Bent forks

[matoc]

Alo

So I came off the CBR and now the forks are bent. I'm trying to separate the fork legs from the chrome tubes and have come into a bit of difficulty.

We (hmurphy and myself) have opened the top of the fork legs up and drained the oil and removed the springs. I now need to separate them and was wondering if it's just a matter of taking the dust cap and retaining clip off and pulling them apart with brute force, or if there's something I'm missing.

Also, does the Allen key bolt at the bottom of the chrome tube need to be removed to separate them? I'm assuming the bolt/screw is there to adjust the preload, so I'm doubting it is necessary.

Lastly, are there any cheap ways to straighten the legs? Taking them into a mechanic will cost at least $250 so I'm curious as to what my other options are.

Cheers!

[hmurphy]

Any help would be greatly appreciated! The whole bike has been painted black and all the other parts have been purchased and all that is needed now is the straightening of the forks. There are no creases, just a slight general curve of the forks.

I'm keen to just get the damn thing out of my garage. Nah, it's just that we have hit a bit of a dead end with the forks. Once they are straigtend, this could quite possibly be the muntest CBR250RR out there. Has new clutch plates, chain and sprockets, after market slip on, after market pegs, black custom paint job with red rims. I am really keen to see it on the road again! It has been off the road for a week or so. And that is a week to long I'd say.

Cheers

[TLDV8]

A

Also, does the Allen key bolt at the bottom of the chrome tube need to be removed to separate them? I'm assuming the bolt/screw is there to adjust the preload, so I'm doubting it is necessary.
http://www.kiwibiker.co.nz/forums/showthread.php?p=1959993&posted=1#post1959993
Lastly, are there any cheap ways to straighten the legs? Taking them into a mechanic will cost at least $250 so I'm curious as to what my other options are.

Cheers!

The lower capscrew on conventional forks screws into the damper rod which will stop the upper tube from being removed.
Same for USD cartridge forks (not sure about conventional cartridge forks) ,in that case you would remove the springs first but need a spring compressor.
Straightening depends,the tubes are quite thin these days so distort easier if bent making them harder to straighten compared to the thick wall items of yester year.

You need some kind of bored fixture to press on to.
Something like this but this was for removing USD tubes from the lower axle unit.
In my opinion unless you can get them within 0.01mm they are !@#$ed.



<img src=http://i30.photobucket.com/albums/c345/manurewa/FR3.jpg>

[riffer]

Hey dude, you're in Upper Hutt are you?

I can pop around and have a look/help you if you like.

It might not actually be the forks that are bent. You could have bent the triple clamp bottom.

See Damon at Cycleworks on Eastern Hutt Road and he may be able to straighten the triple. He did my FZR750R one when I binned that.

[puddytat]

Alo



Also, does the Allen key bolt at the bottom of the chrome tube need to be removed to separate them? I'm assuming the bolt/screw is there to adjust the preload, so I'm doubting it is necessary.



Yup, the allen bolt does need to be removed....can be a bit of a bastard too.
Put yer forks in a vice, with the caps & springs in place (helps to stop the bolt turning the whole dampning rod inside) & youll need an impact driver if poss. If you cant get hold of one then just try with an allen key. If that doesnt work the remove caps & spring & insert a piece of dowling or such & use this to stop the damping rod turning while you crank on the allen key....
Once you get the bolt removed youll need to remove the dust seal & then the circlip that holds the oil seal in place....caution with that screwdriver!!
When yourve got that clip out then dont use a screwdriver to remove oil seal !! Grab an end of the fork in either hand then pull swiftly to smack the seal out..(compress first then pull apart swiftly...will take a few attempts)
Hope this helps

[puddytat]

Just to clear it up " the" allen bolt is the bolt at the vey bottom of the fork which you can only access with the axle removed.....not to be confused with any preload scews etc.....I take it its the standard old school forks ?

