Project Yamaha TTR230 - Part 2 - Dirt bike chains and sprockets

A SIMPLE MATTER OF GEARING - Sidewinder Sprockets and Chain

Aug. 01, 2007 By Rick Sieman

Email
Print
Discuss

Here's the good stuff we bolted on

When we changed the gearing on our Project Honda CRF230F, the bike came alive! Yep, instead of going to a smaller countershaft sprocket - a 12 tooth replacing the stock 13 – we decided to go the other way. First we tried a 14 tooth and the bike pulled it easily. Encouraged, we went up to a l5 tooth and the Honda 230 pulled it no sweat.

We wondered at the dolts who thought that a 12 tooth item would make the bike better in the woods and tighter trails. Stock, first gear on the Honda 230 is a stump puller. It’s virtually unusable, especially when trying to roll the throttle on gently. You end up with a lurch, rather than smooth acceleration.

We wondered if the Yamaha TTR230 would respond in much the same way. We ordered a 14 and 15 tooth item from Sidewinder Sprockets, as well as a quality O-ring Krause chain and a hardened aluminum rear sprocket to replace the boat anchor heavy steel one.

First off, we tried a 14 tooth. The cover on the countershaft is a complex deal, with little bolts holding everything in place. While we were at it, the stock chain got replaced, as well as the rear sprocket, which was steel and weighed a ton.

Here's our target - a 15 tooth countershaft sprocket

The Yamaha pulled the 14 so easily that we only rode it a short distance before heading back to the garage and installing the 15. That 15 barely fit in there and it was necessary to leave the c/s cover off. Quite frankly, I see no need for a countershaft sprocket cover in the first place.

The bike felt great with the l5 tooth c/s sprocket. In fact, the Yamaha ought to come stock with it. With the 13, you can just about walk alongside the Yamaha. Ridiculous. In fact, you can start out easily in third gear with the stock gearing. Using the 15, you can still start out in second gear most of the time without abusing the clutch. Third gear was now useable over a wide range, from about 10 to 40 miles per hour as a guesstimate. In top gear, the bike positively rips. All things considered, the Yamaha is at least as fast as the Honda, and we haven’t even modified the jetting, or opened up the airbox and the exhaust yet.

All things considered, the very first thing any TTR230 ought to do is change that gearing. And while you’re at it, get rid of that horribly heavy steel rear sprocket. The Yamaha, as delivered, weighs a lot more than the Honda. Getting rid of the lard on the rear wheel not only is a big weight reduction, but it’s unsprung weight, as well.