Topic: 15 TOOTH FRONT SPROCKET

[tygrant]

rather than hjack hondariders thread, i wanted to ask if anyone is running a 15 front. i know stocks 17 and 2 teeth will be a big drop, but this is not going to be a highway bike, just for blasting around town.   what do you guys think my rpms would be at through the gears? keep in mind I have never ridden one of these or had this one running im certainly a newby and this board has been fantastic. thanks

[eldar]

Well your accel will increase but so will your rpms. Chain wear will increase as well. You will lose mpg too. At 75 my rpms are around 5500 or so. Yours will probably be at least 6000 if not 6500 range.

[tygrant]

right i understand the chain wear and higher rpm thing but im looking for acceleration.   with the stock gearing can these bikes top out fifth gear or do they hit  wall on the tach some where?     i know with my mustang to get to a higher top speed i have to gear it down because it doesnt have the power to utilize the gears.  just wondering if that the case wtih these bikes?

[eldar]

With the stock gearing, that does not seem to be the issue. Now if you had the 18tooth front, then you would run into that somewhat. The lowest I would drop the front is a 16, I would rather raise the rear though.

[bryanj]

Considering one of Hondas excuses for chain breaking was that the 16 tooth was to small a diameter i dont think i would go that way!!!

[736cc]

 15T w/ a 530 chain not a good idea, the sharp turn around sprocket is marginally too tight for the links, and its spinning even faster. Earliest 1969 CB750's had 16T sprocket and broke alot of chains (and crankcases), enough that the factory recalled them and replaced w/ 17T, eventually settled on 18T.
  Go w/ a bigger rear sprocket, go up 2-4 teeth no problem, just need a longer chain, maybe 106 links. And don't run 2 master links like one bike I found.

[tygrant]

15T w/ a 530 chain not a good idea, the sharp turn around sprocket is marginally too tight for the links, and its spinning even faster. Earliest 1969 CB750's had 16T sprocket and broke alot of chains (and crankcases), enough that the factory recalled them and replaced w/ 17T, eventually settled on 18T.
  Go w/ a bigger rear sprocket, go up 2-4 teeth no problem, just need a longer chain, maybe 106 links. And don't run 2 master links like one bike I found.

hmmm im going to have to think about it now, i didnt want to replace the chain, its in good shape and im trying to keep the budget down on this POS. i know if i replace one thing im supposed to replace all three. i found that out the hard way on my street bike but were talking 120 hp vs like 45 or something. i may still put just a 16 on for now and if it lets go then il worry about it then?  btw i cant imagine this bike blowing up a new xring rated for a 1000 cc if its installed right

[eldar]

It is not really about hp. If the chain is stretched or the sprocket teeth bent, it will wear faster regardless of power.

[Sam Green Racing]

If you are talking Cb750, a 15 tooth sprocket will make you peak in top gear around 90mph.
If it's a stock motor, don't rev it beyond 8,500 in the gears.
Your quarter time should be around 13.5 seconds.

Sam.

[crazypj]

Doesn't the chain contact the swing arm pivot with a 15t?
PJ

[tygrant]

Doesn't the chain contact the swing arm pivot with a 15t?
PJ

it would be really cool if someone knew the answer to that!!

its a 75 550f

[Sam Green Racing]

Doesn't the chain contact the swing arm pivot with a 15t?
PJ

No it don't.

Sam.

[derkafer]

Why cant you run two master links? Just not a good idea in general? 

[Sam Green Racing]

Doesn't the chain contact the swing arm pivot with a 15t?
PJ

it would be really cool if someone knew the answer to that!!

its a 75 550f

It being a 550, please disregard everything I said

Sam.

[tygrant]

[/quote]

It being a 550, please disregard everything I said

Sam.
[/quote]


sooo do you know if the chain will hit or disreguad that too?

[HondaMan]

And don't run 2 master links like one bike I found.

What, you don't like that vibrating massage feeling those 2-piece chains give? I thought it relaxing on my trips across Nebraska. Tug-tug..tug-tug..tug-tug... 

[754]

I have run 17/54 quite a bit.. at the strip, on the street & and a bit on the hiway......it is very close to running a 15/48, check with a calculator.

IMO it is the cheapest way to increase acceleration but often ignored for more pricey mods.

Driven
--------- = Ratio
Driver


Just picked up a 60 tooth that I may have to try..

in about73 I saw a CB750 dust a Z1 pretty good  for the first 300 feet. Ie was stock motor, had Webers, dragbars, 17/54 gearing.. I never forgot it..

and I ended up buying the carbs later(with a raft of jetting), and the 54 tooth sprocket..

[tygrant]

i agree completely, my last street bike was an R6 and i geared the crap out of it, its was a wheely monster. exhaust and carb tuning had it at 11.5 at 124 mph. wich for a first gen R6 with 20k+ miles is really good. 

im trying to keep a reasonabl budget on this cafe build and didnt want to do all new chains and sprocket so im still up in the air

back to my other question will the chain be high enough off the swing arm with a 15?

[hapsh]

15T w/ a 530 chain not a good idea, the sharp turn around sprocket is marginally too tight for the links, and its spinning even faster. Earliest 1969 CB750's had 16T sprocket and broke alot of chains (and crankcases), enough that the factory recalled them and replaced w/ 17T, eventually settled on 18T.
  Go w/ a bigger rear sprocket, go up 2-4 teeth no problem, just need a longer chain, maybe 106 links. And don't run 2 master links like one bike I found.

I gotta chime in here on this.  Many newer bikes have 15 or even 14 tooth sprockets without any problem.  My FZR has a stock 15 tooth front sprocket with a 530 chain without any issues and it is 18 years old.  Years ago I ran my CB450 with a 13 tooth front sprocket without any issues and it gave me amazing take off speed.  Right now I have a 16 tooth sprocket on my 550 and it gives me a slight bit more off the line and I also can get to 105 mph in a much shorter distance than I could with the 17 tooth.  I even get the front wheel off the ground now .  I also notice around 75 MPH I have much more power for roll on acceleration because I am right in the middle of my power band.  I think that a 15 tooth front sprocket would be really cool for around town light to light acceleration, and you would still have a top speed right near 100mph.  I say go for it with no worries.

[Triffecpa]

I run 15T front sprockets on the front of my CB400F race bikes.  Go to a 16 or a 17 if we run at longer tracks.  I prefer to change out the front sprockets because they are cheaper and they have less of an impact on chain length.  Now I don't run 5000 miles a year at the track, but I've never had any chain problems and we tend to rev the crap out of these bikes. 

I ran a 15T on the front of my Cb750 race bike (in my avatar) and jacked the back of the bike up with shock extenders to the point where the chain would drag on the top of the swingarm if the bike didn't have a rider on the seat.  Actually switched to a 16T when I did my GSXR wheel conversion because I had to go to an offset front sprocket and that was the smallest available thru Cycle X.

No problems with either bike running the smaller front sprocket.  Again, I don't put tons of miles on the bikes, but we do run them pretty hard.  Don't run any expensive chains on them either.  Just standard non-O Ring chains.

Tracy

[eldar]

I suppose these days, chains are stronger of course, and that means they will last longer if cared for. The smaller sprocket will still probably wear them faster but the difference is probably negligible. You also do not have to worry about breakage as much. So if the smaller sprockets work, great. Just more gear options.

[tygrant]

awesome, thats what i wanted to hear!

hapsh i never read what you write because i am mesmorized by your avatar, i have to cover it with my hand so i can concentrate on what you wrote. love it. 

[crazypj]

I have a Katana 600 with 14t front. chain was worn out when I got bike, 11,000 miles, 530 'O' ring
PJ