Best Sprocket Combo?

Post Reply
User avatar
Witterings
New kid on the block
New kid on the block
Reactions:
Posts: 15
Joined: 21 Jul 2021, 14:30
Best Sprocket Combo?

Post by Witterings » 26 Aug 2021, 10:14

Trying to find out what the best sprocket combo is .... ideally one that'll get the front end in the air without dropping the clutch although this may not be possible without making it horrible on the road.
I was wondering if I could get away with 13 on the front and 45 on the back without a dropper block (or is 44 the limit without) and if that'd be enough or if I need to go 47 rear which I belive would definitely need a dropper block.

If anybody's found the perfect combo I#d love to hear what it is?

User avatar
777amia
New kid on the block
New kid on the block
Reactions:
Posts: 22
Joined: 03 May 2021, 19:43
Re: Best Sprocket Combo?

Post by 777amia » 26 Aug 2021, 17:12

Not sure on sprocket sizes to be honest, I read on a Japanese site you can remove the noise reduction program (which is first 3 gears I believe) by cutting a wire to the pgm, maybe that'll increase hp in the lower gears? Think it just reduces valve lift, seems to work on AR models :) If you don't want to use a dropper for rear guide you can use a guide for CRF150F 2003-2017, CRF230F 2003-2019, CRF250F 2019-2021 as they run 1cm or so lower than the originals so you could probably get away with a 47 rear and are a direct fit, I just got a black one from China, about £12. Can't remember the wire colour off the top of my head for the pgm trick, but I think it's white/green wire, on top row of wires to pgm (maybe 3rd or 4th from left) I did have info but it was on my old phone, but that's no longer working :/

User avatar
Witterings
New kid on the block
New kid on the block
Reactions:
Posts: 15
Joined: 21 Jul 2021, 14:30
Re: Best Sprocket Combo?

Post by Witterings » 27 Aug 2021, 01:09

777amia wrote:
26 Aug 2021, 17:12
Not sure on sprocket sizes to be honest, I read on a Japanese site you can remove the noise reduction program (which is first 3 gears I believe) by cutting a wire to the pgm, maybe that'll increase hp in the lower gears? Think it just reduces valve lift, seems to work on AR models :) If you don't want to use a dropper for rear guide you can use a guide for CRF150F 2003-2017, CRF230F 2003-2019, CRF250F 2019-2021 as they run 1cm or so lower than the originals so you could probably get away with a 47 rear and are a direct fit, I just got a black one from China, about £12. Can't remember the wire colour off the top of my head for the pgm trick, but I think it's white/green wire, on top row of wires to pgm (maybe 3rd or 4th from left) I did have info but it was on my old phone, but that's no longer working :/
Cheers for hat some really useful info :D

xstian81
NWAA Supporter
NWAA Supporter
Reactions:
Posts: 167
Joined: 06 Aug 2014, 15:02
Bike Owned: Mk3 CRM
Location: Norfolk
Re: Best Sprocket Combo?

Post by xstian81 » 28 Aug 2021, 07:52


User avatar
Ekul250
New kid on the block
New kid on the block
Reactions:
Posts: 11
Joined: 30 Apr 2021, 12:38
Re: Best Sprocket Combo?

Post by Ekul250 » 28 Aug 2021, 18:09

Witterings wrote:
26 Aug 2021, 10:14
Trying to find out what the best sprocket combo is .... ideally one that'll get the front end in the air without dropping the clutch although this may not be possible without making it horrible on the road.
I was wondering if I could get away with 13 on the front and 45 on the back without a dropper block (or is 44 the limit without) and if that'd be enough or if I need to go 47 rear which I belive would definitely need a dropper block.

If anybody's found the perfect combo I#d love to hear what it is?
I'm running 13/45, fitted the 45 (JTR 301) today actually (changed from a 42). Front wheel lifts under power in 1st. I only took it up and down the road, in the wet, but I will be doing more riding soon. The 45 fits fine as per the post xstian has linked. I might consider dropping to 12 on the front, less of a drop than swapping the 45 rear for a 50 rear, and no spacer block. But that'll require working out what sprocket will fit the front; a quick search tells me I'm not likely to find a 12T for the front.

