If Gearing low gives better low end, will gearing up better my top end cruisability??

[SuzukiSteve]

Hey guys.. I know the thing to do on any bike seems to be to add a few teeth in the rear sprocket and reduce one in the front to give you a little more beef off the line. Personally iv only had my 06 kat600 for not even a week, but the last 600-700 miles iv put on it reeeally makes me wish I had just a little more on top. After seeing the chart You guys go by on here where the stock gearing should be 35mph in 3rd and 45 at 4th and 55 in 5th at 4,500rpm.. I suspect my bike had that 2 up in the rear mod and 1 down in the rear cuz im going slower at those speeds. My first hint was on the trip bringing it home. The car that was with me on this trip was averaging a speedo speed of something between 5-10mph less than what my kat was reading.. and if I wasn't really going as fast as I thought I guess maybe my front sprocket was???

If I wanted to cruise at 55mph I could have bought a Vespa, but I feel that running at 6k-7k rpm's is just trashing my gas millage!!.. If going down 1 or 2 in the rear from stock (plus 3 or 4 from what i guess it has currently) and up 1 or 2 in the front (stock or plus 1 from current) would that lower my RPM's at higher speeds thus improving my mpg?? Would the change just take away a bunch of low-mid range power and add hardly any advantage up top?? I had a similar experience loosing low and gaining nothing noticeable when gearing up on an off road bike, but the change was many teeth more.. about 6 less in the rear, but didn't produce speed and don’t remember if the front was the same or not.

Anyways advice is golden guys! thanks.
-Steven

[loudnlow7484]

The speedo is going to be optimistic by a bit anyway, that's just how they are. If you gear taller, it will drop your revs on the highway, sure. The only problem i would have with that, is that you don't want to labor the engine too hard. You could gear it, theoretically, to run at 2k rpm on the highway, but the engine would be really huffing trying to keep it going. Since you have a post98 model, you'll have to add a speedo healer if you want to change gearing drastically and still have a relatively accurate speedo. If you really want to give it a try, spring for a 15 tooth front sprocket and see how you like it. Honestly, though, front sprockets are cheap. Pick up a 15 tooth and put it on, see how you like it.

[ctandc]

Did you check what front / rear sprocket combo you have now, so you can compare to what you would have stock?

[kevin2502000]

Actually 6-7k is suppossed to be the most efficient rpms, thats why suzuki geared it that way.

[SuzukiSteve]

well the rear sprocket I now know is the stock size (47-530). I dont know what the front is yet. but.. do all of you guys see a speedo reading thats really that much off? The car which we know is correct was doing the speed limit of 70, and my kat followed reading 80. If the front sprocket is where the speedometer gets its reading then Im guessings its not stock. Its just not at the speeds it should be at per gear at 4500rpm according to the manual and other threads. I usually shift super quick and make use of second cuz 1st just seams to waste rpm's without getting me too far. Has the same feel those Honda Civics do with the Folgers coffee can mufflers that you can hear using the RPM's, but see that they go nowhere in 1st from the light.

That was a good sugestion with going to more teeth in the front being that its cheaper and sence the rear is stock Im pretty sure going up in the front is going to be the way to go. Im thinking for sure at least 1 up over stock.. maybe 2. 2 really might just be better for 1st gear if it somehow is stock and also for letting me cruise on the highway.. I mean.. Im getting 25 to 30mpg on the highway and we're just talking going with traffic! lol my sports car gets as good or better at those speeds. Its cheap for the front i'll look into it.

[teddy]

Pick up a 15 tooth and put it on, see how you like it.

post 98's come stock with a 15t front

[thetable]

First off motorcycle speedos are notoriously optimistic. From what I have seen, it is usually from 3-7% high. Now while the speedos tend to read high, the odometers are usually dead on. Find a stretch with a known distance and compare the odometer reading. That will tell you if there is something going on with the gearing.

The other thing that can affect speedo accuracy, other than the physical gearing, is the tire diameter. If someone put a 150/60-17 or a 160/60-17 tire in the rear, it would cause the indicated speed to be a bit high, and if the tire is very worn, it will also exacerbate the situation.

