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Finding Intake Manifold Air Leaks |
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| Written by David Tise (Bulldog) | |||||||
| Friday, 11 June 2004 | |||||||
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David is a Technical Moderator, for Baron's Custom Accessories Technical Forum Your engine had been running fine. Recently it has started running poorly or backfiring, maybe when its warm, maybe when its cold or sometimes the problem just seems to come and go. The problem shows signs of both a rich and lean running carburetor. You have done the obvious like change jets, replace spark plugs, check plug wires and replace your air filter element, but the problem persists. You and your mechanic are quite frustrated because you can't seem to identify the problem. Erratic symptoms like these can be the sign of an air leak at the intake manifold or carburetor. The design of the Road Star engine and the intake manifold make it prone to air leaks. Improper installation and age are two major contributors to the condition. Symptoms usually develop just after working on or around the carburetor. Finding an air leak at the manifold is simple. All you need is a can of penetrating oil (like WD-40) with the extended nozzle attached. With the engine idling, direct a heavy spray of the penetrating oil at the manifold gasket area and base of the carburetor. When the spray hits the area leaking, there will be a distinct change in the sound of the engine. If the air leak is major, the change in sound will be quite obvious. Smaller leaks may only create minor changes in the sound. The engine temperature need to match the times the problem most frequently occurs. If you accidentally spray the exhaust system, you may get a little smoke. The penetrating oil can be cleaned up by washing the bike after the engine cools. The CV carburetor has one additional area that can create problems. The slide has a neoprene diaphragm at the top. If the diaphragm is installed improperly or develops cracks, an air leak will occur. Problems are most likely to develop just after re-jetting or making modifications to the carburetor. Make sure you properly install this diaphragm after upgrading your CV carburetor. The diaphragm must be properly seated or an air leak will develop. Using this information, you now have the means to identify the cause of may baffling performance problems on your engine. Bulldog Barons Custom Technical Form Staff
Questions should be asked in our forum (Use discuss link below). The forum is very active and you stand a good chance of getting your questions answered there. If you would like to leave feedback for the author, or have additional information you think will benefit others, please use the comment section at the bottom of this page. Discuss this article on the forums. (0 posts) DISCLAIMER: This information and procedure is provided as a courtesy and is for informational purposes only. Neither the publishers nor the authors accept any responsibility for the accuracy, applicability, or suitability of this procedure. You assume all risks associated with the use of this information. NEITHER THE PUBLISHERs NOR THE AUTHORs SHALL IN ANY EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, PUNITIVE, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, OF ANY NATURE ARISING OUT OF OR IN ANY WAY CONNECTED WITH THE USE OR MISUSE OF THIS INFORMATION OR LACK OF INFORMATION. Any type of modification or service work on your motorcycle should always be performed by a professional mechanic. If performed incorrectly, this procedure may endanger the safety of you and others on your motorcycle and possibly invalidate your manufacturer’s warranty.  Quote this article on your site | Views: 36630
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