Fix my Whizzer!

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The Whizzer is back on the road!

I replaced the copper head gasket over the weekend and took the bike on a 12 mile ride yesterday without incident.

But I'm still having a problem starting the bike from a regular kick start on the stand as it seems that the high compression head has resulted in more transmission slippage than normal. In fact, I thought I still had a spark problem as I could not get the bike to fire using my normal "kick start" method. Upon closer examination I determined that I just wasn't getting the motor to turn over sufficiently. So now I need to ride the bike for maybe ten yards before engaging the clutch to spin the motor and start the engine. Needless to say, with a cold motor and a hill to climb, this can be a bit of work!

The engine has gobs of low-end torque and revs like crazy if allowed (remember, this motor has one of Quenton's custom cast racing heads on it). It now appears that I'm just not getting enough power to the rear wheel. I've adjusted the length of the cable that engages the idler pulley through all possible positions but still cannot get improved power transmission.

Can someone describe the design of this manual clutch 'transmission'? When going up a moderate hill, the engine RPMs will climb, but my speed will drop. Is there a way to easily modify the design (stiffer spring/smaller belt/different pulley/etc.) to get more power to the rear wheel?
 
I should be able to loosen those motor mount bolts blindfolded given the number of times I've done it to rotate the motor to access the head bolts! I must have loosened the belt somewhere along the line while I was doing all the head work. Anyway, thanks for the link and I'll try the fix sometime this week.
 
Hi go-rebels,


Looks like the blown gasket is a NE copper head gasket and the other gasket in the picture looks like one I made for the head. I have never seen a head gasket blown that much. I wonder if the starting fluid might have ushered in a new gasket design. I can see why it didn't want to start.

Have fun, and keep us posted..
 
I think there were two reasons the bike did not want to start.

1st, the blown gasket didn't help. Extra air sneaking in where it's not supposed to enter never helps. But a long spray of starting fluid can more than make up for some excess air.

2nd, my loose drivetrain did not allow me to sufficiently spin the motor to get more than a few sparks at best. Remember, I only tried to kick start the bike, as I always had. The raised compression ratio only made the effect of my loose belts worse.

After I tighten-up the drive train, I hope to be able to start the bike with a kick from the side as before.
 
Tightened the engine drive belt yesterday and now the engine will "kick start" as normal and fire-up. That's great news!

I only sensed a marginal improvement in "grip" when riding the bike and the engine is under load. There is still significant slippage happening somewhere within the belt drive but I suspect that that is normal, so as to prevent engine stalling. But with the big improvement in torque from the new high compression head, I'd like to get more of that torque to the rear wheel.

What belt is designed to slip when the engine is under load? I can't tell from just looking at the belts.

Will a different belt improve torque throughput? Quenton mentioned a Gates belt available at NAPA. Does that belt improve grip or just improve longevity?
 
Also, being a high flow head, I was easily able to reach 40 mph on level ground, and the bike was still accelerating! At that point I lost my nerve having no confidence in the brakes and flimsy rear hub. And that's with the stock 22mm carb!
 
The AX series belts work the best on a Whizzer. I have Gates belts now and I like how they grab. I also have a "special" head from Quenton and I don't have a slipping problem with my belts.

Jim
 
AX 27 is a 29" half inch belt. Because it is "notched" it will bend around the front pulley better [more grip]. It is possible for either belt to slip if loose. The manual clutch requires a "balance" between the 2 belts, and because the arm was made the wrong length, and the clutch handle doesn't travel enough, it often takes a while to reach the "perfect" setting. Read my posts on belt adjustment, but I always make the front tight first and then adjust the wheel/ top motor mount for the rear belt.
Some brands of AX 27 belts "squeel", but I don't remember which. I looked and all in stock are Gates brand and I ordered them through NAPA.

Have fun,
 
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