The mileage you are seeing is unacceptable, and not caused by gearing. If the bike were geared shorter, it would cause the odometer to read higher even if traveling the same distance.

Now all that being said... Can I please buy you some punctuation? It would make your post so much easier to read. Capitalization and punctuation could be the only thing between you helping your uncle jack off a horse, and you helping your uncle Jack, off a horse.

[loudnlow7484]

post 98's come stock with a 15t front

oooooo, good call. I didn't know that. I suppose that's why there are so many members here. It's like a system of checks and balances.

Capitalization and punctuation could be the only thing between you helping your uncle jack off a horse, and you helping your uncle Jack, off a horse.

HHAAAAHAHAHAHHA!

[streebs93]

If I remember correctly, there was a thread around here somewhere about a guy who tried to go to a 17t front and it wouldn't work because the chain would hit the sprocket cover, so be careful with that. Also remember you are not riding a Harley here, its OK for the bike to rev up a little. Obviously you don't wanna be cruising at red-line constantly, but anywhere between 5 and 8k is fine. The engines are designed to be most efficient in that range anyhow...

[tdrcomm]

Now all that being said... Can I please buy you some punctuation? It would make your post so much easier to read. Capitalization and punctuation could be the only thing between you helping your uncle jack off a horse, and you helping your uncle Jack, off a horse.

I freakin' laughed out loud!

[Rocknrod]

I freakin' laughed out loud!

[Stickman]

I have fiddled with the gearing on my '91 Kat and found that going to a smaller rear with stock front did drop the revs but only by about 500 rpm. It also had a fairly significant affect on the performance of the bike making it slower to accelerate and didn't have any affect of economy. The reason for this is that it is working harder and using more fuel to get up to speed. I like having some punch out of the corner so I went back to standard gearing. I also found it a pain in the backside with the chain as the different sized sprocket made it necessary to put 2 extra links in the chain. The motor is most fuel efficient at the point where the torque curve and power curves cross (I have only been told this by a mechanic so I am taking his word for it). This is also the point where the motor is at it's "sweet spot". You will notice on all motors there is a point where it feels smoothest and more punchier (if that's a word). On my kat I find it is around the 7-8000 mark. Someone with more knowledge than me may prove me wrong however.

[SuzukiSteve]

yeah that sounds understandable.. these things aren't 1000's and even being 600's, they are still at the lower end of the HP range. That being the case your not working with much at all to be changing gearing too significantly. how many teeth did you go down to that ended up being too much for you stickman?? also.. You went with a smaller sprocket and required a longer chain?

I'll try and take an extra second on the 1am posts for the commas. I hope a forgotten capitalization or comma doesn't put the image of helping jack off a hoarse for any of you guys, but I supose some imaginations have no bounds..lol.. if MOST of our brains can process a ettler tahts rewittn omclpeelety imxed pu, than I certainly hope a big or small letter and a comma doesn't obscure the context that much for you lol. With that said, I might sugest staying clear from farm animals with an imagination like that.. Even if its.. "your dog".. Its still quite frowned uppon legaly and at least socialy.

[loudnlow7484]

The motor is most fuel efficient at the point where the torque curve and power curves cross (I have only been told this by a mechanic so I am taking his word for it).

A motor is most efficient at WOT at its torque peak. As for efficiency at part throttle/cruise, I couldn't tell you. I can tell you that if your mechanic is correct, I should never use overdrive in my car, because the torque and hp intersection is about 800-1000rpm higher than its actual cruising RPM (well, unless you're cruising at ~110mph)

[SuzukiSteve]

Yeah.. I would certainly think lower rpm is better thus giving perpose to things like overdrive.. These bikes are light and any amount of throttle at any speed and rpm's will maintain that speed quite easily, so logically the lower the rpm's, the less the pistons move, the less the valve opens to spray gas in the cylinder. On top of that its less fuel per valve opening in a lower rpm range over a higher rpm range and as long as its not straining more all logic would point to lower rpm's consuming less gas.