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Old 03-24-2009, 07:49 AM   #1
Marc Miller
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Exclamation R31

Baseline setup for Birel R31
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Old 04-02-2009, 09:30 AM   #2
Marc Miller
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R31 SP Setup

with the 50mm axle:
- you should be at least at the 1040 or perhaps 1000 "B" with short hubs
- somewhere around 53 1/2" wide to 54"
- Try .5mm negative camber and .5mm postive toe per wheel
- caster as close to .5 degree plus as possible
- Two 10mm and one 5mm wheel spacers inside and the balance outside the front wheel. - - Tire pressure 8 - 10 lbs. You may add extra seat support bars as well to stiffen the chassis. If you are running a Euro style rear bumper, try the USA style (620X110).

I would suggest trying a 40mm rear axle set up. To date, the "under 125cc" classes appear to run better with the 40 rather than the 50.
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Old 04-07-2009, 10:58 AM   #3
Evan Batt
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Do you have any suggested baseline information for the RY-31 S1?
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Old 04-08-2009, 09:24 AM   #4
Chris Lobaugh
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Default RY31S1 baseline

We have done some testing with the RY30S1 in Sr. Rotax on both Mojo D2 and Bridgestone YHC's. This is where we ended up at South Bend and will likely be a good place to start:
Spindles up (out of the box position), 1.0 degree caster out, 5mm negative camber, 2mm toe out, 1 thick and 1 thin spacers wide with 75mm hubs and short front bar. Rear track width is 54" with Freeline Mag (DF) wheels and 95mm hubs. We started with a 1040x50x2-F axle down with the middle bearing tight. Then we tested with the middle bearing loose and lost a bit of time in the fast corners but gained twice as much in the slow corners. Next we tested with a 1040x50x2-M axle middle bearing loose and the kart was very good. We have yet to remove the side rail but will test that as the track starts to rubber up a bit. The seat position is 62 cm from the front rail to the front edge of the seat, bottom of the seat 5mm below the frame rails, and the top edge of the seat is 22.5 cm from the top of the axle with a Freeline M seat. Hope this helps...
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Last edited by Chris Lobaugh; 04-08-2009 at 09:25 AM.
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Old 04-08-2009, 11:33 AM   #5
Evan Batt
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Perfect, that's exactly what I wanted to know.

Thanks Chris.
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Old 04-08-2009, 12:01 PM   #6
Christopera
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Any idea how those seat measurements for the RY30 change with the use of medium tillett T-8 or a T-9? I have both, will most likely mount the t-8 but am considering the t-9 since it is much nicer shape.

Also, do you run ballast low on the seat? I'm 5'5"
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Old 07-07-2009, 10:09 PM   #7
Michael Pagano
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hi, do you have good setup for tag with a 2003 birel r31, hopefully using the shockwave medium axle that is in it? It is almost new, never really used, just looking for a good baseline with what it has in it. The 4th rail is also cut out but i can clamp it back in.
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Old 07-08-2009, 05:20 AM   #8
Marc Miller
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Michael,

The baseline above (R31SP) would be a good starting point. the '03 model had a little less caster from the factory. The R31 is a popular TaG chassis/

Couple of things... we provide set-up baseline information using original OEM Freeline components. That is what we use and recommend and it works for us. I can't provide much feedback on to what level your shockwave axle is "medium" or not in comparison to the Freeline range.

What you haven't supplied us is what track you run or tires you run. Also, what seat and position it is in. That might help us provide a better baseline.
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Old 08-10-2009, 05:26 PM   #9
ry3097
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Default Re: RY30S1 Set up with Mojo D2 tyres

Hi Guys,
I have just found this site and I have to say that it is one of the most informative sites for not only birel but general kart info I have found. I race in Irelands Snr Max class with the new RY30S1 chassis & Mojo D2 slicks. I haven't had the chassis long but have struggled all year with set up, generally being a second or so slower than the front runners. Your site here is the first I have found to suggest that the "normal" seat position for the RY30 is incorrect, and this is exactly what i think is a problem with mine. I have never been able to get as comfortable as I have been in other chassis, I always feel cramped and my knees get constant bruising from the fuel tank cap! I have had to let the pedals forward and remove the heel rest to get anywhere near comfy with the "normal" seat position which I took to be correct without question. Can you give me an idea of issues you guys found using the "normal" position ie 59cm brakeside, 60cm gas side, 18-21cm axle-seat, and also maybe a good starting setup to use? I am 5'9 & 72kg using a Tillett T11 MS, full freeline original parts with 25mm front spindles & UK steel rear bumper.
PS when you guys say run spindles in the "up" position, do you mean run the spindle in the middle of the "C" section or run the spindle in the top of the "C" section ie lower the front of the chassis?
Many thanks in advance.
Gary Wheeler
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Old 08-11-2009, 06:28 AM   #10
Marc Miller
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Hi Gary-

Thanks for the compliments on our site. We try to keep it current, but also offer as much technical advice for those utilizing older birel models as well.

