Replacing the Chain And Sprockets on my Crf 250 Rally

[rockdodger]

Iwas wondering if someone could help me as i am wanting to replace my chain and sprockets on a Crf 250 rally 2018
I have recently purchased a Crf 250 Rally that is in need of new chain and sprockets but the chain Honda recommend in the hand book is impossible to find. ( DiD 520 VF)
Does anyone know if there is another chain that will fit the bill. I have been informed if i get a wider chain it will dig into the crank cases.
Cheers

[Magnusson]

Any 520 chain will work. DID is good but you're not tied to that brand. Googling "crf 250 rally chain and sprocket kit" found a DID chain with JT sprockets kit on Ebay for 100 GBP.

[Richard Simpson Mark II]

Best results I've ever had from a chain are the DID/JT combo. DID X ring chains last forever if looked after. Put a set on my KTM 950 Adventure years ago, and there's still no discernible wear on a bike that gets used year-round and off-road.

The one issue you might run into is the chain rubbing on the back tyre, if you've got a wider back tyre than std.

Garyboy will tell you more!

Oh, and make sure the DID chain comes from a reputable UK stockist...there's some horrible chinese knockoff in DID lookee-likee packaging kicking about.

[garyboy]

Iwas wondering if someone could help me as i am wanting to replace my chain and sprockets on a Crf 250 rally 2018
I have recently purchased a Crf 250 Rally that is in need of new chain and sprockets but the chain Honda recommend in the hand book is impossible to find. ( DiD 520 VF)
Does anyone know if there is another chain that will fit the bill. I have been informed if i get a wider chain it will dig into the crank cases.
Cheers

https://didmalaysia.com.my/product-detail/?id=6
just found this. Looks like its in Malaysia, and an o-ring chain, but as others have said, more expensive chains like x-ring, will be just as good or better. It needs to be a genuine DID or whatever, as many fakes out there, so probably best to buy through a reputable dealer, parts section, or reliable seller. Probably, the more expensive the chain, the better quality, but it seems to be a bit of a lottery?

I have often been pleasantly surprised by the quality and good prices of main oem Honda dealers, despite many slagging them off.
I was impressed with the tight fit of my NC750 oem chain, and after 25,000 miles ordered another one. (its goon a bit rusty but that is my own fault).
The gauge matches the pitch for the sprockets (also oem), this means that when you try to wiggle the chain at the rear end of the rear sprocket, there is no play side to side on the sprocket, holding the chain in your fingers. ... [Incidentally, if you hold the chain when on the rear sprocket, and pull outwards, if it pulls out at all, it is worn. .. up to you when you change it, but has more free play and is dangerous].

I did 5 minutes search on google and 5 mins on you tube, so i am now an egspurt on chains lol ..
the Pitch of a chain is the distance between pins ......... but ..... is measured in eighths of an inch .... as is the gauge.
the gauge is the chain width... measured between insides of plates .. so is the internal measurement of the rollers .. and is? the same size as the sprocket teeth at max width.

a 520 chain has a 5 series pitch (as opposed to a 4 or a 6) which is 5 x 1/8" ... = 5/8ths of an inch pin to pin.
the gauge [or roller width], is 2.0 eighths = 2 x 1/8 = 1/4 inch ...... [and should also be the size of your sprocket teeth.]

if you go for a 525 chain, it still has a 5/8th of an inch pitch, but the roller width is now 2.5 x 1/8 = 5/16 inch.
(change them all to 1/16ths so .. 2.5 x 2/16 = (2 x 2/16) + (.5 x 2/16) = 4/16 + 1/16 - 5/16 th of an inch inner width.
I don't think this extra width would rub the casings as there is play anyway and also i believe the front sprocket is offset outwards a bit?

Of course you would then need 5/16 sprocket teeth, as otherwise the chain would rattle or move on the sprockets.
you got to watch this when you buy chain and sprockets separately ... (i knows lol) .. and the whole setup would be knackerred I expect, anyway, as everything is designed for space as wel as for chain weight and optimum power transfer ... a needlessly heavier chain will add weight and so reduce power output.

[garyboy]

I put the imperial fractions as younger members are millennium decimals lol.

Some tips when changing chain and sprockets (for newbies) ..
Rear sprocket .. loosen nuts not bolts.
Front sprocket .. don't overnighten the bolts, if uneven sprocket sides, put the wider gap near the casings.
Honda usually sell chains in set lengths, and you will usually need to cut the length, eg 120 links to 112 links. Don't be afraid to use split links, but soft links got to be safer?

When tightening honda rear spindle, make chain slacker than needed as at the last turn of the wrench the chain tightens up.
Do not overnighten as on the trail you need to undo it by hand with what you got.

Best tip of the day .. when replacing the spacers to rear spindle, place them in from the rear! Took me years to find this out ... yours for free lol .

Clean and oil chain after every ride, while still warm if possible.

Chain better to be a bit slack than a bit tight... for trails ie.

[Brenhden]

Any 520 chain will work. DID is good but you're not tied to that brand. Googling "crf 250 rally chain and sprocket kit" found a DID chain with JT sprockets kit on Ebay for 100 GBP.

I did this for my 2017 rally and it was great.

[rockdodger]

Hi guys thanks for the replies and loads of information.
I will be going for the DiD 520 for sure. Hopefully when I’ve got the chain and sprockets sorted I can go have some fun on my new bike
Cheers

[mechanic]

Scanning this thread it seems as if a narrow chain is preferable. DID who do make the best chains, market a narrow 520 x ring chain aimed at enduro bikes, this lasts really well if looked after.

[garyboy]

Good to know, but probably best to keep as close as possible to standard.. on All items?

[rockdodger]

Garyboy I’ve actually ordered the whole kit from Honda so let’s see if it’s a quality component. I suspect it will be.
Cheers