gx 160 Honda

[fastsled]

Hey does anyone know what size clutch goes on this motor? I tried a 3/4 and it is very tight? should it slip on easy? thanks

[Russ2251]

Tight is a relative term. What might be tight to you might be OK for me. Standard sizes for crankshaft (pto) are 1/2, 5/8, 3/4, 7/8, and 1 inch. Usually they are just slightly undersized so that a clutch, pulley or what ever you want to hang on it will slide on snugly. In your case 3/4 would be correct. It is very rare that shaft sizes deviate from the above mentioned sizes.

[kibble]

What if you lubricate the shaft just a tad so that it will glide in smoother into the clutch?

[2or3wheels]

most 5 HP motors are 3/4 inch.

[Russ2251]

What if you lubricate the shaft just a tad so that it will glide in smoother into the clutch?

I don't like to use lubricants because while it may make it easier to put something onto shaft it also makes it easier for it to fall off. Anything put on shaft depends on a dry friction fit.
If you really feel this tightness is a problem, a good simple fix would be to run some fine emery cloth over shaft while it is idling to polish it up and to remove any burrs. Use caution as it would be easy to go too far with this. Once it is too far undersized, crankshaft will need replacement as there is no way to replace lost metal.
I would just leave it alone. After all, clutch removal doesn't happen all that often anyway.

[fastsled]

Thanks guys for all the answers, after checking a little further, I found out that the shaft is 20mm or .787 just over 3/4 76.2. looks like a different size clutch......

[Russ2251]

Sometimes I wonder why I even bother....

[fastsled]

I guess you "Russ" didn't know about metric sizes other wise you would have said something ....Right... Thanks for your help anyway..

[Russ2251]

Sorry for the miss understanding. As I said, it is rare that shaft sizes are anything other than what was stated. A metric sized shaft could mean a couple of possibilities. Was engine purchased new, or did it come off of something else? Also, does clutch go on and is it just a tight fit, or does it refuse to go on at all?

[robertdjung]

??? Seems pretty simple to find: I googled gx160 honda and got this page: http://www.tulsaenginewarehouse.com/catalog/honda/horiz/gx160/

which seems to say almost all of those engines are 3/4. Why do you have an engine with a gear reduction on it?

[Russ2251]

Kudos to robertdjung. I missed that one:o . I guess that's why we keep you around:D . I also found this:
http://www.trupower.com/honda/gx160.htm

[fastsled]

Thanks again for any and all information you guys have...it's really appreciated...does anyone know of a clutch maker for this oddball? not me the 160?

[Russ2251]

A clutch won't work. You appear to have a 2:1 gear reduction on your engine. This means that if engine is turning up 3600 rpm then output is only 1800 rpm. Some clutches only just start to kick in at this speed. Some at much higher rpms. Clutch will not completely "lock up" at this low rpm and you run a high risk of burning it up because of slippage. Even if it did operate, top end would only be about 15 mph (24 kph) maximum. You can run faster than that.

[2or3wheels]

SO is there a way to fix that then? I bet you have to get a different engine.

[fastsled]

That would suck I have two of these...

[Russ2251]

I feel your pain. I once bought a Jacobsen J-321 2 cycle mower engine off Ebay thinking it was a Clinton kart engine. It had a 6:1 gear reduction on it making it useless to me. I kept it anyway. About a year later I was lucky enough to locate an NOS short block with a 3/4 inch shaft for $15 (Ebay again). It is now (essentially) a new engine. I tried it out last spring and was not disappointed with performance. Easily does 35 mph without any modifications. Pretty good for an engine that is around 50 years old. I may sell it as it is only taking up valuable space in garage.

[robertdjung]

got any pics of that engine? is there some kind of external thing on it which is the gear reducer? I had a briggs with a 6:1 reducer it was huge.

[Russ2251]

I still have remnants of original engine. I'll take pic and post tomorrow.

[Russ2251]

got any pics of that engine? is there some kind of external thing on it which is the gear reducer? I had a briggs with a 6:1 reducer it was huge.

Here it is. Jacobsen J-321 w/gear reduction. Magazine ad is an earlier version of my engine by about 5 or 6 years. Very difficult to date this engine as there are no date codes of any kind on castings. Info on web is very sparse, if at all. This is one of the most underrated 2 cycle engines I've worked on to date. Rated @ 2.5 hp is more like 4 hp. I haven't checked max rpm yet but suspect it is around 7k. It's a real attention getter without muffler. I can generate a crowd of kids within seconds of starting it. I use SAE 30 non-detergent compressor oil mixed @ 16:1 which was correct for most 2 cycles of the day. There were no pre-mix type of lubricants back in 1956. Synthetic what???:confused:

[Jblankster]

diddnt you say it was just a detuned kart racing engine? if it is, i bet the racing version's parts will fit like a new crank, and the side cover to take the GR off.

[Russ2251]

This is a parts only engine. Not worth effort or $$ to restore.