Service

SERICE

BY JOE MINTON

S-S-Shaky Suzuki

I have a 1 990 Suzuki GSX-R. It has plenty of power and good suspension, but considerable vibration at certain rpm levels. For hard charging, it’s not so bad, but I would like to do some long-distance riding. Any suggestions?

Michael Watts Shreveport, Louisiana

As Cycle World has pointed out in various tests, the GSX-R 1100 does indeed, at times, produce annoying levels of vibration. Actually, all inline-Fours are afflicted to some degree with vibration. That vibration can be countered with a counter-rotating balance shaft and/or can be dampened with a rubber-mounting system. Your Suzuki has neither feature. There isn't much one can practically do about this sort of inherent shaking.

Sometimes, though, engines vibrate because they are out of tune. Carburetors that are not synchronized, overly rich mixtures, too much ignition advance, weak ignition coils and worn sparkplugs are common causes of undue vibration. Loose motor mounts will also exaggerate vibration.

Give your bike a thorough inspection and check its state of tune. If everything is as it should be, maybe you can get some relief with soft handgrips, padded gloves and a reworked seat. NBI Upholstery (36 JO Midway

Dr., San Diego, CA 92110; 619/2238801) uses a foam that is unusually effective at isolating vibration, and can re-do your GSX-R seat for about $95.

Blown CB450

I have a Honda CB450 that I can not figure out. I haven’t been doing any hard riding, but I have had two head gaskets blow out. When I put a new head gasket on, 1 have to pull the engine, which gets to be a real hassle. I had the head surfaced to make sure that it was pot warped before I put the last head gasket on. What causes this problem and what can I do to prevent it from happening again?

Lee Stedje

Gruver, Texas

When a motorcyclist says that he has a blown head gasket, the statement can have two meanings. First, that combustion gasses are leaking by the head gasket or, secondly, that oil is leaking by, the oil leak being more common.

Oil seepage around the head gasket is common to many Hondas of the '60s and '70s. There can be several causes. Your 450 cylinder block consists of flanged steel sleeves pressed into an aluminum block. Honda placed Orings around the sleeves, at the base of the cylinder block, to prevent oil from

creeping up 1/u! sleeve and out i/ic to/I ?[[tht' ci'Ii~idt'r w/it're ii will leak hr the gasket. if i/lost' 0-rings have been re,noied or hare gotten hard, oil can find its war up the sleeves. /f't/ie çi'liiider stud nuts are no! torqued corrt'ctlr, oil iiiarfiiid its war past the gasket. Be sure that you re-torque the nuts after the e/Igine has heeii run wit/I a new gasket and has cooled off I hart' never seeii a CB450 i'ithi a trulr hlo~t,i head gasket. 0/it' 1/la! al lowed combustion gasses to escape. You have addressed 0/it' oft/it' miiore (OIflhllOfl (tlU5t'S (?fs1~1 a leak hi miulling 1/it' head to ensure that it is fiat. i)id you check i/Ic' ci'/inder/or flatness? Those sleeves 1/1(11 are pressed into the cylinder have been knoii,i to sink below the level (?f 1/it' aluminum block. This will great/i reduce the clamping pressure bet t't'en i/It' flange all/It' top ?f the sleeve and 1/it' cylinder head. When that happens. gasst's can leak by the sealing ring crimped around the cylinder bore hole in i/ic gasket.

Classic 05550 I own a clean, straight 1 977 Su zuki GS550. Recently. I have been thinking about selling the bike. I was wondering, if I were to rebuild the engine and fix up the bike SO that it was `~bra nd-new." would it he worth something? Or should I keep the bike and wait for its value to go up? David Harrod New York. New York You have run up against an all-to (VIllfllOfl dile,,,,na. Your perft'ctii'tint' motorcycle /1(15 little niarket t'alzie. This situation ha.s' become normal Wit/I Japaneve nioiorcrcles built in the late 70s to ,nid-80s. Somnc' oft/ic finest mo/ore re/es ever m;iade now have little value, and worse. the cost (~f~~'pc1ir11ig or overhauling themii is oftc'n greater than What they cami be sold/or If your GS55() is valuable toi'ou. then it is certainh' worth the expense to repair and maintain. It is a very good motorcycle and should give you ex cellent service for rears. Just don `t expect to ever miiake a profit on it beyond 1/ic pleasure and service it can give you.