TOPIC:

bountyhunter wrote:

grumpy56 wrote:

Check out Z1 Enterprises or Dennis Kirk for rear steel sprockets in various sizes.

I scoured the whole internet including those sites: you can get rear sprockets in steel in stock size and sometimes a bit larger, but there are no off-the-shelf steeel rear sprockets in sizes smaller than stock.

If anybody knows where to get them at reasonable prices, please speak up.

There are larger front sprockets available, but I can only go one tooth up on the front because of size limit. That buys me a 6% reduction in RPM which is eaten up by the 110 metric rear tire which is actually a bit smaller diameter than the stock 4.00-18 tire... so I am at stock RPM even with one tooth over on the front.

If you go too small on the sprockets, you have to worry about the chain slapping the top and/or bottom of the swingarm. That's the main reason you don't see smaller than 32 tooth (630) and 38 tooth (530).

You have about 4" of travel on the shocks, plus you have a chain that can move up/down a couple of inches...

Just put on a 38 rear to go with the 15 front. Runs so much better. I had a 42 on the back before that was on the bike when I bought it.

Jeff.Saunders wrote:

bountyhunter wrote:

grumpy56 wrote:

Check out Z1 Enterprises or Dennis Kirk for rear steel sprockets in various sizes.

I scoured the whole internet including those sites: you can get rear sprockets in steel in stock size and sometimes a bit larger, but there are no off-the-shelf steeel rear sprockets in sizes smaller than stock.

If anybody knows where to get them at reasonable prices, please speak up.

There are larger front sprockets available, but I can only go one tooth up on the front because of size limit. That buys me a 6% reduction in RPM which is eaten up by the 110 metric rear tire which is actually a bit smaller diameter than the stock 4.00-18 tire... so I am at stock RPM even with one tooth over on the front.

If you go too small on the sprockets, you have to worry about the chain slapping the top and/or bottom of the swingarm. That's the main reason you don't see smaller than 32 tooth (630) and 38 tooth (530).

You have about 4" of travel on the shocks, plus you have a chain that can move up/down a couple of inches...

32T rear is definitely the smalles you can go on the B4 750 twin because the chain rivet heads rub against the rear wheel hub. I ran a 32 for a long time, the chain only hit the swing arm if the chain was too loose. That clack sound would tell me when I needed to adjust the chain.

Okay, I didn't read the whole string but here's my 2 cents worth.

Gear ratio charts are worth nothing without knowing the circumference of the tire on the bike, the primary drive ratio and the output gear ratio of each gear in the tranny. Also needed is the weight of the bike and the performance level of the engine. I can pull pretty tall gears with a 150 HP KZ engine and get away with it because of the power. You can't expect the same results, with the same gearing if you're only getting 75 horses out of your engine.

When you're changing gear ratios, everything works on a sliding scale, what you gain on one side you lose on the other. Changing ratios to improve acceleration will make high RPM performance suffer. changing ratios to improve high RPM performance will hurt acceleration.The magic is to end up with a happy balance between the two extreems. That why factories give you guidance on tire sizes and countershaft sprocket and read wheel sprockets....They know what works best with their engine and gear combinations.
Of course all factory specs go out the door when you start building a race bike but the same principles still apply...It's all about math and math is a science....science don't lie!

Buzz
AND PS...I would never go with a smaller countershaft sprocket..the chain has to turn a tighter radius and causes increase friction and wear on the chain and sprocket. If you're thinking about changing to a smaller countershaft sprocket and are currently running a 630 chain then concider changing over to a 530 setup.
Example: On a 1982 Z1000 R the stock Final Drive Ratio is 2.73:1 using a 630 chain, 15 tooth countershaft sprocket and a 41 tooth rear sprocket.
You can get the same Final Drive Ratio using a 530 chain, a (nice large) 19 tooth countershaft sprocket and a 52 tooth rear sprocket. This setup also gives you tons of clearance around the swingarm.

kzz1p wrote:

KZ1000 Gear Ratios

Action 4's was big in the mid 70's,I was at their shop in Santa Ana in 1976. Bill Hahn Sr. the turbo wizard was an original partner at Action 4's and he's just a smart grumpy old funnybike builder now,lol.

Nylon sprockets were big in the mid 70's too. S&W and others sold them,never will forget pulling off the highway after a 100+ mph 2 hr. ride only to have the nylon sprocket disintegrate leaving the 1 st. stop light after the exit...

Point being : this is very old info. and Jeff has some good points in his discussion on gearing and pointing out some of the soft spots in the Action 4's info.

kruzer do you have enough room for that big of a countershaft sprocket underneath the cover.19 tooth seems to be mighty big.

how many of you guy's still have nylon sprockets. i still have one it worked great for a long time the only reason i pulled it off was because it is alot cheaper to replace steel ones and i wanted to keep mine as an oddity.