Need Advice on 1999 Whizzer

KilroyCD

Active Member
Joined
Dec 3, 2007
Messages
1,391
That was a great deal on your Whizzer! Even though it only has 22 miles on it, you should replace the lifters with the mushroom lifters as soon as you can. Here's a thread about the lifters in my 2005 NE5, and how the original lifters were shot after less than 300 miles. http://www.motoredbikes.com/showthread.php?t=14962
Listen to what Quenton has to say, he won't steer you wrong.
 


Quenton Guenther

Motored Bikes Sponsor
Joined
Aug 2, 2007
Messages
2,125
Hi Go,
The current head gasket offered by Whizzer is hard to understand and won't fit the earlier motors correctly. The current offering has an area in the center and actually lays on the cylinder and is located directly in the combustion chamber path. There is no real way to describe what the engineering concept could possible be. I will attach a picture on this post and let everyone try to figure out what it means. I am not sure why, but it appears "some" companies have a problem designing heads with enough metal between the combustion chamber and the head bolt holes. or a head gasket that match the combustion chamber. One of the secrets of making a Whizzer motor run good is to make a "custom" copper head gasket to match the combustion chamber design. In the picture I am going to attach I will show several of my "special" heads with a good head gasket fit. The head gasket should not allow the explosion to spread "between" the head and the cylinder, or have a major part of it blocking the flow from the valves & piston. In the 'ole days many used "eyebrow" cuts or "relieved" the area between the valves and the piston to increase flow to gain additional power on a flat head motor, not locate part of the head gasket in the middle of the path. Also notice how small the area is between the head gasket and the rear center bolt, I can't help but wonder if the tiny area will hold the seal for long. The new haed gasket is the one on the cylinder and the center head right below it, notice the "bridge" across the combustion chamber path. Once again it is important that I state the following: The infromation supplied is intended to help everyone keep their motorbike working well and safer, not intended to "bash" anyone or any company.
I never use any head gasket sealer, but I am sure it wouldn't hurt anything to use.

Have fun,
 

Attachments

Last edited:

go-rebels

Member
Joined
Dec 16, 2008
Messages
194
Nice pics Quenton,

The center pic shows a very small path between the gasket and center-rear head bolt, as you described, and looks similar to the design of the late '60's, early '70's British MGB 4-cylinder head design, which was notorious for blowing gaskets at that point!

The center design is terrible as it only supports the gastket on one side, and when left unsupported will eventually fatigue, break off and get jammed up in one of the valves. At a minimum, the center section must be removed as shown in your bottom pic. But then, when using the stock gasket, you still have that narrow gasket bridge at the center-rear head bolt that will eventually blow out (bottom pic; far right side).

I'm guessing that the two heads on the left and the head on the right are your custom milled heads. The two heads on the left appear similar, and have optimum gasket designs, although the gasket width at the center two mounting holes are still a bit too narrow for my liking. But you can't fix that unless you add more metal to the head. Are they milled for different compression ratios?

The custom head on the right appears to have better flow characteristics and might be used for one of your high-hp motors. Again, nice gasket fit.

It would seem that it would not be too hard to cut a custom gasket from some 0.005" - 0.010" gage solid copper to fit the stock head (like pics of heads on left). Is that about the correct thickness? What tools did you use to cut the sheet copper?
 

RdKryton

Active Member
Joined
Nov 6, 2007
Messages
950
While you have the head off to replace the copper head gasket get the head milled .060 too. It will do several things for you. First it will level the head for a better fit and give you a little more surface area for the head gasket. It will also give your compression a boost and that does several more good things. The power increase will be very noticeable and it will help the engine run cooler plus it will idle smoother. It is a win win situation.
You got a great deal and with a few modifications your Whizzer will be both fast and reliable. Enjoy the ride.
The mods I would do and in this order.
Mushroom lifters
Copper head gasket and mill the head.
Advance the cam timing one tooth CCW
Hi-flow muffler insert if your bike doesn't already have one.

Jim
 

jbcruisin

Member
Joined
May 28, 2008
Messages
686
Hey RD,
advancing the came tooth should be 2nd because he can do that when he installs the mushroom lifters.
 

go-rebels

Member
Joined
Dec 16, 2008
Messages
194
Can the head be removed with the engine still in the bike? I've not tried yet as I've been busy changing out an axle in my 1994 850 Volvo wagon. Ugh!
 
M

MotorbikeMike

Guest
Changing head gasket

Hi Go, I NEVER pull an engine on NE5 for head gasket, and infact recently rebuilt (exchanged out entire top ends, converting to NE from WC1) 2 nice Whizzers in frame, and actually, since it wa a nice day both times, right out in the front yard enjoying the summer air!

Tricks? Hmmm I dunno, I remove the tank, set aside (notice I did not say Drain the tank?), then I use LONG (like 6" or so) Ball-end Metric allens to do the work, using a 3/8 inch pound torque wrench.

I ALWAYS lap the head. What, you are not a "Lapper"? Well you oughta be!

Extremely flat surface new sheet wet or dry sandpaper, used wet. You can use 240-400 depending on how much warp you may have. Lay head on the paper FLAT rotate in circles, continue to read the head untill a nice sanded finish appears evenly on the mating surface.

Rinse well, dry with paper towels (wives will usually scream if they catch you with cylinder head nd thier kitchen towels!

Reinstall, torque down in the usual way. Reinstall tank, Ride Well!

Mike
 

Fred Average

New Member
Joined
Jun 8, 2015
Messages
3
Hi,$400 for a 1999 400 mile Whizzer that runs well sound fair ?
I'm off at 7am to fetch it.
Is Quenton still performing his magic to keep them alive?
Quenton,can we please speak on the phone /exchange numbers?
Thanks,"Fred"
 

Attachments

Top