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XR650R Gears - going to need a mechanical engineer...

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I have always wanted a lower first and higher fifth gear in my XR650R. I have bought a complete transmission off ebay for an XR650R and TRX700 to try and swap some gears but they aren't compatible as the transmission shaft spacing is different.

I have thought about trading up to a CRF450L or the like, but I can't convince myself that it will have everything that I like about the XR650R. As such, I am willing to lay out some cash to get the transmission where I want it to be in the venerable 650.

I have looked into getting a custom set of gears made for fifth gear to get it into the 1:1 range and possibly a 38 tooth gear to replace the 37 tooth gear for first. The thing is, I don;t know enough about gears.

 

First of all, what material are the stock gears made out of? There are well over 20 different steels to choose from and I have no idea which is best.

Second, is changing only one gear for first a good idea? I used to think this was a no-no, but the fifth gear mod in a 650L only changes one gear in a set...

 

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You can change just the one gear..no issues,,the tooth profile is what makes the different ratios mess properly..

But,,getting someone to CNC a gear and harden it properly is going to be cost prohibitive...not worth it...and if not harden the same as the mating gear will cause extreme wear and vertually throwing money down the toilet..

you need to test ride some bikes,,see what would fit your use,,but all bikes are a tradeoff unfortunately..

 

B

 

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1 hour ago, brianhare said:

You can change just the one gear..no issues,,the tooth profile is what makes the different ratios mess properly..

But,,getting someone to CNC a gear and harden it properly is going to be cost prohibitive...not worth it...and if not harden the same as the mating gear will cause extreme wear and vertually throwing money down the toilet..

you need to test ride some bikes,,see what would fit your use,,but all bikes are a tradeoff unfortunately..

 

B

 

 

The only complaint I have ever had with the 650R is the transmission not being wide enough. Otherwise I like everything else about it. Sinking a lot of money into an XR600R would get me close, but water cooling is an advantage when trailing cows in burning hot temps.

I think I could be happy with a 450L - I want to see how it holds up though as I use my two main bike strictly for work and they get a lot of hours and abuse in a year. Both my 250L and 650R are about as reliable and maintenance free as an anvil. I am skeptical that a 450L will fit that description.

The way I see it is if I did trade my 650R for a 450L it would cost me at least $7500 out of pocket by the time I had the 450L where I wanted it (and we all know I wouldn't trade so it would be closer to $11K). Even if I could get 10 sets of gears for a 650R made for $5K (I have no idea if that is realistic or not, just throwing out numbers) and peddle 6 or 7 sets on eBay for my cost and keep 3 sets for myself and my brothers, it would cost $500 and I would have the perfect bike for what I need. Even if it cost me $1K out of pocket when I was all said and done, it would be worth it.

I talked to Advanced Clutch Technologies this afternoon and they initially were not interested (as expected) until I mentioned that I would be willing to purchase 10 sets to cover their R&D and keep costs down a little bit and then they seemed willing to work with me. We will see what happens.

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years ago i had a kawasaki z1r. screwing around in the driveway one day, i ended up launching the bike and bent the frame. had moriwaki build me a new one, bought a set of dymags, turbo'd/methanol'd/nitrous'd the punched out motor. needless to say gearbox wasn't up to the task. san jose gear made me a new gearbox.  dunno if they are even still around...

find someone like bay area machine and marine repair who can do it themselves yet also works with a handfull of outside vendors when the need arises. or search for a gear cutter that offers in house engineering in your area..  maybe search on thomasnet.com for some leads. there is no lack of shops able to do a set of gears.

don't give up

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On ‎9‎/‎27‎/‎2019 at 4:29 AM, Muzz67 said:

Rekluse or similar auto-clutch a possibility?

That's what he needs to do

sprocket gear it up to a higher ratio

and use the Rekluse to go slow without stalling in the now higher first ratio as well............. best fix

get top end and never stall in 1st

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8 hours ago, EarthCruzn said:

That's what he needs to do

sprocket gear it up to a higher ratio

and use the Rekluse to go slow without stalling in the now higher first ratio as well............. best fix

get top end and never stall in 1st

Negative. Need to occasionally put along behind a herd of cows. Need a nice even, steady, slow gear. Do you think a rekluse would do that for me? I have looked into them but got the impression they wouldn't...

 

If someone with firsthand experience could enlighten me on them, I would be willing to give it a try. I have come to the conclusion that while trying to follow a herd of cows with stock gearing and an automatic clutch it would be touch and go the whole time - would this not be the case?

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8 hours ago, EarthCruzn said:

That's what he needs to do

sprocket gear it up to a higher ratio

and use the Rekluse to go slow without stalling in the now higher first ratio as well............. best fix

get top end and never stall in 1st

That's what I run...taller gearing with a Rekluse Radius X. A built motor can pull pretty high with this setup.

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