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In the weeds

Started by codell, December 27, 2021, 09:00:34 AM

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codell

This mess started out because I wanted to perform 'preventative' maintenance. I hydro locked a rod (twice) on a Gen 1 Concours because of l leaking petcock and a carb float valve and I never want to go through that again.
The bike is an '89 with 22k on the clock and it ran fine.

This to me should have been a simple procedure, replacing the float valve and seat, but now I am in the weeds.
My first mistake was using the Clymer manual to check for float adjustment. Yea, I know leave them alone, but I bought this fancy new tool to check for float height and the floats were way off so I had at it. Slapped the carbs back on and they leaked. Pulled them back off and checked everything again and to make sure I hadn't somehow put the floats upside down. Reinstalled, they still leaked.

So now I knew I had screwed up or the parts were wrong. I only use K and L carb kits because in my cheapness I used a cheap China set on my Concours after it had hydro locked and it hydro locked again within 6 months and I had to go through the motor again. Never again. The parts are the right number.

Ok, in desperation I broke out the factory manual (I shoulda studied this to begin with). It said to measure the float height from the gasket surface. Now I thought I was on to something. Carbs back off. I could now see that this fancy tool the Clymer book showed would not work and I had measured the floats wrong. So, I used a depth gauge and rechecked with a pocket ruler, put carbs back on bike and they still leak.

At least these carbs are piece of cake to pull off and on compared to a Concours.
Now, they are back off and it is 14 degrees out and the wife wants this 'stinky' bike out of her garage and back in my shop.
Help!
Questions.
1. Where exactly do I measure at the gasket surface on the flat part or the raised part?
2. Where exactly do I measure at the float, which part?
3. Is there something else I could have screwed up?
I tried to use the search engine.
Thank-you.

red

Quote from: codell on December 27, 2021, 09:00:34 AMAt least these carbs are piece of cake to pull off and on compared to a Concours.
Now, they are back off and it is 14 degrees out and the wife wants this 'stinky' bike out of her garage and back in my shop.  Help!
Codell

Sorry, I can't help with the repairs, but I can suggest that you find every "stinky" part of the bike and take them elsewhere (maybe outside in a solid box, and wrapped in plastic) to help keep the peace at home.  Cap and cover any "stinky" parts that need to be on the bike, to reduce odors.  Peace is priceless.   :yes:  

Where are the leaks happening?  Gaskets? Ports? Intakes?
Cheers,
Red

P.S. Life is too short, and health is too valuable, to ride on cheap parade-duty tires.

codell

It is leaking out the two large overflow ports. Thanks. Everything is covered with ice right now, including the driveway. I have to wear my spiked boots outside now, so the better half will have to live with the odeur petrol for now.

red

Quote from: codell on December 27, 2021, 09:39:25 AMIt is leaking out the two large overflow ports. Thanks. Everything is covered with ice right now, including the driveway. I have to wear my spiked boots outside now, so the better half will have to live with the odeur petrol for now.
Codell,

That is a very unhealthy situation, not to mention a fire hazard.  Humans can become allergic to petroleum fumes.

Your fuel petcock or fuel pump should shut off any flow of fuel from the gas tank.  If that is not happening, I would repair that problem first.
Cheers,
Red

P.S. Life is too short, and health is too valuable, to ride on cheap parade-duty tires.

RPM - Robert

http://www.fjowners.com/index.php?topic=9560.msg90886#msg90886 Shows the proper top measuring point

A few lines down in the same thread  

http://www.fjowners.com/index.php?topic=9560.msg90888#msg90888 shows the proper gasket surface measuring point. Although, realistically, if you set the floats in the middle of the threshold the rib makes no difference as the GYSM states 22.3mm +/- 1mm. That rib is not a mm in height. I set every single set that leaves here at 22mm, no problems.

It is sort of counter intuitive to some but the higher you set the float when measuring upside down the sooner the fuel shuts off lowering the level. Set them at 24+ mm and see if it stops, if they are already with in spec range. If it keeps leaking you have another problem. Which, we already know you do anyways. The fuel pump should not let fuel bypass into the carb when the key is off.

Or if you prefer to wait for colder weather and need to stop the fuel smell. Leave the petcock closed and don't fill the carbs back up.

Dads_FJ

Also - using the drain screw you may be able to tell if it's one particular carburetor or all of 'em that need attention.  And when you initially made the adjustments to the floats did you bend the tab a little or a lot?

http://www.fjowners.com/index.php?topic=3592.0
John S.

'84 Yamaha FJ1100
'89 Yamaha FJ1200
'94 Yamaha WR250
'80 BMW R100S/Sidecar
'39 BSA WM20

codell

Thank-you Robert you were spot on.

What I did was deduct 3mm (the height of the carb lip) from the 22mm and set the carb adjustment tool on the lip at 19mm until I thought I could see it just touch the casting seam of the float. Then I set the tool close to 18.5mm so I could see it slightly depress the float, like a go-no-go gauge.

It starts, runs and no leaks. The world is in order again.

Thank-you again for the frustration relief.

Pat Conlon

On my float gauge, I cut a small notch so the end of the ruler sits on the gasket surface and not the rib.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

codell

Epilogue
First of all, I would like to thank Robert and all who responded. I do appreciate this website and others like it and people who give their time and knowledge for those in need.

Well, I went back in the carbs and set the floats at 23mm, just because I am anal. If I experience any fuel starvation when back in the saddle in the spring, it will be dealt with.

I keep on asking myself how could such a simple job turn into a mess like this? The only answer I can come up with is that I was unprepared, inattentive, in a hurry and in my hubris thought I knew everything. This was a humbling experience for me and that is probably a good thing. Most of my motorcycle experience has been with Keihin's and the only larger Mikuni I can recall working on were 34's.

My observation is that on this type of Mikuni have an overflow for the float bowl, the Concours with the Keihin set-up does not, and this is a major factor in why so many of them hydro lock. If I knew this about the Mikuni carbs before, I probably would have let sleeping dogs lie. Lack of research. Also, I learned about the four-cable throttle system. It is what it is. I think also I could beat the flat-rate times at carb R&R on an FJ. I don't see them lined up though.

Thank you all again for helping me get my act together.

P.S. The wife happily puts up with all my follies.

yambutt

Took my carbs off then sent them to my mechanic to repair a long with K n L parts and when I got them back my carbs leaked like crazy so I took them off sent them back and this time he installed  factory yamaha parts (mikuni) and no more leak

codell

I have installed 5 of these kits on different bikes and never had a problem, except of my own doing. There cannot be that many manufactures of carb needle valves left in Japan. What I read a year ago or so on a post on another forum is that there are counterfeit ones on Ebay and the only way to tell is by the color of the packaging. So, I only buy these from a certified dealer.

The Chinese seem to counterfeit everything, watches, designer clothes, auto parts, coins, artwork and on and on. My own experience with this problem was with Duracell batteries. I bought a box at Wally World and within six months they had all leaked and destroyed everything they were in and even the one's I hadn't put in anything yet were leaking. I called the company and to my shock they said they weren't their batteries and referred me to a site to spot these fakes. The only way to tell is by the serial numbers, one (the fakes) are stamped black on the outside and the real are embossed in the battery. I still see these fakes for sale at different stores.

You cannot go wrong with OEM parts like you said. If I had it to do over again or if I find another decent FJ would be to just get the carb parts from RPM. What I have read on this forum is that they are highly reputable and more than helpful.