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6 speed?? More top end??? Gearing??

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Hi I was wondering if there was any way to get more top end out of my desert race built crf250r. It has 14/47 gearing and I still want more topend . It also has a yoshimura tumble transmission, but I have no idea if they changed the actual gear ratios. IMG_20170409_155809_310.thumb.jpg.912b2aec3f7569037b14f514a4adf369.jpgIMG_20170520_184141.jpg.2a60b2b9a6f486cc0809790af98d5f8b.jpgIMG_20170409_155809_311.thumb.jpg.70445345f27ecb580444f1b57fc0e855.jpg

Edited by Jacob Villalobos

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I agree, a 250 isn't enough for desert.  I would look at a 450x if you want top speed.  I ride a 450r in Ocotillo wells and it seems like I'm trying to shift up when I'm in 5th all the time.

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All depends what you are looking for and I would also base some things off your personal size, are you light, medium or a heavy person? Are you on a 250 because that is the class you like or are you ready to move up to a 300, 450 or larger? Are you really able to ride that bike pinned in ALL situations or are you looking for more power because of drag racing your friends? Are you just play riding or are you looking to race it? There is nothing wrong with the 250R except remember "R's" are really track bikes so it has different transmission gearing than a 250X. I know plenty of racers that can OA a desert race on a 250 and some race R's but most are on X's but it all comes from the proper set up and the skill of the racer/rider. 

Without selling your machine there are mods you can do to it for reasonable cost, like changing the counter and rear sprockets from that 14/47 to a 14/45 but you may find it hard to pull that top gear in some situations. I know some people that race Baja or BITD running 15/48 or 47.  But remember for a 250 if you are building it for speed you may also give up some lower end making it harder to climb hills or find a comfortable set up at the track. Many of us have bikes set up for different situations or we prep for the ride changing our gearing for the ride. But if you are looking to spend money and try to build it as a 250 powerhouse reach out to Paul at AS Racing ( I see you are supporting one of his stickers)  or Bob Bell at Precision Concepts and they can walk you  through many options. Porting/polish, different cam, FI /ECU mapping including changing your internal gears to an X.  But it is a 250 and you will only get so much out if it as compared to a bigger bike. Both Paul and Bob have a lot of data for your machine from what other racers/riders have used and they have no problem talking to you especially if it leads to service. Travis at TBT is also a good source to reach out to...

1 of my 450's is always a 14/47 gearing where the track bike is typically 13/50 and my 300 is normally 14/45 for BITD (desert) but 14/48 for NHHA type events. 

Edited by Diamond-Dave
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11 minutes ago, Diamond-Dave said:

All depends what you are looking for and I would also base some things off your personal size, are you light, medium or a heavy person? Are you on a 250 because that is the class you like or are you ready to move up to a 300, 450 or larger? Are you really able to ride that bike pinned in ALL situations or are you looking for more power because of drag racing your friends? Are you just play riding or are you looking to race it? There is nothing wrong with the 250R except remember "R's" are really track bikes so it has different transmission gearing than a 250X. I know plenty of racers that can OA a desert race on a 250 and some race R's but most are on X's but it all comes from the proper set up and the skill of the racer/rider. 

Without selling your machine there are mods you can do to it for reasonable cost, like changing the counter and rear sprockets from that 14/47 to a 14/45 but you may find it hard to pull that top gear in some situations. I know some people that race Baja or BITD running 15/48 or 47.  But remember for a 250 if you are building it for speed you may also give up some lower end making it harder to climb hills or find a comfortable set up at the track. Many of us have bikes set up for different situations or we prep for the ride changing our gearing for the ride. But if you are looking to spend money and try to build it as a 250 powerhouse reach out to Paul at AS Racing ( I see you are supporting one of his stickers)  or Bob Bell at Precision Concepts and they can walk you  through many options. Porting/polish, different cam, FI /ECU mapping including changing your internal gears to an X.  But it is a 250 and you will only get so much out if it as compared to a bigger bike. Both Paul and Bob have a lot of data for your machine from what other racers/riders have used and they have no problem talking to you especially if it leads to service. Travis at TBT is also a good source to reach out to...

