Tyre pressures

[Lucky Dave]

Hi ,

Can anyone give me best tyre pressures for my 900.
I've only just started riding it and it seems to want to drop into corners too eagerly, or is this normal for a Duke?

Tyres fitted are Pirelli 170/60/17 rear and 120/70/17 front

Thanks
Dave

[stef]

did you buy the monster street fighter who had a gsxr personality crisis of ebay ? was based in leeds ?

[Pedro]

It's more likely to be how the suspension is set up - the ride height at the rear and the forks.

If you fee it's tipping in too quickly (I have set mine to be quicker) then check a couple of things:-

1 How much have the forks been dropped in the yokes? For slower sterring set the forks so they're flush with the top of the top yoke.

2 Rear suspension can be adjusted - more rear ride height means quicker steering.

HTH

Ped

[JMo]

LD - don't be too alarmed if you find the tyre pressure figures are different front and rear... I'm sure the DVLA won't mind... x

xxx

[A Yerbury]

best to be eager I say. as ped says the ride could come down at the back but the front makes more sense and is easier. folks, what is the standard fork rise btw? I have 10mm on the clip ons plus another five I asked for when forks were seal fixed-mind you I'm wearing cheap d****p not bridge......

[A Yerbury]

ooops but to answer its 30 and 33 (I think 9s are the same but mr haynes is downstairs, 20 metres from this wine glass)

[gary tompkins]

Lucky Dave,

Older bikes with the 888 frame have about 25mm proud of the top yoke, my own M600 and later 900 dark were set this way. I've kept the same setting with the 916 legs I've fitted, because it leaves the right amount above the yoke to fix my redline clipons to. Others have experimented with dropping them further to quicken the steering, but there's a limit to how far you can go with standard handle bars fitted, as eventually the top of the legs will hit the underside of the bars.

Later bikes like with the S4/ST4 frame 800's & 620's seem to have a different yoke, (handlebar riser cast in) and the top of the legs sit flush with the top, suggesting that maybe the legs are shorter overall?

Monsters do have quick steering, so depending on what you've ridden before it might feel a bit nervous, and the wide Renthal style bars it has fitted may not help matters. Have a look at a few standard bikes at an UKMOC meet, you might find yours has just been set up badly?

It's deffo a bitsa as the front forks look like 916 or maybe 996 with the later model calipers, and certainly not standard issue on a K reg monster. The footrest hangers look like they have been borrowed from a 900ss too. Have you checked the frame/engine numbers match the V5 to ensure the bikes not bent?

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=9919&item=2493226049&rd=1

[Lucky Dave]

Thanks for the advice guys, it definately is a bitsa, :o it is the one off ebay :o and DVLA will be on the case on Monday. :mad:
By the way, any idea what model the frame is from No. FR11958D ???

[A Yerbury]

looks like a monster frame with a bit added to the top, the supersport frame was diff and has a different shock mounting?

[Lucky Dave]

Thanks Yerbs,
Trouble is I can't just go and look at the thing 'cos it's parked at work. Suppose best thing is to get out and start comparing it with proper M's

LD

[A Yerbury]

gary posted a link above which shows the frame, plenty of the other models online for comparison.

[Pedro]

I reckon it's an 851/888 with a 900ss motor and late forks - perhaps a blown up / pranged 888/851.

Footrest hangers (front & rear) are not Monster and it's registered before the Monster was launched.....

I understood the launch date was March 93 while this bike is registered in Jan 93.

Ped

[Zimbo]

32 front, 34 rear, in answer to your original question.

[coolcatshaft]

ok i got my 620 in july, never bothered to check the pressures, stupid i know!

but it had been running fine, and had just been in for its 600 mile service so i assumed that they would've given it the once over anyway.

so yesterday while i was filling up with petrol, thought might try one of sainsbury's new fangled digital air pressure pump thingy... front was down to 27 put it upto 30, and the rear was 'apparently down to 20!!!' so topped that up to 32.

now ever since yesterday the rear has been sliding all over the place, if i have a bit too much throttle in corners, or even on hard downshifts (even though i have a slipper clutch)

fair enough it is pretty frosty out there tonight but should it feel so twitchy? or is it more likely sainsbury's havent bothered calibrating their pumps recently?

i guess my real question is, just how easy should it be to tease a rear slide out of a 620 at say 20 mph in second at about 4-5000 revs? and is my tyre about to explode?

[bod]

Ive been sliding everywhere this week (mine has a slipper clutch too)Mainly when changing down,the back wheel locks up /slides.
Guess it's just lack of mechanical grip between tyre and tarmac,hence clutch not slipping.....LOTS of fun though :)

[gary tompkins]

...so yesterday while i was filling up with petrol, thought might try one of sainsbury's new fangled digital air pressure pump thingy... front was down to 27 put it upto 30, and the rear was 'apparently down to 20!!!' so topped that up to 32.

now ever since yesterday the rear has been sliding all over the place, if i have a bit too much throttle in corners, or even on hard downshifts (even though i have a slipper clutch)

fair enough it is pretty frosty out there tonight but should it feel so twitchy? or is it more likely sainsbury's havent bothered calibrating their pumps recently?

I know you would expect a new digital pump to be ok, but garage forecort pumps have a reputation for being a joke accuracy wise. I always carry my own gauge to check after filling up at garage pumps, and to monitor pressures at home when using a foot pump. You would be amazed how much some pumps are out, one at an ESSO garage near me (if it's working at all) reads 15psi low!!

If I trusted that I'd be running around at 45/48psi front and back instead of the 30/32psi I normally use :eek: Buy yourself a gauge - a good one will only cost £5-10 and then you'll know your tyres are at the right pressure.

[A Yerbury]

slipper clutchs on 620 s? surely not....

[coolcatshaft]

slipper clutchs on 620 s? surely not....

I've got one of them fancy 620 Capirex's with a slipper clutch, "higher ground clearance", lots of carbon bits and a lateral white stripe in the S4R mould... :D

[A Yerbury]

ah I see, sounds lovely if a tad superfluous.

[coolcatshaft]

superfluous hey? ( looks it up on dictionary.com...) :confused:

not necessarily, slipper clutches are being touted by a lot of companies as safety features now, and not solely the reserve of superbikes. also it helps make the clutch action a lot lighter which is a godsend around town.

the paint job is stunning though!

anyways, an update on the tyre pressure thingy. fished out my halfords pressure gauge from the car and shockingly, the sainsbury digital pump was spot on, and the pressures are exactly where they should be. so i guess it should be sliding after all.

i'm thinking since i didn't check my rear pressure for so long, i been riding around with a semi flat rear tyre (consequently with lots of traction) and taking liberties with the throttle. now that the pressure is where it should be a ham fisted approach is sending enough power to the rear to break traction when leant over... so just need to learn to be more progressive with the throttle again. and of course, check tyre pressures more regularly! :confused:

[bod]

Tis true, slipper clutches are on later model monsters,although again today the rear tyre still slides when droping down to many gears to fast(is my lack of mechanical grip thinking correct)?
Your thoughts......

[coolcatshaft]

i think you are right

from what i understand slipper clutches are designed to sort of automatically slip the clutch (as opposed to us letting it out slowly) thus helping to match the tyre speed to road speed more closely to minimise any skidding.

as the roads are very frosty at the mo even with the slipping clutch there is still enough discrepancy between tyre speed and road speed to skid the wheel.

even on a good road surface in good weather with a slipper clutch you can still skid the rear wheel if you are brutal enough as i found out when i first got my bike in july. i had just returned after a few weeks in india where i had been riding around something called a bajaj pulsar which has its gear shift the wrong way round, i.e. up for downshifts and down for upshifts. so on the monster on my first ride after getting back, i was going round a roundabout in second gear, coming off the exit, rev up to about 5500 then subconciously slam the gear lever down instead of up, end up in first and the rear is suddenly like a dog on wet lino, shat me up!

so i guess a slipper clutch isnt a catch all safety net in the mould of Antilock braking, but just a device to reduce the effect of harsh engine braking not eliminate it and as such i agree with you that it is most likely the frosty road surface causing the skidding.

you also right about it being fun though... keeps you on your toes dunnit?
:burnout:

[Spike]

Doesn't help with the salt on the roads the council had the gritters out over the weekend. Had an intresting moment leaving Julie and Ruths sunday night cold tyres and damp road and its sideways down the road Logyk had a good view. :eek:

[coolcatshaft]

good to know i'm not the only one then!

leicester city council are the culprit!