LC fork mods... what do people think of this setup?

[JonW]

I bought an LC project bike... more on that another time.. What i got came in bits and to me the forks looked, well, ‘interesting’....

So.... My question is.... not only what was the PO trying to achieve, but is this setup any good?

He fitted:

- Progressive springs, they look like new but I think are a few mm shorter than the normal LCs, say 492mm-ish?
(no pic, we all know what these look like)

- He had brazed one of the two holes in the damper rod, leaving the other side is open.
(you can see the braze on the B-side through the open hole in the pic etc)



- He fitted Goki aircaps... old skool mod from the usa from what i can tell to allow older bikes to run air in the forks.




Ok, I guess it should be said... None of this did his riding any good, the forks stantions were bent like bananas! lol


So, what do people think the net effect of his work would be? And would you run it? I ask as I don’t have to re-use any of this, I have OEM spares of all these parts... or I could reuse it all, what do you think?

[Deleted]

Hi Jon

I'm no fluid dynamics expert, that said, I'd say blocking one hole would increase the resistance for the fork oil to pass through into the damper tube and back out again

The net result of this could be more damping, although with more resistance you get more heat, which, depending on the oil used may reduce the damping characteristics of it

Shorter springs may quicken up the steering as the bike would sit lower at the front

My two cents worth

[jackjabba]

Increasing compression damping.

[bare]

As above increased compression damping. From days before centistoke ratings of oil were considered as a factor.. at least for back yard efforts.
The Air valve gizmos ? Well everybody knows what those do and more accurately; don't do.
This is all merely curiosity then. This stuff Of any scrap metal value

[JonW]

Thanks guys!

So increased compression damping with the brazed holes, intersting.

Next up the air caps offer a small amount of preload and then again compression damping, is that right?

The progressive springs offer changes to way the fork compresses too, taking up smaller bumps without using the main part of the spring.

Ok.... That's a lot of mods for extra compression damping, the PO must have really felt these were soft or been very fat!

I knew bare would pan all of these mods lol. Im still in two minds. The aircaps these days I could use to let air out of the system, ala dirt bikes, so i may reuse those as theyre a period mod, I may try progressive springs as ive never had them in a bike, the brazed dampers tho seem like a bridge too far. hmm...

[bare]

:-) happy to be consistent.
Agreed the air caps seem as interesting enough to keep/try.
Just that their benefits are largely subject to the world view of their Owners.
IMO there are Sooo many 'Laughable' mods floating about on the Internet'
Just cuz we love/Own obsolete/geriatric 2 strokes, I see small benefit in perpetuating the Stereotypical image.
(what the general populace sees us as.. Doubt it? prod gently at social gatherings for an interesting/candid viewpoint)) of us as Mouth Breathing Morons.

[JonW]

haha, I already knew your thoughts on the progressives, so it wasnt much of a leap
Yes I was thinking I have air assisted forks in the RZs so having them on the LC isnt an issue as I have the special low pressure pump and gauge etc ...and at worse they can be run with zero pressure of course. I guess these were made as a period mod designed to give the earlier bikes the natty new air assist that the later models had just come out with. All that said i'd be sad to bin them even if they are of dubious advantage as they arent exactly ruining anything and I could play with the air if i wanted. I remember air assist in both my '82 XL500R and '95 RD350R both made a difference to the sag if nothing else, tho it should be noted neither held said pressure for any length of time, tho i could use nitrogen I guess to help that seepage (and yes I do know thats of dubious advantange as well lol!).
As for how the general population sees us, well as a motorcyclist were all just spare parts donars arent we? As an 'astute' person once said, bikers are those whove either had a big crash or are about to have one.

So, upshot is these forks will forgo the lower dampers for now, Im not sure they are needed. Lets see what the progressives and the aircaps are like. I already have a set of standard LC forks that have new seals and are read to go and will do a swap after getting to know these and see what i think.

[Deleted]

all the air adjusters on my bikes did was pop the fork seals eventually, with less than the recommended pressure

[zedixe13]

At least they should be linked to equalize pressure as Honda did with some of their bike in the 80's like the CBX550 .

[Deleted]

Interesting you say that Ben

When I bought my RD350 there was a home made hose fitted to both fork valves with a single valve to introduce the air to both forks at the same time

Id looked real ugly, and I wasn't confident that the screw on fittings to the valves, I reckon they would have leaked like a sieve

I run no air in mine now and the seals stay put

[JonW]

Actually Goki did sell a link pipe with a fitting in the middle...

Howard, I never had any issue with the air rupturing the seals, even years down the track :/

[sbscnor]

I had a CB900FA in 1981 which had individual air forks I could never get the pressures equal in each fork I ended up making a link pipe with a pressure gauge fitted from memory I would run with 5lbs pressure.

[steve h]

Aug 15, 2017 20:12:21 GMT 1 sbscnor said:

I had a CB900FA in 1981 which had individual air forks I could never get the pressures equal in each fork I ended up making a link pipe with a pressure gauge fitted from memory I would run with 5lbs pressure.

I had the same bike from "new". The pressure was always a ball bag to get right , as just taking a reading would loose all pressure.......useless. Just left it in the end...made no difference.

[JonW]

Interesting that as yet no one with an LC2/F1/N1/R etc has chimed in to say they had a problem...

The air defo made a difference in the forks I used it on, its not perfect but it did work. Interestingly these days MX/Enduro bikes have ways to remove the air they gain from being hammered over terrain, times change I guess.

Anyway, thanks all for your thoughts.

[KevtheRev]

Aug 14, 2017 0:08:10 GMT 1 JonW said:

Thanks guys!



Ok.... That's a lot of mods for extra compression damping, the PO must have really felt these were soft or been very fat!

Any "Team Jacomo Racing " stickers ??  Lol .

[JonW]

not that ive found yet. just bent forks lol