800 front sproket change 17t to 18t

[bikeaholic]

Well guys I decided to start a thread in the cruiser's forum for this very topic since we've got 2 or 3 threads around this site talking about the same thing. So now with the topic. As I mention earlier I had a tach on my 800 so I decided to get some hard number's for everyone so were no guessing . First I went out at lunch an changed the 18 tooth back to the original 17 tooth an I'll start from there. 17/42 ratio I've got 3750 rpm @ 65 mph., 4250 rpm @75 mph.,4750rpm@ 85 mph. Now with the 18/42 I've got 3500 rpm @ 65 mph.,4000 rpm @ 75 mph., an 4500 rpm @ 85mph. So that tell's us the 18 tooth front sprocket drop's the rpm's 250 well worth it. when I change out the rear to a 40 tooth I'll add those number's to this thread. By the way< Here's a couple of other number's we can talk about . The rev limiter kick's in about 8200 rpm. from the factory. So I hit the rev. limiter at 72 mph. in 2nd gear with the 17/42 ratio. With the 18/42 I hit the rev.limiter at 80 mph in 2nd gear. The rev. limiter is our friend




17/42 - STOCK

55 mph - 3250 rpm
65 mph - 3750 rpm
75 mph - 4250 rpm
85 mph - 4750 rpm

18/42 (changing front sprocket)

55 mph - 3000 rpm
65 mph - 3500 rpm
75 mph - 4000 rpm
85 mph - 4500 rpm

18/40 (changing front and rear sprocket)

55 mph - 2800 rpm
65 mph - 3300 rpm
75 mph - 3800 rpm
85 mph - 4300rpm



data supplied courtesy of woodchuck

[MIKE P]

Tahnks for the info. Sorry about the length of time since your informatin but I just found this web site. Thinking of doing the same to my Vulcan 800 A. I love the body style but would like a little more power on the highway. What did the change to the 18/40 sprockets do for yur take off from stop. I am alittle worried about bogging down. My mech. said something about if I had a rider on the back it might cause some problems.
I am thinking of just changing the rear sprocket to a 40 tooth and leave the front alone. what do you think? Also did you notice any change in your mpg. I have a kyur. hypercharger and jet kit already on the bike and v&h straight shots for exhaust.
I am writing from work so please use my home e-mail address for replay-
ptrmanmikjud@coastalnow.net

Mike Petermanm
Savannah,Ga

[Calamarichris]

I did the exact same thing to my ZX9R and now get sometimes better than 50mpg on the highway. Lost a little bit of squirt, but already had too much for public road use anyway. Also getting longer life out of rear tires and I'll bet the chains will last a little longer now too.

-CCinC

[Knightrider]

I ride with the little woman all the time and never noticed a bit of difference in take off power from a stop. The 18 tooth front sprocket makes it a brand new bike. You'll love it. It turns th SPORT/CRUISER into a CRUISER.

[dawgblood]

Stupid question from a newbie - what is a rev limiter? Is it like a governor (sp?) on a car?

[woodchucks800]

DB ,let see if I can explain it . It's in the electricial circuit when the rpm's coming from the coil get to high the circuit kick's in an enterupts the electrial charge. thus shuting down the coil . You will know when you hit it because it feels likes when you start running out of gas. It also make's it feel like an electricial short. Go out an run the bike up in any gear until you feel it. It won't hurt the bike,that's what it's there for. (to replace a tach on the cruiser's) all the later model bikes (cruiser's anyway) have them.

[dawgblood]

You're awesome! I'll give it a try. I hope the '97 has it!

[woodchucks800]

DB, yea'll it does just don't be afraid to find it. these 800's powerband is up top so don't try cruising around at 1500 rpm's on the highway because it won't happen. Look at the chart above an you can see the rpm difference at mph's with the gear changes.And just so you know these 800's with the pipe an intake mod's will beat most of the 1500's an the nomad, in there stock form( up to about 90 anyway). An if you want to beat them when they have the pipe an intake mod's also . Just go home an switch out the gear to the 16/46 or 16/48 an you'll watching all of them in your rear view mirror. <LOL>

[dawgblood]

That's some good info to know when I'm sitting beside a "big boy" at a light. Hey, one more question that I thought of - it appears in the chart above that the speed vs. rpm is for one gear. Do you have any idea (on a stock 800) what the max speed is for each of the five gears (just before you hit the rev limiter)?

[woodchucks800]

Originally Posted by dawgblood

That's some good info to know when I'm sitting beside a "big boy" at a light. Hey, one more question that I thought of - it appears in the chart above that the speed vs. rpm is for one gear. Do you have any idea (on a stock 800) what the max speed is for each of the five gears (just before you hit the rev limiter)?

No I don't Dawg but when I get a chance (nicer weather) I'll do some playing around for you. Probably run outta road in fifth gear before I hit the limiter though <LOL>(don't know if I'd be able to get that close in fifth anyway).

[dawgblood]

Just an FYI wood - I hit the rev limiter in first gear at about 47 (as you or one of the other members mentioned earlier, the speedo may read about 10% fast). That's still a pretty darn good first gear!

[ridenagain]

Great info!!! Convinced me to go the 18/40 route to take care of the "looking for 6th gear" syndrome. Parts are on the way right now. I hope to get them on and try them out by next weekend.

Thanks for the time getting this valuable information!!!!

