1982 CB250RS - Rebuild - Valve Springs & Cam Chain

[jmpl]

Hey all,

Some of you may know Im doing a rebuild on the top end of my 82 RS. Enjoying it thoroughly even if I do find the manual and my lacking experience a pain in the butt sometimes :laugh:

Found all my inner valve springs at 36.4 - 36.6mm free spring length.
Should be 38.1 if new, with 37mm being the service limit.

I realise the difference would be minimal, but if there's a set of 4 knocking around somewhere the brings them back into the midrange around 37.5-38.1mm I'd love to have peace of mind knowing Im doing my best for the old thumper?

Part number(s) 14761429003 for 1980 CB250RS, 14761429005 for 1982 CB250RS

Tried with Honda Official Parts.
Been in touch with Anaconda Honda already, no luck for anything over 37mm.
Also no luck on Ebay.
Tried WeMoto.

Anyone recommend a place sourcing this sort of thing, I get the feeling someones got a bag of em sitting in the back of their garage Haha

Cheers, J

[Laava]

Did you try PlenterNZ? Or Wemoto.com?

[jmpl]

Did you try PlenterNZ? Or Wemoto.com?

No luck on Wemoto. Will give PlenterNZ a call/email. Cheers for the suggestion!


Admittedly, 'JAP MC DISMANTLERS' down south has found me a set. Only trouble being, they've said they're all over 39mm??

My service book implies that the free spring length should be 38.1mm new/max, right? (see attached image)


Does anyone know where I could find the free spring length of a NEW OEM inner valve spring? CMSNL has no measurements.


Thanks all,

[husaberg]

I am confused Honda still lists the springs as being available they are not that expensive?
https://genuineparts.hondamotorbikes.co.nz/Parts/PartDetail/14761429005/spring

https://genuineparts.hondamotorbikes.co.nz/Parts/PartDetail/14751429005/spring
So its about $76 you should replace the seals at the same time part they will be part of an aftermarket gasket set anyway
if you need a piston and rod get these from TKRJ


if you are skint you could shim them up or you could stretch them out with a few blows between the coils but i would not recommend doing either unless you were totally skint.
Both would likely do more damage than having slightly short springs anyway.

[Trade_nancy]

Anaconda? What about Econohonda...Malcolm. In Te Aroha.

[jmpl]

I am confused Honda still lists the springs as being available they are not that expensive?
https://genuineparts.hondamotorbikes.co.nz/Parts/PartDetail/14761429005/spring

https://genuineparts.hondamotorbikes.co.nz/Parts/PartDetail/14751429005/spring
So its about $76 you should replace the seals at the same time part they will be part of an aftermarket gasket set anyway
if you need a piston and rod get these from TKRJ


if you are skint you could shim them up or you could stretch them out with a few blows between the coils but i would not recommend doing either unless you were totally skint.
Both would likely do more damage than having slightly short springs anyway.

Hi Husaberg, I did in fact get touch with Honda initially, they said the part was unavailable :facepalm:

Appreciate the tin shed technique of shimming/stretching Haha but think I'll endeavour to find new old stock or oem spares from a parts spot :)

[jmpl]

Anaconda? What about Econohonda...Malcolm. In Te Aroha.

Same place, Anaconda is the new name apparently... https://www.anacondaltd.co.nz/parts

[pete376403]

No luck on Wemoto. Will give PlenterNZ a call/email. Cheers for the suggestion!


Admittedly, 'JAP MC DISMANTLERS' down south has found me a set. Only trouble being, they've said they're all over 39mm??

My service book implies that the free spring length should be 38.1mm new/max, right? (see attached image)


Does anyone know where I could find the free spring length of a NEW OEM inner valve spring? CMSNL has no measurements.


Thanks all,
How much longer are the replacements? Longer will not be an issue UNLESS they become coil bound at full lift? If the head is still assembled rotate the cam until the valve is at maximum opening then see how much more it can be opened before the coils bind - thats how much you have to play with.

[jmpl]

How much longer are the replacements? Longer will not be an issue UNLESS they become coil bound at full lift? If the head is still assembled rotate the cam until the valve is at maximum opening then see how much more it can be opened before the coils bind - thats how much you have to play with.

Gidday Pete, have asked the nice man, now waiting on email reply re measurements.

Head is disassembled and tbh not sure I follow how I would do this test of yours. How am I supposed to see if the coils are binding if the head is assembled? Are you able to explain a little more visually please?

To confirm, by coil bound you mean when the spring becomes fully compressed and it's rings touch? And by full lift you mean when the valves are fully open?

Cheers

[pete376403]

Gidday Pete, have asked the nice man, now waiting on email reply re measurements.