[matoc]

Yup, the allen bolt does need to be removed....can be a bit of a bastard too.
Put yer forks in a vice, with the caps & springs in place (helps to stop the bolt turning the whole dampning rod inside) & youll need an impact driver if poss. If you cant get hold of one then just try with an allen key. If that doesnt work the remove caps & spring & insert a piece of dowling or such & use this to stop the damping rod turning while you crank on the allen key....
Once you get the bolt removed youll need to remove the dust seal & then the circlip that holds the oil seal in place....caution with that screwdriver!!
When yourve got that clip out then dont use a screwdriver to remove oil seal !! Grab an end of the fork in either hand then pull swiftly to smack the seal out..(compress first then pull apart swiftly...will take a few attempts)
Hope this helps


Just to clear it up " the" allen bolt is the bolt at the vey bottom of the fork which you can only access with the axle removed.....not to be confused with any preload scews etc.....I take it its the standard old school forks ?

Yup, that's the one! Damn, guess I do need to take it out. The problem is that we already tried and may have stripped them. Oops. Called up Mitre 10 today looking for an Allen key head for the impact screwdriver my friend already has, but no luck. Apparently they don't stock them. Any ideas of what I could do? By the way, it took a shit load of force to strip them.


Hey dude, you're in Upper Hutt are you?

I can pop around and have a look/help you if you like.

It might not actually be the forks that are bent. You could have bent the triple clamp bottom.

See Damon at Cycleworks on Eastern Hutt Road and he may be able to straighten the triple. He did my FZR750R one when I binned that.

It's definitely the forks, the triple clamp seems fine. I think we'll give it one last shot tomorrow/tonight before wasting your time, haha!

Thanks for the replies so far, I'll let you know how it goes!

[puddytat]

I just sacrificed a standard allen key by cutting the bent bit off & I cant remember what else I used to get it to fit the impact driver, might of been the right sized socket with a 1/4 or 1/2 inch drive somehow....
Bugger if yourve stripped the head Bro, thats going to make it tough. Is it the head of the nut or the thread?
If its the head well you could try smacking the next size up, into it ....
And are you sure it is the head stripped or slogged & not the dampning rod inside turning?
Ive resorted in the past to having to hang onto the allen key with vicegrips & slipping a piece of pipe over one side of the handgrips...or meebe you could carefully tack the key on with a bit of weld , if the bolts farked you got nothin' to lose...Or....take it to a mechanic & he may have the right key which he could put into his air gun for doin' up wheel nuts.....
Good luck with the bastard thing !!!

[riffer]

Yup, that's the one! Damn, guess I do need to take it out. The problem is that we already tried and may have stripped them. Oops. Called up Mitre 10 today looking for an Allen key head for the impact screwdriver my friend already has, but no luck. Apparently they don't stock them. Any ideas of what I could do? By the way, it took a shit load of force to strip them!


I'm not certain you've stripped the allen key socket. They're pretty tough. If you haven't try this. I'll let you in on a secret method Shaun Harris told me one day over the phone when I was completely stumped helping Col with his forks one day.

Put the forks back together. You should find the the Allen keys are a 6mm hex socket. Check this. Get your hex socket and cut it off so you've got a nice straight bit. Put this in the end of a decently powerful hand drill.

Then you need to put the fork on the ground upside down and put as much force on it as possible in a downwards fashion. And put the allen key end of the drill into the hole at the bottom of the fork where this bolt is.

Spin up the drill and it should work like a bloody tough impact driver.

If not, you've well and truly fucked it and that's another story. :niceone:

[hmurphy]

It is absolutely the head of the allen key nut that is stripped. The damn thing hasn't budged at all!! So what can we do from here? Does anyone reckon they have the tools for this kind of job? Or should we have a crack at drilling a hole into the nut and using an easy-out? Those things are lethal, and I don't have the experience to know if it would work or not. Either that or we could slowly drill at the nut until it just caves in.

Basically, what are the options from here in your opinion? This truely is crap! The bike is completely sorted, except for this!

