The quick rule of thumb is that a one-tooth change in a counter-shaft sprocket equals 2.5 teeth at the rear. Bottom line-start with either the 18-tooth CS or the 40-tooth final drive. That should make for more relaxed cruising without straining either the clutch or your nerves. You can always go up or down a tooth to fine-tune it.
Under Pressure (ized)Q Your columns are a great help to me-and to our H.O.G. chapter here in Mendocino County.
I have a 2005 Harley-Davidson Softail Standard that I bought used. The front tire that came with the bike is an Avon from England. I have always kept the front tire pressure at 31 psi, as recommended in my owner's manual. The tire has 9000 miles on it, and there is still good tread on all of it. However, the tire's center band of rubber (middle of the tread, all around) is 1/8 to 1/4 inch higher than the rest of the tire, like a ridge. My Harley dealer said I've been running too low a pressure, that the recommended pressure in the owner's manual is only for Harley's brand of tires. He said other brands should use pressure specified by the tire manufacturer. My Avon tire says the maximum pressure is 41 psi, but I always thought maximum was not necessarily the correct pressure. Do you know anything about this?Bear KamoroffWillits, CAVia e-mail
A First, thanks for the kind words, and congratulations on pulling 9K out of your tire. That's admirable under any circumstances. Your dealer is right on the money-the tire is underinflated. Assuming that you're using the Avon MH90-21-56H-AM41 Venom, which is a popular Softail front tire, the pressure should be set at 36 psi (cold). All tire manufacturers maintain a Web-site listing inflation figures; Avon's is www.avonmotorcycle.com/us/en/Fitments.asp. That info should be in its printed catalog, too.
You are correct in that the max pressure figure stamped on the tire's sidewall is the maximum pressure that the sidewalls can handle under maximum safe-loading of the motorcycle, and as such isn't the tire pressure you'd use under normal circumstances. About the only time you'd need that much air would be if the bike were loaded to the max on a hot day and you were running at high speeds for long periods of time. As a rule of thumb, subtracting 3 psi from the maximum pressure will usually get you pretty close to the recommended pressure.
Short And SweetI plan to install the Bella Corse air-injection block off kit in my 2005 T100 Triumph Bonneville. Does this kit require any carburetion jetting changes?BenVia e-mail
A The Triumph air-injection kit is a passive device that only injects air into the exhaust header to help reduce exhaust emissions. It does not affect combustion in any way, so the short answer is no-removing the plumbing will not affect the jetting, so there's no need to re-jet.
How-To: Installing A Jet KitDespite the fact that carburetors are fast fading from the scene, there are literally millions of them still in use. I've no doubt they'll remain so long after I've gone to a home for doddering old mechanics. In the main, most carburetors work fine most of the time, but occasions sometimes arise when a little surgery is needed. Hence the popularity of the jet kit. While re-jetting a carburetor may seem like a daunting task-especially if your only contact with one has been turning a twist grip-it's actually straightforward. Here's the 411.
What's A Jet Kit? This may sound like an obvious question, but if you've never purchased one, how would you know? A jet kit is a comprehensive assortment of jets that allows you to reconfigure your carburetor's fuel delivery either to suit some specific purpose such as the installation of an aftermarket exhaust or airbox kit, or to correct some deficiency in the way the bike runs from the factory. As a rule, along with the hardware, you'll receive some pretty thorough instructions and in some cases a credit slip for a free dyno run so you can be certain you've selected the optimal combination of jets for your application. Be aware that not all kits include the same pieces. For example, one manufacturer's kit for a given model might include pilot jets, while another's may not.