Alanf’s blog…
Scattered thoughts

Tuesday, December 21, 2004

Box of Shame #4: Beware the temptation of the parts catalog…

Author: site admin
Category: The Box Of Shame

In the Spring of 1998, I brought my GSXR to a track day that our local riding group had put together. I’d prep’ed the bike but it was running poorly and seemed to be running really rich with the spark plugs fouling whenever it was ridden hard. It was also overheating on hot days, which seemed the opposite of what I would expect from an engine which appeared to be running rich. After a few laps on the track, the bike really began to degrade until eventually it didn’t have the power to out-drag a BMW K100RS on the front straight. Clearly this was more than just a jetting problem. Since I planned to ride the bike on an eleven day trip through the Pacific NW in July, this problem would have to be addressed quickly.

Back in my garage, I did a compression test and found that all four cylinders had very low compression. I added some oil to the cylinders and tried the compression test again, only to get the same numbers. Clearly, the valves were the culprit. I tried a valve adjustment, followed by another compression test, but the numbers didn’t improve much. Since that meant either valve seats or valve guides, I called my local shop and arranged to have the head rebuilt.

Just before I brought the bike in for its scheduled head overhaul, I got to thinking about how sloppy the second gear shift had been feeling. I called the shop back and asked if they could install new shift forks “while they were in there”. They said “sure” and that is when things started to snowball. The shop called me back the next day and mentioned that they might as well replace the transmission gears as well, after all once the transmission is apart for the forks there isn’t an additional labor charge to rebuild the whole thing. “Okay”, says I, “how much more can that cost?”

When I brought the bike in to the shop, I got to talking to the mechanic. Marv Rosencranz is an ace mechanic, responsible for building some of the rocket race bikes ridden by local fast guy Ricky Orlando. He’s worked on GSXRs for a long time and casually mentioned how cheap the Wiseco piston kits where for the old oil-cooled GSXRs. Well, now, how could I pass up something so cheap? I mean, after all, they already had the motor apart so how much more could it cost?

It turns out the root of the problem was worn valve seats. They’d finally been hammered into the head, reducing their contact with the valves. The seats needed to be replaced and re-cut. The valves were serviceable but the exhaust valves had definitely been cooked due to poor valve seat contact. Since I was already replacing half the motor anyway, I wasn’t about to put questionable valves back in the head, so I had them order up a new set of those too. Do you see where this is going?

GSXR engine leftovers

In the end, the motor was over-bored to the max allowable by the stock cylinder liners. New stock valves, valve seats and valve guides were installed. A five angle valve job was done. The cam was resurfaced. Wiseco pistons were installed, bringing displacement to 1110cc. New transmissions gears and shift forks were installed, along with a new shift star. New clutch plates and springs replaced the old ones. All new gaskets and seals. The bike was re-dyno’ed making a touch over 125hp, not bad for an ancient oil-cooled GSXR. The total cost was roughly the asking price for a good condition used ‘88 GSXR1100. Ouch.

All the old parts were put in the Box of Shame to remind me not to let projects get so out of hand in the future.

Then, one week later, I loaded up the bike and headed for the Pacific Northwest, were I re-learned the lesson about touring on a bike before you’ve found all the little problems caused by doing last minute repairs but that is another story…

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