Fix my Whizzer!

[Quenton Guenther]

Hi go-rebels,

Use an NGK #BR6HIX [Iridium] and gap it .026" ~ .027".

You might want to set the needle jet with the clip in the second groove from the top.
I have had several contact me lately and spark plugs have been the problem many of the times. I personally have had great luck with spark plugs, but I know it doesn't take much to knock one out. When I raced motorcycles, in order to save money, I often "sandblasted" plugs and re-used them. It didn't take long for me to realize how important a spark plug is in a single cylinder motor, and after having the "sandblasted" plugs fail quickly, and cost me "position" in races, if I even thought a plug was suspect I replaced it.

I do know a few Whizzer owners spent a lot of time and energy looking for solutions to start their motor and it ended up being a bad spark plug.

If a motor is rough on spark plugs it can be caused by intermitten ignition [I have had several sensors causing problems], or a carburetor problem [too much fuel suddently].

Keep us posted on what stopped your ride, and if you need any help let me know.

Have fun,

 

[go-rebels]

I only had time today to pull the plug and check it's condition. It really looked "clean", unlike the usual black sootball I had with the factory head and plug. I think the swirl pattern using the custom head really improves the mixture and provides a more complete burn.

Anyway, I'm not absolutely certain that the plug is good so I'll buy another Autolite "275" before I go for the Iridium or dig into the lifter opening.

Given that I have spark, and the bike would not start after spraying Instant Start through the carb, I suspect that my intake valve adjustment has loosened and the intake isn't opening. Or that plug did die after 2 miles!

 

[Baverian]

The best way to clean a fuel/oil soaked spark plug is to burn them clean with a propane torch.Get the ceramic center insulator cherry red, it will turn white again.Use something other than your fingers to hold the plug.

Baverian

 

[go-rebels]

But my old plug looks perfect. In no way is it fuel/oil soaked.

 

[Baverian]

Just wanted to put this info out there.much better than sandblasting.

 

[go-rebels]

Yes, I agree! A few grains of sand dislodged from the inside of a plug could really accelerate the wear within the cylinder and piston. Does JC Whitney still sell the small plug cleaner (sand blaster) that plugs into the cigarette lighter? I remember seeing these decades ago.

 

[go-rebels]

I had less than one-half hour to do some more troubleshooting. Here is the summary:

Installed a new spark plug; spraying Instart Start into the carb. Whizzer still won't start.

Pulled the carb and decompression plate off the cylinder to get access to the lifters. Lifter gap measured 0.017" on the intake and 0.013" on the exhaust. Everything looked tight; none of the jam nuts were obviously loose. So the crank is spinning with the valves hardly moving at all! Consequently, I'm barely pulling a vacuum through the carb. I'll reset the gap tonight if I get time.

The motor has less than 25 miles since adding the mushroom lifters. Why would the lifter gap change so much?

 

[Quenton Guenther]

Hi go-rebels,

The gap should be .008" on the exhaust, and .006" on the intake. I have seen lifters get out of adjustment, but is caused by the "jam" nuts becoming loose, or excessive lifter wear, but the lifter wear is only possible with the stock "soft" lifters.

Possible things to check, are the valves hitting the top of the combustion chamber in the head [not likely]? The gear is pressed onto the camshaft, and a few have been know to slip. It is possible to use the wrong marks on the crankshaft as a reference, but I don't think it would have ever started.
An easy way to determine if the valves have enough head clearance is to adjust the clearance out of the valves [zero clearance] and make sure the motor turns freely. If the valves are close to the top of the chamber and the clearance is adjusted out the motor will not turn over completely if the valves hit the inside of the head.

I am somewhat puzzled about your motor, please let me know what you find.

Have fun,

 

[go-rebels]

Remember, this is the custom "high fin" head I picked up from a famous Whizzer engine builder that frequents this site (!).

I'll check the jam nuts again. Maybe they are a little loose and I didn't see it in my cursory check. I'll try the zero clearance test too as its easy enough. If I can't turn the motor, then I'll need to go back to the stock head.

But I can't believe that I've got valve interference. The bike would have started and stalled out immediately once the valves crashed into the head. I wouldn't have been able to ride it for 2 miles without a problem.

???

 

[Quenton Guenther]

Hi go-rebels,

You are correct, if the valves hit the head it surely wouldn't have gone far or in fact start at all. If the problem is valves touching the head [which I doubt, just trying to figure out any possble cause], I can easily correct it. The combustion chamber in your special head is very shallow to increase the compression, but the head was tested on an NE motor with a high lift camshaft & mushroom lifters, and shouldn't be too close.

If the valves touch at zero clearance, let me know. It is very easy to machine the top of the valves to add additional room inside the head [if needed, I will provide service free of charge].

Have fun,
252-475-0406 cell