Pulling the Carbs

The Concours' carburetor has become cursed by demons.  These carbs tend to not come back from sitting very well, though last year they didn't have this problem.  When I put them away they were running well, but no longer.

Yesterday I pulled the tank again and went over the vacuum tubes in detail - no breaks, no problems.  After putting it all back together again I took it out and had the same hesitation on throttle and back firing.  The bike feels seriously down on power too.

I was hoping to send the carbs down to Shoodaben Engineering in Florida for a spa session with Steve.  His prices are more than fair, but after having an economist (whatever the hell that is) as a Prime Minister for eight years, Canada's dollar is in the toilet and my $500US carb repair would cost north of $800 with shipping, customs and the exchange rate.  I paid $800Cdn for the bike in the first place.

So I'm rebuilding carbs!

In spite the many terrifying stories of carb removal on a Concours, I found the process pretty straight forward (thanks to Steve's video).  Warm up the rubber on the airbox to carb, they get nice and soft, and you wiggle the whole thing free.  With the carb on the bench, parts are ordered ($200Cdn for 4 kits - 1 for each carb) and I'm beginning to break it down to rebuild each.

There is always one more thing...

The open road awaits, and it's still waiting...

Recent frustrations with the twenty two year old Concours had me saying yesterday, "I like doing mechanical work, but sometimes I just want to go ride a fucking motorcycle."  It was a day in the mid teens Celsius (almost 60 Fahrenheit), and the sound of motorcycle engines could be heard on distant roads.  After spending the winter redoing the brakes, wheels and bearings, I got the Concours back on its feet only to find the carburetor has gone off.  The bike is running lean, not fueling nicely and back-fires when coming off throttle.  Instead of going out for a ride on one of the first nice days of the year, I was popping and swearing my way up and down the road by my house trying to get the carb to play nice.

Some vacuum diagrams on there, but not where they go.  Another
suggestion for lean burning/back firing conditions (which I have) are
the air cut valve (highlighted).

Some research into Concours carbs produced a baffling array of opinion and vitriol.  It appears that no one who works at a dealership has the experience or time to do carbs properly any more, and the carbs on the Concours are fantastically complicated.

I've done carbs before on cars, and labyrinthine vacuum tubes aren't a problem when you have a diagram to follow, but Clymers doesn't include one in their manual (unless it's for California bikes), and the Kawasaki diagrams show bits of vacuum diagram spread across the valve head blowup, the carb blow up, the fuel tank blowup, air box blow up and others.  Needless to say, trying to chase vacuum connections across half a dozen diagrams isn't easy.

Today I'm taking the fairing I just put on back off, removing the gas tank (again) and trying to make sense of the vacuum tubes.  If nothing obvious presents itself it'll be time to remove the carbs and go deeper.  I just did something similar on the XS1100 in the fall.  I haven't had time to work on it since because I'm spending all my garage time on the Concours.

I'm starting to think one project bike is enough.  The other one needs to be modern, dependable and there when I need it so I can, sometimes, you know, just go ride a damned bike.

Sources for Concours carburetor and vacuum information:

As usual, CoG is the place to go first:
http://forum.cog-online.org/index.php?topic=27077.0
http://forum.cog-online.org/index.php?topic=38095.0
http://forum.cog-online.org/index.php/topic,11914.0.html

CoG wisdom on Concours carbs:
Normally it is caused by dirty carbs and and not being sync'd properly. The dirty part can be from just a few days of sitting due to the ethanol evaporating....

it's very likely during the "cleaning" they did not dissassemble the air-cut valves from the 2 carb bodies prior to spraying with volatile carb cleaner. internal to each of those housings is a very delicate diphragm, not unlike the ones that lift the slides....during this process they damaged them, and at the least, never cleaned the rod attached to those diphragms that during decell, when the diphragm moves, opens a port to add fuel to the intake tract to preclude/prevent a "lean burn popping" upon decell. That is the sole purpose of those 2 valves, when they don't function, you get this result.

Check the vacumn stuff like you already mentioned. I had a back fire for a while, peeked under the tank, found the rubber cap on the #3 carb was split. Just for the fun of it, replaced all the hoses while there, good to go now.

You Cannot do away with the reed valves entirely unless you tap the ports in the actual valve cover and thread in some set screws. The easier way here is to leave the reed valves and metal covers on the valve cover, and remove all the vacuum hosing associated with the pair valve. Go to your local auto parts store, and pick up three 5/8" "heater core block off caps". They look like big vacuum caps, and also some 3/16" regular vacuum caps. Using the 5/8" Cap off the 2 ports left on the valve cover, and insert one backwards into the airbox hole. Use the 3/16" to block the intake ports.

http://www.zggtr.org/index.php?topic=15181.0
http://www.justanswer.com/motorcycle/21eu0-1897-kawasaki-concours-looking-fuel.html

Sense of Satisfaction!

