As moderator of J&P’s online forums as well as technical adviser here at the company, I get the opportunity to exchange posts about a variety of topics and interact with hundreds of people each week. And in both venues, I find one of the most asked questions is, “If I change my pipes, will I need to rejet?” The simple answer is “Yes, you do need to rejet.
And now I’ll explain why. But first, a little motorcycle exhaust education: Exhaust technology is the reason two-stroke engines work. Volumes have been written about the principles governing expelling gases out of the beloved internal combustion engine – space forces me … Continue Reading
One thing many of us do in preparation for hot weather is buy an oil cooler. It makes perfect sense, because the oil in an air-cooled engine performs a major role in cooling the engine. Does this mean an oil cooler will enable the oil to do a better job? Well, yeah, sort of — to a point. Fact is, oil coolers do a great job of cooling the oil, unless you pick the wrong unit for your application, or the unit’s not properly installed. In either of those cases, an oil cooler can do more harm than good.
Oil has a tough role in Harley engines. It has to … Continue Reading
During our usual Tuesday get-togethers here on the J&P Cycles blog, we like to tell you about the new pieces of swag you can score for your ride. That includes bagger bling, performance parts, motorcycle luggage or other must-have motorcycle parts that the guys and girls here at the world headquarters have scoured biker-land to find for you. I’m just sitting here, with “Radar Love” blaring in my headphones, staring at my computer screen full of J&P goodies and trying to decide which two gems I want to present to you this week. I’ve come up with a pair of goodies, but be warned: Neither is sexy. But both parts … Continue Reading
July 19, 2010 | By: Bud Milza
Born and bred right here in the USA, drag racing has grown worldwide as one of the most popular forms of motorsports. Perhaps the best part about drag racing is that you can run just about any type of vehicle, including street legal Harley-Davidsons. Whether you ride a stock 883 Sportster or a monster 131-inch Road Glide, you’re free to participate as long as your bike passes the required safety inspection. With literally hundreds of drag strips across the nation, you’ll have no problem finding a legit location to run WFO with zero interference from the man. Aside from hosting sanctioned events, almost every strip offers “test and tune” sessions … Continue Reading
Editor’s note: Today we present the second of two blog entries about carburetors versus fuel-injection systems. Yesterday we heard Patrick Garvin discuss the wonderfulness of modern fuel injection. Today we hear from Kody Wisner, who will opine on the simple magic of a motorcycle carburetor. Read ’em both, compare notes and come to your own conclusion — unless, of course, your mind’s already made up.
By Kody Wisner
In this era of high-tech gadgetry, the trusty carburetor is a survivor — hanging on with bloody fingernails against some very advanced fuel-injection systems. But know this: The modern carburetors of today are very different from those of yesteryear.
Adjustable accelerator … Continue Reading
Editor’s note: What we have here is Part 1 in a two-part series that’s intended to end the bitter brouhaha between proponents of carburetors and those who are ardent fans of fuel injection. Patrick Garvin dominates the discussion today, citing the wonders of fuel injection. Tomorrow, we’ll have Kody Wisner serve up his arguments in favor of old school carburetion. Like most of these pro/con blog posts, we’re probably not going to sway anybody’s opinion. But such musings can go a long way in confirming our right to be hardheaded about such things. And, if one of these blog entries changes your thinking about FI versus carburetion, for goodness sakes, … Continue Reading
In the past, our tech department has been asked to explain the differences between stock Harley transmissions, overdrive transmissions and final drive changes. So we’re going to get your gears spinning on this topic and discuss the history of Harley-Davidson Transmissions and the advent of aftermarket replacements.
In 1936, Mother Harley introduced one of the benchmark motorcycles of all time —the OHV 61-cubic-inch EL. This beautifully styled bike is affectionately known as the Knucklehead. What’s truly amazing about this bike is the design of the transmission, which remained in service until 1986 — an incredible half-century run with the same basic configuration.
There were, of course, different variations available in … Continue Reading
July 6, 2010 | By: Bud Milza
No question about it. Sooner or later the OEM rubber grips on your Harley will be totally spent and need to be replaced. Whether you choose to go with stock replacement or aftermarket grips, the procedure to switch them out will remain the same.
Many of you call us for assistance while in the process of switching out grips but with all the calls we get, sometimes it’s difficult to walk everyone through the process in detail from start to finish. Rather than rush you through it, I’ve put together some step-by-step instructions for you to follow while changing your grips. This procedure is intended for use on models with … Continue Reading
Easily among the most forgotten performance enhancement today is your motorcycle’s ignition system. Adding additional performance parts can sometimes be a waste of time and effort if your motorcycle’s ignition system isn’t upgraded. Today, we’re going to start off with a brief history of Harley-Davidson’s ignition systems, and then we’ll talk about some alternatives.
Mother Harley has utilized a variety of ignitions over the years. In the early days (prior to 1979) a points and condenser system with some type of advance was used. Before 1965, advancing and retarding the ignition was a manual thing, controlled by the left handgrip. Many an unsuspecting soul was pitched over the handlebars attempting … Continue Reading
Electricity and wiring are among the most complicated systems on today’s motorcycle. So what we thought we’d do is attempt to shed some light on this potentially complex topic by defining some of the common terms used when dealing with electricity. These terms are basic Electrical 101 that you’ll hear whenever you’re dealing with any motorcycle electrical system.
Ampere — The practical unit of electric current flow. If a one-ohm resistance is connected to a one-volt source, one ampere will flow.
Circuit — A complete path over which an electric current can flow.
Circuit Breaker — A device designed to open and close a circuit by non-automatic means and to open the … Continue Reading