1 of my 450's is always a 14/47 gearing where the track bike is typically 13/50 and my 300 is normally 14/45 for BITD (desert) but 14/48 for NHHA type events. 

Hey man thanks for all the help. And talking about As racing it was the owner of as racing bike. I'm around 5'10 and 160 pounds , I race , but when I ride with friends I cant keep up on flat out places and I want to keep up, it don't think this bike would really bog down from dropping to 14/45 it's a very fast 250. Alot of money in it as u can see from the mod list.

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What bikes are your friends riding that you can't keep up with them ?

Type of terrain ?

Everyone of equal skill level ?  (going faster around corners and thru obstacles gets you going faster sooner in open terrain)

Edited by mlatour

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6 minutes ago, mlatour said:

What bikes are your friends riding that you can't keep up with them ?

Type of terrain ?

Everyone of equal skill level ?  (going faster around corners and thru obstacles gets you going faster sooner in open terrain)

Yes we are pretty equal and a KTM 350 xr 400 KTM 250 xcf

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Jacob, you're not comparing apples to apples. The XC-F is a cross country bike so it's internal gearing will give it more top end, same with 350 as it has more HP and is made to compete in the 450 class although it's gearing may be closer to yours it just has more power stick. Even the XR400 will not be as fast out of the gate but it will build more mid n top end being almost twice the motor size. Try the 14/45 and see how it goes but remember you may give up some bottom end but your motor sounds like it should pull it. Just remember jump for show, corner for dough. Get them in the turns...

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Jacob, you're not comparing apples to apples. The XC-F is a cross country bike so it's internal gearing will give it more top end, same with 350 as it has more HP and is made to compete in the 450 class although it's gearing may be closer to yours it just has more power stick. Even the XR400 will not be as fast out of the gate but it will build more mid n top end being almost twice the motor size. Try the 14/45 and see how it goes but remember you may give up some bottom end but your motor sounds like it should pull it. Just remember jump for show, corner for dough. Get them in the turns...

I will try the 14/45 and yes it pulls hard, I get through the gears Soo quick
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Quote: "I get through the gears so quick"

Well as you suspect, the close-ratio of an MX gearbox is likely not well suited for the usage you want do.

No matter the final drive ratio you choose, the internal ratios will always be closely spaced versus a wide-ratio off road oriented bike.

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1 hour ago, mlatour said:

Well as you suspect, the close-ratio of an MX gearbox is likely not well suited for the usage you want do.

No matter the final drive ratio you choose, the internal ratios will always be closely spaced versus a wide-ratio off road oriented bike.

Not necessarily - i have a 450sx with a 6 speed conversion - first 4 gears are sx - last 2 are exc. put a smaller front sprocket and larger rear sprocket on it just to tame down the top speed.

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Quote: "I get through the gears so quick"
Well as you suspect, the close-ratio of an MX gearbox is likely not well suited for the usage you want do.
No matter the final drive ratio you choose, the internal ratios will always be closely spaced versus a wide-ratio off road oriented bike.

So should I swap to x gears?

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55 minutes ago, Jacob Villalobos said:


So should I swap to x gears?

As I mentioned already all depends what you are trying to get out of this bike. You said you do some racing on it. What are you racing? Desert, MX, GP, EX, NHHA? All have different requirements for gearing. But yes an "X" internal gearing wouldn't be bad if you are doing majority of desert and it will give you taller/wider gearing. I know some machines come with 5 speeds where the same model cross country bike has 6 speeds, so many people also do 5 to 6 speed changes since many motor cases already support that. I haven't rode CRF's since 2006-08 so not sure on their complete set up but I can talk gearing. If you search this forum I'm sure you'll find more info or reach out to the guys I already mentioned. Paul builds these bikes for many uses. 

Again you just need to figure what you are trying to get out of this machine before just throwing money at it. If you are just looking to beat your buddies in an occasional drag race then start with the counter/rear sprocket changes we discussed. If you are looking for a more versatile bike then you have to decide to go internal changing gears or sell it and get something different. There are other things about an "R" to think about since it has no lighting coil set up. Do you plan to ever need off road lights? That too would be additional mods where other bikes already have that built in. Sit down, right a pro/con list of what you are looking for. That R you have is already set up awesome with the ASR mods but it is mostly MX/GP type conditions. You can use for desert too with the 14/45 gear change but you may struggle on big hill climbs. 

