Xmotos CRT 250 (165FMM) sprocket fitment????

[NathanTC]

OK so im wanting a 10 mph increase to my top CRUISE SPEED, not top speed. So 55mph to 65mph. Currently the bike is 62mph maxed out on rpm. Gets there just fine with no signs of being underexposed. Recently added a better carb and deleted the egr system. So now it has even better power than it did stock.

Bike has a 13t-42t sprocket set and i know its either a 520 or a 530 chain. Gotta double check before ordering sprockets. Im planning on a 15t-40t set up and 0-ring chain.

My main question is this.
Who else has a bike with this engine, and had went to a 15t sprocket in the front? Does it fit?

Below are some photos that may help. The one of the front sprocket looks closer to the engine case than it really is. Its close bit the photo makes it look worse.

[ghostdancing]

i guess 14T is the bigger you can fit

[Megadan]

I have a 520 setup on my Hawk. Keep the 13 front and go down to either a 37 or 35 out back. A 13 front 35 rear is the same basic ratio as the 17 front 45 rear many Hawk guys run with the 428 chain.

[NathanTC]

Originally Posted by Megadan

I have a 520 setup on my Hawk. Keep the 13 front and go down to either a 37 or 35 out back. A 13 front 35 rear is the same basic ratio as the 17 front 45 rear many Hawk guys run with the 428 chain.

I want to gear the bike taller but I also want to keep both sprockets as large as possible. Helps with friction and chain wear. Running two small sprockets will make the bike feel less powerful than running to large sprockets and you will go through chains much quicker. Another negative to running two small sprockets is it runs your chain along the swing arm much more so wearing out the wear pad.

[Megadan]

Originally Posted by NathanTC

I want to gear the bike taller but I also want to keep both sprockets as large as possible. Helps with friction and chain wear. Running two small sprockets will make the bike feel less powerful than running to large sprockets and you will go through chains much quicker. Another negative to running two small sprockets is it runs your chain along the swing arm much more so wearing out the wear pad.

I know this, but if you can't fit bigger than a 13 up front you have to work with what you are given.

I have done thousands of miles with a 13 front and 35 rear. Never noticed an issue.

[NathanTC]

Originally Posted by Megadan

I know this, but if you can't fit bigger than a 13 up front you have to work with what you are given.

I have done thousands of miles with a 13 front and 35 rear. Never noticed an issue.

push comes to shove i may just have to do exactly that. Just hopefully someone here has fit a 520-530 15t sprocket to a 165fmm engine. I dont mind taking a grinder to it to make it fit.

im also guessing the gearing is different between my bike and the hawk. OEM top speed is the same but there is no way you are getting more than 8-10 mph out of first gear on this bike, and maybe 20mph in 2nd, 3rd will get you about 35 mph. 4th and 5th seem to be the same as the hawk according to this. (my bike not listed)
https://www.gearingcommander.com/

[NathanTC]

Originally Posted by Megadan

I have done thousands of miles with a 13 front and 35 rear. Never noticed an issue.

forgot to ask, with that sprocket combo what is your actual top speed level ground no wind and rider weight? What is your top COMFORTABLE cruse speed?

[Megadan]

Originally Posted by NathanTC

forgot to ask, with that sprocket combo what is your actual top speed level ground no wind and rider weight? What is your top COMFORTABLE cruse speed?

Well, my bike isn't representative of a normal Hawk, but my 265lbs of 6'4 body comfortably cruises at 60 to 65mph at about 3/4 throttle and I can regularly hit 70mph top speed and occasionally 74 to 75mph at what is essentially rev cut on the stock cdi

[NathanTC]

Just place my order for a 520 - 15 tooth sprocket. I'll post here if it fits or what I had to do to make it fit. If it's not a possibility maybe this will prevent others from going through this headache.

[NathanTC]

ok well i did it, the 520-15T sprocket is on the bike and made a wonderful difference. I still might reduce the rear from 42 down to 40 for just that little extra.

Bike wheelies even easier in 1st and gets to 60 mph (GPS clocked) MUCH faster than before. This engine makes better power down low than it does up high so the taller gearing actually made the bike quicker. Me and my dad are within 20 lbs of each other and have identical bikes. We ran pretty much head to head with both bikes being carbbed, jetted, and modded the same. Now i just pull on him in every gear.

in this order
OEM 13T
Grinding
15T installed

[NathanTC]

if anyone else gets one of these bikes, the 1985 Honda Rebel 250 uses the exact same size rear sprocket.

So now my bike is 15-40 vs the oem 13-42. Massive improvement off an on road. Can easily wheelie in 1st and ride it now that 1st has some legs to it.






sprockets used are in the two links below

https://www.amazon.com/dp/B006SRYGFO...t_details&th=1


https://www.ebay.com/itm/383818388862

[NathanTC]

next is finding a quality 0-ring chain. The oem one is already shot at less than 400 miles.

[ervinjason]

Originally Posted by NathanTC

I want to gear the bike taller but I also want to keep both sprockets as large as possible.

Helps with friction and chain wear. Running two small sprockets will make the bike feel less powerful than running to large sprockets and you will go through chains much quicker.

Another negative to running two small sprockets is it runs your chain along the swing arm much more so wearing out the wear pad.

I know this, but if you can't fit bigger than a 13 up front you have to work with what you are given.

I have done thousands of miles with a 13 front and 35 rear.

Never noticed an issue.

[NathanTC]

Originally Posted by ervinjason

I know this, but if you can't fit bigger than a 13 up front you have to work with what you are given.

I have done thousands of miles with a 13 front and 35 rear.

Never noticed an issue.

after a little grinding the 15 tooth sprocket does fit. The bike feels absolutely perfect with a 15-40. Just got to count my chain links now and go buy an o-ring chain, the chain that comes with the bike is garbage.

[Zacknoles]

Could you say what you grinded down I’m ordering both sprockets, did the chain work stock? I work at weld shop so not to worried just wanna know how you got it dialed in