Oh I'm with you there Grant - hence making sure my 2.50 width [Excel] rim had a proper tubeless bead-seat - I wouldn't personally run one tubeless without either... although I understand some people do*.

It is not to be recommended however - *hence my 'you'd be on your own' - although concede that phrasing might come across as a nod and a wink if not an actual endorsement - which was not the intention, only as information.

As Grants says - don't do it without checking you have a proper double lip tubeless rim kids!

Jx

ps. with regard to referencing the [Rally Raid] 17/19" wheel size combo for the CRF/Rally models - it was more that those rim sizes offer a wider range of tyres more suited to longer distance all-terrain travelling (than typically skinny and soft 'dirt bike' 18/21" tyres) - so if anyone is building a lighter weight long-distance travel bike using the CRF300 models as a base (as I have), those sizes are definitely worth considering if your route is likely to include a far higher proportion of paved road riding, and give little if anything away on rougher terrain.

In converting my 300L to tubeless last year, I also thought 2.15 on the front would be OTT, but it's fine. As J-Mo said, proper TL rims with the vital sealing bead don't come in the narrow factory widths used by Japanese 250/300 trail bikes. I think Honda choose as thin/light as possible on these bikes for good review performance and low weight figures, but fatter can work better irl.

Be warned though; it's an expensive process which can take months: new rims, hubs (buy from US), lacing and then sealing (which you can DIY) and of course, new TL tyres. I'm not sure I'd bother for domestic day-rides, but for solo overseas travel, it's another matter.
I rushed my DIY sealing, using individual blobs on each spoke (as on many previous TL conversions) but didn't let it cure properly for a day or two, and paid the price. (Tip: avoid puncture sealing fluids like Slime; they may react badly with the spoke sealant and 35°C heat.)
Expecting such problems, I bought some Puraflex 40 sealant with me, and in Marrakech a mechanic did a clean up and re-seal, this time using a continuous band of sealant (not individual blobs). While blobs are better for targeting individual spoke nipple leaks, you also raise the chances of an errant leak by ~36:1 over a continuous band.
As it is, if done well, I've never had a TL spoke leak, nor bent/broken a spoke in decades, but in future will take the continuous band route (like CWC Airtight or Bartubless). If nothing else, it's a lot less time consuming. Probably not needed but adding stretch-free tape round the circumference of the band will resist lifting.

It's true that front flats are a lot rarer, but as I was changing my front to a 19, TL was no added complication and I can leave the levers are home.

I deliberately chose AX41s as close to the stock tyre width, thinking the 300L would do without the extra drag/weight, but though I hate to admit it ;-) fatter rides better on the road, and on the dirt I can't tell at my donkey speeds. Plus as J-Mo also found, a fatter/taller rear on a smaller ø 17 works out same height as original 18er, so speedo reading is back to 8% factory error, and also the gearing drops back down to standard; a nice low 1st.
Below, my link-lowered 300L on fatter-than-stock 17/19 Mitas E07 TLs after wearing out AX41 TLs in 10,000kms. Fat front was all I could buy in Marrakech and felt a bit heavy off the bat, but bike now runs great on the road and fine on the piste for what I do.

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Morocco Overland 4 (2025) • Trans Morocco Trail

Flats !!
Am i right in thinking you can still use a tube with a tubeless conversion ?
I did see a report that a puncture happens every 75,00 to 80,00 miles ?
I always use "slime " in my rear tyre , as fronts are easy to repair .and take a spare tyre inflator , tubes , electric pump and some good luck !
K

Yes, if you've punctured the [tubeless] tyre so much that it can't be plugged, you can always remove the tyre in the usual way, remove the tubeless valve from the rim, and fit an inner tube to get you going again.

fwiw. it's a wise precaution to take a tube anyway on a longer-distance trip, particularly if your route includes a lot of [typcially rocky] off-road miles, since while 99% of punctures tend to be a small object like a nail or screw which leave a hole that can be plugged with a gummy worm or similar, there is always the chance that you'll slice a tyre which is unlikely to be able to be plugged.

Jx

As Jmo says, yes you can put in a tube.
I find the phrase "puncture happens every 75,00 to 80,00 miles" somewhat hilarious! WHO decided that - based on what? Based on riding where? Or is it a car figure based on commuting somewhere?
Sorry but it has NO relevance to travelling the world on a motorcycle.
If you stick to paved roads in Europe, your figure will be vastly different than riding through the Acacia thorn-ridden "roads" of Sudan and Ethiopia. Also, how far do you push your luck on tread wear? Makes a difference.

I'm NOT a fan of slime for regular use. ANY tire manufacturer will tell you the same. Biggest issue that I'm 100% in agreement with that they raise is that it can hide a puncture and the nail moves around with riding and destroys the tire, causing a catastrophic loss of air instead of the usual more gradual loss of air with a nail puncture, particularly with tubeless.

Also, NO shop will want to have anything to do with a slimed tire replacement - or they'll charge an arm and a leg to do the job. Finally, you can't plug a slimed tire, the plug won't stick well. And same issue with patching a tube, you can't patch it reliably, the glue doesn't stick. Cleaning to get it to work is very difficult.

And of course, thinking world trip, what do you do when it's time to replace the tire / tube? No slime available probably, so back to basics.

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Grant Johnson
Seek, and ye shall find.
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Inspiring, Informing and Connecting travellers since 1997!
www.HorizonsUnlimited.com

Thank you again all for the responses. I bought tubeless rims from Haan in the original 18 and 21 inch (but with widths of 2.15 and 2.50). I'm away at the moment so haven't had a chance to fit them to the little CRF. However, I also got tubeless rims for my T7 for a Kyrgyzstan to Bangkok (via China) trip (from Bart factory) and they performed flawlessly. I am sold on the benefits of tubeless over tubed. I will update once I get home and fit the new rims on the Honda .

Is there any tour description available?