| Author | Message | ||
     Captainkirk |
Finally got access to my oil pump drive gear on my '99 M2. The gear looks OK, save for a slight bit of discoloration on a couple teeth. Anyone (Reep?)have any further input on the pump drive gear failures I should know about before I button it up? | ||
| Reepicheep |
Mine was obviously worn, like half the tooth worn away. I think it's obvious if it's worn, button it up and be happy you don't have to pull the cam cover! | ||
| Outrider |
CaptainKirk...How many miles on your M2? | ||
| Reepicheep |
And you are talking about the pinion gear, right? That is the one that wears. You have to crawl under the bike with a flashlight (or use a camera or dental mirror) and look up into the cam cover from the hole where the oil pump used to be. | ||
| Captainkirk |
Outrider: 12K, give or take a hundred. Reep: The cam cover is off anyway for the cam change, so I'm in there now. Just wondered if there is a "new & improved" super-duper oil pump drive gear I should be running. Are we talking oil pump DRIVE gear, or the DRIVING gear on the crank? | ||
| Reepicheep |
The driving gear from the crank is the one that goes, which is unfortunate, because it is the harder one to replace. Zippers used to have a bronze replacement, they don't make it any more. I *think* somebody asked Hoban Racing about he issue, and they indicated the best they have found is the stock part. | ||
| Captainkirk |
Oh... my bad. I thought all this time it was the driven gear, not the driving gear. Anyway, this one looks OK now at 12K. I'm more concerned about the condition of the cam lobe. This is an issue. It's not easy to inspect and there's no way this motor would have gone, say, 20K without metal in the oil pump (like what might have happened to Dyna's motor) or at least serious performance degradation. Normal cam lobes do not wear in this fashion. There's a QC problem here, period. At this point I'd be really ticked if I didn't have a new set of cams ready to roll. | ||
| Reepicheep |
I think Dyna's motor (and many before that) probably had the teeth wear on that oil pump pinion drive gear until they were too thin to support the forces, then came apart. The resulting pieces turned a positive displacement oil pump into a positively displaced oil pump  Thats why I harp on people to check these things. I don't know how many bikes have the gear consumption problem, but it is easy to check, and not terrible to fix before it fails (though annoying). Once it goes, your engine is pretty much instantly trashed. Drop those oil pumps and check those drive gears up in the cam chamber tuber folks! No idea if it is a problem with the new XB's, it probably is not. | ||
| 1320 |
Another thing to check since the cam cover is already off....you will see a race all the way into the case on the main shaft...if you can move this with your fingers or even with plyers on the main shaft you have a big problem waiting to happen..this thing will float on the main shaft under high revs and vibration..when it floats outward it gets against the oil pump drive gear, and the the gear and drive gear on the oil pump get in a cross and shear their teeth...total teardown to remove metal in system and replace oil pump...what I do for all my motors since this happened is to place two small spot welds on the race to shaft...not a problem since... | ||
| Mikej |
1320, Could this be the real reason for the oil pump drive gear failures? Could be people are inspecting their gears when they should look just past that to the main shaft. | ||
| 1320 |
I can only go by what I have experienced on the 5speed XL based motors..I've totally thrashed them on the drag strip for the past 5yrs and I have had very FEW problems. I did have this problem and upon inspection I got lucky that the race was in the floated OUT position or I wouldn't even have thought the thing could move. It is installed on the mainshaft at the factory with some type of cryo and high press fit process.. | ||
| Mikej |
Got it, thanks, when I open mine up I'll take a close look. |
