Pull the Head?

[FJ1100mjk]

Hi:

I had my '85 FJ1100 running briefly last fall in the garage. I have had it less than a year, bought it in a non-running (it had sat for a long time) condition and, have never ridden it. When I got it started last fall, it ran like crap, so I decided to go through it this winter. The usual: rebuild carbs, valve' clearances, clutch slave cylinder, new clutch spring and removal of wire clip in clutch basket, cleaning and greasing shock linkage and pins, little black peg on gas gauge to keep it from going full circle, charging (over) problem, and so on.

I just finished setting the valve clearances.

I know that you're supposed to perform compression and cylinder leak-down tests with the engine warm, but I'm stuck with it not running (carbs are now off), so I did the tests with the bike cold. Compression tests were good with three out of four cylinders at 130PSI, and the other at 140 PSI. However, when I did the leak-down tests, three of the cylinders were leaking past the rings, as I could hear that with the oil filler cap removed, but one cylinder was clearly leaking past the exhaust valve(s), because I could hear that coming out of the exhaust can's opening. And its pressure decay was worse than the ring-leakers. I used a Harbor Freight (PN:94190) leak-down tester, and none of the cylinders' decay rates were acceptable, but I chalk that up to cold engine components. I suppose the ring-leakers' numbers would improve with a warm engine, but I'm not sure if the cylinder with a leaking valve would.

I'm not enthused with taking the cylinder head off and doing the valves. Time and $.

Considering that the compression numbers are good with the engine cold, what are your opinions for (or not) yanking the head with what is stated above? I'm wondering if the valve leaking is such a big deal, and would the bike possibly run all right anyways? Or is this valve leaking (with the parts cold too) and end-all, and I'm forced to yank the head and fix at least that leaking valve?

The cylinder that is leaking past the valve is the one that I found a tight (.003" clearance) valve on, so I'm wondering if the valve got burnt.

The bike has a little over 20,000 miles on its clock.

Thanks in advance for your feedback.

Marty

[Harvy]

Marty, you may find that now that you have the valves adjusted correctly, that when you get her running, the carbon build-up on that exhaust valve will blow out and she will seal ok.
I'd be inclined to run her for a while and then see how she looks b4 pulling the head.

Harvy

[ribbert]

My opinion is, don't get ahead of yourself, if it's a cold motor that hasn't run for a long time the numbers and leakdown test aren't worth much (except the compressions look good under the circumstances). Aside from being cold, funny things happen to motors that haven't been run for a long time. At 20,000 miles everything should be good. Get it rideable, put a few miles on it then re-check everything if you're not happy with the way it runs. If it runs like crap I'd be looking at the carby's. Even a motor with poor compression should run pretty well.
Noel

[grannyknot]

Get her running and take it slow until the fresh oil is warmed up then let it rip. A good hour or more, hard acceleration then back off the throttle completely letting the engine slow you down, that will blow the carbon out. Maybe even some Seafoam in the tank.

[Mark Olson]

go thru and adjust the valves , swap some shims around . 

Then grip it and rip it.   

Just like it has been said already, sounds like you have some carbon build up.  Do some full throttle 3rd gear pulls and engine braking to wake your engine up.

Plan a 100 mile rip and then check it out again.

[bigbore2]

It is cold and snowy in St. Paul in the winter. But this winter not too much snow, get out on one of those 45-50 degree days you occasionally have. I grew up in that area but escaped many years ago. I still keep in touch to know how the weather is doing up there.

[FJ1100mjk]

Everyone:

Thanks much for the advice. I have everything that I need to do through the carbs, and will be going through both sets on the '85 and the '87.

I'll mount the rebuilt carb set on the '85, get it running, and synch the things.

It is cold here, and with a high of 13F for tomorrow, it looks like it will be a little while before I can take the FJ1100 out for a 100-miler shakedown. I look forward to ringing the bike out.

I wish I was in NM, CA, in lands Down Under, or some place warmer to get out sooner.

Marty

[gripit_N_ripit]

. 

Then grip it and rip it.   

thats what i do!!

[Mark Olson]

. 

Then grip it and rip it.   

thats what i do!!

hell ya