Lowrider in progress

Originally Posted by rmillerb View Post
O.K., I know it's been a few months since I started The Low Rider project (motivated by following Elmo's Bike project...Thanks a bunch), but I've made some real progress. My goal was a Christmas test run but that looks like somewhat of a long shot. The rear suspension really slowed me up; hope 1-1/2" of travel is worth it. I went with a 10/24 - 10/44 jack shaft setup, that should push me 41.5 mph at 6000 rpm. Fast enough I think. (Elmo, what do you think of a 10.56:1 Ratio??) I made a copper exhaust with a baffle setup. Nearly no back pressure. It's not too loud but I may pack it with stainless scrubbers to quiet it down a bit more.

I have a friend and neighbor who races carts with these engines and he has been an invaluable resource; that's what its all about; bench racing and garage engineering. Motivated by my cart racing neighbor, I added a high flow air filter, changed the idle and main jets, ported the exhaust and of course removed all the internal governor parts from the engine. It should be around 8 1/2 HP. The bike i almost 9' long tire to tire... not very practical but maybe I'll do a commuter bike next since this one is not likely to be comfortable for more than a half hour at a time.

If anyone else is building a Harbor Freight / lifan project, and wants to do any engine upgrades or tuning I will be happy to relay any info I have found.

Just typing this post has fired me up!! It's Friday night but I'm putting down my beer and going back to the Garage!!

Very neat build. I hope you'll break this loose and give it your own thread. It deserves it. I looked for your previous post & didn't see it... wanted to be clear on what engine that is. It looks like the 2.5 hsp. Is that possible you got that up to 8.5? I'd like very much to know more details of what you've done to that engine and I hope you have some photos of the changes you've made to it. This is what we need to know... how to get better performance and power out of what is already there.
I also like your copper exhaust. I made one up in copper for the HS engine and in just a few minutes it generated so much heat that it melted the silver soldered unions. I'm encouraged to see yours appears to be holding up. I wonder if the Greyhound is less hot at the exhaust. Did you silver solder your unions or use something else?
Do you think it is necessary to remove the internal parts of the governor or is simply disconnecting the externals enough?
I just picked up another 2,5 HSP Greyhound and will be building it into a 53 Schwinn cantilever frame over the course of the winter. Any advice on improving the performance of the engine would be much appreciated and no doubt by others as well.
Looking forward to your test ride. Good luck!
SB

Thanks for the reply Silverbear,
The engine is a 6.5 Greyhound from Harbor Freight. I'm told the trick is to get rid of The governor(& yes you can leave the parts inside - I just wanted them out), The stock air filter, and the stock muffler. Those three things are likely to push you to 8hp. Rejetting the carb to compensate for the added air flow will certainly get you a bit more. ARCRACING.com has these parts for very reasonable prices and can help you with proper jetting. BTW there is an excellent youtube video from ARC that shows the best way to remove the governor in these engines, IMO.

As far as the muffler goes, standard silver solder's melting point is real close to the exhaust temp of these engines ( 1200 f according to the sensor on my friends go cart w/ the same engine) So I used nickel silver brazing rod; I would have used standard brazing rod, but my header flange is 1/4" steel - dissimilar metals proved to be a challenge. So far so good though, I ran the engine for the first time over the weekend. I got it real hot and nothing moved, except for my wife who ran out of the garage with her hand over her ears. Gotta add some backpressure, I guess.

Got the front brakes hooked up today, Now for the rear. Throttle too - this might take a bit, unfortunately the throttle pulls the wrong way when mounted like this, so not just a quick cable thing. ARCRACING has the answer of course, I just dont like the look of it for my application. ELMO have a solution?