Monday, January 14, 2008

Petcock Reprise, Tach Seal

Well, I've put about 60 miles on the bike since getting it running, and it's a sweet runner. The carbs required only a little tweaking to get it down to a sweet, smooth idle, and it fires off on the first button push every morning. The brakes are hard as bricks and a delight to use, and the refreshed suspension gives the bike good behavior over bumpy surfaces with no head shake up to the speed I chickened out at - 115 according to the speedo. It got there mighty quick - this thing has tons of power. It's also enough to cruise in comfort at 80 mph on our LA freeways. The transmission shifts nicely after I adjusted the shift lever down one spline on the shaft to match my boot better.

So what's the catch? Well, there are a couple of small issues that I will have to deal with:

- A slight oil leak at the tach drive, and another at the valve cover gasket. Both dripped oil on the exhaust leaving me with a nice oil cloud at long stop lights.
- A gas smell emanating from the bike. Seemed to be coming from the carbs, which were damp on the bottom. This only appeared after parking.
- A couple of cosmetic issues that I want to deal with, including the caps at the end of the cams, the engine side covers and the chrome starter cover.
- The charging system or battery might be a little weak - at stoplights the lights dim slightly until the revs get back above 2000-3000.
- The clutch rattles (another common GS problem) but that might be solved with a carb balance.

Curiosity got the better of me, and a few days ago I decided to deal with the carb issue. A wet drain tube from one of the center carbs pointed to a leaky petcock. I was a little irritated by this because I had just replaced all the seals. One bolt sets the tank free, and with it on the bench I watched the outlet for a few seconds to verify that it was dripping slowly. I tipped the tank over and disassembled the valve portion of the petcock. Everything appeared to be fine, but there was a tiny bit of corrosion on the back of the valve lever. I sanded it on a piece of glass with 800 grit sandpaper until all traces of pitting were gone.

Back together it still leaked, which meant the problem was with the diaphragm. I pulled the back apart and sure enough, the o-ring on the diaphragm valve was cracked. Damn - Suzuki doesn't see fit to sell it separately, and I was starting to regret not just buying a new petcock. I grudgingly placed an order with Z1 enterprises for a new diaphragm. I always regret buying aftermarket parts, and this time was no exception. The diaphragm that arrived had an o-ring that was too small for the recess in the petcock. Why do I bother? I'll live with the seepage for now, but I will be buying a new petcock soon.

While I had the tank off I decided to reseal the tach drive and valve cover too, and do a valve adjustment. I removed the bolt and cable and started to gently pry the drive housing out of the head. Before I knew what happened, the housing broke off flush with the head surface.

Shit.

For better or worse I was tearing into this thing. I pulled the valve cover and tried to pry the stub of remaining tach drive out of the head. It wouldn't budge, obviously stuck in place with 30 years worth of aluminum corrosion. Damn, damn damn.

The next step would be to pull the cam but I was able to avoid it with a pair of vice grips, pick, punch and hammer. The carnage took out the gear, too, so it looked like I'd be buying more parts than I anticipated. With the valve cover off while I wait for parts, I figure it's as good a time as any to take care of all the engine issues that I still had.

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