Best of Luck Jacob...

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As I mentioned already all depends what you are trying to get out of this bike. You said you do some racing on it. What are you racing? Desert, MX, GP, EX, NHHA? All have different requirements for gearing. But yes an "X" internal gearing wouldn't be bad if you are doing majority of desert and it will give you taller/wider gearing. I know some machines come with 5 speeds where the same model cross country bike has 6 speeds, so many people also do 5 to 6 speed changes since many motor cases already support that. I haven't rode CRF's since 2006-08 so not sure on their complete set up but I can talk gearing. If you search this forum I'm sure you'll find more info or reach out to the guys I already mentioned. Paul builds these bikes for many uses. 
Again you just need to figure what you are trying to get out of this machine before just throwing money at it. If you are just looking to beat your buddies in an occasional drag race then start with the counter/rear sprocket changes we discussed. If you are looking for a more versatile bike then you have to decide to go internal changing gears or sell it and get something different. There are other things about an "R" to think about since it has no lighting coil set up. Do you plan to ever need off road lights? That too would be additional mods where other bikes already have that built in. Sit down, right a pro/con list of what you are looking for. That R you have is already set up awesome with the ASR mods but it is mostly MX/GP type conditions. You can use for desert too with the 14/45 gear change but you may struggle on big hill climbs. 
Best of Luck Jacob...

Thanks for all your help, I think I might swap the 5 the gear out and some other gears to make it longer

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1 hour ago, Jacob Villalobos said:


So should I swap to x gears?

Even if you could you probably wouldnt have the top end speed your looking for although first gear would be more functional after you change your sprockets to 14/45 for higher speed. But there is no kit available to change or swap internal gearing unfortunately.

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2 minutes ago, Jacob Villalobos said:


Thanks for all your help, I think I might swap the 5 the gear out and some other gears to make it longer

More than welcome, Talk to Paul or someone a bit more, you may not just want to do 5th only without checking since the 4th to 5th could be too large of a transition jump. You want to mix the ratios so that you have plenty of pull from gear to gear instead of running into flat spots. You may find that a 3rd, 4th and 5th combo change may be better. Hard to say without looking into it more. Hate to see you having to open the case often as you experiment with changes. Good Luck and Happy Riding... 

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Even if you could you probably wouldnt have the top end speed your looking for although first gear would be more functional after you change your sprockets to 14/45 for higher speed. But there is no kit available to change or swap internal gearing unfortunately.

Oh dang really? So I should just change to 14/45 , stock gearing is 13/48

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More than welcome, Talk to Paul or someone a bit more, you may not just want to do 5th only without checking since the 4th to 5th could be too large of a transition jump. You want to mix the ratios so that you have plenty of pull from gear to gear instead of running into flat spots. You may find that a 3rd, 4th and 5th combo change may be better. Hard to say without looking into it more. Hate to see you having to open the case often as you experiment with changes. Good Luck and Happy Riding... 

Ok thanks I will talk to paul

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3 minutes ago, Jacob Villalobos said:


Oh dang really? So I should just change to 14/45 , stock gearing is 13/48

Here is a link that shows the internal trans gear ratio's in the "differences between a 250R and 250X" section, I dont know if anyone has tried changing any internal trans gears, there are two shared ratio's already.

https://www.rickramsey.net/CRF250X.htm

It looks like the primary gear ratio could probably be changed between the two but your 250R wouldnt benefit from that, nothing to be gained there. 

 

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Here is a link that shows the internal trans gear ratio's in the "differences between a 250R and 250X" section, I dont know if anyone has tried changing any internal trans gears, there are two shared ratio's already.
https://www.rickramsey.net/CRF250X.htm
It looks like the primary gear ratio could probably be changed between the two but your 250R wouldnt benefit from that, nothing to be gained there. 
 

Do you recommend changing to custom gears?

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