Quality of replacement gears

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ggryder

ggryder

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I've just bought a set of gears to replace the worn originals in my Commando gearbox. They are not standard ratios and on close (i.e eye loop) inspection I'm disappointed with the quality and in particular with the finish on the gear teeth. I imagine these things are made in small numbers and they are not produced by grinding to a fine surface finish, but what should my "reasonable" expectations be?

I'm pretty sure that this is not acceptable: -

Quality of replacement gears


This probably is acceptable: -

Quality of replacement gears


but how about this?: -

Quality of replacement gears
 
well someone has an interesting way of cutting gears, looks like they were broached somehow, I've never seen anything like it, best of luck with them.... where did you buy them?
 
madass140 said:
well someone has an interesting way of cutting gears, looks like they were broached somehow, I've never seen anything like it, best of luck with them.... where did you buy them?
Click to expand...

I don't want to mention any names as yet ,the gears come from reputable supplier and the magnification is showing them at their worst. Viewed from normal reading distance they don't look so bad. They might run-in and give acceptable service, but it seems to me that the torn surface is likely to result in the surfaces starting to break up earlier than they would if they were less flawed.
 
I would be interested in knowing who you bought them from, and who made them (if different).
I plan on ordering some gears in the near future and would like to avoid purchasing anything that looked like that.
Stephen Hill
 
They look like stamped out by a cookie cutter machine. Trash even to a shade tree. Correcto-mondo about the surface being flakey and the possible useable one has the best looking stress risers to shear off cleanly from Norton torque. If using better do a few lube changes in a row to flush out some the metalic grit that will be shedding for a while. Might be sticky shifting as the galls on galls try to slip across each other to engage. Dang bad luck of the draw we've herad of once or twice befoe and now 3x's - might imply there's a supply problem with this hobby to learn to deal with the hard way. If stuck in Asia somewhere I'd for sure use em to get moving.
 
Those teeth look terrible.

The Suzuki DR650 has been known to grenade third gear taking out the whole engine in some cases.
When I went to the 780 kit (53 rwhp @ 5800 / 50 ft/lbs torque @ 4800 rpm) I ended up sending the complete transmission to Nova Racing Transmissions in the UK.
They then designed and machined from billet a new third gear pairing, they certainly didn't have the finish of those Norton items.
I will dig though some pics and see if there are close ups somewhere.
Are those gears even heat treated ?

Quality of replacement gears
 
I have a pretty good idea where they come from- an English "Norton Specialist"- and from experience I can say they break in service!

If you are lucky a layshaft gear breaks into two pieces and just falls into the sump (as second gear did on my youngest daughter at Sachsenring some years ago), and your gearbox will not seize up solid. Now if a mainshaft gear broke, or the gear had not just fallen down.........

I must stress these gears have nothing to do with Andover Norton They are made from a different steel and made and hardened by different methods. I have yet to see a similar desaster from a standard production gear.

The gearbox from that day at Sachsenring rests in the "quarantine" corner of my private spares cache in my shop never to be used again. We switched to a Quaiffe 5-speeder from Mick Hemmings for our Commando racer.

Joe/Andover Norton
 
That is a horrid surface finish, the hobbing process was very poorly done.
 
looks to me like they were shaped.
The set-up was not adequate for the cut involved.
The profile tool has inappropriate clearance, maybe in backwards, clapper not lifting, etc..
It may be ok if they were intended to be profile ground after heat treat and all of the bad finish would be removed.
Was a finishing operation maybe missed?
Do they actually mesh when on the shafts?
So much for quality control and fitness for purpose.
Don't use those gears.
 
I am just about to buy some gears. Please can you PM me (or post here) where you got these from as I need to make sure I don't get them from the same place.
 
A number of folks have had variable experiences from various suppliers, myself included.

This is what makes the forum so good - sharing knowledge, including who the good guys are...
I'm always happy to praise the good ones (Like A-N, Mick Hemmings and RGM), but others which may be more, er... centrally located, well... Not all experiences with them have been bad, but for me, one too many.

As for those gears... they weren't gear cut. I think the 'done on a shaper' assessment to be pretty close.
If they have been hardened at all, by the time they've bedded down to meshing on more than just the high spots the hardening will have been worn through anyway.

Utter junk, and you're right to be concerned.
It's right not to name and shame, but a subtle hint may stop some other fool wasting his hard earned.

The gearbox is the Commando's biggest weakness IMHO, and like Joe, I concluded that the only option was to talk to Mick Hemmings and get a Quaife.
 
B+Bogus said:
Utter junk, and you're right to be concerned. It's right not to name and shame, but a subtle hint may stop some other fool wasting his hard earned.
Click to expand...

