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600r gear update

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An update??...Dunno. Far as I'm aware they have never really updated the bottom. They are all the same.

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They changed the countershaft at some point iin the late 80's (increased spline count). The XRL tranny uses a few gears that have more engagement dogs than the early XR600R trannies. I am not sure if they ever used the same gears in the late model XR600R trannies. Have to search the OEM fiches to tell... Someone else should know without doing the search.

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1996

COUNTERSHAFT

23220-MN9-980

1990

COUNTERSHAFT

23220-MN9-641

and i saw a lot of replacement of:

GEAR (17T)

23421-MN9-641 (replaces 23421-MN9-640)

GEAR (23T)

23461-MN1-671 (replaces 23461-MN1-670)

GEAR (23T)

23471-MN9-000 (replaces 23471-MN1-670)

so is it the update of the dogs?

cause it changed and can be mix with the late\early.

did the early COUNTERSHAFT also had the same problem(weak groves in the sprocket area) as the new?

🤣 and tanks for the help 👍

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The early 600s from around '85-87 had a weaker 3rd gear and the counershaft spline went from six to 13 in '91. Not much else has happened to the big RFVC gearbox since 1983 except for a few gear ratios.

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so how is the counershaft spline with the 6 socket(this is how it called?!)?

did it wear out more then the 13 socket?

👍

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Here is a picture of the gears... You can see the XR650L gear on the mainshaft has double the number of dogs (6) as the older XR600R gear sitting next to it.

IMGP3170.jpg

Here's a good pic of the early XR600R countershaft

IMGP3169.jpg

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i see, but as far as i know the weak link in the 600 are the gear that left to the one that you ealking about, and also the counershaft.

the one that you install is the old one,

for the pic it looks like new, so maybe we need to put the old counershaft and we will be good forever 👍

so, if some one know about old counershaft chewing issue, please let me know.

🤣

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I did install the old style countershaft. It came in the XR600R bottom end that I bought (cheap) to steal the kickstart assembly out of... the tranny was in very good shape, so I ended up swiping parts out of it as well. Now that the bottom-end tear down is a non event (done it once... now it's easy) I am not so worried about gutting a countershaft.

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The transmission actually predates the XR600. The pre RFVC XR and XL 500's had essentially the same transmission. I put about 30,000 miles on a 81 XR500R and the six spline shaft lasted the whole time. It had considerable wear near the end, but I never replaced it. The non bearing cam journals failed first. I did tear the splines out of countershaft sprocket once. Way out in the middle of nowhere of course. I had a spare on my 78 XL250 back at camp and I was back on the trail.

I don't think that the six spline countershaft is really any better. The 13 spline version spreads the load over a larger surface and if kept clean it should outlast the six spline one. I've got about the same mileage on my current 13 spline XR600 and while worn pretty good they are doing OK. I really feel that to little chain slack is what kills them. Setup right either shoudl lat several tens of thousands of miles.

I pick up my rebuilt crank tomorrow and I will be using a six spline transmission from a 90. I'll look to see if that gear has 3 or 6 dogs in the 90 transmission.

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yhaa you are right, the pressure sould be smaller with the 13 because the moment is divided the # spline(as you said that it called),

but by fact we know that it's not enough so i think that maybe because the 6 one have more "meat" on it, it should last more then the 13 one,

but if you said that the 6 one also the same s#$t so it doesn't really matter.

i think the problem is with the free play between the sprocket and the spline and impact from on-off throttle.

i need to replace the third (i think it's the third, any way) gear soon because of the known chewing issue.

Now that the bottom-end tear down is a non event (done it once... now it's easy) I am not so worried about gutting a countershaft.

i dont have the mental strength to take that big engine out of the frame, and i need to do it again..👍

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Replacing your countershaft should be a required check-up every couple of winters:smirk:

No other way to get a sense of how everything is doing inside the mil. You get to touch EVERYTHING:lol:

It is a pain in the kester, but spread out over a couple of months, it's not too bad. When I do it again, I will acquire the countershaft and gaskets before I do the tear down so I can quickly put it back together. Let a couple of months pass and it is a challenge remembering where everything goes...👍

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i can do it while sleeping but still i prefer to ride,

i replace the rod that blow out, and when i took the cylinder off i saw that my third gear is starting to show some sign of wear, so i guess i wil have to split the engine and replace it, my countershaft is not new so replace it wont do harm. so i am just thinking what is better..

👍

so what do you think? old/new style of countershaft??

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If you are buying new, get the new style if for no other reason than the increased pool of available sprockets. If you are sourcing out a used one... not sure it makes much difference as long as the used item is in like new condition.

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