Best suspension change I ever made

[Grasshopperus]

Hi guys,

I'd been struggling with the cornering on my zx12 for some time. Kept on 'weaving' as it went around a corner, very disconcerting. So I followed the way of the internet warrior; blindly assumed it was the suspension, read the service manual and browsed heaps of zx12 related websites to glean settings for damping etc. Tried these settings out last night, and it made the bike a little better. This morning, on a whim, I checked the tyre pressures (for the first time ever, I've owned it since April :facepalm: ) and the rear tyre had 0 PSI... I put some of that 'compressed air' stuff into the tyres and wow! It feels like a motorbike now! No idea how long I've been riding around on a flattie :sick:

Just thought you might appreciate a chuckle. I think I've got a slow leak, will take it to the mechanic today, and will be a good boy by checking my tyre pressure every week.

[BigAl]

0 psi..... amazing you are still alive

[Gremlin]

Must be some kind of miracle bike to have handling at 0 PSI.

With 15 odd PSI in the rear tyre (pressure had only been checked a couple of days prior) I did had no idea what lay in store for me as I tipped into a corner and all hell broke loose. I know from a mates experience you can't hold a straight line at 50 with a flat rear tyre (although he too thought there was something very wrong) :eek:

[jellywrestler]

Hi guys,

I'd been struggling with the cornering on my zx12 for some time. Kept on 'weaving' as it went around a corner, very disconcerting. So I followed the way of the internet warrior; blindly assumed it was the suspension, read the service manual and browsed heaps of zx12 related websites to glean settings for damping etc. Tried these settings out last night, and it made the bike a little better. This morning, on a whim, I checked the tyre pressures (for the first time ever, I've owned it since April :facepalm: ) and the rear tyre had 0 PSI... I put some of that 'compressed air' stuff into the tyres and wow! It feels like a motorbike now! No idea how long I've been riding around on a flattie :sick:

Just thought you might appreciate a chuckle. I think I've got a slow leak, will take it to the mechanic today, and will be a good boy by checking my tyre pressure every week.

and check ya guage cause at 0 psi the bike would've been so flat it would've fallen off it's side stand

[Crasherfromwayback]

and check ya guage cause at 0 psi the bike would've been so flat it would've fallen off it's side stand

And been fucking hard to push.

[sugilite]

And check your pressures before each ride for at least the next few, just in case the tyre has just recently acquired this leak.

[Gremlin]

and check ya guage cause at 0 psi the bike would've been so flat it would've fallen off it's side stand
Not always. Just had to deliver the CB900 to the shop for a puncture repair on Friday. It stayed on the side stand, but yes, was very close to upright. The PR2 I have fitted keeps some of the form, even when completely flat.

And yes, fucken hard to push :pinch:

[Phantom Limb]

Got a big fookoff nail in my rear tire on the way to work today. Carried on going not noticing it, until I realized that the bike was a fair bit harder to pull upright again out of corners, like it wanted to keep turning in. Otherwise it was tracking straight and not wobbling at all.

It's amazing how well modern tires deal with running flat, I could have made it to work if I was less alert!

[Trade_nancy]

I just replaced my rear tyre. I found cornering OK - but after two weeks of being unridden in the rain and wind - the bike had gotten closer to the ground at the back. Very hard to push it out of the shed. Oh oh. So up on the mainstand and had a close look - 2 obvious small punctures. Small slivers of hardened steel like broken off cotter pins.
Took the chance to test out the puncture repair plugs and foot pump I carry - worked OK and got the bike going. But pulled the wheel off and took it in for a pro repair. Decided against it when I found 3 more holes in it - only 1 was leaking - but very slowly...and saw the amount of squaring off I had inflicted on the BT23.
I remembered the last 2-3 times when doing pressures at the station - the rear would show about 14-15psi on the gauge. I'd check again next day and it was back to normal. Must have been a very slow leak(s) all along.

[Robert Taylor]

Also dont trust the gauge you are using implicitly. One of the Superbike riders a couple of years back was having no end of tyre problems and of course everything including the suspension setup was being blamed. Until he found that the tyre pressure gauge he was using was reading 7 pounds too low...........

[nzspokes]

Have you fitted Ohlinns air? :clap:

Whens it coming to Sass? Were on Tuesdays now.

