Smoking and oil consumption

[terryk]

OK, smoking on start up and on deceleration when running hard. Runs strong. Adding a quart every 1,000 miles. Mechanic wants $1,000 to rebuild the top end (valve seals,guides) and replace the piston rings. '87 with 25K miles. Opinions?

[yosemite]

 Smoking on startup and decelleration is usually caused by valve guide seals  The mileage seems relatively low,about   1k/year, so has the bike been laid up? seals can harden through age This can llow oil to pass in the circumstances you describe Check your plugs if they are the correct colour then the likelihood of the problem being rings is reduced
  Dont know about the States but in UK Ihave seen second hand motors going fairly cheap so this may be something to consider but you would have to take into account the risks involved in buying something that you cant always be completely certain  of its mechanical history  although you could offset some of the cost by selling your motor
anyway good luck
Yosemite

[JCainFJ]

 What oil are you running in your FJ? I was getting about the same "quart every 1,000 miles" until I started using Redline 10W40 or 20W50 synthetic. Yes, it is a little pricey but it will not burn off like any of the other 5 or 6  synthetic motorcycle oils I have tried. It will help your FJ shift better too. The ester base stocks that Redline uses are expensive, but they handle the high operating temps better then other oils.
You should do a leak-down test on your FJ before you start a rebuild, this test can give you a better idea of the condition of your engine. You probably wont need valve guides (non rocker arm DOHC engines are very easy on their valve guides, the valve buckets take the side loads). You may find that you will need to go to first over pistons and fresh bores because the cylinders on these bikes warp due to heat.

Ride Well,
Jon Cain

[andyb]

What the mechanic suggests will undoubtedly fix the problem, but is it necessary?  Ideally you should find out where the leak is (leaking into the combustion chamber, obv).  A compression check with and without a pinch of oil in the cylinders will tell you what the rings look like.

On the other hand, to fix either the seals or the rings, you'll be pulling the head off, and with the head off doing the rings is really very little additional work, so while you're in there....

Of course, while you're in there can also turn into a number of performance mods as well

If the smoking is bad enough to bother you, have it fixed (or fix it yourself!).  Otherwise, just check it and top it accordingly.