My money is burning a hole in my pocket. Just waiting to see what surfaces in the spring. Belt drive, cvt, shift kit, for my honda and HF.
New in frame 4 stroke kit in development!
- Thread starter tyrslider
- Start date
I tried to post a link but cannot until I have enough posts. There are instructions at affordable go karts dot com that show how to remove the governor on the Honda GX160- I assume the Harbor Freight engine is very similar or the same?
affordablegokarts dot com/govenor-removal.php
affordablegokarts dot com/govenor-removal.php
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Actually looking at it now it is different than I had invisioned.
You guys, look in your HF manuals PG 17 it's online at Harbor Freight if you don't have one.
Look at the outside of the case where the governer mounts (inside of, of course). Does it retard the timing? I'm starting to think so. But regardless, to me it looks to be an on/off switch so you should be able to fix it in the off position and be fine. Best practice, though, is to get that garbage outta there!
You guys, look in your HF manuals PG 17 it's online at Harbor Freight if you don't have one.
Look at the outside of the case where the governer mounts (inside of, of course). Does it retard the timing? I'm starting to think so. But regardless, to me it looks to be an on/off switch so you should be able to fix it in the off position and be fine. Best practice, though, is to get that garbage outta there!
Here is a link to a youtube video that shows what looks like the 6.5 hp greyhound clone gov removal. It looks just like what was inside the honda 50cc that I removed and yes the hardest part was getting the clip that holds the gov gear off.
http://www.youtube.com/watch?v=LJK3HgOs1Gs
http://www.youtube.com/watch?v=LJK3HgOs1Gs
This looks sweet but maybe a little wide though huh? Can the front adj pully be used without the adjustable one in the rear or do you need a spring loaded belt tensioner to compensate for belt slop?
YouTube - Go Kart Torque Converter In Action TAV2
YouTube - Go Kart Torque Converter In Action TAV2
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You would need a spring loaded tensioner, but that's not difficult. I haven't done the math to see if theres too much slop to take up. We'll get the cvt going shortly too.
So that makes a lot of sense about the governer. I'll be pulling mine out!
Good link! I bring a lot of m/c and bicycle experience to the table but this 4 stroke governer crap is new to me!
So that makes a lot of sense about the governer. I'll be pulling mine out!
Good link! I bring a lot of m/c and bicycle experience to the table but this 4 stroke governer crap is new to me!
In my other honda I just left the internal parts inside. I guess I don't know it that little plastic gear spinning pointlessly inside has any ill effect. The only reason I pulled the other one out was I had the side cover off already repairing two holes I had from useing bolts that were just a wee bit longer than the original two long bolts that hold the grubee gearbox on.
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Hey guys,
The HF 2.5 H.P. is a typical stationary application engine...i.e. used for generators, water pumps, hydraulic equipment, etc.
The governor is there for a specific reason: an application specific reason...generators!
The number of poles in a generator dictate the frequency of the output for a given RPM. 60hz is the standard frequency.
3,600 RPM works out perfect for the torque curve of a stationary, continuos duty, gasoline engine. The governor controls the throttle position in order to maintain 3,600 rpm. 3,600 RPM coupled to a generator with the right number of poles will produce a constant 60hz. It's a simple flyball type governor design that pushes against a paddle at the end of the governor rod. The faster the gear spins, the further out the weights move...pushing the paddle to reduce throttle position.
I bought one of these engines, and disassembled it, to have a look at the overall design.
This engine is way oversquare...meaning a large bore and short stroke. The bore is nearly 2", and the stroke is just under 1.5".
Depending on how well the cylinder head "flows" this engine should easily rev to 6,500 @ about 4 H.P. The over square design makes for a relatively low piston velocity, which is the primary concern when a manufacturer dictates a max rpm, or engine "redline".
This engine has a plastic camshaft; and extremely light valve springs. I like the automatic compression release! The valve train may float out before the engine reaches max RPM, I'm not sure yet...I haven't tried it. With a plastic camshaft, I would be a little leary about increasing the spring rate.
I'm not working on a 4-stroke conversion for MB's based on this engine. I'm working on something different entirely.
Jim
The HF 2.5 H.P. is a typical stationary application engine...i.e. used for generators, water pumps, hydraulic equipment, etc.
The governor is there for a specific reason: an application specific reason...generators!
The number of poles in a generator dictate the frequency of the output for a given RPM. 60hz is the standard frequency.
3,600 RPM works out perfect for the torque curve of a stationary, continuos duty, gasoline engine. The governor controls the throttle position in order to maintain 3,600 rpm. 3,600 RPM coupled to a generator with the right number of poles will produce a constant 60hz. It's a simple flyball type governor design that pushes against a paddle at the end of the governor rod. The faster the gear spins, the further out the weights move...pushing the paddle to reduce throttle position.
I bought one of these engines, and disassembled it, to have a look at the overall design.
This engine is way oversquare...meaning a large bore and short stroke. The bore is nearly 2", and the stroke is just under 1.5".
Depending on how well the cylinder head "flows" this engine should easily rev to 6,500 @ about 4 H.P. The over square design makes for a relatively low piston velocity, which is the primary concern when a manufacturer dictates a max rpm, or engine "redline".
