Forum

[Pat M20]

Hi,

I am new to this forum, so a big thank you to Hitchcocks and whoever is involved with the forum.

I am working on what I have been told is a 1993 500 Bullet.

It had huge wet sumping issues, so I decided to start with the obvious (i.e. breather, worm drive seal and timing shaft seal).

The worm drive seal had definitely perished so that will be replaced with a bonded in seal worm drive.

I then took off the timing pinion to find that that seal too needed to be replaced. What I thought would be a simple replacement has proved a problem in that the standard 20mm ID x 30mm OD x 7mm W seal has too large an outside diameter to fit inside the machining on the crankcase.

On closer inspection it would appear that originally a rubber seal was not used and a steel cup has been machined and pressed into the crankcase to house an oil seal.

My problem is as follows:

1) I do not no the measurements of the seal that I took out as I had to mangle it to get it out.

2) I measure the required seal should be 20mm ID x 27.5mm OD x 7 or 8mm width. However, the two closest seals are 20 x 27 x 5 or 20 x 28 x 7.

So, my questions are has anyone out there seen this conversion before (i.e. is it some form of standard conversion) and two what might the required seal be?

I am hoping that the 20x28x7 fits, but I suppose next best is the 20x27x5 and hope the seal is man enough.

Hope someone out there can help.

Regards

Pat

[John M]

Is the metal insert part of the old oil seal?

[Pat M20]

Now that is a very good point!

If so, what is the best way of getting the remains out?

Regards

Pat

[Pat M20]

Hi John,

You were spot on!

All out with little drama.

Thank you.

Regards

Pat

[Tim NZ]

There is no oil pressure present on the seal. For years the motors got by with just 0.001" clearance between the end of the shaft and the crankcase. (a bush in effect) It was with the introduction of the N205 roller bearing in 1972 that the crank began to experience flexiture and oil drainage issues from out of the timing chest.


Even an Viton O ring would be adequate to prevent oil drainage from the timing chest into the sump.


Both pump discs and Seats MUST be with out ANY scores to either mating surface to overcome wet-sumping issues.

[Tim NZ]

If you have left the residue (steel backing) of an oil seal within the crankcase, it is a super tricky job to extract (Cut/Split and hook-out) short of splitting the crank cases...

[binary]

Hi Tim NZ I am just wondering what type of bearing was used on the timing shaft before the N205 roller bearing. When I pulled the Indian motor apart on my 350 RE I found a 25x52x15 ball bearing in there. This engine was so badly bodged I had to ditch it and I bought a 2000 engine replacement off Hitchcock's. Have you ever found a ball bearing in here before.

[Chris Tindal]

binary my 59 500 Bighead had a ball bearing in the timing side. It originally would have had a caged roller though so this was a modification sometime in its life. The perpetrator also machined a recess for an oil seal, but broke through behind into where the cam dips down, thus allowing oil in behind the seal so totally pointless.

[Tim NZ]

The original timing side bearing for the 500 and the post '55 350 was a built-up Double-row caged roller.


With 24 loose 1/4 x 21/64 rollers, ALL hand sized to fit, and were originally available in no less that TEN sizes with 0.0001" increments covering the range of 0.2490 to 0.2500.


Yes, One ten thousandth of an inch accuracy. Fit ONE wrong dia roller only 0.0001 size too large and expect the bearing to be stuffed in 5000miles. To accurately measure the rollers you MUST NOT (never ever!)touch them with your fingers! OR measure them in direct sunlight!!


Your motor had been well and truly fornicated.




Have not seen a ball bearing fitted to the timing side previously, but I have encountered an Angular Contact bearing in the gear box. :-O


A well and truly fornicated gear box...