Problem with GSXR front brakes.
 

Hi all,

I have a serious problem. I have just completed a GSXR front end conversion on my SV k4n. I have got GSXR k6 forks, bottom yoke and spindle with GSXR 1000 k6 callipers and a GSXR 1000 k5 radial master cylinder. For the front wheel I have a SV1000 wheel and disks. Evrything bolt up ok. Put after fitting the wheel and callipers and blending them up I got a heavily binding front wheel. I stripped and cleaned the calipers and greased the pistons and rebuilt. The binding has improved but when I test rode the bike after 1 mile the pressure on the lever increased to the put where the front brake locked on and I coulden even move the lever. After allowing to cool for 10 mins I was able to ride the bike again but the rubbing is so bad it causes the disks to get so hot.

Has any body experienced this problem before? Or am I using incompatable parts? I am really stumped with this one and and help will be appreciated. Has anyone done the conversion with the same parts I have used?

Please help guys as I really need my bike sorted :(

Cheers

Re: Help! Problem with front brakes.
 

It sound like the calipers need a rebuild with new seals.
Is the brake lever a pattern or genuine one?

Re: Help! Problem with front brakes.
 

try testing another master cylnder to rule that out

Re: Help! Problem with front brakes.
 

I'm using a pattern brake lever. It's one of the short spazzo type that are on eBay. I have rebuilt and copper greased the calipers the seals where all ok, no dirt or grit. The only other master cylinder I have is the standard naked sv one non radial is it worth trying that?

I think I read something on sv rider about wheel compatabilty and am wondering if the 06+ forks only take the wheel and disks from the same years??


Did you get my message Dave?

Re: Help! Problem with front brakes.
 

Check the brake lever, some have been known to cause this problem I seem to recall

Re: Help! Problem with front brakes.
 

Yes few racers have had brakes lock on and spit them off.
Typically whats happens is what your suffering

Re: Help! Problem with front brakes.
 

So put the standard brake lever back on? Worth a shot.

Can anyone confirm or deny for definite my thoughts about the wheel?

Re: Help! Problem with front brakes.
 

I think the SV1000 wheel is compatable
Others will confirm this

Re: Help! Problem with front brakes.
 

assuming there is some play at the lever (it shouldnt be pressing against the master cylinder plunger when the lever is in its normal position). Check the caliper positions laterally, do the discs look to be roughly in the center of the caliper gap or miles out? If all looks well then I would agree with Andrew, the pistons may be binding and not returning properly in to their bores when you release the lever.

If so, then strip and service the calipers.

Re: Help! Problem with front brakes.
 

The disks don't look to be central, the outside pistons seem to be tighter against the disk than the inside. I have allready striped and serviced the callipers, and copper greased the pistons. The calliper seals where very clean so didn't replace just removed, cleaned and replaced

Re: Help! Problem with front brakes.
 

so you copper greased the calliper seals?

Re: Help! Problem with front brakes.
 

can you post up a pic?

Re: Help! Problem with front brakes.
 

Not a great idea to do that as the grease may attack the rubber of the seals. I doubt that this is the cause of your problems though although its possible that the seals have swollen.

Really should use a rubber friendly grease, red rubber grease is a favourite.

Re: Help! Problem with front brakes.
 

Yea I copper greased the pistons and seals, should I strip clean and re try with rubber grease? I will try and get a pic up tomorrow.

Any thoughts yet on my wheel concerns? To me it seems like the Disk mounting surfaces are too wide so the outside disk face rubs on the outside pads??

I'm clutching at straws though lol

Re: Help! Problem with front brakes.
 

You need new seals TBH
Copper grease ain't the best for rubber

Re: Help! Problem with front brakes.
 

depends on how long the copper grease has been on them. copper grease will swell the seals.

wait a minuet i think i see your problem...

k6 forks
k6 yokes
k6 callipers
SV 1000 wheel with SV1000 discs

SV1000 discs are 320mm and k6 gsxr are 310mm so discs will be rubbing on top of the gap on gsxr callipers.

Re: Help! Problem with front brakes.
 

Bollox wish I remembered red rubber grease yesterday, got to do the job again :(

Still this doesn't explain the par rubbing and lock up as it did that before I stripped the calipers?

Will definatly change the seals now though and use rubber grease

Re: Help! Problem with front brakes.
 

Bibio do I need k6 gsxr disks then?

Re: Help! Problem with front brakes.
 

yes or look for calliper spacers for radial callipers.

Re: Help! Problem with front brakes.
 

Ok how much do I need to space the calipers? Is it 5mm, does the 5mm spacer replace the little collar that is in the fork legs or do you put it in as well as that standard collar.

Or will k6 gsxr disks fit on my sv1000 wheel? That handy guide that was posted on sv rider about all the componants seems to have dissapered.

