Replacing the forks or not?

[brinkys]

The jury is out on this one at the moment, I have a CB550 that I want to turn into a Cafe Race, the dilemma that I am in it the moment is whether to change the front end on the bike or not. 

I have a set of CBR600 forks (rwu) and yokes, the question is do I fit these?  Any thoughts? 

Has anybody any experience fitting alternative forks and photo's?

Thanks

[K2-K6]

Most things are possible but it depends if you want it to work afterwards.

You see many specials with changed forks so not a difficult mod, just have to be a bit careful about the geometry that you construct to give the ride you want.

Going from a 19" rim and quite a bit more Kg's with lazy steering, trail etc will take some informed guestimating to arrive at 17" rim and modern trail, also you'll have the older head angle (rake) still mixed in to give you a good pot to stir!

Not trying to put you off, but you do need a reasonable plan to get there.

Don't know if it's possible, 600legs into original yolks could be the way to go as less variables will come into it (you'll have to measure it). Then lift or drop the front end on the legs to trim head angle approx.

Then you may need a test pilot+parachute

[rigwit]

if you dont i'l have forks and yolks  

[matthewmosse]

Would the cbr wheels suit the cb as a bike? Would possibly look odd unless you did a swap over of both wheels, which would be new swing arm time and chain alighnment issues in all likelyhood. Also cbr forks much fatter so you'd need the cbr yolks and swap headstock bearings around or more likely replace, plus shorten steering stem. I'd stick with period rubber and wheels personally, the engine only puts out 50bhp after all, a cb400n front end slots streight in yolks and all and comstars plus standard twin disks and more modern calipers does look good. My first 550 was on comstars and they do look smart on a 550. I do wonder with putting modern brakes on an old machine if the frame and handling might get 'interesting'
Just my thoughts, but don't be too put off, I'm a luddite as my dad keeps reminding me and I tend to shy from modern technology, it's why the 550's will stay, they have the benefit of kickstarts.

[rigwit]

 comstars iv'e found are hard to get, pluss the likleyhood of finding a pair of 400n forks is like the proverbial rh s ive searched and searched  and apart from a full bike  nothing of use has turned up  is why im thinking of running either newer honda wheels (which to me look bland) or going for another manafacturer's products and machining to suit, .............. but a bit away from any do or die decisions  so you never know  some might pop up 

[matthewmosse]

Comstars hard to find? I have 2 very nice sets off of 650's that I was thinking of using for a cart (did have one set on a 550 with twin disks). As for 400n / superdream (I think they were called that, the so called 'euro styling' bike') I have a set of them forks with calipers lying around somewhere, one of the forks was awol when I last looked but won't be far away as we dug them out to see if they'd fit my mates xs400 when he bent the forks, but we ended up streightening the forks he had instead. I really must clear the shed out, there's also a lovely set of 'Melbur' period alloys off a 500/4 that take standard disks etc too, but I think I'll prefer to use spoked wheels for that bike. Best bit about using the comstars is everything else can stay stock - forks, brakes, spindles, speedos etc

[brinkys]

Hi guys, I appreciate your comments, like you say proper planning and due consideration would need to be made if making this change.  I don't want to detrack from the bike original appearance too such (says the one who wants to turn it into a cafe race), I like the idea of twin disc's with original front forks and spoked wheels, maybe of black rims.

[K2-K6]

They do look good with twin discs of original type as they are quite big and suit the cafe racer style, I had a pair on CB750 and they are quite potent compared to a single and the power you've got.

If you want a neater look and are having new rims laced up then you could go to an 18" rim at the front also as this gives a different choice of tyres, and with a small drop of the fork yolks, say 25 mm will massage the steering into a slightly quicker response without changing much (this assumes you are using clip-ons as the fork legs will hit standard bars. Also need to check mudgaurd to exhaust clearance at full compression.

Shorter american spec rear mudgaurds look good too if you are keeping anything like that on it.

[brinkys]

That sounds like a good option, 18" wheel, I was thinking more of clip-ons rather than monza bars.  The short mudguards also look good, I need a front one at least as the bike hasn't got one at the moment and I was planning on replacing the rear.

[rigwit]

Comstars hard to find? I have 2 very nice sets off of 650's that I was thinking of using for a cart (did have one set on a 550 with twin disks). As for 400n / superdream (I think they were called that, the so called 'euro styling' bike') I have a set of them forks with calipers lying around somewhere, one of the forks was awol when I last looked but won't be far away as we dug them out to see if they'd fit my mates xs400 when he bent the forks, but we ended up streightening the forks he had instead. I really must clear the shed out, there's also a lovely set of 'Melbur' period alloys off a 500/4 that take standard disks etc too, but I think I'll prefer to use spoked wheels for that bike. Best bit about using the comstars is everything else can stay stock - forks, brakes, spindles, speedos etc

If you can dig out the 400n forks n comstars youl save me a massive engineering task to go -modern  that is is your willing to sell them  pm  me if might be off for a few days  so dont despare if i dont get back straight away

[Yoshi823]

Always loved the look of drilled twin discs on my 550F1...

[brinkys]

Hi folks, just a quick update, I have decieded to stay with the standard folks to maintain the look of the bike, I have although bought another disc and caliper to do the twin disc conversion.  For those of you who are interested whilst I have the bike totally stripped down I tried the top and bottom yokes from the CBR 600FX that I have kicking around the garage.  They fitted straight on, even with the original CB550 bearings fitted, although there is limited steering lock, which would require slight modification.  I was really temped to fit them, but that would mean having to change the rear end for a suitable rear wheel, I thought it would detrack the look and the lines of the bike, so I'm staying with the standard arrangement.