As per your question, what "other site" are you referring to in regards to the seat measurements? We suggest you move the seat back - as we would have started there, given the fact you are using a Tillett T11 instead of a stock seat. The baseline set-up above is a pretty good starting point as well.

We have seen a great deal of success with the RY30 this season. It is a kart that seems to be good in almost any category and is very good for Rotax Snr. as well.

As far as spindles, you are correct that when we say "spindles up" that means to move the spindles up in the "C" carrier, moving the frame down. Feel free to post follow up questions.

Best of luck!
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Old 08-11-2009, 05:49 PM   #11
ry3097
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Default Re: RY30S1 Set up with Mojo D2 tyres

Hi Marc

Many thanks for the prompt response. The "normal" seat position as outlined above was supplied in documentation that came with the chassis, maybe this is only for freeline original seats?

Regarding setup, do you guys run the rear chassis height in the middle position or would you also run the rear axle "up" ie the chassis down?
Also, regarding the setup above, do you put 1.0 degree caster on the top pill only or do you use 2 x 0.5 degree pills, ie one on top and one on bottom of the stub. Btw what is a "short front bar"?

Regards

Gary Wheeler



Quote:
Originally Posted by Marc Miller View Post
Hi Gary-

Thanks for the compliments on our site. We try to keep it current, but also offer as much technical advice for those utilizing older birel models as well.

As per your question, what "other site" are you referring to in regards to the seat measurements? We suggest you move the seat back - as we would have started there, given the fact you are using a Tillett T11 instead of a stock seat. The baseline set-up above is a pretty good starting point as well.

We have seen a great deal of success with the RY30 this season. It is a kart that seems to be good in almost any category and is very good for Rotax Snr. as well.

As far as spindles, you are correct that when we say "spindles up" that means to move the spindles up in the "C" carrier, moving the frame down. Feel free to post follow up questions.

Best of luck!
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Old 08-12-2009, 04:58 AM   #12
Marc Miller
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Quote:
Originally Posted by ry3097 View Post
Hi Marc

Many thanks for the prompt response. The "normal" seat position as outlined above was supplied in documentation that came with the chassis, maybe this is only for freeline original seats?

Regarding setup, do you guys run the rear chassis height in the middle position or would you also run the rear axle "up" ie the chassis down?
Also, regarding the setup above, do you put 1.0 degree caster on the top pill only or do you use 2 x 0.5 degree pills, ie one on top and one on bottom of the stub. Btw what is a "short front bar"?

Regards

Gary Wheeler
Hi again Gary,

It is possible your documentation was taken from a Freeline seat. Try it moved back, you will likely enjoy it better that way. Regarding your other questions, if you are trying to find more grip, then you can move the axle down in the chassis (chassis up). Running it up or down is entirely dependant on what the balance of your kart is. I would suggest to move the seat first, then drive it, then adjust from there.
Pills- it does not matter either way in regards to pills. If you are looking at adding or decreasing caster, using just one 1-degree pill is easier. If you are also adjusting camber, then two pills (one for bottom) should be used.

The "short front bar" comment is for the Ry31 chassis. That model has dual front torsion bars that may be interchangeable. The Ry30 does not have this option so you shouldn't have to worry about it.
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Old 03-31-2010, 09:39 PM   #13
Scuderia
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Default RY31S1 and Lots of Questions

Any revisions to the baseline set up of the RY31S1 chassis after its introduction last year? In post #4 you have the title headed as RY31S1 but you refer to RY30S1 in the comments. In the interest of accuracy, which kart are you actually referring to? Also, have you tested the 40 vs 50mm axle in this chassis and what are the effects of the new plastic rear bumper vs the full width tubular steel version? Finally, do you have any comments on MG yellow (FZ) slicks? I'm racing in Rotax Senior with a class weight of 364lbs on a 650 meter track with tight corners and am 5 ft 10 inches at 160 to 165 lbs.
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Old 04-02-2010, 08:09 AM   #14
Marc Miller
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Hi Scuderia,

Good questions. First, The RY30 and RY31 are different in design and the 31 comes with the dual front bar option. While they are different in construction, the baseline set-up for each remains the same - except for the front bar position.

