Ok I think it's time to replace my chain for the first time but I have a couple of questions. The guy who had the bike before me changed out the front and rear sprockets, the rear is a Vortex 251a. I'm not sure what the front is.

first question, will changing the sprockets throw off the "replace chain" guage on the the chain tensioner?

Also should the chain pitch be stamped on the chain somehwere?

 

Changing your sprockets will absolutely change the readout on the swing arm. The position of the rear wheel will be closer or further away depending on sprocket choice. I run a larger sprocket on the rear so my rear tire is closer to the swing arm pivot and actually off of the chart. I simply keep the chain clean and lubed and check it often for wear. I really can't check chain stretch, ( other than indivual links), but more often than not, it is a roll pin that fails, not the link. I keep a close eye to make sure I do not have excessive play side to side and make sure the rollers do have excessive play. Once that happens, the chain is replaced. But, if you put on a new chain, you can mark where it is, then place another mark the same distance away as the chart shows. On average, a good maintained chain will last about 20,000 miles. Actually, probably much longer, but thats about the point I begin to be concerned and replace it wether or not its worn. Just my own piece of mind I guess.

referring to wether or not its a 520,525 or 530, you can simply measure the width of the chain. Im not sure if it is stamped anywhere on the chain, however, I believe it would be stamped on the rear sprocket. If you measure between the chain plates, a 530,(usually used on bikes 900cc and bigger), will be roughly 3/8 on an inch. A 525 chain (most common for 600cc bikes), will be roughly 5/16, and a 520 will be around 1/4 inch.

Also, depending on what sprockets you put on, it will affect how the bike gets its power down. Depending on the bike you have, will depend on what ratio is stock. If you like the current ratio, simply count the number of teeth on both sprockets. If you want power sooner lower in the rpm range, go up the number of teeth in the rear, or down in the front. If you want less power down low and lower rpms for highway driving, do the opposite. One down in the front is very close to 2 1/2 in up in the rear.

Also, you didnt mention it, but you should always change the sprockets and chain as a unit. the chain and sprockets wear together, and if you introduce a new chain or sprocket, the new part will wear out much faster as it "sets" into the old part. Also, you won't have full contact and this can create a weak spot in the system.

 

ya nailed it Squid .....100%

 

I don't change out my chain whenever I change my sprockets, but I'm changing out my sprockets on a weekly basis though depending upon the track. If you're riding on the street, I would suggest changing the chain and sprockets together as a set though or you will wear the sprockets out prematurely.