Custom Gearbox for the RZ

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crazydiablo
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Custom Gearbox for the RZ

#1 Post by crazydiablo » Thu May 06, 2010 1:52 am

Banshee

Transmission type: 6 speeds, constant mesh
Clutch: manually operated, wet multiplate
Transmission primary ratio: 66/23, 2.869

Transmission 1st gear ratio: 32/13, 2.461
Transmission 2nd gear ratio: 29/16, 1.812
Transmission 3rd gear ratio: 27/18, 1.500
Transmission 4th gear ratio: 25/20, 1.250
Transmission 5th gear ratio: 23/22, 1.045
Transmission 6th gear ratio: 21/24, 0.875
Transmission final ratio: 42/13, 3.230


RZ350

Transmission type: 6 speeds, constant mesh
Clutch: manually operated, wet multiplate
Secondary reduction system: Chain
Secondary Reduction Ratio: 40/17 (2.352)

Transmission primary ratio: 66/23, 2.869
Transmission 1st gear ratio: 36/14, 2.571
Transmission 2nd gear ratio: 32/18, 1.778
Transmission 3rd gear ratio: 29/22,1.318
Transmission 4th gear ratio: 26/24, 1.083
Transmission 5th gear ratio: 25/26, 0.962
Transmission 6th gear ratio: 24/27, 0.888


Looking at this I was wondering why not combine these two to make a gear box that will really wake up the RZ. If you just compare these two I feel the RZ gear ratios are pretty lazy. The last two gears are like overdrive. Any ideas for a custom gear box?

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RZ250350OZ
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#2 Post by RZ250350OZ » Thu May 06, 2010 9:22 am

A feast of ratios can be seen below. For the RS500 we use Banshee 1st gear pinion and output shaft, with the rest of the ratios RZ350, with 2.68:1 primaries. We also provide a new two-stroke oil pump pinion to mesh with the s/cut primaries (this is to give increased oiling for stroked/big bore engines ... together with judicious piston stroke shimming, the Autolube can be retained and dialled in for bigger/angrier than stock engines):

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Primaries are US$275/set, and the oil pump pinion is $35. We also throw in a new clutch hub bush (This presses inside the primary gear/clutch basket/kickstart ring gear, and is not available from Yamaha - they expect you to buy a new clutch basket!):

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But for comparisons' sake, check out the following ratio combinations:



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motoholic71
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#3 Post by motoholic71 » Thu May 06, 2010 10:45 am

I cannot believe I paid 375 $US plus vat and custom taxes just for the straight cut pris.,from a online US shop :smt011
Steve I'll talk to you soon,I need the pump gear,and some other bits and a radiator,will email.
Anyway,I observed this gears issue,and what I understood is that the banshee is a offroad box,basically a linear ratio box ,from 1st to 6th because these wont have to face wind at high speed.
The RZ is set as a short ratio box on the last speeds,so we are able to face wind,while shiftting and keeping the engine inside the powerband.
I belive the banshee 1st gear is the only worthy mix,IMO.
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#4 Post by crazydiablo » Thu May 06, 2010 11:19 am

That pretty much clears up my confusion. Both the yamaha hybrids seems to be a good option combined with the 2.68 primary gear ratio.

On the RS the 2.68 is a must but is it a necessary mod for the stock RZ?

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#5 Post by motoholic71 » Thu May 06, 2010 2:59 pm

I don't think so.Though straight cut primarys are available in 2.87:1(stock ratio) and are worth a couple of hp at the final rpm,but this is not good bang for buck deal for the street stockish bike.
2.68:1 is to divert torque from the clutch,preventing clutch slippage.I have it because I don't care for silence or confort on my bike, [smilie=director1[1].gif] :smt013 :smt015 :smt015
but it would perform almost the same with stock gears.
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Considering a "hybrid" gearbox...

#6 Post by Vintage Smoke » Wed Jun 02, 2010 3:23 pm

I have an iteresting project I am currently working on....don't laugh...

It's basically a 77RD400 frame, with wheels and front end from an 88 Honda Hurricane, and a Banshee motor.

