Hi there. I just ordered a 13t front sprocket from sprocketcenter.com. I have a quick question about shimming that is mentioned in other threads about the 13t setup. What is it exactly lol? I've searched and all I could come up with is shimming your needles.

Makes you accelerate faster.

Shimming/adjusting the needle height has nothing to do with your sprocket change. By moving to a 13T in front, you're lowering your gear ratio, which means you'll be accelerating faster and your theoretical top speed will be lower.

As mentioned, shimming adjusts the needle height in the carburetor which adjusts the overall fuel flow into the intake flow from the vacuum. Most people on here are shimming their needles because many Ninjettes run close to lean from factory (for emissions, they say) and when adding slip-on or removing the snorkle, it pushes their bike more into the lean category. Raising the needle increases the fuel to air ratio at about any given RPM and brings the combustion closer to the ideal.

EDIT: If you're talking about putting a washer or shim in between the keyed washer and the 'folding lock washer', some people have found that when changing the front sprocket there is a gap even when the nut is tightened. Adding another washer, or shim, will close the gap and the sprocket will remain tight.

dont forget you have to oil it more often. The 13T causes a tighter chain bend which forces the lube out faster.

The needles are in your carb. A shim is something you insert to alter the spacing.

Well, my dad was explaining that the stock sprocket is probably thicker than an aftermarket sprocket so a small shim might need to be placed to make sure the front and rear sprocket are perfectly aligned, so I get that now. How often would you recommend to oil the chain though?

I learned how to ride on an 72 Kawasaki 750 h2 surprisingly, at my parents acreage. I would say I'm a newbie when it comes to mechanics not necessarily riding capability. Crotch rockets are definitely different in terms of turning I have noticed, so I do have to learn in that department. I ride with buddies of mine that have GSXR 750's and the like, we don't ride at all on the freeway, only city driving; so I would like to be able to keep up with them off the go a bit more.

We're small business owners of a semi-towing company and have a few employees that are motorcycle savvy, so I'll probably have them do the mod and have my dealership look over it when I do the 500-600 mile service.