preload adjusters not working

Forum rules
Please can you post items for sale or wanted in the correct For Sale section. Items / bikes for sale here will be removed without warning. Reasons for this are in the FAQ. Thanks
Post Reply
KiwiBiker
Settled in member
Reactions:
Posts: 61
Joined: Fri Aug 07, 2015 12:09 pm
Bike owned: '94 GSXR400, '14 CBR300
Location: Southland, New Zealand
preload adjusters not working

Post by KiwiBiker » Sun Sep 25, 2016 10:13 am

A buddy was giving me a hand today to set up the rider sag on my front forks. As it was 44mm we thought we'd screw down the preload adjusters a bit to raise the ride height. But it made no difference to the measurements at all, even when we screwed them all the way down/in.
Anyone else had this dilemma??
I did have the forks apart a while back fitting racetech front springs so I'm thinking maybe it's something ive done wrong on re-assembly or such like. The racetech springs are 9mm shorter than the OEM ones but they provide you with washers to pack out the difference, which I did.
Hmmm...

moforockband
Familiar Member
Reactions:
Posts: 388
Joined: Wed Jun 03, 2015 9:41 am
Bike owned: GK73a SP CRM250 mk3
Re: preload adjusters not working

Post by moforockband » Tue Oct 04, 2016 9:42 am

How much does the rider weigh.
Have you solved it anyway?

KiwiBiker
Settled in member
Reactions:
Posts: 61
Joined: Fri Aug 07, 2015 12:09 pm
Bike owned: '94 GSXR400, '14 CBR300
Location: Southland, New Zealand
Re: preload adjusters not working

Post by KiwiBiker » Wed Oct 05, 2016 9:21 am

I weigh 70kg with my race suit kit on. (Before anyone suggests it - yes, Ive tried the pie diet! :grin: )

I rode the bike as is on the wkd at a race meet as i ran out of time to disassemble the forks and have a look at preload adjuster issue..
Unfortunately it would appear at this stage that despite spending $700 on fork springs and a GSXR600 rear shock that I got rebuilt, I have only improved/masked the handling issue but not got to the root of it.
Basically when the bike is pushed hard on exit out of a corner it moves around like the rear end is loose. Kind of feels akin to that old saying 'like the frame is hinged in the middle'. Also gets very unsettled flicking from one side to the other.
Coming hard into the slowest 90 degree corner on the track and then releasing the front brake and throwing it over it gets very unsettled at this point too.Not particuarly confidence inspiring.
Any suggestions on where to start with compression and rebound damping adjustments and at which end would be appreciated. I have about 30mm of rider sag at the rear which I'm happy with but would like to get front down to 35mm in the least, hence the need to sort out preload adjuster problem. Im running 5W fork oil in front. Wondering too if this a bit light?

moforockband
Familiar Member
Reactions:
Posts: 388
Joined: Wed Jun 03, 2015 9:41 am
Bike owned: GK73a SP CRM250 mk3
Re: preload adjusters not working

Post by moforockband » Wed Oct 05, 2016 10:04 pm

It may be the tyres??

When I raced this bike 20 years ago, I used to ride it like a nutter on std suspension. I did weigh 5kg more than you at the time. I thought it handled beautifully when racing it against early 90's bikes. I used a kr364 front (used to be good, they are now total hard compound shite), and a 207gp rear. I used to nearly win races with 64rwhp, and I'm not that talented. The gsxr had a beautiful turn in, which really inspired confidence I thought.

But b4 I waffle on for ever, yours is probably a 76 right?? Mine was a 73asp!! I would have thought the 76 should handle better with stiffer forks etc.....

Maybe stick some supercorsa's on 27 psi hot rear, and 30 front, and see how you get on. Supercorsa's mask all sorts off issues, as they have a really soft sidewall, and you can still grind engine cases off :))) Running the rear low on psi will get you a tiny bit more grip, but lose the speed /feel on turn-in.

Nick.

KiwiBiker
Settled in member
Reactions:
Posts: 61
Joined: Fri Aug 07, 2015 12:09 pm
Bike owned: '94 GSXR400, '14 CBR300
Location: Southland, New Zealand
Re: preload adjusters not working

Post by KiwiBiker » Thu Oct 06, 2016 10:36 am

Thanks for your thoughts and racing story Nick, sounds like you had a ball racing your 73a back in the day, as am I. :grin:

Yes, I have been wondering about my tyres more and more. Its a good starting point to have fresh rubber. I have two more races this year then the season is finished and I will fit new rubber.

My bike is a standard 76a and I'm running Dunlop Sportmax D211's but they are quite old I have just discovered from reading the 4 digit code. The front is 3 years old and the rear is 5!

A racer buddy of mine thinks the rear end may be losing grip hence the 'moving around'.

moforockband
Familiar Member
Reactions:
Posts: 388
Joined: Wed Jun 03, 2015 9:41 am
Bike owned: GK73a SP CRM250 mk3
Re: preload adjusters not working

Post by moforockband » Fri Oct 07, 2016 10:50 am

Yeah ditch those, you need fresh rubber if you're racing. It still must feel real grippy and pliable otherwise you're on the back foot straight away. Old hard rubber is ok on a real hot, sunny day, but when you 'need' the tyres, ie when it's cool, damp or greasy they won't be there for you, and you'll crash.
Remenber those dunlops you have run silly low pressures on the rear.
Ditch the dunlops and fit supercorsa's, you won't look back (well only to see 2nd place, haha)


Post Reply