hf, lawnmower or ht bicycle engine?

Y

young grease monkey

New Member
I am going to build a new bike with a specialized rockhopper, getting it powdercoated black. But I don't know what engine to use. My last (and first) build had an ht 66 and well they have a lot of problems and it wasn't very fast. I have a few options; a nice Honda OHC lawnmower that's begging to be torn apart because the self propeller is broken, I could get another ht and mod it but how much HP would I get? Not much. I want a big four stroke, seems to be the cheapest way to go fast. I could also get a 99cc harbor freight engine which would be easier because its a horizontal shaft but I want to keep the budget as low as possible. I don't mind taking stuff apart to make it work, but how can I convert a vertical shaft engine? And do you think it would fit in a bike frame?
 
Re: hf, lawnmower or ht?

A vertical shaft can be used, but when the smoke clears you most likely of spent more then if you started with a horizontal shaft engine. Personally these HT engines, mounted on a bicycle frame will go faster then I want, the frame is not made for both the vibration and speed. But that's me. Umm what is not very fast?
 
Re: hf, lawnmower or ht?

If you're speaking of the Honda GCV160, it's an easy engine to convert to horizontal shaft. The crankcase is split diagonally and the output shaft side is removable and interchangable between the vertical and horizontal versions of the engine. The horizontal parts get you the bottom mount and correct oil fill location for horzontal duty. These pieces show up occasionally on Ebay.

Having said all that, I believe vertical shaft engines are a viable option if you can get them cheap enough...even the one's you can't convert so easily.

MHF
 
Re: hf, lawnmower or ht?

Well, I got $100 so I think I will go with the 99 cc HF predator, seems to have the best bang for the buck. Im thinking single speed, with a belt pulley tensioner as the clutch. I will probably make a mount from cast aluminum using metal from a busted up ht engine, lol. Piston, cases, covers, all taste good to the furnace! Same for the jackshaft. I will have to get the bearing holes bored on a lathe if I go that route, so where can I get a good Jack shaft if I can't have it machined? Trying to keep the budget low, I already have a throttle assembly and sprocket on the wheel so what do I need besides a gas tank? Oh and I can have stuff welded, powder coated and maybe machined cheap or free, so I don't have to worry about fabrication cost. My dad has a lot of connections. One more thing, what can I expect the weight to be? The engine itself is 25#. Weight and handling is a big deal for me, I like to ride on the edge. Maybe I will save some by using an aluminum mount?
 
Re: hf, lawnmower or ht?

You are on the right track with the 99 preddy. They're cheap, reliable and easy to fit into a frame if you're a DIY'er.
You can find 20% off coupons in Popular Science ect. mags, and wait for the $99 sale and get one for $87.99 like I did. I even got a free multimeter with another coupon.
I bought one of these a couple weeks ago for my new engine. Bolts right on, and bearings are already mounted.
http://www.ebay.com/itm/330717252331?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2648
 
Re: hf, lawnmower or ht?

Fisher, it is not fast enough because I can't accelerate with cars or keep up on bigger streets. Being forced to the edge of the road by passing cars is not safe or fun. Strange, most things that aren't safe are fun for me... anyway, I think I will go with a cvt. There is one on eBay for $165 free shipping. Says its a comet clone, here it is: http://item.mobileweb.ebay.com/viewitem?itemId=330737447278&index=0&nav=SEARCH&nid=42695910087
Will it work with an adapter for the ⅝ shaft?
 
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Re: hf, lawnmower or ht?

one more thing; would it be ok to use the ragjoint I have or am I just nucking futs? Another option would be to get a hub for a disc brake and mount the sprocket to that, might as well get a whole new back wheel, and a good one. My wallet hurts...
 
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Re: hf, lawnmower or ht?

For a few $ more you can get much better customer service from AGK (and a better reputed product), look for model #1002.
AGK web site

You will need to shim up the engine output shaft to 3/4 inch though, an easy enough thing to do.
 
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