Head is disassembled and tbh not sure I follow how I would do this test of yours. How am I supposed to see if the coils are binding if the head is assembled? Are you able to explain a little more visually please?

To confirm, by coil bound you mean when the spring becomes fully compressed and it's rings touch? And by full lift you mean when the valves are fully open?

Cheers
I'm assuming its possible to see whats inside the cam cover, ie the cam, cover is removed and you can get at everything - I dont know if that is the case with your engine. So the with head assembled, valves springs, cam etc in place, the cam is rotated till the nose of the cam has the valve fully open, then you see if you can push the valve any more open, measuring what clearance there is between the cam and the tip of the valve stem. Coil bound is where the spring is fully compressed. Valve guide seals take up a bit of space too, not unknown for seals to be removed to accomodate a high lift cam

[Grumph]

I'm assuming its possible to see whats inside the cam cover,

It isn't. Cover has cam bearings incorporated.
With stock cam, they're a mile away from coil-bound. I wouldn't worry if the free length is up to 40mm or so.

[jmpl]

Thanks @pete376403 for clarifying, sadly as @Grumph says this isnt the case with the top end of the CB250RS.

See pictures attached for reference :)

Thanks @Grumph for the heads up re 40mm clearance. That's the length of the springs Ive been offered so am going to give them a go!

[husaberg]

Hi Husaberg, I did in fact get touch with Honda initially, they said the part was unavailable :facepalm:

Appreciate the tin shed technique of shimming/stretching Haha but think I'll endeavour to find new old stock or oem spares from a parts spot :)

you are correct sorry i never pressed order to confirm. As normally if they are not available they have no price also i never properly read your original post.

Looking in the Fiche there are two distinct part numbers for the springs i would say Honda issues lengths or rate as a change.
Make sure the service manual you are using as a reference covers both or all years 1980 and 1982 i would say Honda changed the length maybe in combo with the cams/rockers but your service manual might not cover both. Honda normal indicate the springs with a colour dab. The springs number hanges are not a subrceeded number so it not a change later and therefore i would suggest there is diferent specs.
They all should all play with each other as the parts fiche doesnt list up to cerain engine number etc for the parts listing.
Interestingly the same pairs were used on a lot of models

CB250RS 1980 and 1982
XL250R 1982
XL250R 1983
XL250S 1980
XL250S 1981
XR250 1980
XR250R 1981
XR250R 1982
XR250R 1983
XR500 1979
XR500 1980
XR500R 1981
XR500R 1982
XL500R 1982
XL500S 1979
XL500S 1979
XL500S 1980
XL500S 1981
FT500 1982
FT500 ASCOT 1983

but in aftermarket catalogs they list different springs
Web cam list new springs
http://webcamshafts.com/pdf/catalog.pdf

there are NOS listed on Ebay and other sites under the parts numbers.

personally, i would just have a look through the XR250R and XL250S for the same years and see what they list.

There wll be service manuals for the correct matched XL XR on the net.

Shiming isnt really that bodgy this was done by many tuners from new less damaging than HD springs.
Stretching them is but is pretty common thing to do on saggy clutch springs you use a chisel

[jmpl]

you are correct sorry i never pressed order to confirm. As normally if they are not available they have no price also i never properly read your original post.

Looking in the Fiche there are two distinct part numbers for the springs i would say Honda issues lengths or rate as a change.
Make sure the service manual you are using as a reference covers both or all years 1980 and 1982 i would say Honda changed the length maybe in combo with the cams/rockers but your service manual might not cover both. Honda normal indicate the springs with a colour dab. The springs number hanges are not a subrceeded number so it not a change later and therefore i would suggest there is diferent specs.
They all should all play with each other as the parts fiche doesnt list up to cerain engine number etc for the parts listing.
Interestingly the same pairs were used on a lot of models

CB250RS 1980 and 1982
XL250R 1982
XL250R 1983
XL250S 1980
XL250S 1981
XR250 1980
XR250R 1981
XR250R 1982
XR250R 1983
XR500 1979
XR500 1980
XR500R 1981
XR500R 1982
XL500R 1982
XL500S 1979
XL500S 1979
XL500S 1980
XL500S 1981
FT500 1982
FT500 ASCOT 1983

but in aftermarket catalogs they list different springs
Web cam list new springs
http://webcamshafts.com/pdf/catalog.pdf

there are NOS listed on Ebay and other sites under the parts numbers.

personally, i would just have a look through the XR250R and XL250S for the same years and see what they list.

There wll be service manuals for the correct matched XL XR on the net.

