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New sub section guys, should be easier to keep track of ratios and percentages with it all contained here.
 

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A few pictures of a 54% GR build, I’ll add more as I find them.
 

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Discussion Starter #3 (Edited)
Most common GR tooth count and percentage for 300 Fourtrax/Big Red.

Stock 65-27

18% 68-24 (300ex)

54% 74-20

62% 74-19

There are two other reductions to which are currently kept quiet, an 82% and one a fraction bigger. Details will emerge in due course.
 

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Attached is an image of a price guideline from Redction Boss. Notice he states with spring or solid drive gear. Solid drive will cause some chatter on the centrifugal shoes when they come into contact with the drum, basket gear with springs reduces said chatter. No springs in basket gear and heavy duty in centrifugal makes for a sharp pull away also.

Cores required. This means the builder needs your stock primary and basket gear, if not there is a core charge to pay also.
 

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Attached is an image of a price guideline from Redction Boss. Notice he states with spring or solid drive gear. Solid drive will cause some chatter on the centrifugal shoes when they come into contact with the drum, basket gear with springs reduces said chatter. No springs in basket gear and heavy duty in centrifugal makes for a sharp pull away also.

Cores required. This means the builder needs your stock primary and basket gear, if not there is a core charge to pay also.
Sam,

When he says "Solid Drive Gear" he isn't talking about the basket. He still machines his basket gears to have the springs in them where some builders don't. RB has a process where he is actually cutting new teeth on the primary. He's not machining and welding different gears on the primary anymore. This allows the primary gear to be matched exactly to the basket gear so there is no whine.
 

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Ohh ok. Well the whine doesn’t usually come from the gears because the gears are all Honda so the mesh is the same, only the big reductions use other brand gears and they also are matched with the same brand primary so no whine. The whine is caused by the back of the gear not being machines out to accept the washer that goes on before the primary. As far as I’m aware all RB reductions have the washer.
 

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I plan on putting a 300EX set up in my 450 , let me see if I got this right ------- Is the ratio going to be = 35% ?? ----my primary gear is going to have to be cut/machined and welded to the 300ex gear , the rivets in the basket are going to have to be drilled and the holes tapped to 1/4"

Got a pic pick of where to cut the gear or what it would look like when finished ------is this one just a little different cause the 300EX gear is a one gear piece where the 450 is two gears on one piece to start with
 

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I have limited experience with 450 GR’s, I’d have to ask a few questions.

Have you got pics of the 450 primary? The basket your spot in with, grind heads off rivets, kncok the centres out and tap with the necessary size. Pretty sure 1/4” is to small though, pretty sure I used 5/16” on the 300.
 

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Calaculation is, primary reduction x first gear ratio x secondary reduction x final drive ratio
 

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Fish, the ex gears in the 450 make a 35% Reduction. I would take your primary and the ex gear and let the machinist make them up. All he needs to do is make sure it’s the same length as the factory gear.
 

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I would also second LBZ’s comment, get a machine shop to do the primary. You’ll need a decent sized lathe, big enough to get zero flex and a diamond tipped tool. The only other way would be to fab a mount for the tool post to attach a die grinder but then you get sparks over the lathe bed. Diamond tips don’t come in cheap either, £160 for one when I looked, cheaper to get it machined. The basket is easy.
 

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Thanks for the info , hope my machine shop friend can pull it off -------- if he says he can't then I will mail it off to get done ---- the basket and gear are on the way thanks to LBZ , and thanks to WheelSquad would bought some parts that paid for it

I need to start looking for a good set of clutch disc to handle the 35% and 29.5's Outlaws ---- what do you think about the clutch
 

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If he’s got a shop he’ll manage it I’m sure, it’s the size of the machinery needed that limits you really. You need a robust lathe.
I’d use EBC clutches and springs, the stock centri will handle the tyre size and reduction but fit new OEM springs or HD from EBC. The HD flick out HARD and make a noise, I’ll try and get a video before I take the GR out the 300.
 

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try to follow me on this one , I put the 15.5% in my 2002 , but I can't remember what Dick's did , I gave him a 300 gear and basket , when it was finished he gave me back a gear and basket , I am sure that basket is a 450 , I wonder what that gear is ----- so what I am asking is

??? on a 15.5% you would not use the 450 stock gear or would it have to have been cut ????

or maybe he gave me back the 300 gear , not sure what gear I got at the moment , I need to dig up that set tomorrow -------- worst case I would have to take a spare engine apart --- you never know I might ride this green 450 this weekend

It is nice to be able to come to this site and get info
 

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15.5 would be 300 basket and primary gears. What you had back are 450 gears.
 

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try to follow me on this one , I put the 15.5% in my 2002 , but I can't remember what Dick's did , I gave him a 300 gear and basket , when it was finished he gave me back a gear and basket , I am sure that basket is a 450 , I wonder what that gear is ----- so what I am asking is

??? on a 15.5% you would not use the 450 stock gear or would it have to have been cut ????

or maybe he gave me back the 300 gear , not sure what gear I got at the moment , I need to dig up that set tomorrow -------- worst case I would have to take a spare engine apart --- you never know I might ride this green 450 this weekend

It is nice to be able to come to this site and get info
All the 15.5 reduction is on a foreman is a stock fourtrax300 basket, no modifications at all.
 

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Reduction Calculation??

Calaculation is, primary reduction x first gear ratio x secondary reduction x final drive ratio
I don't think the formula in #10 post by SamUK at this forum is correct. It seems logical to me that the series of reduction ratios involved should be simply added together to get overall ratio -- not multiplied as he has posted. Thus my 300ex with primary reduction of 2.833, 5th gear reduction of 1.178, and final chain drive reduction of 2.923 (13 teeth to 38 teeth) should end up at 6.923 overall not the 9.7548 as obtained by multiplying the reductions involved. I don't want to have to run my engine at 8000 rpm to barely hit 40MPH -- anyone agree??

And while we are at it, what is max safe engine RPM on a MY2000 Honda 300ex?? I have posted this question before but never got a response.
 

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I think having a sub section for GR's is a great Idea
would also like to see a sub section for SUNK ATV"S too LOL

heck they might go hand in hand here too LOL
 
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