KZP Gearing

Hey Gang, I need to replace the old 630 chain on the KZP with a 520 and I am looking for recommendations for gearing. I intend to use this as more of a freeway flyer and wanted to reduce the revs some. Right now, with my limited time on the bike it looks to be turning around 4500 RPMs at 65 MPH which is not bad. I've done the math and the final ratio is 2.73 and I was thinking about dropping that to 2.65 or so...
Just wanted to see what others have done...

520 is a very narrow chain (6.35mm) for a big bike; even the little 428 chain is wider at 7.75mm. Have you considered a 530 chain (9.53mm). I believe that is a more common conversion for big bikes, and it works well. It's still lighter than the 630 but quite robust so you won't be replacing sprockets and chain as often. Ed

Z1 Enterprise have a 630-530 conversion calculator. I think 530 is what you should be looking at.

I've been thinking on the conversion myself. Chains are cheaper but a good O ring chain should last 30,000 miles if taken care of. The sprockets will wear no matter what so replacing a chain is a temporary fix at best. I'm running a 15/35 combo now. I had a 16/35 not long ago and I was at 3500 RPM at 55 and 4000 at 65 MPH. Tall gearing will be harder on the chain and pick up will suffer too especially on take off. I love how it gets off the line with the 15 but at 5000 at 70 just don't cut it. :whistle:
Steve

The speed limit out hear northeast of Denver on the freeway is 75mph. Nobody drives that slow even in the right lane. If I don't ride at least 75mph-80mph in the right lanes, I get blown over!!
RPM? 75-80 feels frantic for the 15-20 miles into town.

Rustyhama wrote: Z1 Enterprise have a 630-530 conversion calculator. I think 530 is what you should be looking at.

Right 530 is what I meant. I have that on my GPz.

ThatGPzGuy wrote: Hey Gang, I need to replace the old 630 chain on the KZP with a 520 and I am looking for recommendations for gearing. I intend to use this as more of a freeway flyer and wanted to reduce the revs some. Right now, with my limited time on the bike it looks to be turning around 4500 RPMs at 65 MPH which is not bad. I've done the math and the final ratio is 2.73 and I was thinking about dropping that to 2.65 or so...
Just wanted to see what others have done...

If you move to 2.65, you won't notice a difference. You have to go down to at least 2.33 to make it noticeable. I've got a 2.20:1 ratio on one of my bikes and I still wish there was a sixth gear. It pulls fine. You may have to downshift to overtake someone. Getting started from a dead stop requires slightly more clutch than usual, but around town you never have to shift out of 1st if you don't want to. You'll definitely know if something's wrong (valve clearance too tight, bad gas, one cylinder down, poor idle) because you'll have to rev it up to 4k to avoid stalling when taking off.

I think the best compromise is probably around 2.33:1.

As I said, right now one of my bikes is 2.20:1 and the other is 2.47:1. 2.47:1 is not noticeably different than the stock gearing, so I'm going to switch the front sprocket to bring it 2.33:1 and see how I like it.

When you buy your new stuff, get a good chain breaker and rivet tool. You'll probably have to remove a few links from your new chain, as the 530 setup requires a 116 link chain but only 118 link are widely available.

jackleberry wrote: I think the best compromise is probably around 2.33:1.

Wow. That seems pretty dramatic.
According to my calculations I can get that ratio with a 18T front and a 42T rear. If I can get those sizes...
That would put me right at 3,841 RPMs at 65 mph. That would be a pretty comfy cruising RPM.

ThatGPzGuy wrote:

jackleberry wrote: I think the best compromise is probably around 2.33:1.

Wow. That seems pretty dramatic.
According to my calculations I can get that ratio with a 18T front and a 42T rear. If I can get those sizes...
That would put me right at 3,841 RPMs at 65 mph. That would be a pretty comfy cruising RPM.

That's what I'm soon to be running. I got everything from Z1Enterprises the first time. They are perpetually out of stock on the 18T front sprocket, though. Luckily, the later models of KZP had an 530 chain with 18T front sprocket stock (or so I believe). So I have one of those on order. It's $10 more than the aftermarket one...

There may be some others available but they lack the boss that the OEM sprocket has, so you'd need 4.5mm of spacers on them to make them fit. Spacers were going to cost me more than the extra $10, so I went with the OEM part.

When you install the rear sprocket, be sure to measure it carefully. If I had followed the instructions in the FSM (chamfered edge in), then it would have offset my rear sprocket by ~2mm. The correct orientation for the 42T rear sprocket from Z1E was chamfered side out (which was also number side out). You're not going to get instructions with any of this stuff and every part may be different, so just measure the stock stuff you take off and be sure the replacements will line up the same.

Whether 2.33:1 is comfortable at cruising depends on you. I can tell you that cruising at 2:20:1 isn't too bad and I get between 36 and 40MPG on that bike. However, if you cruise at 80MPH, you'll still wish you had that sixth gear. But, hey, it's not a Harley... I find that the motor runs much better at higher RPM when I wear earplugs--gets me over that psychological barrier of feeling like I'm grinding it to bits by cruising at 6000RPM.

Great information Jackleberry: exactly what I was looking for.
Regarding the cruising speed/comfort I don't have anything to compare to but I know it is much quieter and "leisurely" at 55 mph than at 70 mph. I attribute that to the RPMs but some of that might be wind noise as well. I should try the earplugs...

Partzilla has the 18T front sprocket for a 2005 KZP for $28.81. It doesn't say it is a 530 but with 18 teeth it probably is.

ThatGPzGuy wrote: Partzilla has the 18T front sprocket for a 2005 KZP for $28.81. It doesn't say it is a 530 but with 18 teeth it probably is.

Yeah, that's the one I bought... Still waiting for it though. I know it's 530 because the KZP line switch to those from 2002 on. I believe the first few years were 17T then they switched to 18T. I never found any conclusive evidence that it's an 18T sprocket, just that the part number ends in "18" and an offhand remark or two on forums. Did you find something?

I probably based it on the same evidence you have. The stock 630 gear is 15T and the stock part number ends in 15T.
Makes sense.