Re: Help! Problem with front brakes.
 

best thing to do, before filling the brake system is have all the components in place and check for smooth rotation of the wheel. Nothing should bind. If it does you should be able to see where.

Check that the calipers are roughly central to the disc they are surrounding. The pistons should find there own relative position when brake pressure is applied, it doesn't matter than one side extends out of the caliper more than the other (within reason). Also check that the pads are lined up so that they contact the disc in the correct place.

If all that checks out then you likely have a problem up at the handlebar, my guess though is that the pistons aren't returning into the calipers properly due to swollen seals or some other problem.

Re: Help! Problem with front brakes.
 

Ok guess i will have to take a trip to my suzuki dealer and get some seals and stripping down the calipers again today, and rebuilding with rubber grease this time lol.

I need some more information on the calliper spacers as well anybody got any ideas?

Re: Help! Problem with front brakes.
 

Just pop it all together and measure the gaps.

Re: Help! Problem with front brakes.
 

Which gaps? There are no gaps between the calipers and fork legs if that's where you mean

Re: Help! Problem with front brakes.
 

its a simple case of maths to work out the size you need.

320-310/2=5mm

Re: Help! Problem with front brakes.
 

Ok so a 5mm spacer between the calipers and the fork legs. Is that as well as the locating collar that is between them at the moment?

Re: Help! Problem with front brakes.
 

you have to replace the collar's with another that is 5mm bigger to give you the extra 5mm required to lift the callipers clear of the disc. this 5mm will end up what looks like a washer between the calliper and the calliper mounting on the fork lower bracket.

like these
http://customspacers.co.uk/products-...oulders-10mm1/

no they are not the ones you want but you could try phoning them to see if they will make a set for you.

Re: Help! Problem with front brakes.
 

where are these dimensions coming from?

Re: Help! Problem with front brakes.
 

he has 320mm sv1000 discs and gsxr k6 callipers that are designed for 310 discs so you have to raise the callipers to fit the 320 discs or go and buy 310 discs. the cheaper option is to spacer them out.

Re: Help! Problem with front brakes.
 

yep, was just out of interest wondering if all these dimensions were available for reference somewhere.

On the spacers though, I wouldnt have thought necessary assuming everything runs freely and the pads line up with the braking surface well enough. The link you provided shows spacers that would move the calipers laterally rather than reposition them further away from the front axle center line?

edit..... aha....I'm with you. The calipers are radially mounted rather than side on as with stock SV items right?

Re: Help! Problem with front brakes.
 

yup, penny dropped :-)

i personally use k4/5 600/750 forks as they have taller mountings with k6 callipers and 320 discs and it fits like a glove. the reason for this is that the 320 discs are readily available cheaply from blackshadow.

Re: Problem with GSXR front brakes.
 

Ok so I spent some time on the lathe and have turned up some spacers. The front wheel does seem to spin more freely than before now so hopefully problem solved.

Just about to test ride so I will let evryone know the result.

I was under the impression that the sv1000 discs where 310mm but mabye I was wrong lol

Re: Problem with GSXR front brakes.
 

SV1000 are 310mm.

Clean the copper slip out. Use red rubber grease.
You should be able to push pistons back by hand, if you can then seals are OK for now.


Personally I think master cyl is problem.

Test it, then crack nipple off and retest. If it is master cyl cause then that will free it off.

Re: Problem with GSXR front brakes.
 

Well the spacers seem to have worked so hopefully that's case closed. I made a spacer out of some stainless on the lathe.

Thanks for all you help guys will post some pics soon.

Re: Problem with GSXR front brakes.
 

double check the pads on the discs to make sure that they are landing on the disc face properly.

and yc is correct the sv discs are 310. my mistake. but i suspect that you have actually got a gsxr 1000 k1-2 front wheel or similar. is there any way you could actually measure the discs?

Re: Problem with GSXR front brakes.
 

Aye but are your pads overhanging the disc now? You don't want this.

Re: Problem with GSXR front brakes.
 

The pads look like they are on the disk face ok, I suppose the real test is to look at pad wear in a few hundred miles.

I got the wheel of davepreston who said it was a sv1k wheel, but arnt the k1-k2 gsxr wheels the same as the sv1k?

Re: Problem with GSXR front brakes.
 

I suppose this will tell me what the wheel actually is. I can mesure them on Monday

Re: Problem with GSXR front brakes.
 

The Wheels are from a K1/K2 GSXR1000 to my knowledge
But maybe wrong on this

Re: Problem with GSXR front brakes.
 

don't matter about the wheels as all the diamond spokes fit radial forks up to k8 (cant remember the exact cut off) with different spindles but if preston sent him a front wheel from a 1000 k1-2 with discs to match then the discs will be 320mm.