Does anyone here know where we could get ahold of some second hand CBR250RR forks...?

Cheers guys

[riffer]

Okay, so the bolt ain't coming out.

So we can effectively sacrifice it then.

Get a slightly bigger hex key, cut the end off, and bang the fucker right into the end of the bolt hole.

Then use the drill method outlined beforehand.

It'll work.

Then buy a new bolt.

[matoc]

Okay, so the bolt ain't coming out.

So we can effectively sacrifice it then.

Get a slightly bigger hex key, cut the end off, and bang the fucker right into the end of the bolt hole.

Then use the drill method outlined beforehand.

It'll work.

Then buy a new bolt.

Yea, sounds good. And I think Mr Murphy may have an Allen key bit the right size that we can put into the impact screwdriver.

If that doesn't work we'll try using a punch and a flathead in the impact. And if it still isn't budging we'll probably drill it out, lol.

Cheers, I'll keep ya updated.

[riffer]

No worries.

And if you're completely at a loose end, give me a call.

I'll PM you my number.

[hmurphy]

Freakin' success!!!!! We put the fork back together entirely then smashed the 6mm (correct size) allen key into the bolt but smashed it in so that it made new grooves and smashed it in really deep so that it would have a good bite. Then used the impact screw driver with the socket extension and bashed the living CRAP out of it... and BAM! It worked! On both forks. You would not believe the amount of smashing it took to get the f*cker out! But, got them both out.

Another question. It appears that there are very very small creases where the forks were bent from. How bad is this? Could they still be straightend? We didn't notice them until now, and the creases are really small.

Anyway, cheers HEAPS guys for the help! And riffer, you are the man!

[matoc]

Yea thanks dudes. riffer, puddytat... you just made my day! Now hopefully the creases aren't a problem, that would really suck. Murph will take 'em into TSS or Motomart tomorrow and see what they have to say, so fingers crossed.

I'd still like to hear if anyone has spare CBR250RR forks lying around though, just in case!

[xwhatsit]

That damper bolt you don't want coming loose, so there's normally a bit of thread locking compound on it. The factory stuff is designed to be loosned with hand tools, but if somebody's had the forks apart themselves before they might've gone with a really heavy-duty Loctite compound. Hence the angst in undoing it.

I've heard a lot of people say that if the forks are creased then they're toast. Sounds like you need to give a wreckers a call.

[matoc]

I've heard a lot of people say that if the forks are creased then they're toast. Sounds like you need to give a wreckers a call.

Yup, they're creased. Looks like I'm going to need new ones after all. I've already sent an email to Naenae wreckers and I'm keeping an eye on Trademe. Damn this is annoying, it's the last piece of the puzzle before my bike is roadworthy again.

FAAAAAARRRRRRRRRRRRRKKKKKKKKKKKKKKKKKK!!!!!!!!!!!! !!!

[matoc]

Oh, one other thing. There are a pair of CBR250 forks on Trademe atm but I think they are for the older '86 or '87 model (MC14 or MC17). Do you reckon there is a chance the steel legs are the same size as the MC22's? They're going for $40 so I'm thinking I might just risk it and buy 'em.

[hmurphy]

I say buy em and if they don't fit, sell them off again on TM! Motomart in Lower Hutt seemed to think that they were very similar if not the same part.

[riffer]

Have a look on the online partsfiche:

http://www.partsfish.com/

They should tell you if the part numbers are the same.

[vagrant]

These guys, motorcycle-parts australia (http://www.motorcycle-parts.com.au/Std_Fork_Tubes.htm)
do aftermarket fork tubes, not cheap, but way cheaper than factory, if you can't find some second hand ones.
You could also try the eBay global hub (http://global.ebay.com/)

[vagrant]

And saying that, here's a set MC22 forks (http://global.ebay.com/HONDA_CBR_250_CBR250_MC22_FORK_STANCHIONSTUBES_/260376807534/item)
Brand new, $150 Aus, plus $70 Aus freight.