40 vs 50 - We have only really tested the 50mm for the RY31, but have mounted 40mm axles in the RY30 before for 100cc applications.

The new plastic bumper "frees" up the back of the kart, making it looser on exit. We suggest using a cross bar on the rear bumper (not a torsion tube, but the same type of bar used on the bottom of a euro bumper) if you want to add more rear grip.

MG Yellows - The MG Yellow is unlike most other tires. It produces a massive amount of cornering grip without sacrificing straight-line speed. Mounting up a set of MG's after running MoJo's or Bridgestones will tighten the rear of the kart, so if you are a little free middle and off on either of those tires, the MG's will be set-up perfectly. They are at least a second or two faster on certain tracks.

If you are in Rotax Sr., then MOJO is what you will have to run, but when you run TaG, then I would suggest the MG Yellows if the tires are open.
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Old 04-03-2010, 12:19 AM   #15
Scuderia
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Thanks Marc, your reply is greatly appreciated.
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Old 11-29-2010, 12:14 AM   #16
Michael Pagano
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On a 2003 R31 in jr rotax on mojos @ orlando where should i start? Is it common to run the front bar in this kart? Where should the front ride height be set, seems to run better on high in the rear. My cassettes are cut, should i leave the pinch bolts barely snug? If i crank down on them the axle gets hard to spin. Thanks
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Old 11-29-2010, 10:30 AM   #17
Chris Lobaugh
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The baseline set up for Orlando would be 1040x50x2-F axle down, middle bearing tight. 100mm rear hubs set at 23.5 cm from the cassette to the outside edge of the hub. 1 seat stay each side, front bar in, spindles with two black spacers on the bottom and one on top (if your kart has silver spacers the thicker one goes on the bottom, thinner on top), 75mm hubs set at 2 thick and 1 thin spacer wide, .5 caster in.

we do not recommend cutting the bearing cassette...since yours is already cut I would tighten the bolt enough to keep it tight but obviously if you tighten it too much it will pinch the bearing like what you have experienced.

hope this helps...see you in Florida
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Old 11-29-2010, 04:17 PM   #18
Michael Pagano
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Thanks, just a few more questions if you dont mind.

How many mm of camber while aligning on the stand?

I have these 2 kind of concave spacers that slip on top of each other(gold) that go between the pill and regular ride height spacers. I can only fit the complete concave slip spacer set on top and only one of them in the bottom. This still leaves a gap for the spindle to move up and down, but when tightened its fine. Do you understand what im trying to say? Can i run it like that?
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Old 11-29-2010, 05:16 PM   #19
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called you and got it taken care of, thanks again.
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Old 05-03-2011, 12:49 PM   #20
Sealtiel
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Hi, could you help me with the baseline set up for a Birel R31S. I have already look into the "Birel by Year" page but i still don't know the year of my chassis. I have this numbers. R31S 230488. Back plate. Hom No. 041/02 - 042/02. Category. ica/j ica.
I run into 160 Kg (353 lb) category.
IAME Reedjet 100 cc (watercooled)
Bridgestone YJL Tyres
50 mm rear axel.
The crown we use is between 90 - 92 teeth. (1100 m. asphalt track)

Thank you.
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Old 05-09-2011, 12:26 PM   #21
Marc Miller
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Hi Sealtiel.

You likely have a R31 model of around 2002 (and it might say "S" because it was made for a different country or was a pre-production test model" - Regardless, the standard R31 set-up baseline is a good starting point with the Bridgestone tires. If the kart shows understeer or oversteer you may adjust from there - so please let us know!

BASELINE:
- 1040x50x2-F axle in down position (chassis up)
- middle bearing tight
- 100mm hubs at 54 ”wide overall rear track width.
- Front bar in
- spindles in middle
- .5 to 1.5 degree caster in
- 75mm front hubs hubs set 2 thick and 1 thin spacer wide
- toe set 2mm out
- camber 0mm
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Old 05-10-2011, 06:29 PM   #22
Sealtiel
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Thanks Marc for your reply. I'll try the settings and i would let you know how it works.
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