So, why'd I do this? Well, I think I'm definitely at a point with the bike that I could handle more acceleration, so I was originally thinking of just gearing down a bit. After reading various threads on T595.net, it seemed to me that going up to 46 in the rear (from stock 43) would be the thing to do. People were saying they had to mill the brake caliper mount (I think?) in order to be able to move the wheel far enough forward to use a stock 108 link chain. This also will decrease the wheelbase of the bike, which could add to instability, but from all that I read, lots of people enjoyed the shorter wheel base, commenting that it made the bike more nimble, with no added headshake. Okay, sounds good. Also figured I'd go with an aluminum rear sprocket, since it saved some weight (and the high quality ones seemed to last just fine). After reading some more threads, I heard about various people doing 520 chain conversions (stock is a 530, of course). The motivation behind this is to save weight (and it's rotating mass, which is more important for acceleration). I was a bit nervous about this, due to the torque the Daytona generates, but after reading the figures, I determined it probably wasn't anything to worry about. It seems the stock Regina ORP 530 chain has a tensile strength of 9390lbs. The DID superbike 520 chain is somewhere around 8500 lbs, but AFAM makes one with 10% thicker side plates, the 520OHR Hyper-Reinforced O ring chain. I can't seem to find the tensile strength of it now, but I seem to recall it's actually around 10000lbs.
Okay, that all sounds good. But what gears to go with then? I was a bit worried about the thing being too revvy around town, and also loosing top speed. However, I then actually ran the numbers, and came up with some interesting things. Remember how I commented on my central Oregon trip that I couldn't get the bike going faster than an indicated 170mph? This was at 9500rpm, even though the bike redlines at 10800. Running the numbers through a gearing calculator, I was actually only doing 157mph. Okay, so what gears make roughly 157mph my top speed? Well, with my 180/55 rear tire, 17/45 would be 161mph at 10800rpm. That sounds about good, and lots of people like that gearing. Also, as my friend Dennis pointed out, since 17 is a prime number, it won't establish any odd wear pattern at any particular spot. So will this make the bike rev like crazy around town like so many people say it does? Seriously, people are way too whinny. :-) Running through the calculator, with stock gearing in 6th gear and 75mph, you'll be doing 4550rpm. With the 17/45 gearing, you'll be at 5000rpm! 450 revs more! Big deal. Probably will barely even notice it. Nice. After reading more about the various manufacturers, there seemed to be some quality control issues with Sprocket Specialist sprockets, while I heard nothing but good things about AFAM. So, I called up AFAM and ordered the 520OHR Hyper-Reinforced O-ring chain + 17 tooth front (steel), and 45 tooth rear aluminum sprocket. The guy on the phone wasn't the friendliest gentleman with my questions, but did get nicer when I said "okay, I'll order that." He explained that the 520OHR chain actually wasn't that much lighter than the stock 530 chain at all, since it's so reinforced, I guess... seemed strange, since everyone was raving about them so much. Most of the weight is saved in the thinner sprockets. In any case, a few days later they arrived nicely packaged. Price delivered was roughly $252 (I don't have the breakdown of sprockets vs chains).
I took it all out, and once the time came to do the task of the conversion, I first weighed each component of the 520 kit, and once I got the 530 stuff off, weighed that. A bit surprising numbers.
|Chain||71.4 oz||78.5 oz|
|Rear Sprocket||10.4 oz||35.1 oz|
|Front Sprocket||6.8 oz||11 oz|
|Total||88.6 oz||124.6 oz|
So, 36 oz total savings (2 1/4 pounds), or 29% over stock. Not too bad, but I certainly was surprised how close the chains were in weight! The 530 chain had 108 links, and the 520 had 110 links. So... on with it.
I started off with a trip to Sears to pick up the massive 36mm socket needed to remove the front sprocket. Boy, this bike sure needs some large drivers. The first thing to do is bend back the tabs on the lock washer (I used a screw driver and a hammer):
Lots of people said they absolutely could not get the 36mm nut to budge, even with a 6 foot long breaker bar... so I was a bit nervous, since all I had was a 2 foot long pipe. I strapped that sucker to my wrench, put the thing in gear, and was ready to give it my all... but it was pretty darn easy! I'd guess I only needed about 150Nm of torque to break it free... kind of strange. Oh well, no issues here! The next thing to do was remove the chain... to do so, I put a cut off bit on the dremel and cut the riveted bits off, and then pushed the pins through with the chain break tool.
