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Over the holiday weekend my wife and I traveled to Western NY to visit my family, and so I could help my brother Tim troubleshoot his hard-starting 550 TX. I was also bringing a fender for an 850 GL that my cousin is buying. That's another thread.
Now then, this 550 has the reputation of being hard to start, especially when the engine is warm, and it takes forever to warm up and run on all cylinders. It has about 12000 miles on it, and an Electrosport stator and regulator less than 500 ago. We knew that in 12000 miles, it had probably never had the valves adjusted, so we planned to do that at least.
Before taking it apart, we decided to check voltages at the coils, see how hard it really was to start, etc. Well, it cranked awfully slowly, and had no chance to start. We pretty quickly determined that the battery wouldn't take a charge. So, we grabbed a good, charged battery out of one of the two 850's in the garage and tried again. It started pretty easily, but seemed to be running on only two cylinders. The left exhaust was blowing smoke. I'm told it always did that until it warmed up. All 4 plugs were getting a fair spark. It wouldn't charge the battery at any rpm we could get it to reach. I don't think we saw anything over 13V, even after moving the r/r ground from the airbox (!!!) to the negative terminal post.
Well, we thought about this for a few minutes. I told him about the stator papers, and we decided that we need a good battery and a decently running engine before starting that. We needed to check the valves anyhow.
So, we started into the cam cover. About four of the screws were impossibly soft rust piles. They literally left a pile of rust when the cover came off. Half of those broke off flush to the head, under the frame. Two that didn't break were blue. Blue as in drawn temper blue. This reminded him that he had once let the bike overheat while warming up. He walked away and forgot it for about half an hour. Oops.
Our dad advised him to put a for sale sign on it as is. I gave him my best guess what it would take to pull the head and get the broken screws out. Tim decided that he wants to get this bike into good running shape, so the decision was made to pull the head. There was just no other way those broken screws were coming out. Notably, the broken or blue screws were all along the exhaust side of the head.
We checked the valves before proceeding. All the intake valves were still within spec, but low. We got a .0015" feeler under #2 and #4 exhaust, but had to swap shims on #1 and #3 to get a measurement. #1 had negative clearance.
After Tim showed me how to get the carbs past that insane airbox, I pulled the cam chain tensioner, and we removed the cams. Cam cap bolts come loose in a scary fashion, especially after breaking 4 cam cover bolts. We labeled some ziplock bags and started removing shims and buckets. All 4 exhaust shim buckets had the brown color of cooked-on oil varnish. Sorry, I didn't get a good picture of that. About half of the exhaust screws broke, but this head was coming off for thread repair already. That makes things simpler.
The 10 head nuts that are not chromed acorn nuts were very scary-looking rusty things, including the ends of the studs. We had been soaking these with WD-40 while we worked on everything else, and they came off without breaking anything. Big sigh of relief. The 550 head overhangs the cylinders very nicely. We had no trouble knocking the head loose from the cylinders. Not a bad afternoon's work. Here's what we saw:
#1 piston.
Any of the other 3 pistons.
Everyone can identify the chambers, right? Hint: They're in order.
The base gasket was stuck tight as if the cylinders were welded on. I couldn't convince Tim or my dad at the time that we should pry the cylinders up.
Here, finally, are the questions. What all should be inspected for heat damage? We're already planning to change the valve guide seals, so we'll check the valve springs. I'm thinking now that we should pull the cylinders so we can inspect the pistons and rings for heat damage. Any other thoughts are welcome.
After checking the valve clearances and seeing it run, I think I can say that the valves do not fully account for hard starting and long warm-up. The local dealer "did" the carbs before any of our family knew anything about working on an old bike. If I remember the story correctly, it ran worse afterwards. I'm thinking now that the carbs have a few circuits clogged, especially the idle circuits, and the floats are probably set to the wrong step. Time for a dip and new o-rings, yes? Any other diagnoses are welcome.
