CRF #2 - 250R - LGX P41A 20s1p - EM200

bananu7

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Sep 27, 2024
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505
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Poland
Sooo.... I might have bought another bike.

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It's a yet another 2005 CRF 250R, virtually the same as CRF #1. This has been going for a while behind the scenes, but I wanted to wait for a bit before I posted so that I at least had the bike on hand.

I should probably say why I'm even getting into this while #1 still isn't finished, with at least a couple dozen hours of work left still. Thing is, even in the unfinished state, it has given both me and other people so many smiles and pleasant moments, I just wanted to have a second one to share with people, do dual test-rides together, and just have double the fun. I also had some leftover parts, but most importantly, I already put so much effort into learning all this, it just didn't feel right to build only one bike. So when this one showed up, I pulled the trigger and ordered it shipped, without the engine.

This one isn't a project someone started, it sits as it was, just minus the engine and exhaust. Considering I did virtually everything on #1 myself anyway, I'm not too concerned. So let's look at the planned specs.

* Honda CRF250R motocross frame from 2005
* QS138v3 - exactly same one as in #1, new version, no surprises
* Votol EM200S - I got it because it was shipped from Poland and was really affordable even compared to the 260S. It can run at up to 250bA which I think should be just fine, especially given it's the "large radiator" version. The only thing that's concerning is if I'll manage to fit the radiator on the bike, as it is quite bigger than the 260. I thought about getting a 96V Fardriver as well, but the cost just didn't seem to justify it.
* LGX P41A cells. I'm going with a 20s1p with this one, with 41Ah cells. They have 204A continuous and 380A peak discharge rating, so hopefully they'll be up to the task. I'll put them in a support frame and enclose in fiberglass again. The cells weigh 660g each, so hopefully we'll shed some weight from #1 without sacricificing performance. I got them brand new, likely rejects, for a really absurdly low price of around 11.50 eur / cell. That's 230 eur for a 72V41Ah battery, which is impossible to match with cylindrical cells, and should save me from welding - I'll just clamp the electrodes together.

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Another upside of using them will be much smaller battery size.

I'll likely start with 15-54 gearing with this bike to make it faster with more range, but less uphill pull. That means I can reuse the steel 428 54T I already own, for a really durable drivetrain; I'll just need a new chain. Other than that, I plan to keep the bike in original plastics and look.

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The long-term plan for this bike is to get it to rideable state as quickly as possible, enjoy during the summer and sell right after, for a small profit that could fund more projects. As such, I likely won't be going into as much detail work as with mine, and just get it to work well enough for an average dirtbike rider/newbie. It will definitely get a better rear tyre (thankfully the seller has included one that's still usable). I will need to do a basic front suspension service, as they lost most of their oil during upside-down transit, and give it all a good clean and grease job.

I've ordered a Surron throttle for it as well, so it will be interesting to compare it to my cable throttle.

As always, questions, comments and words of encouragement are welcome, as well as visits if you want to ride it once it's complete ;)
 
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I stripped the #2 down to the frame today, for cleaning and inspection. Swingarm bearings are rusty and likely shot beyond repair. I do have another swingarm with the broken adjuster, so I could either move the bearings or repair the adjuster.

I also finally got the front wheel free. When the seller shipped it to me, he pulled the fork together with the front wheel out. Turns out one of the axle pinch bolts was welded to the aluminum block despite nickel coating.

I took a trip today to get a 600Nm air impact wrench, but the socket just rotated on the bolt. Tried cutting it and using a flat head but the one of the flat bits chipped, and the other twisted:

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In the end I used a regular hammer with a good screwdriver and tapped the bolt loose. It's a small miracle I didn't damage anything else in the process. PSA: please use copper grease and a torque wrench in aluminium treads.

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I had a bit of time today so I decided to take a look at the rear tyre situation. Long story short, both tyres landed in the trash and I'll get a Shinko 505 or 525 for it (and maybe a fresh front one while I'm at it). The good news is that the rim seems straight and with no dents, with just a couple of rusty nipples. Rear disc is shot which explain horribly crooked rear pads. Oh, and the wheel used to have bearings at some point, I'm sure.

All in all we're getting a couple new items to order, and given the overall bike condition I think I'll check other bearings and get everything in one go. Thankfully those things aren't too expensive when ordered individually and not in dedicated kits.
 
I had a bit of time today so I decided to take a look at the rear tyre situation. Long story short, both tyres landed in the trash and I'll get a Shinko 505 or 525 for it (and maybe a fresh front one while I'm at it). The good news is that the rim seems straight and with no dents, with just a couple of rusty nipples. Rear disc is shot which explain horribly crooked rear pads. Oh, and the wheel used to have bearings at some point, I'm sure.

All in all we're getting a couple new items to order, and given the overall bike condition I think I'll check other bearings and get everything in one go. Thankfully those things aren't too expensive when ordered individually and not in dedicated kits.
i don't seem to recall having that bad of a bike when I bought some bike previously, but with the Suzuki (bought with a shot engine) you can really tell it finished it's ICE life with proper hack mechanics. At the same time spending more than bare minimum for an electric conversion doesn't make much sense financially so I guess we are destined to have to fix these sort of things 😅 At least now you have loads of spares and you are proficient in 2008 CRF lol.
 