The motor is fairly fresh, but I plan on going through it before I use it. Basically a thorough cleaning, paint the cases, new gaskets & seals. I may do some quick mods while I am in there like shaving the heads and trimming down the rotor. Possibly a very light clean up of the ports if time allows (no actual "porting" though).

If I stick to my minimalist plan I would like to see the weight as low as possible....hopefully around the 250 lb mark.

Here's my question: Besides the complete Banshee motor that came out of a running ATV, I have a pretty complete bottom end (particularly the transmission) from an RZ.

My intention is to build a bike for fun. Mostly stop light to stop light and back country twisty riding. Highway riding will be occasional, but I would like to be able to cruise safely (for the engine) at about 70mph.

If you had both transmissions in front of you (Banshee and RZ) which combo of gears would you use and why. I did read all the info above, but I would appreciate any more input you guys might be willing to add.

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#7 Post by crazydiablo » Thu Jun 03, 2010 2:34 am

I have come to the conclusion that 1st gear from the Banshee and rest from the RZ would be a good hybrid.

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#8 Post by RZ250350OZ » Thu Jun 03, 2010 3:00 am

Yep, that's our conclusion too!
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motoholic71
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#9 Post by motoholic71 » Thu Jun 03, 2010 5:11 am

I think for a top speed of 70 mph at lets say 8000rpm,like you said,what you want is a MX box,so for that max speed the banshee would be best IMO.
But if you decide to go faster and put a bigger sprocket later,you will end up falling out of the power band when up shifting.The RZ box is good for +90mph
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#10 Post by Vintage Smoke » Thu Jun 03, 2010 10:00 am

RZ250350OZ wrote:Yep, that's our conclusion too!
I really appreciate the info!!! Without sounding ungrateful....would you guys mind telling me why?

Is the RZ first gear THAT low? In otherwords is there a big gap between 1st and 2nd in the RZ trans? Will I wind out the RZ first gear too quickly and then suffer a RPM drop going into 2nd when I shift?

I just can't help it. It's an affliction. I have always needed to know the "why" behind something....even if I know it works. Mom wasn't too happy with me when I took her toaster apart as a kid to find out why the toast popped up when it was done!!

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#11 Post by Bare » Thu Jun 03, 2010 1:42 pm

Confusing for sure. But then for me this is only of curiousity interest.
Seems that swapping Banshee 1st for RZ 1st only changes the Ratio by 0.1 approx.
Not exactly a massive change ? Or did I get it all wrong :smt007

For me in my modded enough to 'maybe ' approach Yama's stock HP claims for the 1UA engine, Ist to second shift seems OK Not overly short nor a big hole to 2nd
Ain't No VW beetle trans:-)
Sure 1st could always be a bit longer, but the clutch needs a wee bit of initial slipping to get off the line smoothly, as is, but then there's No WOT in 1st as my wheel lifts way too readily, ready or not.
Hanging over the bars and getting out of 1st as soon as possible is my drill... not overly elegant
Would such a wee ratio change have any noticeable effect for my mostly semi urban riding?

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#12 Post by RZ250350OZ » Fri Jun 04, 2010 9:16 am

The way to fly is a proper CR box.

We talked with Graham Dyson of Nova transmissions about his CR box for the RZ - http://www.novaracing.co.uk/yamaha-lc350-and-ypvs.htm - they are out of stock on these but in the process of making new units. Feel free to email the main man there, Graham Dyson on info@novaracing.com to indicate your interest.


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magee
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Re: Custom Gearbox for the RZ

#13 Post by magee » Tue Nov 22, 2016 8:46 pm

I would like to try and shim My transmission where can I find information on how to do this
I did a Google search and could not find anything
Any info appreciated
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Zombie
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Re: Custom Gearbox for the RZ

#14 Post by Zombie » Tue Nov 22, 2016 9:07 pm

Why not a wide ratio box for a higher top speed?

alex2218
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Re: Custom Gearbox for the RZ

#15 Post by alex2218 » Fri Feb 17, 2017 7:18 pm

If it can help, sorry, i'm French :smt003

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