Also- take great care with the nuts that attach the sprocket to the hub. I worsened the stripping on one by making the foolish mistake of untightening from the hex head, as opposed to undoing the nut :oops: They are still in stock, in some places, but are around £3.50 per bolt.

User avatar
Witterings
New kid on the block
New kid on the block
Reactions:
Posts: 15
Joined: 21 Jul 2021, 14:30
Re: Best Sprocket Combo?

Post by Witterings » 30 Aug 2021, 00:23

Ekul250 wrote:
28 Aug 2021, 18:09
I'm running 13/45, fitted the 45 (JTR 301) today actually (changed from a 42). Front wheel lifts under power in 1st. I only took it up and down the road, in the wet, but I will be doing more riding soon. The 45 fits fine as per the post xstian has linked. I might consider dropping to 12 on the front, less of a drop than swapping the 45 rear for a 50 rear, and no spacer block. But that'll require working out what sprocket will fit the front; a quick search tells me I'm not likely to find a 12T for the front.

Also- take great care with the nuts that attach the sprocket to the hub. I worsened the stripping on one by making the foolish mistake of untightening from the hex head, as opposed to undoing the nut :oops: They are still in stock, in some places, but are around £3.50 per bolt.
I posted the same query in the Facebook group as well ... someone from leisuretrail posted 13/47 as the best combo but they didn't say if that'd get the front wheel up in 2nd ... which is all I'd ideally like.

That said as I get back into it more I'm sure I used to drop the clutch going uphill fast over big tree roots but I'd now like to go a step further going over logs etc. and whilst I'm sure you can do it with the right technique, if you can lift the wheel without dropping the clutch it means there's definitely enough grunt and it should be easy and it'd give loads of low end pull in more techical boggy stuff / hills I would have thought.

Just my 2 p's worth.

User avatar
Ekul250
New kid on the block
New kid on the block
Reactions:
Posts: 11
Joined: 30 Apr 2021, 12:38
Re: Best Sprocket Combo?

Post by Ekul250 » 30 Aug 2021, 13:22

Witterings wrote:
30 Aug 2021, 00:23
Ekul250 wrote:
28 Aug 2021, 18:09
I'm running 13/45, fitted the 45 (JTR 301) today actually (changed from a 42). Front wheel lifts under power in 1st. I only took it up and down the road, in the wet, but I will be doing more riding soon. The 45 fits fine as per the post xstian has linked. I might consider dropping to 12 on the front, less of a drop than swapping the 45 rear for a 50 rear, and no spacer block. But that'll require working out what sprocket will fit the front; a quick search tells me I'm not likely to find a 12T for the front.

Also- take great care with the nuts that attach the sprocket to the hub. I worsened the stripping on one by making the foolish mistake of untightening from the hex head, as opposed to undoing the nut :oops: They are still in stock, in some places, but are around £3.50 per bolt.
I posted the same query in the Facebook group as well ... someone from leisuretrail posted 13/47 as the best combo but they didn't say if that'd get the front wheel up in 2nd ... which is all I'd ideally like.

That said as I get back into it more I'm sure I used to drop the clutch going uphill fast over big tree roots but I'd now like to go a step further going over logs etc. and whilst I'm sure you can do it with the right technique, if you can lift the wheel without dropping the clutch it means there's definitely enough grunt and it should be easy and it'd give loads of low end pull in more techical boggy stuff / hills I would have thought.

Just my 2 p's worth.
Yeah, 13/45 seems to not be as good as I first thought, it'll lift it in first but not effortlessly. With that being said, I have changed the end can (big thanks to knackeredmk1) and I've not adjusted the jetting (similar to your issue), so it is a little flat, then pops off above 50% rippums. I'm waiting on some jets to arrive now.

I have been trying to work out the dimensions of the spacer knackered has in the post xstian linked, but it's being a bit of a pain, total length isn't there, and gaps between the holes also aren't there. Doing this so I can CNC or 3d print a spacer block; they seem to be difficult to source.

Once that's done, I might consider a 50T. Because yes, lifting the front under throttle alone (and a bit of body weight) is far more usable than juggling the clutch too.

