Lowering British forks

[hudsoncustom]

I seem to recall reading in a bike mag (maybe the Horse) about how to lower a set of British forks. I think it involved making some spacers or something.... I can't find it for anything now.

Anybody know what I'm talking about, or am I just imagining things?

Ok, don't answer the second part there....

[Craven Moorhead]

You cut the main tubes down and re-thread them.

[scraper]

i just lowered mine without cutting the tubes. if i cut the tubes the wheel would've bottomed out on the lower tree. i added 2" spacers to the top out springs on the shuttle valves & cut the main springs down 1.5". it took me about an hour to do the whole deal.

[hudsoncustom]

Originally Posted by Craven Moorhead

You cut the main tubes down and re-thread them.

Can't get more than an inch out of a BSA fork. That's the rub.

[hudsoncustom]

Originally Posted by sojerscraper

i just lowered mine without cutting the tubes. if i cut the tubes the wheel would've bottomed out on the lower tree. i added 2" spacers to the top out springs on the shuttle valves & cut the main springs down 1.5". it took me about an hour to do the whole deal.

That's what I was talking about. Do you have any pics of the process? How much did it lower the front end?

Thanks!

[hudsoncustom]

Surely I wasn't dreaming, I know there was an article somewhere on it...

Anyone?

[aj650]

The Horse did some Narrow Glide forks in issue #49... My scanner is busted though. Did you ever try called Forking by Frank? It might not be that expensive to have them do the work.

[scraper]

Originally Posted by hudsoncustom

That's what I was talking about. Do you have any pics of the process? How much did it lower the front end?

Thanks!

when i took the springs out of my fork & let the bike drop as low as it could go, the tire was about 1/2" from the lower tree. it didnt make sense to me to cut the tubes down since that would then let the tire hit the tree when it was fully compressed, quickly leading to some heavy crashing. it may be different on other bikes, but my setup is a 70 TR6C frame with a 71 fork.

after a bit of brainstorming & looking around to see what i had i came up with this sketch:

the drawing on the left is the stock setup with 6.5 inches of travel (total) and the one on the right, with the 2 inch spacer, has 4.5 inches of travel. still plenty enough to be safe. you could probably go more or less depending on the stance or ride quality you were going after. it all depends on how long the spacer you put between the top out spring & the shuttle valve is.

here is the spacer i made, cut out of the old spacers that were originally in the fork with the chopper tubes. - making them longer when installed on top of the main spring.


since the fork was going to have less travel, i thought it would be wise to firm up the spring a bit by adding some preload. i did this by cutting the main spring a half inch less than i cut the spacers. this makes the spring sit up above the top tree a bit when its in the fork so you have to compress it some to get the caps on. aka - preloading the spring.

[scraper]

heres what the shuttle valve looks like with the spacer installed.


and here it is being installed into the fork tube.


so, overall it shortened the fork 2". take into account how much weight is going on the bike too because it will have the weight of the motor, gas, oil & your ass on it.

here is the bike with the modified fork and a 4" stretch/2.5" drop hardtail. overall i wanted a very flat stance but low as hell. the bottom of the frame is about 4" from the pavement so shes right where i wanted her.


the stock fork tubes were pretty cheap & the "lowering kit" was free. it took me about an hour, tops to lower the fork. its safe, looks good & its ready to roll.

good luck dude, give a holler if you need any help.

[hudsoncustom]

Thats exactly what I was looking for. I had called forking by frank before and was quoted $250 for a set of 1" lower tubes.

Thanks for putting this together sojerscraper!

Now, out to the garage...

[scraper]

Originally Posted by hudsoncustom

Thanks for putting this together sojerscraper!

no sweat man. let me know how she comes out.

[rukwikenuf]

Originally Posted by hudsoncustom

Thats exactly what I was looking for. I had called forking by frank before and was quoted $250 for a set of 1" lower tubes...

i called them as well, and they said it'd be like 35 bucks to shorten each tube. i asked them to cut em down 4"..........mines for an Ironhead narrowglide, but i don't see any major diff in cutting.....

[Nads]

Originally Posted by hudsoncustom

Thats exactly what I was looking for. I had called forking by frank before and was quoted $250 for a set of 1" lower tubes.

Thanks for putting this together sojerscraper!

Now, out to the garage...

How's your mangina holding? Someone told me it was leaking awful bad.

[FHK13]

is this pretty much universal, need to do it to my yammy. Also can any of you guys recomend a place to get spacers or is it possible to make fairly easy.

[scraper]

just get some pipe or tubing that fits without binding on anything. cut them to the length you want to lower your fork. cut the springs to match - you're done.

[greggski]

Boy sure is nice to see some Tech threads! Thanks Scraper!

Maybe we should have Tech week like they do on the Hamb? Just an idea.....


Gregg

[hudsoncustom]

Originally Posted by rukwikenuf

i called them as well, and they said it'd be like 35 bucks to shorten each tube. i asked them to cut em down 4"..........mines for an Ironhead narrowglide, but i don't see any major diff in cutting.....

Wow this is an old thread...

Well there is a big difference in BSA forks from a standard run of the mill Harley or Yamaha...those bikes have straight fork tubes, so it is a simple process to cut and thread...

Unit BSA's have a tapered fork tube that can only be cut an inch or so before you run out of enough metal to taper again...

Either way, I wound up goosenecking and raking my frame to get the bike lower...I used the stock fork length.

[Dan]

so...
I've got a 39mm narrow glide with +4 tubes on it, I also have the stock lenght tubes for it, can I just replace the +4 with the stock ones to lower it without having to cut springs?

[scraper]

yeah man, no sweat. the 4+ tubes on probably have 4" long spacers inside. just put the new tubes on & take out the spacers - then you'll be riding at stock height.

(fyi - my fork was the same way when i got it & i ended up cutting the spacers that extended my fork as spacers to lower it. just depends where you stick the spacer in the fork. you'll see once you get it apart)

[Dan]

cool, I have two bikes I need to lower and have never been inside a front end before (as well as lots of other parts of a motorcycle)...