Cross Cutting Gears?

[Hobicus]

First, a bit of a background:

I have a friend who's trying to fix a slipping out of 2nd gear problem on a V45 Saber. He opened the lower half of the engine, replaced 2 shift forks and the upper gear, but didn't replace the lower gear. Now it doesn't slip all the way out, but it still slips a bit. He's got a set of lower gears, but of course, it means dropping the engine and opening up the cases, and it's a huge amount of work, so he'd like to find some way to make sure that it works right this time when he re-assembles the whole thing.

So.. We were talking, and the concept of "Cross Cutting" the gears was mentioned. Both of us understand that the idea is to machine the gears in such a way that it makes slipping out of gear much less likely. But... how to tell a machine shop what to do, etc, well, we're clueless.

So, can anyone provide me some details as to what it's all about, and if there's someplace that we could send the upper and lower gears and have them done?

Thanks

[cbrxxquad]

First, a bit of a background:

I have a friend who's trying to fix a slipping out of 2nd gear problem on a V45 Saber. He opened the lower half of the engine, replaced 2 shift forks and the upper gear, but didn't replace the lower gear. Now it doesn't slip all the way out, but it still slips a bit. He's got a set of lower gears, but of course, it means dropping the engine and opening up the cases, and it's a huge amount of work, so he'd like to find some way to make sure that it works right this time when he re-assembles the whole thing.

So.. We were talking, and the concept of "Cross Cutting" the gears was mentioned. Both of us understand that the idea is to machine the gears in such a way that it makes slipping out of gear much less likely. But... how to tell a machine shop what to do, etc, well, we're clueless.

So, can anyone provide me some details as to what it's all about, and if there's someplace that we could send the upper and lower gears and have them done?

Thanks

I may be wrong, as I have never heard it called this, but the way I do the repair on this problem is to angle the dogs so they don't have a slope out. but into the gear with a die grinder and a cut off disk as well as a small die grinder cone. This causes the dogs to connect in instead of force the gear out bending the forks.

Normally the dogs are flat, as well as the cutouts in the connecting gear, and when sloppy shifting, power shifting, hard gear changes cause the flats to angle away from engagement. Sound like what you are talking about?

If that is what you are referring to, cool,,,,,if not never-mind.

Oh, and yes!

[MrBadExxample]

"The Man" for those older V4 Hondas is David Dodge - (704) 892-7961. If that number is no longer correct, I'll try to get his current contact info. He's a very helpful guy and would be happy to speak with your friend.

[rockmeupto125]

I don't think that's the term you are looking for. Its "backcutting" or something like that. Basically you are cutting back the engagement dogs at an angle so they can't slip out.

[Northman]

I don't think that's the term you are looking for. Its "backcutting" or something like that. Basically you are cutting back the engagement dogs at an angle so they can't slip out.

Or undercutting.

[Involute]

If you're undercutting the actual gears (spur gears) is called "adding protuberance".

If it's done to bevel gears it's called "Toprem".

(Nerd hat off now)

Since it appears you're doing something with the dogs I have no idea what you're doing as I don't even know what a dog is. I just wanted to type "protuberance" and "toprem".

[Banshee]

Bikes, unlike cars, use constant mesh dogboxes. The gears are constantly meshed together, but one of each pair freely rotates on the shaft. The dogs are essentially a disk that is mounted splines on the shaft with cylindrical "dogs" that lock into matching holes in the gear. As one gears' dogs disengage the next engage, thus changing gear.

Well, that's the (very) quick and dirty explanation.

edit: Oh yes, the gear selector forks are what push the dogs in & out. Which is why gears don't change properly wheh the forks get bent.

[dunedain]

I thought cross cutting was a drag racing thingy but I remember hearing about it somewhere on here I think. Way back when.

So his bike is coming out of 2nd gear into neutral?

[cbrbear]

there are a lot of shops you can send your 2nd and 6th gears (which mesh together) to get under cut and hardened. You can also check to see if factory racing makes a shift kit for the bike which gives it a more positive shift which will eliminate kick backs.

[Mach VIII]

First, a bit of a background:

I have a friend who's trying to fix a slipping out of 2nd gear problem on a V45 Saber. He opened the lower half of the engine, replaced 2 shift forks and the upper gear, but didn't replace the lower gear. Now it doesn't slip all the way out, but it still slips a bit. He's got a set of lower gears, but of course, it means dropping the engine and opening up the cases, and it's a huge amount of work, so he'd like to find some way to make sure that it works right this time when he re-assembles the whole thing.

So.. We were talking, and the concept of "Cross Cutting" the gears was mentioned. Both of us understand that the idea is to machine the gears in such a way that it makes slipping out of gear much less likely. But... how to tell a machine shop what to do, etc, well, we're clueless.

So, can anyone provide me some details as to what it's all about, and if there's someplace that we could send the upper and lower gears and have them done?

Thanks

Undercutting is the terminology I'm familiar with, and yes, Dave Dodge is THE guy to talk to about Honda V4s (especially the older ones). Dave can undercut the gears. In fact, if your buddies gears aren't too badly worn, then he can often undercut the existing gears to solve the problem, thus avoiding the cost of buying new. Even still, he charges around $500 just to do the gears, plus you're going to spend some money on gaskets and fluids. I know all about this as my '88 SuperMagna just started popping out of 2nd gear. :icon_doh: I'll get to tackle this project myself - likely this winter.