Engine swap and scarry performance.

Rapidrob

Well-Known Member
#1
I pulled the clone engine,a Hawg-Ty off of my modified Hiawatha mini and installed a new Greyhound 6.5 with the lighting coils I installed.
The engine was just tall enough that the fuel tank would not fit in the frame and have the gas cap reachable.
I replaced the tank with a Brigs&Stratton tank and it fit OK.
I took off the engine governor and set the max RPM via the throttle stop to prevent engine over-run and possible damage to the fly wheel.
My first run to say the least was scary. This little bike was so much faster than the old engine that great care is needed if you crank the throttle open and the front wheel is slightly turned.
Wheelies can be a problem on pavement if I don't take care. On my dirt road spinning the rear tire is an issue with loss of traction in a corner if I goose it.
The bike only has one brake,a drum / band at the rear. It is original to the bike and the band material is pretty much worn from age and use. Before I go crazy on the paved roads I really do need to replace it.
I'm not complaining, it is just a different beast with the engine swap.
I have no idea what the top speed will be but it is much faster than the old governed 30 MPH on paved roads. With a billet flywheel I may try it some day.
I got to drive a "Popper" bike while at a rally in CA a few years back and that was what a ride to be sure. While nothing like
a Popper bike my little mini is a hand full if your not expecting it.
I'm sure the clutch will have a short life if I don't keep the acceleration down to normal while putting around my mountain.
 

Rapidrob

Well-Known Member
#4
I won the engine a few years ago and had not used it.
In CA The guy who had the 212 Predator engine putting out 18 HP called it a "popper bike" as the engine at idle makes a very loud mean popping sound.
 

Harquebus

Active Member
#5
...I have no idea what the top speed will be but it is much faster than the old governed 30 MPH on paved roads...
If you don't have a smart phone or have a smart phone with a GPS Speedometer App installed, you can use a Garmin or other such GPS device and determine your speed. Or borrow a friend's. There's just no excuse for not knowing, not in this here 21st Century there ain't. :laugh:

I'm sure the clutch will have a short life if I don't keep the acceleration down to normal while putting around my mountain.
You might be exaggerating in the sense of all this new-found power you're getting out of the new Greyhound mill, but cent clutches like to be engaged and don't suffer for it. They will last many years of full throttle riding if proper care is taken. . . .

...but you knew that, no?
 
#7
For next time I would have just modified the governor to reach a higher speed instead of using the throttle stop. Its a safer way to limit RPM. Was the brigs tank a bolt on deal or did you have to make anything to make it fit?
 

Rapidrob

Well-Known Member
#8
One hole on the Briggs tank had to be opened elongated two millimeters. The Briggs tank fuel outlet is twice the size of the Honda clone inlet hose.
I do have a app for speed. The old engine would do 30 mph, This one should do much more.
 

Rapidrob

Well-Known Member
#10
I decided to replace the governor springs back onto the engine. While the bike is fun to ride due to is really small size, the power going to the rear wheel is almost uncontrollable and on the dirt trails I ride on, the rear tire brakes loose causing the bike to fish tail badly.
The other problem is the tire wants to spin on the rim shearing off the valve stem to the inner tube. Replacing the inner tube is a nightmare due to how the rear wheel is mounted to the drive sprocket. Increasing the tire pressure does not help.
It was a fun experiment to try with the engine running at full power.
 
#11
Part of the problem with tires spinning on rims are the use of improper lubricants on the tire when mounting. Dish Soap and any lube that dries is ok but if you use silicone or petroleum that stays wet and slippery there will always be a reduction in friction between wheel and tire. Also the increase in tire pressure definitely increases the tire grip where it meets the rim.
 
#13
I dont know what bead sealer is but I would want to use clear silicone construction caulk/adhesive if I still had a problem with tires spinning on rim. It has the flexibility that I would want when cured that some other glues or adhesives lack.
 

Top