Sorry Jaided - don't know how I missed that. So, what's it reading, and what do you think it SHOULD be reading? Have you got someone with an accurate speedo that can time you? Whatever the % difference is, that's the % difference you need to make with a gear change.
Example. Let's say it's reading 60, but it should be reading 75. That means it's reading 25% too slow. If it has a 19 tooth in there now, then you need a 25% change in the driven gear which is like a 14 tooth. 16 is the lowest I've seen. So you can put a 16 in, and still be about 10% off; or you'll have to change the drive gear to the next highest one.
Have you checked to see what drive gear you have? If you know the % you're off, and what drive and driven gear you have, we can figure out what combo will get you there.
Example. Let's say it's reading 60, but it should be reading 75. That means it's reading 25% too slow. If it has a 19 tooth in there now, then you need a 25% change in the driven gear which is like a 14 tooth. 16 is the lowest I've seen. So you can put a 16 in, and still be about 10% off; or you'll have to change the drive gear to the next highest one.
Have you checked to see what drive gear you have? If you know the % you're off, and what drive and driven gear you have, we can figure out what combo will get you there.