GP460 Engine On Friction Drive

[DetonatorTuning]

5-7,

do you have a set of Staton's 3,000rpm engagement springs yet ?

the stockers hit like a train at 8,000rpm, the clutch savers at 6,000rpm, there are some DDM heavyduty springs that i think are just as bad.

the only way you will keep it from just spinning the roller right thru the tire when it comes in is to have it down around 3,000rpm where you can pedal the bike up fast enough every time for the clutch and engine to be catching up with the momentum. at about 23:1 that would be close to 8mph.

steve

 

[kerf]

Absolutely, what DT said. I got the only set of 3400 RPM springs David had, they were a prototype. I would think the 3000 RPM ones would work just as well or better. I idle 26 - 27 hundred, it will go even lower.

 

[5-7HEAVEN]

Steve, I believe the engine I purchased from Zomby has low rpm springs. I'm also ordering two sets of Staton 3,000 rpm springs.

The TLE43 is more forgiving and predictable. kerf, I have great respect for power.

I guess I need to pedal more on takeoff untill I find the optimum point of engagement.

Time will tell.

I sawed off the Dominator pipe and mounted it onto the engine.It was a feller gauge's clearance from pipe to engine channel.

Then I realized when I machine .333" off the clutch spacer, it'll bring the engine channel that much closer to the engine and pipe. The left rear strut might interfere.

Time to remount everything again for trialfit.

 

[duivendyk]

The torque characteristic of the GP 460 is not much different than other engines this size at low/medium rpm,however it has a peak torque at around 8.5 krpm and peak power at 9/10k.Either a 1.25 or a 1.5" roller could be used.The 1.25 " results in 37.5 mph at 10k rpm,the 1.5 " in 45mph at 10k,which is probably not attainable,depending on aerodynamic drag, which goes up steeply at this speed.For instance to go from 37.5 mph to 45 requires a power increase of over 60%.At 8.5k (peak torque) the speed will be 38mph.I would go for the smaller roller to have some torque (throttle in hand)

 

[5-7HEAVEN]

dui, two 1.5" rollers on front and rear tires drive my twin-engined cruiser. I started with 1.25" front/1.5" rear drive, then progressed to 1.375" front/1.5" rear and finally 1.5" front/1.5" rear.

There was a major loss of acceleration upgrading to Staton's largest-diameter spindles. However, having two working powerplants made up for it.

In the end, it's all about quickly getting up to and maintaining highway driving speeds of 35-40mph.

Here's hoping that this engine combination can do it.

 

[DetonatorTuning]

Steve, I believe the engine I purchased from Zomby has low rpm springs. I'm also ordering two sets of Staton 3,000 rpm springs.

The TLE43 is more forgiving and predictable. kerf, I have great respect for power.

I guess I need to pedal more on takeoff untill I find the optimum point of engagement.

Time will tell.

I sawed off the Dominator pipe and mounted it onto the engine.It was a feller gauge's clearance from pipe to engine channel.

Then I realized when I machine .333" off the clutch spacer, it'll bring the engine channel that much closer to the engine and pipe. The left rear strut might interfere.

Time to remount everything again for trialfit.

WARNING Will Robinson WARNING

5-7, DON"T modify the length of the head pipe or the shape of the chamber on the Dom. to get it to fit. the port timing on the 460 is very aggressive and as i found out is just as sensitive to alterations of this pipe.

you can loosen the weld connections and reposition the segments some , just make sure they don't move in length.

good luck,
steve

 

[kerf]

That port timing is a bear, with my high gearing, if I get into the throttle at low RPM, the return pulse through the carb will clog my air filter with oil. Thought about installing the TS reed valve setup but decided too much $$$$ and trouble. Brake parts cleaner is much cheaper.

 

[5-7HEAVEN]

Thanks for the warning, Steve. I read the informative posts regarding Dominator pipe modifications on your installs and the other pioneers.

Only the mouting brack needs to be modified. I will grind down the engine channel to provide necessary clearance.

 

[DetonatorTuning]

5-7,

what are you going to do about deflecting the exhaust out put away from your seat and leg ?

also air flow streaming against and into the end of the pipe will alter the characteristics of the pipe and engine negatively.

steve

 

[5-7HEAVEN]

Steve, I'll reroute the exhaust via 5/8" ID rubber exhaust tubing. The hose will either go down the seatpost towards the crankset or to the rear axle, along the right seatstay frame.

I use that same tubing to route my front engine's expansion chamber towards the crankset. It is so effective in silencing the exhaust that I don't use a muffler, just the rubber hose.

The hose is the same as the 4" tubing ADA uses to connect their expansion chamber to their silencer/muffler.