Bump:

I don't care about no stinkin' upper chain guard; referred to as "tassles" on dirt bike tv. What about the lower chain guard and the 51-er?

Lance

 

You may have to be the guinea pig for us and pick up a 51 and try it. I don't recall hearing anyone here say they are running a 51 rear sprocket, but I could be wrong. Do it and let us know!

 

I weigh 175 and stood mine up in second the other day. Scared the crap out of me because I wasnt expecting it. I was screwing around in a friends driveway hit the clutch and reved the hell out of it and let out in second. It almost got away from be because I wasnt expecting it to come up.

 

Doh! Richt runs a 51 - sorry about that, it didn't click in my feeble brain.

 

Just to clarify slightly - I ran with 14:49 for about 20 miles or so - a few miles of pavement to the the trails, a few miles of trails, then the pavement back at which point I took it off. The 49 went on without any clearance issues that I noticed, but honestly I didn't look too close. If it rubs or causes the chain to rub a bit, it wasn't enough for me to notice on my short ride with it on. I think several folks here run with a 49 rear sprocket and can verify for sure any interference with the lower chain guard.

I reciently went to a 49 T rear sprocket with the 14 front. I havn't found any interference with the lower chain guard as Nobrakes states. I switched out the stock chain for a 115 link Krause Racing chain to try to keep the stretch down to a minimum. (it came as a 120 link unit but a bit of 'dremeling' and I was in business with the 115....)

 

This response is a general response to anyone that comes along later trying to educate themselves on gearing. Almost everyone on this forum knows more about this stuff than I do, but I think this is a pretty decent summary of what I have learned here about chain gearing. If I insult anyone's intelligence, it is not intentional. It goes without saying that if I mistate anything here, someone please correct me. I am pretty new to all of this.

Going smaller on the front by 1 tooth is analagous to going larger on the back by about 3 teeth. The 45 tooth on the back will ADD gear ratio, NOT CANCEL OUT the effect of the 13T on the front. Folks have posted gear ratios before, but here are a few that will help illustrate how they work out.

42/14 (stock) = 3.0
42/13 (common mod) = 3.23
45/13 (fairly common mod, but not as common as the 42/13) = 3.46
45/14 (about same ratio to 42/13 w/ quieter stock front sprocket, but requires new chain) = 3.21

The ratio between back sprocket and front sprocket, is just that - a ratio. It is calculated by dividing the tooth count of the back sprocket by that of the front. The number is a multiplier that tells you how many time the camshaft has to rotate in order to turn the back wheel by one complete revolution. If the number is large, you get less turns of the rear wheel per turn of the crankshaft, but with a more direct translation of power (I might be misusing the word power here). The bottom line is that you pull stronger with a higher ratio. With a lower ratio, each turn is less powerful, but you get more turns of the rear for each turn of the shaft. That means that the bike has the potential to go much faster because a given number of shaft turns spins the back wheel more times.

As with all things, gear ratio is a tradeoff. Luckily, we can mix and match front and rear sprockets fairly easily to match our individual riding style.

As for adding links, I am pretty sure this can be done, but I don't have a clue what is involved. I would imagine that there is some equipment required that costs as much or more than a new chain. If you end up modifying several chains, it is probably worth getting the equipment and extra links. I expect that I will not change back and forth on chain size much, though, so I just bought a 108-link chain to go with my new 45T rear sprocket.

I hope this helps.

 

get rolling and rev up to about 5000 and feather the clutch and up u go. all the mods i have done are full evox exhaust, snorkel removed mixture opened to 2.5 turns out. all stock air filter,stock gearing. im 200 pounds. i justpush down a little on the front end and up she comes.