2008 CRF250R - QS138v3 70H - ANT - Sanyo UR18650-RX 20s20p - Votol EM260

It sounds like you have too soft rear spring with that 24mm static sag, do you know how much preload?
But the shock likely needs a rebuild too ;)
I think I have changed springs 4 times, and it is still too soft..
I haven't measured the preload on the spring, just the sags. I agree that it likely needs a rebuild, because pretty much any issue in there will also manifest as it being too soft, like not enough pressure, not enough damping etc. I have another one ordered that should be coming to me soon, I'll see how it compares and will have a spare to give out for service so that I have something to ride on.

speaking of...
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I still can't get over how nice it is to jump off of my commuter bike and onto this thing. I rotated the bars to the +2 position (to the front), let out a bit of pressure from the front tyre and added half a turn of preload in the rear. It's not exactly the most comfortable (as I'd prefer the bars neutral but mounted 2cm forward) but at least it turns now.
 
New shock should be here tomorrow, fingers crossed. In the meantime, I did some fitment tests and managed to get 15T in:

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I think 16T could maybe barely fit with enough slack, but I might just wait for the chain to lengthen, lol. The new sprocket is a cheap variety, but with a decent fitment on the shaft. Not as good as JT or AFAM, but not as bad as what came with the motor. I was more surprised about the locking plate - the plate I used with the AFAM 14T was so thick that it wedged really solid in the shaft slot. That meant that when i tightened the sprocket, there was no play at all. This one is so thin that it freely fits in the slot, resulting in quite a lot of play.

I think it might be for the better, since this is how the sprocket I took off looked like:

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Not horrible, but clearly showing signs of uneven wear. As far as I understand it, the play should allow the sprocket to self-center. I did put everything together and went for a quick spin, but it was raining and I wasn't going to test the WOT pull. It feels just as strong as before, maybe a tad more twitchy from standstill, and seemingly much quieter.

For the people not up to date, this gearing change means going down from quite absurd 10.07 to a more standard, but still quite short 9.40.
 
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I managed to sniff out the Votol protocol on the PC side (PC-usb adapter) as well as the hardware side (usb adapter-votol). Confirmed the data format used and CAN bus transfers. Parts to interface with it directly should arrive today. I also ordered a couple of display options, because I decided I want to have some onboard monitoring after all. We'll see how the programming goes and how it looks IRL
Looking in depth to your build thread, do you mean you managed to find a way to interface with Votol controllers?
That's interesting as I was looking for hacking friendly controllers available.
My first choice was getting Electro&Co Zapper controller as it is using VESC but it is not available yet for purchase.
Then, I came across discussions on this forum about 3Shul being VESC friendly, but hardware doesn't seem that great given several reports of overheating.
Another option but not sure if hackable though is X9 controller which seems to use VESC too.
Finally I also considered Fardriver as I've seen github project which seems to have reversed engineered communication protocol, but not sure what can be done.
 
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Looking in depth to your build thread, do you mean you managed to find a way to interface with Votol controllers?
That's interesting as I was looking for hacking friendly controllers available.
"Hacking" and "interfacing" are sort of different in my book. I can talk to it enough to get the rudimentary runtime data over CAN. I know that at least a few people were also able to put new settings on it without using the crappy official app.

We do know that it uses a very common STM chip, though. There's firmware around and you can ST-link to it directly. I tried taking a stab at decompiling the firmware but it's veeeery unreadable, as you'd expect from a freestanding embedded implementation. Having open source firmware for them would be killer and would mean no need for time-consuming reversing of the comms protocols.

Incidentally I think I might have an update to the swingarm/shock/height situation even before the new shock arrives. I was damn sure the new swingarm I bought will "just fit", and when it had a different chain guide mounting point, i just handwaved it away. Well, turns out there might have been more changes in the swingarms, especially if by accident I got one from a 450. They will generally bolt together fine, but there might be an offset in the shock mounting eye causing the wheel resting location to be whack. The easiest way to check would be to measure it against the old swingarm, either on the bike or off, and see if there's any difference. If there is, and if the shock(s) are fine, I might need to either:

- go back to the original swingarm, fixing the adjuster
- buy a new swingarm but one that actually fits
- try to source a connecting link for the new swingarm which might be a tad different length

It's kinda crazy that those parts might almost fit, but not quite, to the point where it's really not clear if they do. If the rear does indeed sit lower than it should, I don't think it's more than 20-25mm of a difference, but that's of course enough to cause significant weight distribution issues.
 
Sooo I gathered all serial numbers for all swingarms, rockers and links from all years spanning 2004-2008, both for 250 and 450. I definitely have a connecting link from a 250, with 132mm length. The new swingarm seems to be exactly the same mounting-holes-wise as the old one. and yet I measure 31-32 degrees fork angle right now, while it should be 27.50 :/

Shock should be here tomorrow.
 
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