Gearbox Modification for sleeve gear pinion

I was getting involved with dragging off topic another post on neutral gearbox indicator.
the Mick hemmings gearbox video has a bit about the bushes in the sleeve gear pinion I am looking into ways to improve this area.
So I’m going to throw this out to all you Engineers and see if this is a good idea or not.
Background: Awhile ago (years) I was talking to Rick Harrett from Highway Cycle about the bushes in the sleeve gear pinion and the differences between Triumph gearbox and the AMC gearbox. He knows a lot more about Triumphs and I know squat about them. He stated that the triumphs never had worn out bushes as often as the Norton’s. The triumph gearbox bushes were oil groove spiraled and are longer. http://www.nsamotorcycles.co.uk/57-1370 ... 4647-p.asp The spirals carry the oil through the length of the sleeve gear almost to the other end (stops about ½” from the end, possibly to dam oil from leaving the pinion from the sprocket side). Part #57-1370 Triumph high gear bush compared to Norton 040062, oil impregnated sintered bronze (I have seen 2 or 3 installed in the sleeve gear pinion). The 57-ID fits the main shaft diameter perfectly on the Norton. But the OD of the bush needs to be taken down by machining by .0025” maybe more up to 0.003” to allow for compression when the bush gets pressed into the pinion gear. I am planning on doing just that as an experiment.
Now looking at the spiraled bush from the gearbox internals, the spiral is clockwise in direction and stops ½” from end as mentioned above. Does it make a difference, which way the spiral is cut in relation to the direction of the main shaft rotation to feed oil into the spiral efficiently? In other words will I get more oil in there if the spiral is counter or anticlockwise? The bush will always be slower or stopped as in neutral position and will be equal speed to the main shaft when finally in 4th.
I think hobot would be interested in this too.
I am going to grab a beer and have a think. Waiting for some comments.
Cheers,
Tom
CNN

Did what Hobot said. Gave new longer bushes a scroll with Dremel tool cutter in spiral stopping just short of drive side. Can't much recall spiral direction but happy with result for sure.

Looking from the inside of the gearbox you would want the spiral to go clockwise to pull in more oil.

My gearbox has the long MK3 bushing with a snap-ring. It has been in there for around 100,000 miles and has been a sloppy fit for at least the last 80,000 miles. But it works fine. Jim

hm how does one determine which side to look at bush to label CW or CCW. I do think the slight extra pumping inward would help return some lube. I've thought about drilling cogs so their rotation tended to pump oil in and A very thoughtful examiner actually figured out and listed which cogs got which direction passages but I failed to copy it. Mystery with this holes concept is whether it'd just spray oil out faster regardless of the holes facing rotation flow. Oh yeah ya don't want to groove the outer most sleeve bush all the way to pop through DS end as not seal there so depends on not much oil up that far to need a seal what with the bushes so chronically dry. Peel even had Ti dioxide friction coat but turned to ceramic abrasive exploring her tri-link advantage with modern squids.
For sure this is the place sintered oil sweating friction bush factory un-distrubed finish comes into its own to preserve. Best practice I can summarize is always feel guilty when not in 4th but not so guilty ya lug below cam surf rpm.

comnoz said:

Looking from the inside of the gearbox you would want the spiral to go clockwise to pull in more oil.

My gearbox has the long MK3 bushing with a snap-ring. It has been in there for around 100,000 miles and has been a sloppy fit for at least the last 80,000 miles. But it works fine. Jim

Click to expand...

Thanks Jim,
That is good to know.
By being sloppy does that affect the amount of wobble in the clutch basket? I wasn't aware of the MK3 long bush. I have only used the short.
I've seen some pretty bad cases where the basket is really moving about when it is being driven.
Cheers,
Thomas
CNN

hobot said:

hm how does one determine which side to look at bush to label CW or CCW. I do think the slight extra pumping inward would help return some lube. I've thought about drilling cogs so their rotation tended to pump oil in and A very thoughtful examiner actually figured out and listed which cogs got which direction passages but I failed to copy it. Mystery with this holes concept is whether it'd just spray oil out faster regardless of the holes facing rotation flow. Oh yeah ya don't want to groove the outer most sleeve bush all the way to pop through DS end as not seal there so depends on not much oil up that far to need a seal what with the bushes so chronically dry. Peel even had Ti dioxide friction coat but turned to ceramic abrasive exploring her tri-link advantage with modern squids.
For sure this is the place sintered oil sweating friction bush factory un-distrubed finish comes into its own to preserve. Best practice I can summarize is always feel guilty when not in 4th but not so guilty ya lug below cam surf rpm.

Click to expand...

Ok Steve,
Here are two of the bushes one with the lead chamfer and the other to right is upside down.
You can see the spiral oil groove on left in a clockwise swirl and coming to an end about 1/2" from the end on the right bushing.
There is a center section within the bush that is larger in diameter to hold oil. I can feel it with my finger and you can just see it in the picture where the tooling marks change colour.
Thomas
CNN

any thing that has play in it in relation to the clutch basket be it sleeve gear bush's or the bearing in the hub can make it wobble. another trouble is trying to find a straight main shaft. MKIII bush's is an old trick or use 3 of the short ones. the MKIII will give you a small space between them IF you put them in from opposite ends.

CanukNortonNut said:

By being sloppy does that affect the amount of wobble in the clutch basket? I wasn't aware of the MK3 long bush. I have only used the short.

Cheers,
Thomas
CNN

Click to expand...