[Robert Taylor]

Have you fitted Ohlinns air? :clap:

Whens it coming to Sass? Were on Tuesdays now.

Unlikely, theres an abundance of hot air in Glen Eden. What did you contribute to this thread other than trying to score cheap points?

[nzspokes]

Unlikely, theres an abundance of hot air in Glen Eden. What did you contribute to this thread other than trying to score cheap points?

The same amount as you champ.

[Robert Taylor]

The same amount as you champ.

Incorrect of course, like others who actually contributed something useful to this thread I offered some advice from my own experience.

Tyre pressures that read incorrectly are a very common problem. I purchased a very expensive and highly accurate one from a well known race car supplier in Auckland. I could of course have procured it more cheaply from overseas but chose to support local business and workers.

[PeeJay]

Incorrect of course, like others who actually contributed something useful to this thread I offered some advice from my own experience.

Tyre pressures that read incorrectly are a very common problem. I purchased a very expensive and highly accurate one from a well known race car supplier in Auckland. I could of course have procured it more cheaply from overseas but chose to support local business and workers.

Win-Win
You could have purchased it cheaply overseas
then sent the well known race car car supplier half your savings.
that way
you save on the pressure gauge,
they still make a profit to pay their kiwi worker
and you feel good because you got a cheap gauge and you have supported a local business.

win win all around I'd say.

I feel another business plan coming on

[Robert Taylor]

Win-Win
You could have purchased it cheaply overseas
then sent the well known race car car supplier half your savings.
that way
you save on the pressure gauge,
they still make a profit to pay their kiwi worker
and you feel good because you got a cheap gauge and you have supported a local business.

win win all around I'd say.

I feel another business plan coming on

Yes, you have opened your mouth and removed all doubt..............

[fridayflash]

ive found folly in different pressure guage readings before too, a mate has a high quality unit he has owned since 1980
and did him good service throughout a 25 year car racing campaign but recently i found it reads 5psi too low......
i have a quality 'pen' type one in my jacket and a decent dial at home, i check tyre pressures as a matter of habit
pretty much before any ride

[FlowRider]

ima tryin 2 get ma neez dwn and ima real close
iz their a suspension upgade for ma GT250 if their is dat be sweet az

[Drew]

I know the RF needs air in the back tyre, when it doesn't weave a bit doing wheelies, but does on the sweepy type corners.

Should I be using a different method of checking tyre pressures?

[Robert Taylor]

ima tryin 2 get ma neez dwn and ima real close
iz their a suspension upgade for ma GT250 if their is dat be sweet az

Personally Id be very happy to answer with what I know about how we can make that bike work better. BUT (and I can hear all of the indignation on its way ) I think sending questions in bastardised text language instead of using written English as it was intended to be just doesnt cut the mustard

[Robert Taylor]

ive found folly in different pressure guage readings before too, a mate has a high quality unit he has owned since 1980
and did him good service throughout a 25 year car racing campaign but recently i found it reads 5psi too low......
i have a quality 'pen' type one in my jacket and a decent dial at home, i check tyre pressures as a matter of habit
pretty much before any ride

Yes of course, as with any form of measuring equipment they should be tested themselves periodically and recalibrated or replaced.

''Throwing'' them in the toolbox and lending to all and sundry also doesnt help in their continued accuracy / longevity. Of course also ''cheap'' purchase is often synonomous with being made in mainland Asia and the attendant low standards / low ethics so often prevalent

People that are dealing with keeping the air in their ''air spring only'' motox forks are now largely abundantly aware that there are air pressure gauges........and then there are air pressure gauges

[buggerit]

Also dont trust the gauge you are using implicitly. One of the Superbike riders a couple of years back was having no end of tyre problems and of course everything including the suspension setup was being blamed. Until he found that the tyre pressure gauge he was using was reading 7 pounds too low...........

Is there a gauge you would recomend? At the moment I use 2, a pencil and a digital to try to eliminate dodgy readings.

[Drew]

At the race track, the gauge is used to set a base every morning, and then used to measure pressure changes (small amounts where the accuracy is likely to be out by nothing of note), on performance and tyre wear.


On the road, within 2 PSI is accurate enough to ride at the pace I do.

[Grasshopperus]

Hi guys, the mechanic withdrew a 5cm piece of wire from the tyre and patched it up with a rubber mushroom thing.

