Geariing question -- 12t front


11 replies to this topic
  • mach1jonny

Posted June 27, 2010 - 03:32 PM

#1

Any one riding an MX track using a 12t/49r spockets with a WR450????
Or is this too low? The reason I ask is that with the wide ratio transmission gears, the 12/49 should give the bike higher torque in each gear or am I off base???


Thanks in advance for your advice.

  • tribalbc

Posted June 27, 2010 - 05:35 PM

#2

I run 13/51 and have run 13/52 before. Definately gives the bike more low end for hitting jumps out of corners. 12/49 would be a pretty small loop and harder on things. 13/53 would give you the same gearing but depending on motor mods you'd probably like 51 or 52 teeth better.

  • mach1jonny

Posted June 27, 2010 - 07:04 PM

#3

Thanks - I current use the 13/51 combo. I am hitting this uphill double, but coming up a bit short. I'm getting into 4th, but not into the meat of the power band. Just thought changing gear ratios would help.


Thanks

  • tribalbc

Posted June 27, 2010 - 07:25 PM

#4

Thanks - I current use the 13/51 combo. I am hitting this uphill double, but coming up a bit short. I'm getting into 4th, but not into the meat of the power band. Just thought changing gear ratios would help.


Thanks


I liked 52 untill I put YZ cams and a high compression piston in my bike. Then second revved out too fast for the offroad riding I do so I run a 51. I think if I was just track riding I would run 13/50, get just that little more pull out of the top end of third, but my bike has lots of low end with motor mods.I ran 12/50 in the past as well. That'll give you the meat of the powerband in 4th on a hill but 1st and second are pretty useless, not that you ever really use them on the track anyways. Is your bike piped or anything??

  • mach1jonny

Posted June 28, 2010 - 07:42 AM

#5

Yeah the bike is jetted, piped, with all the free mods done.

  • mach1jonny

Posted June 30, 2010 - 09:04 PM

#6

I liked 52 untill I put YZ cams and a high compression piston in my bike. Then second revved out too fast for the offroad riding I do so I run a 51. I think if I was just track riding I would run 13/50, get just that little more pull out of the top end of third, but my bike has lots of low end with motor mods.I ran 12/50 in the past as well. That'll give you the meat of the powerband in 4th on a hill but 1st and second are pretty useless, not that you ever really use them on the track anyways. Is your bike piped or anything??

hey Tribal - do you have to use high octane fuel or any octane booster. I spoke with a tech at Roseville Yamaha today about the YZ Cams and high compression piston. I'm thinking of doing that. Is there anything that you know of with this set up that I should be aware of????

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  • tribalbc

Posted July 01, 2010 - 05:58 AM

#7

hey Tribal - do you have to use high octane fuel or any octane booster. I spoke with a tech at Roseville Yamaha today about the YZ Cams and high compression piston. I'm thinking of doing that. Is there anything that you know of with this set up that I should be aware of????


The piston is 13.5-1 and I use 94 octane RON+MON/2 pump gas I can get from Chevron. I've also used 94 and 91 mixed 50/50. I haven't tried straight 91 yet. I haven't had any detonation :)
With the YZ cams the estart doesn't work as well, but it kick start is almost easier. You could just put in the YZ intake cam for some gains and then estart works normal or if you have the $'s you could get Hotcams and you will have the same gains with no loss of estart. YZ cams can be had cheap though. I got my pair of cams on TT classifieds for $100.

  • mach1jonny

Posted July 01, 2010 - 08:15 PM

#8

Thanks again

  • mach1jonny

Posted August 11, 2010 - 09:46 PM

#9

had the YZ cams and high comp piston done. WOW!!!!! what a difference. thanks for the advice. Of course now the starter gave up the ghost, thinking of removing it.

  • tribalbc

Posted August 12, 2010 - 06:14 AM

#10

had the YZ cams and high comp piston done. WOW!!!!! what a difference. thanks for the advice. Of course now the starter gave up the ghost, thinking of removing it.


Yeah she rips eh :eek:

If you're not in a rush to start it, ie racing, then the electric start will work, it just takes time ;)
2 squirts of throttle then hotstart and estart. It takes quite a few revolutions, hence no rush, but it will start usually.....
I had given up on mine for ages but recently I've been trying, and shes been firing up :banana:

  • mach1jonny

Posted August 12, 2010 - 08:15 PM

#11

I wish- my doesn't even turn. i checked the button, by replacing the start button with the engine kill switch. -- No luck. but hey thats why I have a kick starter.

And yeah she sure does rip.


Thanks again.

  • erickdj

Posted August 13, 2010 - 12:01 PM

#12

I wish- my doesn't even turn. i checked the button, by replacing the start button with the engine kill switch. -- No luck. but hey thats why I have a kick starter.

And yeah she sure does rip.


Thanks again.


It won't turn when you push the start button? If it doesn't even try to turn the engine over then you have a different problem. I've got the yz cams on mine too(no hc piston), and it doesn't start as easy/fast as before, but it does.




 
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