Rollers are like a rpm holder in the variator.

Now beyond 8400 rpm the pipe is starting to fall out of its powerband range where it and the engine produces its peak horsepower, to gain more speed the rpm has to raise higher by a factor of around 7-15%, think of this power curve like a hump on a graph the top of the hump is peak HP, but beyond that it starts to slope away and the hp starts to lower by 9000rpm the horsepower has dropped to 4.5hp because the motor is maxed out on its fixed gearing and cannot keep the powerband. so ideal area is getting that variator to hold the rpm at 7900rpm thats a very defined rpm and is going to be very hard to nail it perfect.Ī sports pipe like a q-tre will have a nice wide'ish rpm spread so if a newbie tuner was to say put slightly to heavy or light weights in it wouldnt matter to much as that wide rpm spread can cope.Ī highly tuned race pipe will have an even more narrow rpm band like 9000rpm to 9300rpm so you have a very narrow 300rpm band to fit into with this coupled with a say high end 70cc race cylinder setup your powerband could be 9hp but because of the very narrow powerband spread its going to be even more harder to tune the variator for this rpm range Lets say at 7.4k rpm your bikes producing 5hp at 7.9k its producing 5.9hp and at 8.4k is droped back to 5hp. Your pipe is made to produce peak horse power at a certain rpm range spread, so the TG Q-tre is about 7.400 rpm to around 8.400rpm. the bike will tell you whats up, order a few sets and have a play over explaining something fairly simple tbh. just be sure there even, so if using 3 pairs they sit OPPOSIT each other in pairs, if using 2 diff weights of 3 rollers each, they go heavy light heavy light heavy light as you install them. can do this with 3 pairs of diff rollers. so 3 6.5g rollers and 3 4.2g rollers i would add the two diff weights together then devide by how many diff weights. so add the weights devided by the number of diff weights. if you use more than one weight then you need to work out the avarage weight. go up on the rollers, alternate them with the original (so 3 and 3) and you will gain a little weight.

66 sounds about right on a 17.5mm carb on a piaggio engine, anything from 5g to 7g is usually about the ballpark for a pipe, its a case of buying a few sets and seing, ive not used these pipes so can only assume, again the majorioty of piaggio pipes made for 50 cylinders (so the word sport) run around 5.5g rollers, as they dont make any more power, just move it around a bit and most sport pipes hit power at around 7800 to 8400rpm. so get to the top of the gearing and then the revs rise and rise. A thinner belt will lower the gearing potential, you will feel it rev out tho.

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