I guess we are destined to have to fix these sort of things
The first one I bought was supposed to be in well-maintained state, with everything replaced. That was true, the issue was it was all replaced incorrectly. I'd much rather do the regular maintenance job myself than fix a half-assed garage repair someone else attempted.

Honestly #2 isn't in that bad of a condition, it's just regular wear. Nothing seems outright damaged (I'm especially pleased with the wheels so far), just needs fresh consumables, which is about a perfect state for a conversion/restoration project (because that also means I could grab it for a fair price).

I have a budget in mind for this project because it was supposed to go on sale, and that includes a buffer for things like that, so all good.
you are proficient in 2008 CRF lol.
At some point I realized that #1 is actually a bike from 2005 as well :D. The seller didn't really know or care I suppose, I figured it out once the parts I ordered didn't really fit. They didn't change much over the years though.
 
I did some research and related shipping. I always like to post such stuff into logs for posterity.

The 2005 CRF has
* 25x42x9 6905 rear wheel bearings (x3)
* 20x37x9 6904 front wheel bearings (x2)
* 32x43x7 rear wheel seals (x2)
* 26x37x7 front wheel seals (x2)

To replace them, you need a 47mm OD special 6-sided tool.

I took a chance and ordered bearings from MGK, which I think is a Polish company. They had very affordable SS 2RS options (double seal, stainless) which should work great as wheel bearings.

For the rear wheel, I decided on Dunlop D952 in a 110/90-19 size I thought about going even smaller, with 100/90, but the larger one was slightly cheaper and I figured for the trail riding with a 19" i might want a bit more rubber at lower pressure. In fact, browsing through the tyre options is slowly convincing me that I might actually want to go with a 18" if I ever get to replacing wheels in the #1 CRF.

With the new rear brake disc and the new steel sprocket I have, I think the rear wheel is (will be, once I get and mount all of this) pretty much there, but I'm also considering replacing the spacers. This is annoying because I already ordered a set that didn't fit, despite all websites listing them as fitting "2004-2009" models or somesuch. Worst case scenario I'll just machine them myself. Hmm, now that I wrote it, I remembered that I might need a new rim band...

What else is there? Sprocket bolts looked good, disc bolts looked good, tube looked good. I think that's pretty much it.
 
Fun development! I am now pretty sure that my rear wheel (or at least the hub) is from mid-2000s Kawasaki KX250. They share the same axle diameter (25mm) with the CRF, but use different diameter seals (42 instead of 43mm), and the sprocket and disc are totally different sizing. I spent a good part of yesterday's evening cleaning everything and putting the new tyre on, just to realize the sprockets i have don't fit - and neither would the brake disc or the seals that I'm getting today.

So now I have a bit of a dillema - either build this wheel back (with a fitting disc, sprocket and seals - at least the bearings are the same) and hopefully it will all fit, or get a used CRF wheel and simply swap it in. I think this wheel looks fine, but I'm a bit concerned about the sizing/spacing. If the rear disk is offset by a small amount, the rear brake carrier has no chance of fitting it properly. I saw it had extremely crooked pads but I attributed that to disc wear, hopefully it wasn't actually forced in or anything. I can machine new spacers if need be but that might put the wheel off-center...
 
You're going into small series production;)
Too bad it's entirely dependent on the supply of used frames. Good that Honda made so many of them :D

I'm now pretty sure I do in fact own a KX250 rear hub. I found a disc for it, but for the sprockets I was in a pickle again - as I am determined to stay on the 428 chain. MJ corse actually has a 56T for KMX200 / KDX 125, but that's another pricy item. Instead, as I wanted to make the bike a bit faster anyway, I opted to go with JTR459.52 steel rear, which with 14T front will give me 8.73:1. I will definitely need a new engine mount, but I have to make one anyway.

As far as the wheel alignment, I was thinking about it, and correct me if I'm wrong, but with a floating brake, the exact location of the disc shouldn't matter, no? As long as the brake has enough slider/caliper space, it should self-center, so as long as the disc is roughly in there, it should all work fine.
 
I disassembled all the swingarm and rocker bearings today. Everything is complete trash, rusted out as I was expecting at this point. I'll grab a kit from Aliexpress, as that comes out to less than half the price, so mechanically I likely won't put it together until next week. Unfortunately the swingarm is also eaten by the chain, which I specifically asked the seller about and he claimed that wasn't the case. I think I'll just use some epoxy metal putty and fill that in rather than try to weld like I did with my 990 swingarm.

The frame also has a couple bends, I suppose it didn't have an easy life. Everything is still reasonably straight and I don't think it's going to impact the durability all that much, but that's yet another item to check when buying older/used bikes.

At least the steering head bearings are fine - show slight signs of wear visually, but not enough to warrant replacing yet.
 
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