Need advice about my boonie bike project

[44619herman]

In the process of completing my boonie bike, the orginal 5hp motor had serious corrossion on the side crankcase side. It had two small holes right through the end case and corrossion on the mating flange. I ended up using JB weld and patched up the two holes in the crankcase. Then I had a little problem with oil leaking on the bottom of the end piece. So I used some RTV and that seemed to temporary stop the oil leak. I rebuilt the carb and the engine has plenty of power. That being said, I also bought a brand new 6.5Hp OHV motor on sale from harbour freight. It looks like a honda clone. I paid $106 for it on sale including tax. I would have a little bit of work making the throttle cable adapt to it. In any case, I plan on using the 2 speed jack shaft that came with the boonie bike. My question is as follows: Do you think I would be more satisifed with performance from the new 6.5 hp clone or the orginal 5hp briggs and stratton.
From a collectors standpoint or value standpoint, should I keep the American made engine versus the made in china engine?

One last question, I just bought a new BMI double sprocket clutch. Other than the key way, what keeps the clutch on the shaft? I can't tell but does the 3/4 inch engine crankshaft suppose to be able to accept a threaded bolt and washer to keep the clutch from coming off? The shaft was filled with mud and I didn't know if it was threaded internally or not. My old boonie bike used a comet industries clutch and had allen screws to keep it attached to the shaft. Thanks again.

 

[leathernun666]

I have had 3 Boonies in the past. I am down to one, and yes I run a clone on it with a single clutch and jackshaft. The bike runs awesome and is as fast as I would ever want it to be. I piggybacked the gov spring for a little more top end. You can always switch it back to the Briggs if you decided to sell it. Trust me the clone will run like a raped ape if set up right gearing wise.Save your money and run it the way I did. 12th clutch to 14th primary to 12 th to 72 rear. I think ... I can check if you need me to:thumbsup:

Here is a before pic.

I dont have any recent pics with the clone. sorry

 

[44619herman]

I probably should have posted this before buying the double sprocket clutch from bmi. I wasnt sure, so I have been trying to follow the manual. I also don't have a shifter, so thats probably another reason that I should have just gone with the single clutch. Thanks for your input

 

[44619herman]

By the way, nice mini bike pictures. I was wondering, if I could just use the double sprocket clutch, but only use one of the sprockets. Do you see any problem with that? Do you have any sources for the rear brake drum pads?

 

[leathernun666]

The drum pads . I think in the OldMiniBikes warehouse the AZUZA 5 " brake assy, might be an easy switch. Thats whats on mine but I am not sure if its the original sproket on the back , as the wheels were changed by the previous owner.

Yea you can use a double clutch without running the 2 speed. To be honest I here the stock 2speeds are so so, and once that piece that always breaks does, they are toast. They are newer versions of the 2 speed jackshaft out that dont require a shifter. There is a guy on here selling them for $75 shipped.(jpr95) I think is his name. but I am sure you could sell that 2 speed clutch and get 95% of your money back.

 

[44619herman]

Thanks for all of your feedback. With my BMI double sprocket clutch, what do you rely on to keep the clutch on the shaft. My old comet clutch had set screws that screw into the keya dn the shaft. The new BMI clutch doesn't have any such set screws. Is there suppose to be a bolt and spring washer threaded into the crankshaft to keep the clutch from coming off of the shaft? If so, hopefully, my old briggs has such an internal thead. It appeared to be plugged up with dirt or something.

 

[leathernun666]

Yes if you dont have set screws , you will need a tapped shaft.( the clone motors are tapped ) Like I said I would either put that clutch on a shelf or sell it, I dont know if BMI will exchange the part for you or not, but I would just go buy a Max Torque clutch and set it up that way. Remove the 2 speed and save it. It is worth some coin to someone doing a spot on resto. Then get yourself a 5/8 jackshaft (take the measurement first) and get the sprockets from BMI. If you sell that clutch , you would be able to get everything you need for the same price as that clutch almost.The Honda clone motors will fit in the stock engine plate holes, but they dont line up exactly on regular bikes, but since you are using a jackshaft, you will be able to put the sprockets where you need them to line up. (make sure you get some 5/8 collars with set screws) I can take some pics this weekend if you need me to. So you can see exactly what I mean. :thumbsup:

 

[44619herman]

I really could use some pictures so that I can things right ono the jack shaft. In regards to the clutch, is there anything special? I am going to contact BMI and see if they are willing to take the clutch back, especially if I am going to buy another one and some other things. In regards to the clutch, would I order a Max torque, witht a 12 tooth sprocket,#35 chain? Thanks again for all of your help.

 

[leathernun666]

Yea a 12 tooth clutch is what you want :thumbsup:

I just remembered my set up,

12 tooth clutch
13 tooth primamry
12 tooth secondary
72 tooth rear sprocket

You can go to this page and find the best set up for your needs. I think you use 3600 Rpm's for the motor, I used 3800 since I rigged the gov spring :thumbsup: The clones have plenty of torque. I am 6' 220lbs and it pulls me around anywhere I wanna go. Boonies are good street bikes, but honestly they suck off road. No suspension will rattle your teeth.

(Rawge's Mini Chopper Information Site - Jackshafts)

I will try to get some up close pics this weekend for you. Actually I would post the clutch up in OldMiniBikes nini bike parts and sell it. I get my clutches off of ebay for (sledpartsguy) They are $26.99 plus $5.99 shipping I think. Cheapest I have found anywhere.:hammer: