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Discussion Starter · #1 ·
i was told when i bought the bike thats its a ypvs, it even said this on the original panels but i dont think it is.. i just have a metal cap on the side of the engine and nothing else..so not ypvs or are they refered to as ypvs even though they dont have the pulley thing i keep hearing about

next thing is this.. i rode the bike a little futher today and found that it would easily achieve 75-80, but drop it into 6th and it loses speed..quickly.. there is no pull at all in 6th gear!

any ideas please?
 

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Have you taken off the cover?

They refer to YPVS (Yamaha Power Valve System) because it is fitted to all TZRs...

What differs on the bikes is whether they have got the servo and controller box to adjust its position.

Have a look under your fuel tank, is there a servo motor near the front of the bike? and under the side panel on the right hand side, just back from the battery, there is a metal bracket with a small box with cables on it. If there is a larger box with cables also next to it, this is the YPVS controller box, then it looks as though you have got the full YPVS kit.

If you havent got either the servo or controller box, then you will either have to get hold of them along with the cables and the pulley, or manually open the powervalve.....

Quite easy to manually open it!

It does mean that below 4000rpm you get no power at all, 4000-6000rpm you get a tolerable amount, and between 7000-10000rpm you will be amazed at the go these bikes can have!

just ask if you need any more help, or advice!

EDIT:
it would easily achieve 75-80, but drop it into 6th and it loses speed..quickly.. there is no pull at all in 6th gear!
This sounds as though your bike could be restricted, and basically when you click it into 6th, the engine cant accelerate any more so if losing power....if you clicked it back into 5th, did it go easily back to 75mph again?
 

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no offence mate, but what build are you?i have the same problem, beig a 6 ft 3 wind block,and an 18 stone lead weight.6th gear i have to tuck in, put my feet on the back pegs, and tuck my left arm under me arse, to try and streamline myself
 

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haha......

never thought about what build you are!

I must admit..... I dont get 80mph....75mph is pushing it!

being 6 foot 2 tall, and across the shoulder (thats how it feels!), I am not the most streamlined either!

But....there is another way of looking at your size TZRFreak.....you might not be as fast....but you create extra traction on the back wheel!!!

And it helps at times!
 

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all tzr's are 6 speed box.if you dont have a fairing that will, kind of explain the problem
 

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i have just thought of another little thing that will affect it slightly .. tyre size.

now the standard front is 90/90 (is that right) and i have a 110/80,

i once did a formula for a renault 19 forum to prove that a car was actually going faster than the speedo read when you fitted 18 inch tyres ,
this equated to the fact that the speed was measured from the gear box and so it would make a car tyre turn a certain ammount of revolutions giving a set speed for the ammount of turns,regardless of tyre size. so if you had a 13 inch tyre on it would still read the same speed as an 18 as the speedo is measured from the gearbox. (yes i also adjusted for tyre wall death)
using circle measurements i worked out that the difference between the standard 15 inch tyre and the 18 inch low profile was quite significant and it worked out that at 100mph on standard rims you were actually doing about 110 on the non standard..

ok so putting this onto the bike , this is slightly different as the speed is measured from tyre rotations, so you can forget all about engine speed, revs, gearing etc.. if your front tyre is oversize your speed will read slower because its taking longer to rotate..

ok i just spent the last 20 minutes working out that my tyre is oly 2.9% longer on the circumfrence.. big deal. so when my clocks read 100 i am really doing 102.9.. , theres probably more error than that anyway!!

at 60 mph i am really doing 61.74..... i think i will give up now as its not worth trying this one anymore..there obviously isnt as much difference between tyres on bikes, i suppose this is because your only changing the side wall height by a tiny ammount and not the entire rim and side wall..i will put down what i did roughly below .

17 inch =43.18cm wheel diameter
profile =% of width so a 90/90 is 90% of 90 width = 81 or 8.1cm
mine is 110/80 so 80 % of 110 which is 88 or 8.8cm

mutiply the tyre profile by 2 (two sides) and add the rim diameter
8.8 x 2 + 43.18 = 60.78 (110/80)
8.1 x 2 + 43.18 = 59.38 (90/90)

multiply these figures by pi.. 3.1415926536

pi x 60.78 = 190.95cm (120/80 tyre circumerence)
pi x 59.38 = 185.55cm (90/90 tyre circumfernce)

so to work out the % difference we take the following

190.95-185.55 = 5.4

5.4/185.55 x 100 = 2.9% difference

however i can take joy in the fact that the tyre will should last longer....

190.95/100 = 1.9095 (converted to metres)
185.55/100 = 1.8555

1 mile = 1 609.344 meters

so over 1 mile the tyres rotate the following ammount of times

1609.344/1.9095 = 842.81 (120 tyre)
1609.344/1.8555 = 862.34 (90 tyre)

lets say a normal wearing tyre gives 5000 miles then that would be 4311700 rotations on a standard 90 tyre(bloody hell!!!)
5000 x 862.34 = 4311700

so if the 120 tyre does the same ammount of rotations we can work it out as follows

4311700/842.81= 5115.86 miles... so screw you guys i get another 115 miles out of the tyre.. lol.. thats not actually true
i will appear to get an extra 115 miles due to that 2.9% difference.. if a tyre last 5000 miles it lasts 5000 miles so all the above is bullsh*t..

anyway im off out now to do things that are constructive... LATERS
 

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3pc2 has a larger front wheel than the 3pc1/2rk
 

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the 2rk and 3pc1 has got the 16 inch front wheel
the 3pc2 and 3pc3 have got the 17 inch front wheel

the other big difference is that the 2rk and 3pc1 have got 6 spoke wheels, where as the 3pc2 and 3pc3 have got 3 spoke as standard.
 

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if you only get 75-80 then its restricted, just take the valve cover off and rotate the power valve and it'll easily do 95, maybe a ton down hill with the wind behind you!
Easily do 95... yeah, as long as you're riding solo and took a good sh*t before you got on at the top of the hill!
 

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not only am i tall and broad,im a fat b*st*rd too, so my poor tizzy, has no chance of touching 90 without a fooking long road,and a back wind,until i get the control box for the ypvs
 

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YPVS control box won't make a difference to the max speed, just drop down a gear, slap some more revs on and open the pv completely before you ride it.
 

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im over 6ft an 17 1/2 stone and i still pulled 95 out my 4dl with revs left

agree with DJunreal just drop it down a gear and max the rev's before changing up...

Jas
 
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