Thanks for the heads up about the pressure gauge, interesting how much tyre pressure can affect handling, that superbike rider who had been using a faulty gauge for all those years must've been extremely pissed off but thankful to find out he wasn't going crazy.

[Robert Taylor]

Is there a gauge you would recomend? At the moment I use 2, a pencil and a digital to try to eliminate dodgy readings.

Personally we use a very large diameter and ''industrial quality'' Longacre gauge. It has a protective rubber shroud and we ourselves are very protective of it and VERY careful with it. One thing that I have noticed with this gauge and other high end gauges is that there isnt a needle stopper at ''zero'' position. While I havent researched why per se or asked anybody I figure that its because the needle resting position will vary a little according to the atmospheric pressure of the day. So if you have a stopper the amount of resting preload against that needle will vary, not ideal. Perhaps someone else who knows a lot more about pressure gauges can explain why?
Our gauge to the best of my knowledge cost us in excess of $300 but its a neccessity given what we do at road race meetings and we get frustrated with people using gauges that have been thrown on the deck, used by all and sundry and with a blind assumption that they actually read accurately. Especially where rapid tyre distress is occurring and settings should be looking after them. An inaccuracy of as little as 1-2 psi can be the difference between success and failure in that sporting code.
If a gauge is say 5psi inaccurate at normal setting pressure also dont assume that the level of inaccuracy is the same at all pressures. Another thing to consider is that the air that you are adding to your tyre is as dry as possible. Compressors that havent had their water traps emptied constantly will have very humid air that you are pumping into the tyre. That means a higher rise in tyre pressure with use, again not ideal, especially with very sensitive race compound tyres with a very narrow operating window where they work best
In answer to your question about which tyre pressure gauge to reccommend thats really a tough call. Sometimes you get lucky with the cheap and nasty Chinese made ones but never assume that they will remain accurate indefinitely. While you cannot make a blanket assumption some of the better quality stick gauges can be surprisingly accurate and more tolerant of less than careful handling. Digital gauges still have an analogue element to sense the pressure so we cannot assume that they are all accurate as well. If the change in readout is overdamped and ''slow'' that can also lead to misreadings.
We went through this also with tyre temperature pyros. We only use core temperature reading where we stab a needle into the tyre to a certain preset depth. That is the proper and only way of reading tyre temperature, not by reading surface temperature with a laser type gauge. We purchased some medium price pyros and were frustrated because they read lower and had a very slow response time. This compared to our trusty Intercomp brand pyro ( at 3 times the price) that read instantly so that you could very quickly and accurately measure tyre CORE temperature at several points.

[nzspokes]

Hi guys, the mechanic withdrew a 5cm piece of wire from the tyre and patched it up with a rubber mushroom thing.



So see you next Tuesday then?

[SMOKEU]

Does anyone here use a push bike floor pump on motorbike tyres? I have a decent one, but since it's a high pressure pump (gauge goes up to 180psi), will it be accurate in the 32-38psi range?

[Robert Taylor]

Does anyone here use a push bike floor pump on motorbike tyres? I have a decent one, but since it's a high pressure pump (gauge goes up to 180psi), will it be accurate in the 32-38psi range?

Id be dubious at best and you could only verify by comparing with a known accurate gauge. Its a little like using a regular torque wrench and then asking it to accurately torque very small fasteners that have ( using imperial system ) torque settings in inch pounds rather than foot pounds

[BigAl]

Does anyone here use a push bike floor pump on motorbike tyres? I have a decent one, but since it's a high pressure pump (gauge goes up to 180psi), will it be accurate in the 32-38psi range?

Yeah I use a floor pump and have compared to several gauges and it is within a couple of psi, so good enough for me.

[Robert Taylor]

Yeah I use a floor pump and have compared to several gauges and it is within a couple of psi, so good enough for me.

But thats assuming all floor pumps are the same? If yours seems ok thats fine but that doesnt mean everything else is, to state the obvious.

[nzspokes]

Does anyone here use a push bike floor pump on motorbike tyres? I have a decent one, but since it's a high pressure pump (gauge goes up to 180psi), will it be accurate in the 32-38psi range?

As long as its an ok quality one and not a plastic cheapy it is most probably fine. I would cross check it against another pump to be sure. Just realize that it will be the pumps best guess.

Mines fine and ive checked it against a couple of digital units and all 3 match.