Shiming isnt really that bodgy this was done by many tuners from new less damaging than HD springs.
Stretching them is but is pretty common thing to do on saggy clutch springs you use a chisel

Heya Husaberg,

No worries! Certainly appreciate your research re part hunting, dang, hats off :msn-wink:

Are you able to share a link to the Fiche page you were looking at for the 82 CB250RS?

Yep, my CB250RS service manual covers 1980 - 1984 so all good there. Have compared this with the XL/XR service manual I have that covers 1978 - 1984.

*Note the different length in springs there between the 250cc and 500cc models....

Will be paying attention to the factory paint colour on the top of the replacement springs when they arrive

I'll keep this thread posted with how it all goes!

[husaberg]

Heya Husaberg,

No worries! Certainly appreciate your research re part hunting, dang, hats off :msn-wink:

Are you able to share a link to the Fiche page you were looking at for the 82 CB250RS?

Yep, my CB250RS service manual covers 1980 - 1984 so all good there. Have compared this with the XL/XR service manual I have that covers 1978 - 1984.

*Note the different length in springs there between the 250cc and 500cc models....

Will be paying attention to the factory paint colour on the top of the replacement springs when they arrive

I'll keep this thread posted with how it all goes!

that Hayes manual looks wrong re the 250 i know this as the valves and set up etc are completely different for the 84 so i would suggest they listed only the later. Or does it break them down per year?
Same with the 80-83 XR500 the 83 on is different. but only list one set of figures. Or is there more?

For the parts Fiche

it would have been CMS
i would have picked AUS at a guess
but it matters not as all models had the same springs.
i never crossed checked the 500 or the XR250R to see if they had succeeded new part numbers but its a longshot. (i just checked but they all list the dame parts sorry)
349686
Partxzilia a and honda of the troy list the same numbers
David Silver in the UK has a huge nventory of NOS parts and makes up parts to original spec.

oh here you go R&D list them
https://www.rdvalvespring.com/spring-kits
349687
only listed for one model.

edit
here is gen XR500R 81-82
honda service figures
https://davesbikes.weebly.com/uploads/4/8/4/5/4845046/xr500b.pdf
349690

[jmpl]

Hi all,

So the parts just arrived 10 days after payment ... Shipped up from a place down South Island called Jap MC Dismantlers.

They arrived today, being the wrong springs in literally every dimension but one (the longer free spring length), allbeit very close to the measurements of my own OEM springs. See attached images for ref.


Im going to be frank here, and given that its COVID times please take what I say with a grain of salt because Im sure there's two sides to every story. Here's just what happened from my end and the sucker punch that is putting a whole rebuild on hold for parts only to find when they arrive they are the wrong ones.


So with Jap MC Dismantlers, the correspondence and service was crap from the get go, I started an open email chain specifying what I was looking for with solid detail/images/measurements and yet after 3 weeks of delayed back and forth including a few moments of being told I was "splitting hairs" for wanting to know if their springs matched up with the specs, they arrived.

Wrong width, wrong wire gauge, wrong winding count...

Anyway, Im here now disgruntled as I may be with the question on my brain. Should I use these replacement springs or just put the old ones back in? They are longer around 39.5mm+/- 0.5mm so thats nice, but with the wire gauge a little thinner they do feel a bit softer than the old ones (I can compress them to binding point by hand, whereas I cant with my OEM ones)

[jellywrestler]

Hi all,

So the parts just arrived 10 days after payment ... Shipped up from a place down South Island called Jap MC Dismantlers.

They arrived today, being the wrong springs in literally every dimension but one. See attached images for ref.


Im going to be frank here, and given that its COVID times please take what I say with a grain of salt because Im sure there's two sides to every story. Here's just what happened from my end and the sucker punch that is putting a whole rebuild on hold for parts only to find when they arrive they are the wrong ones.


So with Jap MC Dismantlers, the correspondence and service was crap from the get go, I started an open email chain specifying what I was looking for with solid detail/images/measurements and yet after 3 weeks of delayed back and forth including a few moments of being told I was "splitting hairs" for wanting to know if their springs matched up with the specs, they arrived.

Wrong width, wrong wire gauge, wrong winding count...

Anyway, Im here now disgruntled as I may be with the question on my brain. Should I use these replacement springs or just put the old ones back in? They are longer around 39.5mm+/- 0.5mm so thats nice, but with the wire gauge a little thinner they do feel a bit softer than the old ones (I can compress them the binding point by hand, whereas I cant with my OEM ones) whose to say yours are the right ones in the first place? from memory this is a back yard business, Is it someone who has seen trademe and in, knows how to use a tool kit supplied with a bike and little more maybe?

