Vintage Dirt Bike Q & A :: View topic - '79 CR250 fork springs

I have yet another question from my '79 resto. I dismantled the front forks and it is obvious they were recently
rebuilt (good seals, clean fluid, no stuck bolts), I measured the springs and checked that number against the
specs in all of my reference books (Honda, Clymer, etc). The problem(s) is, my forks only had one spring
while the factory installed two (spring A and B). That isn't a problem if the new spring is a one piece
replacement but the overall length is 21" which is roughly the length of the original spring B. Also, the
reference sources call for a 17"+ spring A and a 20"+ spring B for a total of more than three feet of spring
in each fork! That has to be a typo, but what are the real numbers? Looking at the diagrams it looks like
spring A might be 1.7" and spring B 20" but that's just a guess. Anybody know the real numbers? And, does
anybody running a one piece replacement spring know the free length?

Thanks in advance for any help/input.

dogger

Author:	dogger315 [ Fri Sep 05, 2008 9:43 am ]
Post subject:	'79 CR250 fork springs
I have yet another question from my '79 resto. I dismantled the front forks and it is obvious they were recently rebuilt (good seals, clean fluid, no stuck bolts), I measured the springs and checked that number against the specs in all of my reference books (Honda, Clymer, etc). The problem(s) is, my forks only had one spring while the factory installed two (spring A and B). That isn't a problem if the new spring is a one piece replacement but the overall length is 21" which is roughly the length of the original spring B. Also, the reference sources call for a 17"+ spring A and a 20"+ spring B for a total of more than three feet of spring in each fork! That has to be a typo, but what are the real numbers? Looking at the diagrams it looks like spring A might be 1.7" and spring B 20" but that's just a guess. Anybody know the real numbers? And, does anybody running a one piece replacement spring know the free length? Thanks in advance for any help/input. dogger

Author:	b-joe [ Fri Sep 05, 2008 12:02 pm ]
Post subject:	Re: '79 CR250 fork springs
dogger315 wrote: I have yet another question from my '79 resto. I dismantled the front forks and it is obvious they were recently rebuilt (good seals, clean fluid, no stuck bolts), I measured the springs and checked that number against the specs in all of my reference books (Honda, Clymer, etc). The problem(s) is, my forks only had one spring while the factory installed two (spring A and B). That isn't a problem if the new spring is a one piece replacement but the overall length is 21" which is roughly the length of the original spring B. Also, the reference sources call for a 17"+ spring A and a 20"+ spring B for a total of more than three feet of spring in each fork! That has to be a typo, but what are the real numbers? Looking at the diagrams it looks like spring A might be 1.7" and spring B 20" but that's just a guess. Anybody know the real numbers? And, does anybody running a one piece replacement spring know the free length? Thanks in advance for any help/input. dogger at my 79 owners manual it is spring a: 41mm/1.6in. spring b: 517,5mm/20.37in. but this is the wear limit.

Author:	dogger315 [ Fri Sep 05, 2008 2:35 pm ]
Post subject:	Re: '79 CR250 fork springs
Thanks again b-joe. Your wear limits match mine once the decimal is moved to the correct location. My Honda manual service limit states: Spring A 410 (16.142) Spring B 517.5 (20.3140) move the decimal on the Spring A number and you get 41.0 (1.6142). Transferring that correction to the standard length: Spring A 45.3 (1.7835) Spring B 529.5 (20.8465). Add the upper spring seat and the total stock spring length is 577 (22.7165). So the spring I have now is either 1.8" too short as a replacement one piece, or right on the money for Spring B. dogger

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