im going to look at 2 seca 2's for sale tonight

The guy wants 1200 for both bikes, a 95 and a 98. Said he bought the 95 as a parts bikes, and the 95 ran better than the 98 so he just rode that one. Apparently the 98 is a bit hard to get running, he said the carbs will need cleaned, the bikes have been sitting for a year so both will get cleaned regardless.

What should I look for on a seca 2? I'm going to try and borrow a compression gauge, anything else?

 

Same stuff as any other XJ. It's all the same mechanics, minus a few little things. Valve shims are a different diameter. Airbox and filter are easier to get to. Rear disc brake, which is nice.

A Seca 2 is probably most like the XJ550 you're already got than any other XJ (650, 750, 1100, ect...), being chain driven.

Oh and there's a vacuum fed fuel pump with a fuel filter near it. It needs to be flushed out if the bike has been sitting with gas in it for a while.

Can't think of anything else at the moment. But a compression test as you mentioned is critical. $600 ea. for some could-be-dailys is fair.

 

Thanks.

Were you saying the fuel filter would need flushed?

Do these bikes have that same chain rattle at idle too?

 

I dunno the price might be a tad high depending on the actual condition of the motors.

As Andrew said, they're quite similar to your 550 and will need the same "checklist" of things attended to. The key is the compression test results. My Clymer shows specs of 142~156~164 (min/std/max) but that's for the FJ600; my book only goes up to 1987.

Maybe Andrew can give you the specs for the later motors.

 

Yep, the manual states the same thing: 156 psi standard.

And sorry, I meant the fuel pump should be flushed. If you get to that point, I can describe the best way to do it.

Cam chain rattle -- just as susceptible. They have a similar tensioner on the back of the motor that usually takes care of the rattle when you reset it.

Yea, if the motor is good and cosmetically it is decent, $600 is fair. But if they need tires and brakes and fork seals and there's rust everywhere, I'd try to haggle him down a bit. But you mentioned he was riding one, so hopefully that's a good sign.

People don't seem to take very good care of the Seca II's. I think mainly because they get 'em as commuters. They're not old enough to be considered "classic", and not new enough to be that "sparkling gem in your garage". Shame. They're really neat bikes.

 

Much appreciated guys. I think I'm gunna pick up a compression gauge on my way to look at em tonight. Are the plugs on these a common size, or am I gunna have to find an adapter for it? Ive never done a compression test before but I'm sure I can figure it out.
Crank it over a bit and watch the highest point the gauge hits right? Add some oil and if numbers get more ideal it indicates a ring problem right?

 

They use NGK CR8E plugs, which are 10mm.

Yep and yep. You'll want to bring a charged battery, too.

 

The "common size" spark plug is 14mm; your 550 takes a 12mm, and apparently these things take a 10mm! Make sure the gauge you pick up "does" 10mm. (And 12mm so you can test the 550 too.)

Remove all 4 spark plugs, disconnect TCI (should be obvious under the seat) hold throttles wide open and crank until gauge stops rising. Record result. I generally do all 4, then come back and do all 4 again.

I wouldn't worry about a "wet" test unless you really WANT to buy into a to-end rebuild; I generally walk away from anything with soggy numbers just because there are so many "tight" motors avaliable out there.

A seriously healthy motor will blow between spec and max; and within a couple pounds on every cylinder. Find one like that and you've got a gem.

 

well, lets see them!

 

didnt even look at em last night. The guy seems nice, just hard to meet up with.

Me and a friend of mine were going to split the money, and we wont have it for a week or two, so theres no huge rush on my end. I told him that too, so maybe hes not in a huge hurry either.

If he winds up getting rid of them before then, which for some reason i doubt will happen, i have an opportunity at a cheap ducati.

Apparently an acquaintance of my roomate got arrested and his mother is selling his newer ducati for less than a grand to help get him out, or pay for a lawyer or something. The details for it are a bit weird so ive been trying to get the guys mother's phone number to talk to her about it. apparently its legit though, we'll see what happens in the next two weeks.

 

Funny, now that ive posted this, the guy got a hold of me and im heading out there in about an hour. Ill post pics in a bit.

 

Well I took a look today.

There's a running 95, and a 98 that runs with a bit of effort.

The 95 is complete except for a fairing that is the wrong color. Tires are 3 years old, its been sitting for a year and started. The compression numbers were 150 across the board.5xxx miles.

The 98 was complete, he said it starts with a bit of force fed fuel. When I did the compression test it read 130 on 1,3, & 4. On cylinder 2 it read 30 psi. Put a bit of oil in it and read about 70. Has 7xxx miles.