Put all that back together and we can start on the stator papers. What are the odds on the airbox ground cooking that new stator?
Now then, this 550 has the reputation of being hard to start, especially when the engine is warm, and it takes forever to warm up and run on all cylinders. It has about 12000 miles on it, and an Electrosport stator and regulator less than 500 ago. We knew that in 12000 miles, it had probably never had the valves adjusted, so we planned to do that at least.
Before taking it apart, we decided to check voltages at the coils, see how hard it really was to start, etc. Well, it cranked awfully slowly, and had no chance to start. We pretty quickly determined that the battery wouldn't take a charge. So, we grabbed a good, charged battery out of one of the two 850's in the garage and tried again. It started pretty easily, but seemed to be running on only two cylinders. The left exhaust was blowing smoke. I'm told it always did that until it warmed up. All 4 plugs were getting a fair spark. It wouldn't charge the battery at any rpm we could get it to reach. I don't think we saw anything over 13V, even after moving the r/r ground from the airbox (!!!) to the negative terminal post.
Well, we thought about this for a few minutes. I told him about the stator papers, and we decided that we need a good battery and a decently running engine before starting that. We needed to check the valves anyhow.
So, we started into the cam cover. About four of the screws were impossibly soft rust piles. They literally left a pile of rust when the cover came off. Half of those broke off flush to the head, under the frame. Two that didn't break were blue. Blue as in drawn temper blue. This reminded him that he had once let the bike overheat while warming up. He walked away and forgot it for about half an hour. Oops.
Our dad advised him to put a for sale sign on it as is. I gave him my best guess what it would take to pull the head and get the broken screws out. Tim decided that he wants to get this bike into good running shape, so the decision was made to pull the head. There was just no other way those broken screws were coming out. Notably, the broken or blue screws were all along the exhaust side of the head.
We checked the valves before proceeding. All the intake valves were still within spec, but low. We got a .0015" feeler under #2 and #4 exhaust, but had to swap shims on #1 and #3 to get a measurement. #1 had negative clearance.
After Tim showed me how to get the carbs past that insane airbox, I pulled the cam chain tensioner, and we removed the cams. Cam cap bolts come loose in a scary fashion, especially after breaking 4 cam cover bolts. We labeled some ziplock bags and started removing shims and buckets. All 4 exhaust shim buckets had the brown color of cooked-on oil varnish. Sorry, I didn't get a good picture of that. About half of the exhaust screws broke, but this head was coming off for thread repair already. That makes things simpler.
The 10 head nuts that are not chromed acorn nuts were very scary-looking rusty things, including the ends of the studs. We had been soaking these with WD-40 while we worked on everything else, and they came off without breaking anything. Big sigh of relief. The 550 head overhangs the cylinders very nicely. We had no trouble knocking the head loose from the cylinders. Not a bad afternoon's work. Here's what we saw:
#1 piston.
Any of the other 3 pistons.
Everyone can identify the chambers, right? Hint: They're in order.
The base gasket was stuck tight as if the cylinders were welded on. I couldn't convince Tim or my dad at the time that we should pry the cylinders up.
Here, finally, are the questions. What all should be inspected for heat damage? We're already planning to change the valve guide seals, so we'll check the valve springs. I'm thinking now that we should pull the cylinders so we can inspect the pistons and rings for heat damage. Any other thoughts are welcome.
After checking the valve clearances and seeing it run, I think I can say that the valves do not fully account for hard starting and long warm-up. The local dealer "did" the carbs before any of our family knew anything about working on an old bike. If I remember the story correctly, it ran worse afterwards. I'm thinking now that the carbs have a few circuits clogged, especially the idle circuits, and the floats are probably set to the wrong step. Time for a dip and new o-rings, yes? Any other diagnoses are welcome.
Put all that back together and we can start on the stator papers. What are the odds on the airbox ground cooking that new stator?
If the head bolts were blued, Id be pretty worried that head might be trash..
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