[jmpl]

whose to say yours are the right ones in the first place? from memory this is a back yard business, Is it someone who has seen trademe and in, knows how to use a tool kit supplied with a bike and little more maybe?

A fair point to make! :)

Thankfully, my bike has all the positive signs of not having been opened since factory with all the og paint markings matching its year and all the casting numbers matching up nicely etc.

[pete376403]

"Found all my inner valve springs at 36.4 - 36.6mm free spring length.
Should be 38.1 if new, with 37mm being the service limit."
Fair enough if you were blueprinting the motor for racing or similar, and if new parts were readily available, but so far thats a lot of agro and faffing about for 1.7mm of spring. Are you going to be bouncing it off the rev limiter all day?

[jmpl]

"Found all my inner valve springs at 36.4 - 36.6mm free spring length.
Should be 38.1 if new, with 37mm being the service limit."
Fair enough if you were blueprinting the motor for racing or similar, and if new parts were readily available, but so far thats a lot of agro and faffing about for 1.7mm of spring. Are you going to be bouncing it off the rev limiter all day?

Nah, but I do want to have the freedom to push the bike to it's stock limit when I feel like it :)
To my thorough way of thinking, it makes sense to go through the book and make sure all is in spec where it should be to have it in ideal running condition for years to come?

If I can improve something by switching it out with a less worn part to bring it closer to that spec, I will. Simple as that.

Like I mentioned, I dont have the experience to know when 1.7mm of lee-way is worth fighting for or not, so that's on me. I also dont have anyone with motorcycle wits nearby that I know who can help me make those judgement calls. Hence the reason I have to rely on my own research, asking the folks and blokes on these forums and among other online faffing when trying to source info/parts.

Given all that, what do ya reckon? Should I go with the replacement springs, or stick with the OEM ones?

[pete376403]

You tried these guys? https://yumbo-jp.com/en/parts/21/14761429005.html

[pete376403]

Nah, but I do want to have the freedom to push the bike to it's stock limit when I feel like it :)
To my thorough way of thinking, it makes sense to go through the book and make sure all is in spec where it should be to have it in ideal running condition for years to come?

If I can improve something by switching it out with a less worn part to bring it closer to that spec, I will. Simple as that.

Like I mentioned, I dont have the experience to know when 1.7mm of lee-way is worth fighting for or not, so that's on me. I also dont have anyone with motorcycle wits nearby that I know who can help me make those judgement calls. Hence the reason I have to rely on my own research, asking the folks and blokes on these forums and among other online faffing when trying to source info/parts.

Given all that, what do ya reckon? Should I go with the replacement springs, or stick with the OEM ones?

There is nice to do, and have to do. You could shim the inner spring with a washer of appropriate dimensions (you would probably have to make one) under the spring, but the the afore mentioned "coil bind at full lift" thing would have to be checked.

[husaberg]

What about Martin the restorer
https://www.trademe.co.nz/a/motors/motorbikes/parts-for-sale/wrecking-bikes/listing/3286778744

[jmpl]

You tried these guys? https://yumbo-jp.com/en/parts/21/14761429005.html

Not heard of them before, thanks for the recommend! Have sent them a request, will see what they get back to me with.

[jmpl]

What about Martin the restorer
https://www.trademe.co.nz/a/motors/motorbikes/parts-for-sale/wrecking-bikes/listing/3286778744

Oh gosh, I'd almost forgotten about Martyn. Will flick him a message also. Thanks!

[jmpl]

Hi all,

Checked with YUMBO.COM - No springs available, discontinued.

Checked in with Martyn @HondaRestorer on TradeMe, had a wee chat and decided on shimming the old springs. Easy enough to do if you're able to fabricate the right size of washer/shim yourself.

Still have the "replacement" XL250S springs to hand atm, but may sell them off for petty cash.

New cam chain went in at the same time, whole cam movement feels good and taught now.


All back together, ready for the first start! :) Im excited

Cheers, J

[husaberg]

Hi all,

Checked with YUMBO.COM - No springs available, discontinued.

Checked in with Martyn @HondaRestorer on TradeMe, had a wee chat and decided on shimming the old springs. Easy enough to do if you're able to fabricate the right size of washer/shim yourself.

Still have the "replacement" XL250S springs to hand atm, but may sell them off for petty cash.

New cam chain went in at the same time, whole cam movement feels good and taught now.


All back together, ready for the first start! :) Im excited

Cheers, J


i was chatting to a guy yesterday who had a S head if you still want some. He is a mechanic and he was surprised to find they were unavailable he said the same as others just dont worry and ride it. Or shim it.
All hondas have the shims as std to stop the springs diving into the head you just add more of the std ones.
Back in the day conmpanies sold the shims for high performance