After all the Maker talk this week at a conference I attended, I was keen to spend some quality time in the garage working on the 35 year old XS1100 basket case.  It's easier to walk the walk than talk the talk when it comes to Making.  Unlike the education approach infused with collaboration for your own good, I did it the way I always do: alone in a garage.  It's wonderfully cathartic to get something broken working again, and meditative when I don't have to explain everything I'm doing.

How do you get a 35 year old motorcycle left outside for several years unattended working again?  Very carefully!

The front brakes were seized, the throttle body was seized, the rear brake is still seized, as are other things I haven't found yet.  Motorcycles aren't like cars, when they're left in the world they don't have a shell protecting the mechanicals from the weather.  Restoring a car tends to be more mechanically salvageable as a result.

Yamaha XS1100 Mikuni Carburetor by timking17 on Sketchfab

I ended up having to take the end carburetor off the rack of four Mikunis that line the back of the Yamaha engine.  It was the most carboned up and filthy one, and the grit had seized the throttle body rod.  A complete dismantle, cleaning and reinstall has the carb working again (before this you couldn't move the throttle body without great effort and a nasty creaking sound...

It took a couple of hours to break it down, find the problem and rebuild it.

It was pretty before, but the Mikunis are even prettier now that they work!

Rainy Day Carburators

A cold, rainy Saturday had me break down the carburetor on the Yamaha XS1100.  A Triumph Spitfire and Mercury LN7 owned as a teen made me pretty handy with carburetors.  In addition to multiple rebuilds I also got handy at jury rigging manual chokes thanks to the utterly crap Ford Escort carb set up.

The beautiful Mikuni unit on the Yamaha looks like a piece of industrial art in comparison to the pedestrian Triumph and Ford carbs, unfortunately it's seized.  After breaking down the top end I soaked it and freed up the seized throttle body.

The next to-do with the Yamaha is to clean up the gas tank and then reassemble the fuel system.  The engine isn't seized and spins easily, so I think I'll have an easy time firing it up for the first time in years (knock on wood).

Here are some pics of Mikuni's Yamaha masterpiece:

The throttle cable wasn't playing nice even after taking apart the handle bar - so into the carb I go...

The Yamaha XS1100 engine block with the carbs off - it got the Warhol treatment....

Like everything else so far, the internals look to be in good shape on the old (35 year old!) Yamaha

Cleaning up the fasteners using the caps from each carb to keep things organized.

XS1100 is in for surgery

Not many riding days left as the weather turns up here in Canada

Yamaha PW80

After doing a partial dismantling of my son's new (to us) '04 Yamaha PW80, I put it back together again and learned a valuable lesson in dirt bike ownership:  always turn off the fuel tap.  Other than carb pressure and gravity, there is nothing else stopping your garage from smelling like gas and a puddle forming.

The second dismantling came when it wouldn't start after the flood.  The spark plug was always dodgy, so I've gotten a pair of new ones (no problem finding them at Canadian Tire).

Good advice, straight from Yamaha

A tiny amount of Googling found me the Yamaha shop/operating manual, that covers everything from not carrying dogs on the bike with you to how to tear down the engine.

This is such a simple machine that it's a great way to get a handle on the basic motorbike system.  If you want to get handy with bike maintenance, start with a dirt bike (I started with a Concours...).

The next strip down has been more comprehensive, though to remove the tank, fairings and seat takes all of seven bolts.  The air filter was pretty bad with chunks of mud in the air box.  It's a shame that people treat a bike like that then just chuck in storage.  Why not clean it first?  In any case it's clean now.

The metal shop at school
sorted out the broken muffler.

I've got a busy hands afternoon after work checking the new plugs for spark (it's definitely getting gas) and putting it back together again knowing that I've taken it right down to the engine.  With how it took off last weekend (I impromtu wheelied down the driveway thinking it would barely be able to move me on it), I'm looking forward to seeing how spunky it is with a complete tune up.

With a new plug in it has strong spark - the carb is stinking of gas and it still won't start.  Time to pull the carburetor and sort it out before giving it another go.  Leaving it open overnight doesn't appear to have done it any favours.

The unhappy carburator

A Yamaha PW80 down to the mechanicals

I've got to get my mits on a me-sized dirt bike so we can go into the woods together up at the inlaw's cottage.  That DR600 Dakar is still for sale, I wonder if he'd take a grand for it.  It's a bit more than a mid-sized dirt bike, but it would do the business and also eventually adventure bike for me too.


It'd make a good Swiss army knife bike.