Bonneville America Forums Forums Technical Forums General Tech Toad The Wet Sprocket

Well, not really, no toads, or music for that matter, just some SPROCKET talk.
Prolly around a year ago I changed out my 18 for a 19. This morning on my way into work I was out on the interstate pretty much all to myself. So I'm cruising along in 5th about 70+ mph and about 3.5k,about 1/2 or so on the throttle. So I decided to open her up a little, steady roll up to WOT. She starts climbing in speed not to slugishly but once I got to 'round 95mph, about 5.3k there wasn't much more UMPH!
I could've dropped her down to 4th before I started my upward climb but I was just testing out 5th.
Been kicking round the idea of dropping back down to a 16 and from what I gather mpg won't really change that much either. FYI most of my daily commute is slab, usually in the range of 65-85mph. I originally went from the 18 to the 19 to lower my RPM at highway speeds and to stop searching for that elusive 6th gear. But now I'm really missing the low end torque. And a engine build just isn't in the checking account at the moment.
Thoughts?

wind and riding position are critical when approaching the ton. At times my bikes won't do a ton, other times no problem.

Your question is unanswerable. take for instance the farmer that had enough wire to run one strand along his field for a fence. He had cows and pigs. Well, positioning the wire high enough so the cows could not step over it allowed the pigs to walk under it.

But you know all that...

switch it back to the 16. (did you ever have a 16 on it?) You'll always have the 19 and 18 for future install. The 19 is a really tall gear.

I easily hit 100 anytime I want with the 16 42 combo no matter the wind or weather. (that's indicated not actual) and so far 120 anytime too with more throttle left. (i think I was at about 6,000 RPM at 120 but not sure, I know I wasn't at red line yet.

Nope, never had the 16, never had a 17 either. I've broke the ton several times but that was winding 4th pretty high (not close to redline) , but at least 6k.
Think I'll give it a try , see how I like it.
As far a the cows and pigs, dig a trench and that the cows can jump and THEN position the wire low.

Never had a bit of problem with my 19t. 3500 is low in the band for 5th. Drop to 4th let it get its revs making HP for you to about 5.5k then hit 5th hard. You will be starting at about 80 in 5th. That should make a lot of difference. Unless you have a big windshield on it. Thats like pushing a sail down the road.

Right at a real 106-110 you run out of HP on our bikes no matter what the gearing.

I think the 19t is well worth it unless a really heavy two up type load is the norm. Even with that the gears are taller, you just lose the 1st gear jump.

Effortless cruising.

IMO the 18 is a good solution, still have enough torque to get you there and the rpm not to bad on the hi-way

My Speedmaster had a 16 and I when to a 17 and am pretty happy. Still has all kinds of torque and gets about 10 more miles per tank full.

Well seeing as how I still have the 18 and it's in decent shape I recon I could throw it back on.Then decide if I want to go any lower. I'd be really happy if I could just figure out a way to incorporate just one more fgear into that tranny of ours.

With a basically stock motor 790 I suggest a 16 or 17T front. With a basically stock motor 865 I suggest a 17T front. When either motor starts putting out more power an 18T is pretty good all around. Just my opinions.

Top speed is more limited by wind resistance than anything else. A taller geared bike just won't be in the power band at higher speeds, these engines continue to increase in power all the way to the limiter.
I run a 16 front and 44 rear. 100+ is easy to attain. I've never pushed it to the limiter in 5th, but I've gone to 110 mph at about 7k rpm.

110 is about 5800 on a 19t but it runs out of horses there with the wind.

Yep and yep. Like I said I was already in 5th and only about 3.5k when I was rolling on. Around 95mph is when it seemed like there wasn't much more...., I mean I was still climbing just not rapidly.

However today I let 4th climb to somewhere around 6k about 95mph before I shifted to 5th, rpm dropped back to about 5.2 or so and kept on pulling strong, I didn't jet a good look at the tack after this but I backed off the throttle around 105. I still thinK you may be right about asperation at WOT. I've noticed that for a while, its not like to bogs down just feels like I have better responce before I get there.

Good! The 19t is like having 6th. You just have to keep the revs up. For the first 6 months I ran it I was riding like I had a 17t. The 19t is a great setup for everything but drag racing.

Well just last week I had some little turd on a crotch rocket if front of me at a red light turning on to the interstate. He took off like a bat outta hell, so I followed. He was racing thru the gears, prolly hit 4th before I got outta 2nd. I backed off after hitting 90mph,still in 4th (heavy afternoon traffic). Anyway I'm sure if he knew what he was doing he prolly could've dusted me but he never had more than a 30' lead.

Yup, you just have to let them breathe.

Yep, breathe is right. Hit the ton in 4th today, little over 6k, then up to 5th. Backed off around an indicated 105. Checked gps app on phone it showed max speed of 103.

That is right. Your 4th is almost a 16t Speedmasters 5th.

I've always loved the acceleration from a 16T.
The mileage is 33mpg at 100mph/6000rpm.
It will run there as long as the police stay in the donut shop.

What is meant by "let it breathe?" Let it run up the r's some?

No, breathe means open up the pipes and intake to allow better air/exhaust flow. Have to jet the bike correctly then to go with the less restriction.

Well I was taking it that Ron (saxtron) was meaning running up the RPM'S in each gear, let it "Breathe" in each gear. But if we're going with what Ian is saying I got that covered too. Ditched the airbox years ago, running K&N pods, completely gutted pipes ('cept for the reduced cone) and jetted with 152.5 mains and 42 pilots. She's got the lung capacity of a frogman.

I meant let it breathe as in run up the RPMs to where they make HP. I am sorry for confusion. I also advocate but did not mean letting it breathe with a K@N filter, ProCom brain, open up the pipes. Moving air in and getting it back out helps a ton. But you don't need a lot to do a ton