The difference between 45T and 47T really doesn't seem like much when using gearing commander, so I may well skip that step entirely. Though, saying that, the JTR301 comes in a max of 48 (and they don't have a 47), which looks like a significant enough bump for me to try that out.

User avatar
Witterings
New kid on the block
New kid on the block
Reactions:
Posts: 15
Joined: 21 Jul 2021, 14:30
Re: Best Sprocket Combo?

Post by Witterings » 31 Aug 2021, 08:18

Yeah, 13/45 seems to not be as good as I first thought, it'll lift it in first but not effortlessly. With that being said, I have changed the end can (big thanks to knackeredmk1) and I've not adjusted the jetting (similar to your issue), so it is a little flat, then pops off above 50% rippums. I'm waiting on some jets to arrive now.

I have been trying to work out the dimensions of the spacer knackered has in the post xstian linked, but it's being a bit of a pain, total length isn't there, and gaps between the holes also aren't there. Doing this so I can CNC or 3d print a spacer block; they seem to be difficult to source.

Once that's done, I might consider a 50T. Because yes, lifting the front under throttle alone (and a bit of body weight) is far more usable than juggling the clutch too.

The difference between 45T and 47T really doesn't seem like much when using gearing commander, so I may well skip that step entirely. Though, saying that, the JTR301 comes in a max of 48 (and they don't have a 47), which looks like a significant enough bump for me to try that out.
[/quote] [/quote]

I wonder if 13/48 might be quite good .. any more than that and it probably wouldn't be great on the road and leisuretrail do dropper blocks although they're £30.

I obviously did have the jetting issue as they'd gone up to a 50 as opposed to going down although I think I found a 2nd issue that was affecting it.
With the jetting sorted I'd ride for approx 20 mins and it's just stall and not start for 5 / 10 mins. The fuel cap had been changed for an aftermarket one and I don't think it was alowing enough air into the tank causing a vacuum, it's not happened since I swapped it back to the original.
If I were you I'd try winding out your air screw before changing the jetting although you may have already tried that.

User avatar
Ekul250
New kid on the block
New kid on the block
Reactions:
Posts: 11
Joined: 30 Apr 2021, 12:38
Re: Best Sprocket Combo?

Post by Ekul250 » 31 Aug 2021, 11:41

Witterings wrote:
31 Aug 2021, 08:18

I wonder if 13/48 might be quite good .. any more than that and it probably wouldn't be great on the road and leisuretrail do dropper blocks although they're £30.

I obviously did have the jetting issue as they'd gone up to a 50 as opposed to going down although I think I found a 2nd issue that was affecting it.
With the jetting sorted I'd ride for approx 20 mins and it's just stall and not start for 5 / 10 mins. The fuel cap had been changed for an aftermarket one and I don't think it was alowing enough air into the tank causing a vacuum, it's not happened since I swapped it back to the original.
If I were you I'd try winding out your air screw before changing the jetting although you may have already tried that.
Yeah, on one hand I'd like to use leisuretrail, on the other hand I loathe phoning places up and they have very restrictive opening hours. They have an eBay shop but it doesn't seem to have all of their stock. The CRM bits they sell seem to bit a little overpriced, but that said they are reputable and the parts are pretty scarce to begin with. So I understand that. If I can make my own spacer that's robust enough for the bike, I'll do that, else it'll be handing over the £30.


On paper it certainly has the potential to be good! I've ordered a 48 sprocket, so once that arrives I'll stick it on and have a short blap without the chain guide to see how it feels. Given that the 13/50 would drop the top speed to about 80 as opposed to the 13/48's 83, I'm not too fussed about the road characteristics. 6th felt pretty useless with 13/42. Top speed isn't everything, mind, and it might create that awkward situation where 30-40mph is in a very antisocial part of the rev range... Still, I already smoke the village out when warming it up, no complaints yet!

Good tip on doing the air screw first, I've only played with the throttle stop screw to keep it idling happy when it was a bit colder.

I've got the original fuel cap! I assume you've got a mk2 based on your question about the oil capacity?


Post Reply