I think the dremel got a few bits of the link too. :-) Off came the chain. The next order of business was how much CRAP was in the sprocket cover and case. It was totally disgusting! There was fairly sizable bits of gravel in here, as well as all kinds of other nasties. Check out these pictures.
I went to work with some rags and WD40 to totally clear all that crap out. I forget if I cleaned it out back when I swapped the chain roughly 4000 miles ago or not... if all this developed in 4000 miles, that's pretty scary!
Now I went to work with the new sprockets. The front is significantly thinner than the stock one, and the stock one has rubber on the outside of it to dampen vibration. It would probably be nice to have that rubber, but everyone says it's not really an issue. I could not find the torque spec for the rear sprocket, and I pulled a dumbass move of figuring it was pretty high, and in the process wound up stripping the first bolt entirely. I put the other bolts at 50Nm, only later (two days after I posted the question on t595) to find out that the proper spec is 33Nm. So I'll have to adjust those now. The front sprocket was to be torqued to 132Nm, but I hear you really need help to have someone hold the rear brake while it's torqued. I just put it "kind of tight" and went to work with the chain, hoping someone would eventually stop by to help.
I wanted to shorten the wheel base as much as possible, so I moved the adjuster all the way forward, and test fit the chain. The chain came from AFAM with 110 links. It wouldn't fit with two links removed, but pulling the wheel back a bit, I did seem to be able to fit it just fine, at the proper tension, with one link removed. I went to work with the dremel again.
After this, I just needed to lap the new master link on there, rivet it, and then tighten the 36mm nut on the front sprocket. Since I never did get anyone to help, this was a bit of a tricky part... I wound up setting the bike on the side stand, and trying to stand on the rear brake while reaching over the bike to the torque wrench. It was odd how even with all of my weight on the bike, when I turned the torque wrench the whole bike just started going backwards. Okay, more weight on the brake! It was hard balancing all my weight on this one little pedal while also trying to apply 132Nm of torque to the wrench. But, I was able to do it, and I heard the click of the torque wrench! AND I was kind of able to take a picture of the whole thing, with use of a self timer...
Now it was nearly a done deal. I adjusted the chain tension properly. Here's before and after pictures:
Yup... the front one's smaller... the rear one's larger... and the chain is gold. Cool. On went the sprocket cover and it was done.
My first feeling driving out of suburbia and into the country was that I didn't notice hardly any difference, which is good. The first rake on the throttle once I got a bit away from civilization was nice. Everyone wrote about what a drastic difference going 17/45 makes... I doubted that, since it's only a 10% difference in gearing. The bike definitely rushes through the revs quicker. I hit the rev limiter a few times because I wasn't used to it. Overall, I'd say it seems about... oh... 10% quicker. ;-) It definitely is quicker... honestly, probably feels like a bit more than a 10% improvement. I'm in fifth gear in no time, and even at the top of 5th, around an indicated 150mph, it's still pulling pretty hard... that certainly wasn't the case with the previous gearing, where it kind of petered out after 4th. The gearing does rock, but I wonder if maybe I should have gone even a bit more aggressive. Obviously the real test will be on the track where I can have consistency. I'll also probably actually use 6th gear now.
The thing does seem quite a bit buzzier than it used to be, though. Any time above 6500rpm or so, there's pretty intense, high frequency vibration in the foot pegs and handle bars. Almost like an in-line 4. Not sure what's causing that. I'm not suggesting something is faulty; just an artifact of this mod. The stock front sprocket has rubber on both sides of it, so perhaps this isolates some of the vibration? I don't believe any 520 sprockets that I know of have the rubber. Or perhaps since things are rotating at relative different speeds, it has introduced new resonances? Whatever the case, for a 10 minute stretch of my ride I was keeping very high in the revs and my body was buzzing afterwards. Rather annoying... Again, I'll see whether this drives me nuts on the track. As for "buzziness" around town... well, for one, I don't ride my bike around town, so I wouldn't care if it did have any... but I don't think it has any with this gearing.. all of the added buzziness is above 6500rpm, which won't be seen around town (legally, anyway).