[78_KZ750_Cafe]

I'll be changing sprockets and chain before the start of next season (so sad that this one is almost over) I'm probably going to go with a new front rear sprocket setup on my bike since I suffer greatly from the aforementioned "looking for 6th" syndrome and never the "this thing is too slow" syndrome. For an old bike its got more than enough pep and with gas prices heading north of $3 i'm going to squeeze every mile I can out of a gallon. I have to count what I've got, but rears are available from 45T all the way down to 38T for mine - maybe that's a little too slow, phew, I could go 13/45, bet that would rock and roll.

Edit: I did a quick count last night, its already sporting the 38T rear, D'OH! There goes daydreams of +50 mpg.

[drifterguy2004]

Does anyone know of a place to get an 18teeth and 40 teeth sprocket for a Drifter? Also is there a brand of sprockets that's prefered over others?

[woodchucks800]

Originally Posted by drifterguy2004

Does anyone know of a place to get an 18teeth and 40 teeth sprocket for a Drifter? Also is there a brand of sprockets that's prefered over others?

This is where most of us get the 18th. www.sprocketspecialists.com I don't remember right off hand but I think the drifter comes with a 40th. rear stock ,so you might check it out. If not Jt sprockets makes a 40 th. steel. whatever you do for the 40th. don't get an alum. one there junk and won't last long.

[orangevale]

woodchuck,

new to forum,have 05 800 classic, considering sprocket change, if I install the 16/46 range how much off the line will I lose and with a kury HP will that make up any power off the line and how much at the top will the HP increase the horse power, any suggestions??? before I commit to these changes???
Thanks, orangevale
PS. have installed HK stripper pipes, jet kit as well.

Originally Posted by woodchucks800

DB, yea'll it does just don't be afraid to find it. these 800's powerband is up top so don't try cruising around at 1500 rpm's on the highway because it won't happen. Look at the chart above an you can see the rpm difference at mph's with the gear changes.And just so you know these 800's with the pipe an intake mod's will beat most of the 1500's an the nomad, in there stock form( up to about 90 anyway). An if you want to beat them when they have the pipe an intake mod's also . Just go home an switch out the gear to the 16/46 or 16/48 an you'll watching all of them in your rear view mirror. <LOL>

[woodchucks800]

Originally Posted by orangevale

woodchuck,

new to forum,have 05 800 classic, considering sprocket change, if I install the 16/46 range how much off the line will I lose and with a kury HP will that make up any power off the line and how much at the top will the HP increase the horse power, any suggestions??? before I commit to these changes???
Thanks, orangevale
PS. have installed HK stripper pipes, jet kit as well.

You don't want to run the 16/46 set up unless your racing stop light to stop light9 because you won't loose anything of the line, keeping the front end on the ground will be fun!) It's the 18/40 set up that you'll loose a tad bit when starting off,but will become unnoticeable at around 10mph or less. It will add about 10mph on your top speed with the 18/40 change and yes the HC or any aftermarket intake will give you back the miminum power that you loose fronm the sprocket change.

[orangevale]

Woodchuck800,

Thanks for info, since I can not get a 18t sprocket without manufacture retooling and that cost is $50.00 for setup fee, I was thinking of going with the stock 17T front and 38t rear to accomplish the same thing as the 18/40 ratio, will the 17/38 require me to replace the chain size since the stock chain is not adjustible?, and if so will the 17/40 ratio give me the 250rpm reduction??

Thanks,
Orangevale

[woodchucks800]

Originally Posted by orangevale

Woodchuck800,

Thanks for info, since I can not get a 18t sprocket without manufacture retooling and that cost is $50.00 for setup fee, I was thinking of going with the stock 17T front and 38t rear to accomplish the same thing as the 18/40 ratio, will the 17/38 require me to replace the chain size since the stock chain is not adjustible?, and if so will the 17/40 ratio give me the 250rpm reduction??

Thanks,
Orangevale

Not sure where you got your info about retooling prices for the 18th. because the above posted link will sell you a 18th for around 17bucks plus shipping. Yes you can go the 17/38 route and your stock classic chain will work. The 17/40 will reduce the rpm's by 250 and the 18/40-17/38 will reduce the rpms by 500.

[esornivram]

Originally Posted by orangevale

Woodchuck800,

Thanks for info, since I can not get a 18t sprocket without manufacture retooling and that cost is $50.00 for setup fee, I was thinking of going with the stock 17T front and 38t rear to accomplish the same thing as the 18/40 ratio, will the 17/38 require me to replace the chain size since the stock chain is not adjustible?, and if so will the 17/40 ratio give me the 250rpm reduction??

Thanks,
Orangevale

different bikes have different gear ratios inbetween gears, with that in mind each model/bike will have differences in these numbers, difference between 5 speed and 6 speeds, and not all 6 speeds have the same gear numbers spacing, older zx10 6 speed has 6th at true 1 to 1 ratio, the conours 6th speed is an true over drive, its .94 to 1
so light differenes will be seen
second lower rpm doesnt always get better gas mileage,
operating an engine in lower rpm than where its sweet spot of HP and torque production are can result in poor gas mileage, just like trying to pull an steep up hill in the wrong gear, on flat road doing interstate speeds and have too low of rpm can bring about poor gas mileage, or you may be cruising around in fourth instead of fifth, so too much change can produce negative affect
keep that in mind