Cracked Fork

[Natebat5]

So I've been restoring a 1975 rd350B and just the other day I had my wheels off (get new tires) and I knew my forks needed service, the left fork caught my attention right away as it was sagging? Down a couple inches before there was any resistance so I already had purchased new seals and fork oil so I disassembled the fork and got the old seal out which was a huge pain! I thought I was gonna be good to go at this point but right as I finished installing the new seal pop 2 little cracks in the aluminum fork lower, right where the dust cover would go, now these cracks are pretty small and from as well as I can tell do not go beneath the oil seal but will it be safe? I put some jb weld to try and cover the cracks because I didn't have any better options. Now before everyone tells me to go buy new forks simply put I can't afford it I'm in high school and I am barely gonna be able to afford insurance for the bike! Ok so will the fork be ok if not is there anyway I can fix it? Also I do have another set of forks I'm not sure what there from i think a rd400 maybe but here's the weird part the the side I would attach the brake caliper is flipped so I'd have to spin them backwards? Idk if that's a good idea basically if you have an idea that costs more than $100 bucks it's useless to me. Thanks

Edited January 20, 2017 by Natebat5

[ThePhatomfart]

Hi Nat , are they above the oil seal circlip and only where the dust cover sits

[Natebat5]

They start at the very top rim and go down towards the the oil seal they stop right beside the oil seal so I think my biggest concern would be if they will seal properly or whether they will leak fork oil... I don't think I have any structural problems but I'm far from an expert. I'll try to post a picture later

[Natebat5]

So yes they go past the circlip but not past the oil seal

[ThePhatomfart]

Hi Nat , the only problem there being that if the circlip comes out so could the oil seal, you could try the weld gum and as a back-up put a large jubilee clip around the top of the fork tube to hold it in stasis, its not a perfect cure but it might help. Have you got a manual for it

[Natebat5]

Yes I have a service manual but it sucks barely any info on the forks

[Natebat5]

I think I'll reassemble the fork today and keep and eye on it make sure the cracks don't get worse or start leaking oil.

[ThePhatomfart]

Hi Nat , people used to put "gaiters" on the forks to protect the chrome, so a gaiter on each fork and the Jubilee clip would look alright, and keep dirt from getting in,like these

http://www.ebay.co.uk/itm/Black-Motorcycle-Fork-Rubber-Gaiters-boots-Gaitors-Size-280mm-x-50mm-Set-Pair-UK-/222317807464?hash=item33c32c8768:g:5ZAAAOSwXeJYLbFV

here's the manual

https://www.dropbox.com/s/klimvb48wvmm4u0/yamrd250350man.pdf?dl=0

[mas101]

pics?

I'd be very cautious of a crack in the fork - cracks spread and the fork is under pressure so....

[DJP]

pics?

I'd be very cautious of a crack in the fork - cracks spread and the fork is under pressure so....

 

Me too.

What you have here is a 43 year old structural component with a (possible) stress crack in it.

You can always buy another fork (when you have the cash) but you can't buy another you.

[Guest]

Personally I would not ride with a cracked fork leg. As stated the crack will likely propagate, even if you JB weld it or stick a jubilee clip on it. The fork tubes are worked hard and any failure will have pretty catastrophic results.

The BMW F650's had an issue with fork legs snapping on some models, which while a bit different to your problem does show the results. If's it's already cracked I'd be worried about something like this happening:

http://advrider.com/index.php?threads/crash-in-destruction-bay-yt.371650/

Maybe not that likely but a definite possibility. I wouldn't be able to have any confidence in the bike and it would thus ruin my enjoyment. You say you can't afford an expensive fix...I'd suggest saving up for a bit longer before you ride the bike in that case. I don't mean to come across as harsh or callous but If it's really that tough then can you really afford to run a bike right now? It's your call of course.

[Tango]

Sounds to me more like the steel in the old seals/dust seal reacted with the alloy in the fork sliders, causing the cracks. I wonder if you could get them alloy welded? Although not ideal, I don't think it's indicative of the imminent failure of the fork legs.....

[Natebat5]

First Of all the forks won't fail like in that picture because the cracks are at the top not by the axle second they are not on any part of the fork lower that gets the major stress infact the only thing that touches the damaged area is the fork seal and dust boot. And even if the area the cracks are in exploded the fork would still be connected to the axel. Now don't take this as ingratitude I'm very thankful for all the answers but like I said in my original post I can't afford new forks for now although judging by everyone's responses looks like when I get enough money for dg expansion chambers I should get new forks instead.

[Natebat5]

Sounds to me more like the steel in the old seals/dust seal reacted with the alloy in the fork sliders, causing the cracks. I wonder if you could get them alloy welded? Although not ideal, I don't think it's indicative of the imminent failure of the fork legs.....

How or where would I go to get something like that done and how much would that cost

[Stu]

A local fab shop may be able to help

Although it really depends how the forks was made as to whether they can weld them ore not!

cast alloy can be a nightmare although a decent place should be able to sort the job out

[JRH]

Sounds to me more like the steel in the old seals/dust seal reacted with the alloy in the fork sliders, causing the cracks. I wonder if you could get them alloy welded? Although not ideal, I don't think it's indicative of the imminent failure of the fork legs.....

How or where would I go to get something like that done and how much would that cost

 

Look here http://www.yellowpages.com/bakersfield-ca/aluminum-welding-repair

May be Try here http://www.yellowpages.com/bakersfield-ca/mip/aluminum-chuck-wagon-453498876?lid=453498876

Hope you can get it sorted

[Natebat5]

Just to follow up on what has happened the fork began to leak oil like I feared it would, so I put the other fork on (had to spin it around 180) but I've ridden the bike and no issues so looks like Ive beaten one isssue.