This engine has a plastic camshaft; and extremely light valve springs. I like the automatic compression release! The valve train may float out before the engine reaches max RPM, I'm not sure yet...I haven't tried it. With a plastic camshaft, I would be a little leary about increasing the spring rate.
I'm not working on a 4-stroke conversion for MB's based on this engine. I'm working on something different entirely.
Jim
Thanks Jim,
Yeah after seeing the vid I got the jist. But, I did not know about the generator stuff. Good to know!
Also, good to know on the > square situation. Plastic cam, not so good. I've got an extra one that I've been meaning to explore but have not had the time.
Good lookin out Jim, Thanks!
Yeah after seeing the vid I got the jist. But, I did not know about the generator stuff. Good to know!
Also, good to know on the > square situation. Plastic cam, not so good. I've got an extra one that I've been meaning to explore but have not had the time.
Good lookin out Jim, Thanks!
Do the HS engines have a plastic cam shaft? The whole plastic camshaft thing seems a bit scary to me...... Planned failure.
I haven't even put oil or gas in my HF's yet. Should I run it with the gov intact for a break in period before I dig inside and remove it's appendix?
Although a plastic camshaft doesn't sound that good, I think we have to look at the application. This engine is OHV, so the cam is simply overcoming the resistive force of the valve springs. According to the post above, the valve springs are pretty lightweight. So maybe the plastic used is acceptable for this application?
Glacknoid,
Break-in:
It won't make any difference either way. Just don't over-rev it, and make sure to load the engine without lugging it. Standard break-in procedures apply.
atombikes,
The plastic camshaft will undoubtedly last for many, many, hours. I would be willing to bet that this method of making a camshaft is common among many of the small 4-cycle engine manufacturers. The cost saving is huge!!!
Looking at both methods,
8620 Steel:
Drop forge to create a blank...with accompanying tool cost.
Hob the gear...again tooling costs.
Copper coat and case harden, (heat treat), to .045-.060" depth.
Finish grind the lobes...More tooling costs.
Plastic: I don't know the compound, but I would suspect it is something similar to glass filled teflon. It may be as simple as graphite acetyl.
Manufacture a precision pin...case harden.
Place pin in injection mold...fill mold and release.
This method requires an injection mold that would be equivalent in cost to the drop forging die for the steel cam.
All subsequent operations pertaining to the manufacture of the steel cam have been eliminated...which results in a huge cost savings.
The engine is very well made, and nicely machined...the price is incredible!
Obviously, if this engine takes-off for use as an alternative MB power-plant...a lot of owners will be looking at ways to increase the RPM...which goes back to my original post.
Unlike a flat head, (valve-in-block), engine...the overhead valve engine is encumbered with the mass of pushrods and rocker arms. Of course the overhead valve engine is capable of making more horsepower...but there is always a trade-off!
There is a point where the inertia from these moving parts will overcome the tension of the valve springs, (valve float). For those who don't know...when the valves float, they fail to seal...and the engine will just fade away power-wise until the RPM drops to a point where the valve springs can seal the valves.
Naturally stiffer valve springs will resolve the valve float issue and allow the engine to continue to rev...but then we have...the plastic cam.
I'm going to rework this engine to turn 8,000 RPM, using the plastic cam...I'll let ya'll know what happens.
Jim
Break-in:
It won't make any difference either way. Just don't over-rev it, and make sure to load the engine without lugging it. Standard break-in procedures apply.
atombikes,
The plastic camshaft will undoubtedly last for many, many, hours. I would be willing to bet that this method of making a camshaft is common among many of the small 4-cycle engine manufacturers. The cost saving is huge!!!
Looking at both methods,
8620 Steel:
Drop forge to create a blank...with accompanying tool cost.
Hob the gear...again tooling costs.
Copper coat and case harden, (heat treat), to .045-.060" depth.
Finish grind the lobes...More tooling costs.
Plastic: I don't know the compound, but I would suspect it is something similar to glass filled teflon. It may be as simple as graphite acetyl.
Manufacture a precision pin...case harden.
Place pin in injection mold...fill mold and release.
This method requires an injection mold that would be equivalent in cost to the drop forging die for the steel cam.
All subsequent operations pertaining to the manufacture of the steel cam have been eliminated...which results in a huge cost savings.
The engine is very well made, and nicely machined...the price is incredible!
Obviously, if this engine takes-off for use as an alternative MB power-plant...a lot of owners will be looking at ways to increase the RPM...which goes back to my original post.
Unlike a flat head, (valve-in-block), engine...the overhead valve engine is encumbered with the mass of pushrods and rocker arms. Of course the overhead valve engine is capable of making more horsepower...but there is always a trade-off!
There is a point where the inertia from these moving parts will overcome the tension of the valve springs, (valve float). For those who don't know...when the valves float, they fail to seal...and the engine will just fade away power-wise until the RPM drops to a point where the valve springs can seal the valves.
Naturally stiffer valve springs will resolve the valve float issue and allow the engine to continue to rev...but then we have...the plastic cam.
I'm going to rework this engine to turn 8,000 RPM, using the plastic cam...I'll let ya'll know what happens.
Jim