Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: hunterso on July 16, 2014, 11:08:20 PM

Title: CB550K3 - Fork Springs - Which way up?
Post by: hunterso on July 16, 2014, 11:08:20 PM
Just changing the oil in my forks and noticed the springs were fitted with the tightly wound coils uppermost.

Is this correct?

I'm sure i read somewhere on here that the tightly wound coils of the spring should be inserted downwards into the fork leg

Can anyone confirm the correct way to install

Thanks
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: UK Pete on July 16, 2014, 11:10:40 PM
I am sure its downwards, i doubt if you would notice the difference though
pete
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: Green1 on July 16, 2014, 11:15:36 PM
I'm sure the tighter coils go at the bottom I put them the wrong way up in my pegaso and it would bounce violently on bumpy stretches

Mick 
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: hunterso on July 16, 2014, 11:19:03 PM
Thought so - tight coils downwards it is.

Thanks chaps
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: Lobo on July 17, 2014, 07:22:42 AM
Phew...
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: deltarider on July 17, 2014, 04:28:38 PM
I'm not sure. I recently got the advice (German site) tight coils should be up on my CB500. For the effect one would say it doesn't matter but you want to avoid unnecessary unsprung weight.
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: ka-ja on July 17, 2014, 05:09:39 PM
Hi,
     It well may be that Honda springs have the tight coils at the bottom, but I have just fitted Hagon progressive springs on my 400/4, and they advise tight coils to the top!---Ken
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: Lobo on July 17, 2014, 08:05:02 PM
Well, funny old thing, because when I first looked at the 500/550 manual it showed the springs tight coils UP. I then noticed the thread was CB550.... and went to the CB550 differences / addendums where the springs are tight coils pictured DOWN.

And most bloody helpfully, the blurb in both cases simply says, "Reassemble as they came out"

Anyways, here the pic of the CB500 springs, appearing, as I say, UP.

And my Cb400F parts manual shows a constantly wound coil - no ups / downs... but note that you're 'upgrading' Ken!

There must be a physical reason for all of this... I'm trying to think (eg) tight / dense / ineffective coils lower most to lessen sprung weight... or is there some mechanical restriction in the legs themselves which would inhibit compressions anyway, or maybe differing road conditions / export models would require inverting the springs (yea, grabbing @ straws)....there must be some logical reason...
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: deltarider on July 17, 2014, 08:11:07 PM
The 500 had various front legs. I remember decades ago a Honda mechanic and I looked at a view of the front legs and he commented: don't look at the picture, it is wrong. The stupid thing is I can't recall what picture it was, so I know nothing...
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: Lobo on July 17, 2014, 08:14:21 PM
.... maybe just play, er safe... and put one up & one down....
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: hunterso on July 18, 2014, 12:00:53 AM
Nothing's ever straight forward is it  :-\

The one thing i did notice is that with the tight coils downwards, the other end of the spring was a nicer fit into the slight indent in the fork caps.

Anyway its all back together now - will see how they feel when its back off the stand and on its wheels.
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: hunterso on July 20, 2014, 06:08:50 PM
Update:

Bike back on its wheels now aaannnd...... the forks are crap - really crap  :-\

Push down and they stay down - have to pull on the bars to get the bike back to normal

Used 10w castrol fork oil and put 185cc in both legs measured with a big syringe type thing.

Checked for oil leaks and all is well.

Going to put it back on the stand and turn the springs round again.

Does anyone know what the free length of k3 springs should be?
In the manual it just says to measure the free length but it doesn't explain what the measurement should be.


Buggeration!



Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: deltarider on July 20, 2014, 06:17:49 PM
Quote
Push down and they stay down - have to pull on the bars to get the bike back to normal
Did you tighten from the bottom to the top and by the manual? It is easy to do it wrong and as a consequence legs will bind.
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: Green1 on July 20, 2014, 06:23:11 PM
Buggeration indeed

I emailed hyperpro a few days ago and forgot to post they recommend putting the tighter coils to the top but also said it doesn't matter what way they go as the spring will work the same either way up.I was told tighter coils to the bottom you will get less spring noise but they recommend the other way up not to affect the oil level in the leg.

Mick
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: Trigger on July 20, 2014, 06:31:48 PM
K3 forks are 165- 170cc, and 10w synthetic is a little light for these old girls, try 15w. Tight to the bottom for the spring. Something wrong if the spring is not returning.
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: hunterso on July 24, 2014, 10:59:49 PM
Finally got some time on the bike again.

Managed to find a copy of the honda manual on ebay - find it hard scrolling the pdf sometimes - so this is a godsend

So bike is back on stand - wheel dropped out and springs out again.

The plot thickens - the manual states spring free length is 443.5mm (this is in the supplement for the k3)
Measured my springs and they are 473mm - now you would expect them to sit proud of the fork tubes being that much longer but they sit about 10mm below the tube tops - any thoughts?

Pumped the fork legs up and down and the right hand (non brake side feels a little sticky but not excessively so) im not sure if this is the damping action of the oil in the leg though.

Think i might dump the oil out again and see how it moves when empty.



Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: billy192 on July 25, 2014, 08:21:53 AM
my Little G5 had forks that were sticking. when i removed the mud guard, front wheel (with jack under engine) i slackened the triple clamps and as i turned the stanchions the end where the spindle was moving in a circular motion. meaning my forks were ever so slightly bent. it must have had a tap on the front end in its 30+ years.
i turned them til they both pointed forward the most tightend up and boom work great. i will replace when i can afford.
not saying yours are the same but worth a check
Billy
Title: Re: CB550K3 - Fork Springs - Which way up?
Post by: Bitsa (Ralph Wright - RIP) on July 25, 2014, 10:27:08 AM
Billy
Don't know where you live but in Maidstone Kent there is a company that straights out the whole front end forks trees etc assembled.Did my old gs550 came back like new and very reasonable cost.Cheaper than new tubes etc.You may want to think about it.
Cheers
Bitsa
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