'82/'83 1100e gearing

[Rob S.]

That's why I let a professional racer/tuner/builder do most of the work on my bike. (He's got a dynamometer.)

I did just install a new clutch cable by myself...you guys would've been proud.

[AJ]

sorry sorry

18/50 is what i ment

18/50

18/50 with a 116 link 530 chain is perfect. The ratio is nearly identical to the stock ratio and both the countershaft and rear sprockets are the same size diameter at the stock 15/42 630 sprockets, so there will be no worry about the chain rubbing on the swing arm. The 116 link chain will give about 5 times better chain walk for improved wear. 114 links will move your wheel forward a tad and the chain walk is slightly reduced from the stock setup but still acceptable.

[CivilRock]

So if I have a 40 rear, and I'm revving approx 4,650 rpm at an indicated 70 mph, can anyone figure out how many teeth are on my front sprocket?

In a theoretical world, this is pure math, and any nerd can figure out your front sprocket size. The problem is we don't know the error on your speedometer, we don't know the error on your tachometer, and we don't know the size, brand, pressure, and wear depth on the front and rear tires. Those 3 factors, even if they're off 3% each the same way makes the nerdy math inconclusive and inaccurate.

One of the reasons I'm confused is that stock is 15/42, and that produces 3811 rpm at 60. I think I'm revving slightly higher than that, but my 40-tooth rear leads me to believe I should be revving less. Smaller rear, "geared up," revving lower, correct?

So my front must be very small, correct? How much smaller than 15 could it be?

Stock bike: 3811 rpm at 60mph. Rear = 42t Front = 15 Ratio: 2.8
Rob's bike: 4650 rpm at 70mph. Rear = 40t Front = X

So, a stock bike should turn 4446 rpm at 70mph.

I've done some more math on a notepad, but I'm getting somewhere between a 13 and 14 tooth front. Which is either an error in my math, or too much error in your tach/speedo/tires.

When you take off the shift shaft linkage, take some white out or a sharpie and mark the splines for re-assembly. Then get back to us.

BTW, I just went to 17/50 (530 chain) in prep for the track. I thought 17/47 was great for the street/highway. Before that I tried 17/45, but I'd only use it if I was going to be cruising the superslab for many miles. I also bought a 16t front to play around with.

16/50 = 3.125 (drag racing end)
17/50 = 2.941
16/47 = 2.938
16/45 = 2.813
17/47 = 2.765
17/45 = 2.647 (super slab end)

In my head, to make this simple, the front turns 3 times for every 1 rotation of the rear. That's with a 15/45 = 3.000. And the real ratio is stated 3:1, but most people just talk with just the first number.

"Let me tell you what Melba Toast is packin' right here, all right. We got four eleven Positrac outback, 750 double pumper, Edelbrock intake, bored over 30, eleven to one pop-up pistons, turbo-jet, 390 horsepower. We're talkin' some F-in' muscle."

[Rob S.]

Thanks, CivilRock. This is about what I'm turning now in fifth:

70 mph - 4,650rpm
80 mph - 5,300 rpm

I'm thinking my (apparently) small front sprocket is causing, or contributing to what sounds like the chain slapping against the chainguard at sudden transitions.

When I bought the bike eight months ago, the chain was so loose it was slapping against the swingarm. As soon as I can get her into the shop, she's getting new sprockets, chain and swing arm bushings, as well as the very nice 1150 oil cooler and brand new 1150 filter cover installed that I have. Plus anything else I can think of.

I'm sure it'll cost more than enough to generate some questions in the house. Too bad - Suzi gets what Suzi needs.

How's your Black Beast running?

[blowerbike]

1 in the front= 2.5 in the rear but rounded up to 3 makes the math easier.

here's a little spam for the peeps that don't look in the "for sale" area of the forum.

http://www.thegsresources.com/_forum/showthread.php?t=222889

[CivilRock]

How's your Black Beast running?

Good. Trying to get time to go back to the strip for some real testing.

This week I installed a 50t rear and ended up buying a new chain instead of adding mismatched links. While I was at it I shimmed out the rear sprocket just a hair, and drilled the nuts for safety wire. My chain now doesn't rub the sides of the 190 rear, and the nut lock tabs were ugly and hammered. I also semi-polished my cush drive, and all the hardware while I had it in my hands. Turned a 20 min job into over 3 hours. But I totally enjoy it. I only needed 4 more links, so I'm at 124 links now. That gave me enough to go around the bigger sprocket and move my axle back about 1". I still wanted a little room to take up the slack, but as far back as possible.

I really wish you would do this work yourself, but I understand. And shoot, the shop mechanic has to pay his bills too. I just know that a shop tech isn't going to take the time to polish all the zinc plated hardware while they have it apart. But they're going to do it right.

If you don't have the confidence to do it yourself, it can affect your state of mind when you ride. Working on your own bike can also play mental games with you. There's nothing worse than going into turn 1 at 155 mph and instead of thinking about your braking point or the people around you, you're wondering if you properly torqued and wired your front brake calipers. It doesn't have to be racing; it can be edging your bike up and over 80mph on the freeway. Instead of watching for fingers reaching for a turn signal in the cage beside you, you're worried about your chain flying off. Confidence in your machine plays a large role in how you ride. If you don't have that mechanical confidence, then by all means, take it to a pro.

Sorry for the book. Here's a picture to make up for it.
-Kevin

[rapidray]

4.6K is 4600 rpm. (4.6 thousand)

He edited the post, or did you not notice that?! ORIGINALLY it said 46K. He added the decimal point later to look better.
Ray.

[bwanna]

I know this is an old post, but wanted to add this for the archives. When I up'd my gs450 with jugs/pistons form a 500, I regeared to take advantage of the slight increase in power. Concerned about all the details I found this website that just made it so easy and allowed for the 'what ifs'. Don't know if anyone else mentioned it.

http://www.gearingcommander.com/