Bladder Problem on My '85

[FJ1100mjk]

 

I don't have my end-all, use with concidence, Clymer manual in fronrt of me right now. However, I thought that I was in the tolerance +/- zone given by that manual for the maximum (high) fuel level in the bowls.

I know Randy had posted pics of the official Yamaha's Service Manual's diagrams for the float and fuel levels. I need to do a search and find those again. BTW, what do you use as a value for the maximum fuel level wjen you do your adjustments? I also read (here we go again) that using too low of a level will cause mid-range performance issues. Possibly.

Thanks.

Marty

[SlowOldGuy]

5mm maximum fuel height.  It's easier to lift/richen up the needles to compensate for a lower fuel height than try to drop them further to correct a too rich fuel height.

Also, I've seen far more midrange acceleration problems from high fuel level than low fuel level.

Plus (minus?) it causes fuel leaks.  :-)

DavidR.

[FJ1100mjk]

David:

Thanks for the info. So if I use your 5mm value and adjust to that using the method that I described above, then I shouldn't have the fuel level set so when the carbs are mounted on the bike and there inclined, the level will not be such that fuel will not overflow and run out of the overflow tubes?

Thanks.

Marty

[SlowOldGuy]

How many negatives are in that sentence??

I can't really guarantee you won't have a fuel leak since I still can't explain why mine were leaking.  But that fuel height adjustment "should" give you the best opportunity to NOT have a leak and get proper tuning of the mixture.

You might want to try a new set of brake shims also.  :-)

DavidR.

[FJ1100mjk]

David:

Which sentence is "that" sentence? Not the one where I'm thanking you, I hope :-)

Seriously, I'm not looking for any guarantees, since as the saying goes, there are none in life. A should is good enough for me. Your Super Hero Member status and you being a carb SME (Subject Matter Expert) carry a lot of weight with me and I appreciate the constructive feedback that you and others who share this forum provide.

Off come my carbs. Again. I don't think I'll use those brake shims for the carbs. I'd hate to add their mass back onto my bike. The old FJ handles so much better with the two grams that I lost from each caliper. You know what they say about the benefits of reducing un-sprung mass :-)

Marty

[FJ1100mjk]

5mm maximum fuel height.  It's easier to lift/richen up the needles to compensate for a lower fuel height than try to drop them further to correct a too rich fuel height.

Also, I've seen far more midrange acceleration problems from high fuel level than low fuel level.

Plus (minus?) it causes fuel leaks.  :-)

DavidR.

All:

New float settings (5mm) with carbs on the bike worked! No more leaks or smells. Filled the tank up and got it nice and hot, then put it on the center stand, and waited. Nary a drop! Yippee!

Also shimmed the needles while I had it apart. Ran good, and hope to get more time in the saddle after work in the coming days.

Thanks for the help.

Marty

[FJ1100mjk]

 

Started to leak again, damn it!

After reporting that all was well, and dry after doing some local rides of 20 miles or so, I figured that I had the leaks fixed for good. I took the FJ out for a 300 mile ride this past Saturday that included all kinds of riding, and the beast didn't miss a beat. On the way back to the stateline, I got caught in a rainstorm with the hardest rain I ever rode in. The FFJ never even hiccuped. After that, I figured that I was golden. Came home with soggy gloves and water-filled boots, but feeling pretty good, all things considered. Parked the bike on its centerstand, went and got cleaned up, and went out for some overnight fun.

When I got home the next morning, and opened the garage door, I was greeted with the all-tooo familiar strong smell of gasoline. To my dismay and utter disbelief, the FJ had once again pissed itself. Suprised my place didn't blow up with the fumes and all.

I'm at a loss to come up with what is the problem.

After, a near week of watching and smelling gas drip, I took the tank off to stop the flow. I expected to see gas flow out of the petcock's outlet after I removed the tank, but none does! I'm stumped and throw myself at the feet of the carb gurus. HELP!

I feel (sometimes) like taking a friggin hammer to the FJ, but love it too much.

Thanks in advance for your assistance.

Marty

[Arnie]

Couple of thoughts here.

You could put a solenoid valve inline with the fuel hose.  When you turn off the ignition, the valve shuts.
http://www.clippard.com  should have a unit properly sized for this.  Check that it is safe for fuel use.  You'd probably have to have port size of .250 inch or greater since your's is a gravity feed bike.

Also, David Godfrey, in WA sent me a couple of pics which showed the socket that the float needle seats fit into, had been machined poorly.  This actually cut the new O-rings he'd just installed and let his bike leak, overflow, and run very rich.  He cured the problem by touching up the edge of the chamfer with a jeweler's riffle file.  Would be worth checking anyhow.

Cheers,
Arnie

[Dads_FJ]

This couldn't be a fuel tank venting issue could it?  Pressure built up in the tank and pushes fuel past the petcock and carbs.  After your next long ride open the fuel tank to 'vent' it when you're done riding.

[FJ1100mjk]

Guys:

Thanks for the replies.

Arnie:

I looked at Clippard's offerings and some of the spec drawings for their valves. It looks like they may not fit in the space between the tops of the carbs and the bottom of the tank. And when you take into consideration the valve's associated fittings and short runs of hoses for installation, I think that they'd probably add to the space claim problem. I know that there is another valve out there that I could entertain (http://www.dan-marcrvparts.com/12vomufushof.html), but I think that it and its associated fittings and short hose runs would cause the same space claim issues. Perhaps others here have some comments related to these valves. I appreciate your feedback though.

Dads_FJ:

Yes, I had considered that there may be pressure build-up in the tank in after the long ride. I'd even thought that when I rode back in all of that hard rain, that perhaps the venting system in the cap became filled with some water, and didn't allow it to vent. I haven't gotten to the point of doing the flapectomy on the vent system in the cap. It's on my list of to-do items, but the tank seems to be venting. I know that after the bike pissed itself in the garage, that there was so much on the floor, that I opened the filler cap to look into the cap to try and determine just how much had leaked onto the floor. A lot after 18 hours of sitting! So, I vented the tank at that point, and the bike continued to leak the rest of the week, until I pulled the tank completely from the bike.
I'm kind of wondering if grit in the tank is migrating through the fuel system and keeping things from sealing. When I last took the carbs off and removed their bowls, I found some particles that had made it by the petcock's and needle seat's screens. Too bad one can't put a better fillter in-line, but because of space problems and concerns of fuel starvation with the gravity-fed system, I guess that 's a no-go too.

I've been in direct consultation with Randy@RPM and he's offered some advice, and some tests to do. I'll get to them and report my findings.

Dads_FJ, this weekend in our neck of the woods, is supposed to be rain-free (and I had my share of rain last weekend) for the first weekend in the last five. I think I'll be riding (non-FJ iron) instead of wrenching on this one!

Thanks again for your help and comments.
Marty

[Dads_FJ]

My '84 used to leave a puddle now and then.  I took the petcock apart and stretched the spring to give it a little more holding power, which worked for a short while.  In the long run I ended up replacing the petcock (new OEM) and all the carb needle/seats.  It was spendy, but with the cost of gas, and piece of mind it was worth it.