Both bikes were cold for the compression test.

Noticed a college sticker on the 98. Maybe the kid rode the piss out of it and didn't touch the valves, and damaging other things in the process

I'm curious about possible causes so I can talk this guy down and level with him, not to mention what I would need to fix if I did pursue this.

From what I'm thinking, rings and valve work atleast.

One question I have too. I hear about "burnt exhaust valves" from neglecting valve clearances. Can someone explain what a burnt valve is?

 

That is sad - two lost pups. One has been ghetto repaired and the other ridden by Evel Knieval's frat house relatives.

30psi is way low and too low to support combustion. Hard to start-yea no fire in #2 at all. Your wet test shows a ring problem. Burnt valve is possible, but not definitive by that test. You could explain to the seller that it will need serious engine work to be fixed, and that should give you leverage - cause it's true!

Proper valve clearances and seating must be maintained so that during each stroke they are in the correct position. Critically important for the exhaust valve to be firmly closed during the combustion stroke. Opening in advance it is fully exposed to the high temperature of the combustion gas which deteriorates the valve.

Also anything that prevents a valve from seating properly for the maximum amount of time means it can't dissipate it's excess heat into the larger heat sink of the head. It then heats up to critical levels and can warp or melt to the head-so you have a burnt valve. Intake valves can get burnt, but 9 of 10 it's exhaust. If you think about the 4 strokes and where the valves are you can see why.

With the low mileage, the age of both bikes, and the fact that even the bad one will run - I would say go for it if the price is right. It might be fun to fix and possibly profitable.

 

One thing I forgot to mention is the extras. He had about one spare of everything except.for a motor. Spare gas tank, 2 spare rear fairings, spare starter, rack of carbs, full wiring harness, spare frame with a few bits still attached, spare forks, turns signals and brake lights.

there was more back there too.

I would love to give these bikes a good home, and my buddy wants the 98. Even with the problems, he said hell pay more since ill be doing all the work.

I'm Thinking about talking to the guy and seeing if he buys shims, ill change em and do another test.

What would the plan of attack be if you owned this motor? What order would you troubleshoot, and what's the worst case, mainly that #2 cylinder.

 

To directly answer your more important questions:

A burnt valve is a valve that hasn't been closing all the way, and as a result, has become physically burned by the exhaust gasses streaming past. This can cause all sorts of bad things to happen, right up to and including its little head snapping off and tearing up the piston and combustion chamber.

That #2 cylinder could have burnt or "dropped" a valve as described above, or it could have a damaged piston/rings/cylinders.

 

I think you should go see him with 1100 $ and don't ask him any more questions

 

I was thinking about offering him 1000$ and if he doesn't bite by the time we have the money maybe 1100$

If the valve had broken off that would result in no compression right? Or is it possible that maybe a small chunk of the seat broke off?

If I were to replace a valve in the head don't I need to consult a machine shop to "lap" them? Or is that only for a valve that has been used?

 

New valves need to be lapped too. A machine shop isn't a requirement you can lap valves yourself if lapping is all that's needed. You need a machine shop for things like cutting seats, replacing guides, etc.

There's not a lot of difference between 30lb and zero; the most likely diagnosis would be a burnt valve but you wouldn't know until you tear it down.

 

Called a podunk yamaha shop for a quote on a valve, seal and gasket. It's 160 bucks. I talked to the guy and apparently he's pretty familiar with xj's. He highly doubted a burnt valve for some reason, kept saying how these engines are bullet proof. He did recognize the valve clearances as a possible cause for the compression, but not for a burnt valve.... weird.

anyway, were gunna try to get these. The 95 is pretty much road ready, ide probably tinker with the carbs and brakes, nothing major (labor & cost wise). Then Ide also have the 98 to tinker with, he doesn't plan on riding until next year. I'm looking forward to trying to tackle this myself. Im not afraid of the top end. It's splitting the cases that's unfamiliar territory.

 

Why would you need to split the cases?

Oh, and even the most "bulletproof" motor in the world can burn a valve that isn't closing tightly. Based on what the guy quoted you, he has NO IDEA what's involved. Be very afraid. Do it yourself.

 

I would never pay someone to work on anything that I can reasonably do myself.

The reason I got that seca was mainly for the experience to work on something new, and branch out my skills. I wasn't sure if riding was going to befor me or not. I got to ride it for a week and I was hooked.

The only reason I talked to that guy was for a price, and when he was talking to me about all this it sounded like every other mechanic out there we hear about on the boards. I had never experienced that until now.

I would assume that I should change the guide in case valve warped. I would think that would do a bit of misshaping to the guide.