Thanks Thomas for a couple good pointers for me to follow up on, direction of groove for 'drawing' drip down oil inwards and a hollow in mid bush to hold more left over oil when in lower gears. Very good point windy about the shaft straightness which escaped my attention 1st time I ruined bushes on Peel and got clutch wobble again very soon after till I went in again and found bend shaft that was more corkscrewed candy cane twised than simple bend so took a long time beating and micing it in frustration till it dawned on me what I was facing. Got Peels main shaft back to ~.002" run out and quite but lasted fine till Peel's over rev in N. I think i have enough parts left over now to assemble 2 more AMC's besides one in Trixie. When I got around to checking Trixie's closely I'll go ahead and assemble the left overs while still remembering all the factors I tend to forget too soon. I sure love to use 2nd gear from low idle to over redline in Peel but know its wasteful in ordinary isolastics with mere factory level Combat power so don't try it anymore on Trixie. Too cold to ride w/o windscreen which have cracked apart so thinking time to have the shafts and bushes dry friction coated for fun.

https://www.google.com/?gws_rd=ssl#q=dr ... on+coating

I have also seen the maim shaft break @ the circlip groove. all in all the gearbox is a way over stressed POS for a commando. about the only parts I have not seen break is the inner and outer covers.

hobot said:

Very good point windy about the shaft straightness which escaped my attention 1st time I ruined bushes on Peel and got clutch wobble again very soon after till I went in again and found bend shaft that was more corkscrewed candy cane twised than simple bend so took a long time beating and micing it in frustration till it dawned on me what I was facing. Got Peels main shaft back to ~.002" run out and quite but lasted fine till Peel's over rev in N.

Click to expand...

bill said:

any thing that has play in it in relation to the clutch basket be it sleeve gear bush's or the bearing in the hub can make it wobble. another trouble is trying to find a straight main shaft. MKIII bush's is an old trick or use 3 of the short ones. the MKIII will give you a small space between them IF you put them in from opposite ends.

CanukNortonNut said:

By being sloppy does that affect the amount of wobble in the clutch basket? I wasn't aware of the MK3 long bush. I have only used the short.

Cheers,
Thomas
CNN

Click to expand...

Click to expand...

Windy,
I do check the main shafts with a dial indicator and two v blocks. Good to know on the MK3 bush.
Thanks
Thomas
CNN

How does one solve bent AMC shafts when to do so is more like unwinding barbed wire strands than bending a bar straight. To me it was as frustrating as spoking a rim or tuning a wooden piano fix one bad measure and a new one almost a large shows up. If significantly bent now I'd just bite the bullet to skip being mechanic-machinist and buy a good one and ride on off into the sunset.

hobot said:

If significantly bent now I'd just bite the bullet to skip being mechanic-machinist and buy a good one and ride on off into the sunset.

Click to expand...

+1...on... "If significantly bent now I'd just bite the bullet". I use the V blocks and Indicators to check for straightness. (Piece of Mind)… I have never tried to bend a mains shaft straight. I am not sure how hard they are or whether they are heat-treated or case hardened.
Thomas
CNN

CanukNortonNut said:

hobot said:

If significantly bent now I'd just bite the bullet to skip being mechanic-machinist and buy a good one and ride on off into the sunset.

Click to expand...

+1...on... "If significantly bent now I'd just bite the bullet". I use the V blocks and Indicators to check for straightness. (Piece of Mind)… I have never tried to bend a mains shaft straight. I am not sure how hard they are or whether they are heat-treated or case hardened.
Thomas
CNN

Click to expand...

They are case hardened. Pretty hard. They will crack if you put too much pressure on them. I have straightened them if they are not too far off. Say less than .010 TIR. Jim

I know a 3# sledge on hard wood or Al block can bend AMC shafts supported in wood V's, so hobot logic agree's with both Ken and Jim, if ya can beat it back good enough yea, if not oh well was scrap anyway. I suspect most the cases of un-straight shafts is from one or more past over tensioned primary events.

Foe what its worth, oillite bushes are supposed to hold the oil. Also as they are not solid, grooving them could weaken them. If someone was to design a system where the oil could flow through the bushes that would be good [ ie return oil back to g/box.] As it is, we don't want to have the oil get out onto the chain. Blind spiral grooves are effective on king pin bushes because grease guns have a lot of pressure behind them.
If you want to Hobotize your g/box [ sorry Steve ] then use auto trans fluid. That should find its way through the bushes [ as recommended by Hobot ]
Just think, that g/box design has been around for a while. Admittedly we have more hoses going through it now. I also realise the attitude " I have been doing things this way for year" is an ignorant answer for someone who hasn't updated his thinking to the modern way.
As Jim has said here, he has done 100,000 miles on a set of those bushes without problems. Most of us now will be lucky to use our bikes for 5,000 miles a year, so they will outlast us wouldn't you think. Bugger, lets go for another ride.

If the bike stands unused for a length of time due to winter say then oil in the void between the bushes will leak out till it finds a level that is low enough to be trapped at the lowest part of the void.
When you then start the bike an are worried about your cam not having enough initial lube your sleeve gear is having the same problem an having to rely on it ability to absorb an retain oil.
So just as with the cam (if not wet sumped) an crankcase seal (if wet sumped) the first usage after long period of standing is not a good time for the sleeve gear.
So yet another reason why there is true in the old saying USE IT OR LOSE IT.

I think I will leave mine in the garage after yesterday's weather.

kerinorton said:

Bugger, lets go for another ride.

Click to expand...

Buggers nice smooth low levelish snow field is great surface to practice stunts and not crashing as easy on THE Gravel slopes but I only got to do it on SV650 since '01 as every year something has kept my Combats off it. No big storms yet in NW Arkansas so most the flame color still on trees to hurt your eyes in the bright sunlight, so prefect day for me to do some more on Peel project outside and Trixie pieces inside before more fire wood sawing after working up a sweat - not riding.