New Gen - Crankshaft End Play - HK2012 - VRS - 6904

[Wrench]

Howzit Everyone,
I know this topic has been talked about before. This is what I know and what worked for me.
In 2007 there were 2 types of cranks made for the Whizzer.
I'll talk about both styles of cranks.
I will break this thread into two posts. Early NE crank and Later NE, NER and Cruzzer cranks,

Late NE, NER and Cruzzer Crank end play.
This crank was designed to be used with the 6904 open bearing and side cover
There is a lot of crank end play with this crank. About 1 mm or .040 th
I found the best way to take up the end play was from both sides of the crank.
I put a .016 th copper shim between the crank bearings and the case, one on each side.
The pictures should explain everything.
By using a shim on both sides I have centered the crank in the case.
Now the crank has about .003 th end play on each side
The Stock crank end play was around .020 th on each side. WAY TOO MUCH. Taiwan Specs close enough is good enough?

How To make copper shims.
If you can find and buy the correct shims then GOOD for you.
I use .016 th copper sheet I cut the shims out with the correct hole saws.
Put the copper sheet between 2 pieces of 1/2" wood then drill out shims with hole saws.
This will get the shims close to the correct DIA.
Next trace the bearing on the copper. Use a dremel tool and a sanding disc to finish to correct size DIA.
Make sure inside DIA. of shim is larger than the DIA. of inner bearing race. or inner bearing race will rub on shim.
Here's a tip to make shims
Drill a pilot hole. Start larger hole first. Drill only 1/4" into first piece of wood for reference. Drill smaller hole. Drill larger hole.

Here's a tip
How to measure crank end play.
With cylinder off (use rubber mallet) tap crank to each side of case. Measure movement. Measure with precision instruments.
A properly centered crank with the correct crank end play will help your motor last longer, run smoother and go faster.

Next post I'll talk about the early NE Crank with the HK2012 and 6904 side covers.

I hope this info can help someone.
Modifications are just suggestions. There are other ways to skin a Cat
ALOHA Wrench

 

[Wrench]

Howzit everyone,
Let's talk about the Stock HK2012 needle bearing for the early NE crank - VRS - the 6904 open bearing and their crank end play.
I know this topic has been talked about before. This is what I know and what worked for me.
The Early NE crank was designed to be used with the HK2012 needle bearing and side cover.
I found the HK2012 too sloppy and the HK2012 damaged the crank end after a few 1,000 miles.
I think the crank end was not hardened properly in Taiwan. Yes I use oil with zin

How to use the Early Ne crank with 6904 bearing and side cover?
I decided to use the 6904 bearing and side cover.
I made a spacer to go on the crank RH end between the 6904 and crank gear.
The spacer is 3.50 mm thick to take up the huge amount of crank end play on the RH side.
I also used a .016 shim on the LH side between the 6205 bearing and case.
The goal is to center the crank with around .003 th end play on each side. The spacer and shim will get it very close.
To make a 3.50mm spacer use an oil imp bronze bushing 12mm long x 20mmID x 24mmOD cut to length Cut square and true.

HK2012 - VRS - 6904
I know someone came up with a solution for the huge amount of end play when using the early NE crank with the 6904 side cover.
His solution was to throw away the 6904 open bearing and machine a holder for the HK2012 needle bearing.
He installed the HK2012 in the side cover where the 6904 used to be.
Sure it worked great, Good idea If your IN LOVE with the HK2012.

The 6904 is a great idea and a huge improvement over the HK2012
When ya think about it the HK2012 needles are always in contact with the crank end race, can you say FRICTION.
The HK2012 bearing shell is always rubbing on the crank gear face creating more end play. More FRICTION.
6904 creates NO FRICTION on the crank

Pennies and the HK2012
Some say to use as many as 4 pennies and to slip em inside the HK2012 to correct the crankshaft end play. So the crank don't rub on the cam gear. The crank is still gonna have a lot of FRICTION against the pennies and side cover. But at least the crank won't rub on the cam gear. All's I can say is "At least you gave it your 2 cents worth"

I know the argument. The needle bearing must be the best. Because why did Vintage Whizzer use a Needle bearing?
That was Whizzers best idea at the time. All Vintage whizzers were made with a needle bearing so ya always used a needle bearing.
Bearings have improved a great deal over the last 70 years.
Most all Modern Scotters and Motorcycles use a shielded or open bearing on each side of their cranks.
So Modern Whizzer had the right idea to switch to the 6904 open bearing.
But poor Quality control in Taiwan. All the parts got mixed up and bikes came out with the early NE crank and the 6904 side cover.

Here's a tip.
If the 6904 bearing is shielded. Just pop off the shields from both sides and make it an open 6904 bearing.
Get that oil flowing. There is an oil passage in the RH end of the crank and ya want to use it.
Shielded bearings should not be used in a crankcase oiled by the splash method.
A small amount of oil will get past the shields and dilute the grease. Bearing may fail.
If you don"t trust the Taiwan bearings. Buy Nachi or another Quality brand bearing.

I hope this info can help someone.
Modifications are just suggestions.
There is more than one way to skin a Cat.

ALOHA Wrench

 

[Wrench]

Howzit Everyone,
Some more info I would like to share.
Sometimes Pictures can say a thousand words.
ALOHA Wrench

 

[Wrench]

Howzit,
I bought this Bearing puller at O'Reilly Auto Parts store for $17
The Slide hammer is $50
They will let customers borrow one for free.
I made my own slide hammer out of a long bolt and an old sledge hammer head.
ALOHA Wrench

 

[DaleIce]

great info....can a side cover be machined to take the 6904 bearing instead of the old needle bearing?

 

[Wrench]

great info....can a side cover be machined to take the 6904 bearing instead of the old needle bearing?

While anything is possible
You can buy the RH side cover with the 6904 bearing.

www.whizzercruzzerparts.com/product/engine-side-cover/

 

[DaleIce]

Before I spend money on a new side cover, I'd like to see if I can shim the crank to the original needle bearing.
I've never hear this bike run(just got it a week ago) and would like to know if its viable as is. I tried the penny trick and the motor wouldn't turn at all.

 

[Wrench]

Before I spend money on a new side cover, I'd like to see if I can shim the crank to the original needle bearing.
I've never hear this bike run(just got it a week ago) and would like to know if its viable as is. I tried the penny trick and the motor wouldn't turn at all.

I did get the penny trick info from a very reliable source
Maybe ya used too many pennies, Try 3 pennies if that don't work try 2 pennies
Honestly I never tried the penny trick, I just switched over to the 6904 side cover and made a spacer.