any type of cooling system. They briefly warm them before a 'race', then run them for just a few seconds.

That being said, it seems like you might also have room on your 'rig' for the associated cooling system (radiator, etc.). If you're willing to spend the dough (I'd guess you're talking north of 5K), I'd call one of the bikesaw guys and see if he could set you up with something for extended running. As delivered from the motorcycle company, those engines are timed and ported for all day use (with a cooling system). It seems you should be able to configure one to drive a saw chain all day, as well.

 

[brokenbudget]

he'd be better off running the bar/chain off of hydraulics. any 5 hp briggs can do that job.

 

[350 Vortec]

I dont understand why a hyd saw cant be used,if you already have the flow for that ram whats the problem??you cant split until you have something cut for it to split so cut during the return cycle?if your just building it either use a ram with a large shaft to reduce return flow required or two rams(two push one return,one could even be smaller bore to speed things up even more) a simple restrictor on the return and you'll be able to time things(restrict return flow so you get flow to saw and wood cut while ram is also returning )..i'm no expert... just thinking

 

[stumpjumper83]

ok, so on a bike saw, other than mounting the bar, the chain is ran directly off the output shaft of the motor right?

I'm not making a processor for just cutting a load of poles a year, I'm designing one for commercial production. My production goal is as fast as possible, but ill settle for one face cord in 10 minutes, that means in 16" wood, 5 seconds to the cycle. Splitter will run auto cycle, powered by 3, 28 gpm 2-stage pumps. Splittling is the slow spot in processors, or at least the videos I've watched & in my flow charting. I don't want to do anything that will slow the splitter down.

I'm contemplating a gravity powered feed table, with a normally applied, momentairly released clamp system. Saw will not be mounted to the side requiring a return cycle, it will mount overhead and cut bi-directionally. Return cycles are wasted seconds that I don't have. Also I'll probably power the saws movement pneumatically, cause its faster...

Again, on a bike saw, other than mounting the bar, the chain is ran directly off the output shaft of the motor right?

 

[Captain Crunch]

I think what everyone is trying to say is, use an industrial rated engine to power industrial equipment. Dirt bikes are recreational, not designed to run hours on end at full power. Cooling aside, it comes down to basic designed in durability.

For example, I work in marine propulsion. A pleasure craft rated 7 liter diesel might make 455 HP. To get the same 450 HP in a continuous duty rating, the engine jumps up to 18 liters!

Back to small engines, Honda's GX490 on my splitter is 490 cc and 11 hp. How much power can a stock 500 dirt bike produce, 40? 50? A whole lot more than 11, I know that. FWIW, that GX490 might make a kickin saw engine with a belt drive to a sprocket...... assuming you don't want to find a small diesel and do the same thing.

As far as using pneumatics to run the saw carriage, my experience is that air makes for very jerky cylinder movement, especially if there is any variation in the friction of the device being moved. Like your carriage gets dirt or dust in it. Pressure will build up until there is enough force to move the carriage, then the air will act like a spring (it essentially is a spring in this case) and the carriage move all at once, slamming with uncontrolled speed into the log being cut. Since hydraulic oil does not compress, to speak of at least, you can get pretty constant speed and much smoother motion. Not sure why you feel you can't get the speed you need from the hydraulic rams?

How about a bi-directional stepper motor and chain drive, control the saw carriage speed based on the chain speed, as the chain slows down, you slow down the carriage......Ok, I get carried away here, but I do like closed loop control.

 

[trappermike]

I agree. Adapting something like a Briggs or something similar of correct HP would be much simpler,cheaper and reliable. Adapting something like a Briggs for the job would be much simpler,you would find that modifying and machining parts to make a bike motor drive a saw chain would definitely pose some real (expensive) challenges(what about a centrifigal clutch too?),mounting the bike motor,exhaust pipe etc.,whew sounds like a lot of work and money,then you'll have a noisy bulky setup. The Briggs would be quiet and reliable,used to hard work in a stationary position.
A bike 2-stroke running hard and steady may not last long,and if your motor isn't so new parts may be harder to find.
Sounds like a labor of love or creating a conversation piece.... Do-able,but I'm glad it's not me.

 

[Johny Utah]

:monkey:

ok, so on a bike saw, other than mounting the bar, the chain is ran directly off the output shaft of the motor right?

I'm not making a processor for just cutting a load of poles a year, I'm designing one for commercial production. My production goal is as fast as possible, but ill settle for one face cord in 10 minutes, that means in 16" wood, 5 seconds to the cycle. Splitter will run auto cycle, powered by 3, 28 gpm 2-stage pumps. Splittling is the slow spot in processors, or at least the videos I've watched & in my flow charting. I don't want to do anything that will slow the splitter down.

I'm contemplating a gravity powered feed table, with a normally applied, momentairly released clamp system. Saw will not be mounted to the side requiring a return cycle, it will mount overhead and cut bi-directionally. Return cycles are wasted seconds that I don't have. Also I'll probably power the saws movement pneumatically, cause its faster...

Again, on a bike saw, other than mounting the bar, the chain is ran directly off the output shaft of the motor right?

:bang:

 

[trappermike]

Bike saws cost thousands to build,and only cut for 5-10 seconds in a race.

But if your bank account is REAL FAT I'll be happy to make you one.....:msp_biggrin:
Just kidding

For commercial use reliability and simplicity plus ease of repair are the key importance. Briggs idea or hydraulic...

 

[Captain Crunch]

Elvis has left the building.


OP are you still with us?

 

[Johny Utah]

He must have fallen off his chair, hit his head and come to his senses. Maybe now he is just going to work on shoe hornning that v-10 into the Austin mini so he can be the first in line when the grocery store opens on Sunday.:hmm3grin2orange:

 

[Jkebxjunke]

question... why not use a circular saw blade? or a sawmill blade?

 

[Johny Utah]

question... why not use a circular saw blade? or a sawmill blade?

the kerf it leaves is to large chicken boy. saw blades need constant sharpening.
:hmm3grin2orange:

 

[Jkebxjunke]

the kerf it leaves is to large chicken boy. saw blades need constant sharpening.
:hmm3grin2orange:

go yank a bull... sheep boy...:hmm3grin2orange: