4spd gearbox leaks

[jbs-shovel]

Hi,

My old shovel gearbox leaks oil from behind the tranny sprocket, which is apparently fairly standard for these!
Problem is i have its an open primary and a rear sprocket/brake setup, so as you can imagine rear braking is challenging due to oil build up!!!
Ive spoken to various people, replaced all the seals around the shaft, but to no avail yet.
Before i take it out and strip it down to look at seal running surfaces, does anyone have any usefull info.

Cheers

[Phil]

The problem is the main drive gear bushing worn out. It allows the main drive gear to wobble on the mainshaft. It will leak past any seal.

[kevscrivener]

What Phil said. There are various things on the market including the "Jims nut" which does give a better seal than the stock setup, but if the bushing is worn none of them will be totally effective.

[jbs-shovel]

Cheers Phil and Kev.

Just looking at drawing in manual, can see what you mean.
I might wait a bit longer, get in last few rides this year and replace neccasary parts over winter.
Gearbox was oily when i got, just cleaned/painted it and replaced all seals + gaskets before installing.It was ok till first rode it, so didnt suspect anything else may be worn, but as with most things 2nd hand..you never know.

Thanks again,

Jason

[hippy]

Shovelhead jackaroo is a good site for info,ive just had the same problem on my shovel,my mate did a welding job on my gearbox and put in a new mainshaft and he maqde the bushing a tight fit and it still leaked i put and extra seal [the small one that goes over the shaft]plus some silicon seal on the the sprocket threads as well as the double sealed mainshaft nut and everythings ok so far fingers crossed,good luck

[Phil]

Sorry to hear that Chris. The Harley bushing is spirally wound inside, so as the shaft spins it drives the oil back into the box. As the bushing is quite long installation & correct reaming can be quite tricky.

No offence, but it if is done correctly it should not leak. Be careful to install the correct bushing. This video explains the Supernut, but it is available from Custom Chrome. It is a new item that should always be used these days.

YouTube - HARLEY® (FOR HARLEY®) 4 SPEED TRANSMISSION SUPER NUT SEAL BY EVEL CYCLES® PTY LTD AUSTRALIA


Catalog Full Page - Section: 11. Tranny & Clutch / Page 11.42 / Custom Chrome

When I first came over here & was hired as a mechanic, I soon became Mr four speed, spring clutch & all that went with it, as nobody else wanted to do it. Give it to the new guy!

Like Chris said, make sure to silicone the splines inside the pulley, make sure that the bushing is correctly done & use a Supernut. I t should be fine.

[kiwidave]

Good link, Phil.

Alex at Evel Cycle here in Melbourne is a top bloke. Real old-fashioned one-man shop, full of 1970s H-D/Evel Knievel memorabilia on the walls....and his daily driver to work is a tatty Ironhead with hard bags.

He is a good eBay seller too, often with those useful videos he makes at his counter....