New sprockets & WTF

[sharpie6]

So I had 13/48 sprockets on my bike for a while and got tired of the high rpm's and resulting gas mileage, so I switched to 15/45 expecting some serious top end difference. It appears however that it has actually slowed me down. Keep in mind that I have a speedohealer that was calibrated for both set-ups.

The 13/48 had me topped out at about 115mph

15/45 barely got past 100mph

Whats the deal? I'm wondering if it is my K&N. (I'm replace it with the OEM from CP)

BTW bike is an '02 600

[scottynoface]

Take the K&N out. With the lower gear ratio the bike has less effective torque to get it moving, the K&N makes it worse. I bet it does fine with simply installing the stock filter

Also remember though that the Kat600 will barely tickle 130mph stock, so dont expect much more.

[GregS]

How are you accelerating to your top speed? Are you just rolling into it in 6th or are you winding out in each gear? You should not have lost any top speed, but you may get a faster speed in 5th. Also make sure your vacuum controlled petcock isn't closing down on long hard pulls.

[sharpie6]

I don't think i winded the gears out now that i think about it. (muscle memory from the 13/48) I only go for those speeds on a particularly long stretch of road that i don't get out to very much. (happened to make a trip out there today) What do you mean by "closing down"? I've never had petcock issues before.

[Psycho1]

sounds to me like your main problem is just too much gear for the power you have. a 14/46 or 14/48 probably would have been just right.

[djstormxx]

shoot i get past 135 with my kat, haven't really seen if i could push it to 140-145ish though.

[SilentTJ]

another member came on here saying he couldn't get much past 100 on his kat with stock gearing. it was his air filter as well. go back to stock and you should be blowing past 100 with ease. i rarely top my bike out, but the couple times i have, i easily reached 130

[H-2 CHARLIE]

My 2002-600 kat with stock gearing i hit 118 mph at 7 1/2 rpms and still pulling

[etskatana]

mine is jetted and has a k&n and still my 06 has no prob going 135 mph.... all on stock gearing !!!

[GregS]

What do you mean by "closing down"? I've never had petcock issues before.

A vacuum petcock needs vacuum to open. Under WOT you can dip down to such low vacuum that there isn't enough to keep the petcock flowing. If you put the petcock on Prime when doing your speed runs it eliminates this issue.

[sharpie6]

cool, that's handy to know.

[wicked1z]

I hit 115 on the highway the other day just trying to open her up. I am still a new rider so I back down real quick but I still had a lot more gear to go. BTW mine is a 99 600 with stock gearing.

[ICEG]

130 with some mods
ivan jet kit
ignition advancer
freeflow d&d exhaust
and i have the same gear set as you

[talonguy450]

good info.

[kidblooper]

have you put the bike on a dyno ? logic would tell me that bigger gears = better top end speed, unless you have flat spots at higher rpms due to the air filter and jettting/mapping. just food for though