I'll let everyone know what happens, but at this point I'm waiting for the vendor's feedback. The only reason I made the original posting was to find out from others what are reasonable expectations. I don't think many gears for motorcycle applications are ground, so they're probably never going to look dead smooth (although those DR650 gears from Nova look beautiful) and since they are going into a race bike/gearbox, that I'd expect to chew up gears fairly rapidly, a nice finish might not offer much advantage.

"Other Fool"?

Cheers! ~ Gary
 
The gears that came out of my stock tranny looked like junk gears from any Jap bike. The problem is the replacements I ordered were just as bad and they were still functioning. They had pits and places where the hardened metal appeared to be flaking. If I saw that in a Jap bikes they would have been tossed out and it would have had problems.
 
If the shiftings not done by a baboon , Id think theres more than one manx with the original cogs in the box .

The Norton ones pictured would suit arm chair worriers . They could discuss how they wore out as shown , without
actually haveing to use them . High Quality ( expensive :x ) cogs like Quafe of Quality modern top line stuff should
give durable reliable service . Low Quality ( Explosive :( ) sorry looked to good to miss . :wink:

If you were getting entirely naggerty raceing , punching them through regardless you may well knock them about .
but some degree of sympathetic , of disiplined practised shifting / coordination should see near indefinate life .

You weep at old prices for say a Quaife 4 speed gearset . One of the areas were economics / cost were dubious
occasionally on standard commandos . Mk III internals would appear to be the best developed of the stock parts.

Did they occasionally have ' a bad batch ' on the MkIIIs too ? win at all cost , is self explanatery . :x Big Ones . :?
 
The gearbox is the Commando's biggest weakness IMHO, and like Joe, I concluded that the only option was to talk to Mick Hemmings and get a Quaife.
Click to expand...

Bogus misinterprets me there- I was talking about racing gearboxes. The reason for the original purchase of the close-ratio 4-speeder was not dissatisfaction with the standard gearbox, but a standard gearbox is not much use on the racetrack. On the track one has virtually no use for the (road) 1st gear, hence ends up with effectively 3 speeds. The close-ratio, from a ratio point of view, was much better on the track, but manufacture was very poor definitely crossing the line to dangerous.

For the track we then went on to a Quaiffe 5-speeder, as I don't want to risk my life with an iffy gearbox, and even less the life of my kids who love to ride our Commando on the track.

On the road I have always used the standard gearbox, making sure when I rebuilt one I got Genuine Norton Factory Parts for my gearboxes. And that is going back to the 1970s, i.e. decades before I became the owner of Andover Norton. Never had a standard gear give up on me.

Joe/Andover Norton
 
ggryder said:
"Other Fool"?

Cheers! ~ Gary
Click to expand...

Oops! Sorry :oops:
Rather got carried away there, I'm afraid :roll:

ZFD said:
Bogus misinterprets me there- I was talking about racing gearboxes.

Joe/Andover Norton
Click to expand...

Indeed - when I read about the non-standard ratios I guess I assumed racing.
An old friend campaigned a Seeley 920 years back and went through 14 gearboxes in one season. I believe they were all standard though.

I had to replace the 2nd gear pair on my MkIIA due to excessive spalling.
I'm in the process of rebuilding a Combat box and the gears are nowhere near as bad, despite having done 3 times the mileage - I think the 'A' gears went through the same heat treatment process as the chocolate cam :cry:
 
Those gears are a disgrace, and who ever retails them should be Named. forget pussy footing! that standard is ZERO . I would be ringing the bells as Loud as i could :!:
 
john robert bould said:
Those gears are a disgrace, and who ever retails them should be Named. forget pussy footing! that standard is ZERO . I would be ringing the bells as Loud as i could :!:
Click to expand...

The supplier of the gears is embarrassed by the quality of the really bad one and will be replacing it. He acknowledges that the typical finish is not great, but that the gears have proven to provide good service. I've taken advice from someone who has made one-off gears for me in the past and I've decided to go ahead and use them. Some might think that stupid, but may be using a standard Commando box for racing is stupid anyway; so far I've had good luck using a standard box, but I'll be keeping a close eye on it from here on.

I'm not going to name the vendor, he's seems to be honest about the quality issue. Much of the stuff made available for racing (at a reasonable price) comes from very small outfits who obviously do not have the resources to test exhaustively or even at all, so I think the buyer must always accept an element of risk. I'm not prepared to ding this guy's reputation based on the look of the gears. I'll run them, check and take pictures at intervals and report back.

Cheers! ~ Gary
 
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