Bike runs good until it's warmed up, then terrible

[gggGary]

TwoManyXS1Bs That's too funny, the CB650 carbs are 1980, last year before they went CV so bet I'd you are right. They are fiddle/flucked to get within the EPA until the new design CV's came out. Then they even had to change the head because the diaphragms made the carbs too wide to fit the old spacing.

5twins I'd be happy to shoot any pics needed, I think I have sets of carbs from every year.

 

[TwoManyXS1Bs]

Sorry, I had to run outside and douse myself with water just to calm myself down, running-off on a tangent like that... Yes, a MASTER pictorial of carb evolution, theory of operation, an expanded/enhanced upgrade to 5twins doc, including the proper pharmaceuticals,,, good idea.
Wonder how Oldskool deals with this...

 

[gggGary]

And it needs to be done so the newby's can see it all on their phone.... Right 5T?

 

[5twins]

Screw those phones, lol.

 

[Rexxis]

Haha, no comment..

 

[Rexxis]

.

Gaskets: You may not like this, but I personally like the old racer trick of coating gaskets with a very thin film of grease. A little bit on the fingers, spread around real good, just enuff to make gasket slick, not too much to make a mess. Generally helps to hold gasket in place, later disassembly real easy, gasket can be re-used. The old original gaskets of the `70s were made from a composition of asbestos, fibers, and reclaimed oil. Hence, compatible with the thin grease trick. They never leaked, but would leave a telltale dark line along mating surfaces. Comes off at car wash after you're convinced you won't be disassembling any time soon.

So I'm all ready to start reassembly. I've got all new Athena gaskets. Should I still use a thin film of grease or are modern gasket incompatible w grease? I can't imagine that they would be.

 

[5twins]

I just use motor oil on many (but not all) of my paper gaskets. It's basically the same thing as using grease I guess, I just find it easier. I coat both sides of the gasket with oil and let it soak in for 5 or 10 minutes, then install.

OK, first, what not to oil - Don't oil the head or base gasket. Next, what I choose not to oil - The intake manifold and left side cover gaskets. These are also some of the few I use a bit of gasket sealer on, on the part side. I do this not so much for sealing purposes but rather so the gasket comes off with the part any time I remove it. The other gasket that gets some sealer is the head gasket. This consists of thin beads of sealer applied to both sides with a toothpick around the oil flowing areas. This is just added insurance against leaks. Here's where I put it. The red lines are where I originally applied it. The additional yellow lines are how I do it now after my head gasket began weeping slightly along the front edge after several years .....

What I oil - the right side cover gasket, oil filter and sump gaskets, e-start gear cover below the sprocket, points/advance housing gaskets, breather housing gasket, cam chain adjuster housing gasket.

 

[Rexxis]

Both sides of the gasket get sealer in the indicated areas I'm assuming. This is perfect. Thank you 5T.

 

[5twins]

Yes, both sides of the head gasket get the thin lines of sealer. The 4 outside studs are ringed because those are where oil drains back down to the crankcase from the head. The cam chain tunnel is ringed because oil is constantly splashing around in it, pulled up and flung around by the cam chain.

 

[Rexxis]

Timing the cam to the crank... AHHHH! This part makes me more nervous than anything else bc if you do it wrong, disaster can result. Haynes says to put left cylinder at TDC on the compression stroke. As far as the bottom end is considered, there is no compression/exhaust stroke right? Just as long as the piston is at TDC then you can line up the cam with the mark vertically centered on top with chain taught on the frontside right?

 

[Rexxis]

I think I messed up. See the two studs at upper left and lower right?
The holes they pass through in the cylinders are slightly larger than all the others. Are they supposed to get the little sleeves in them?

Little sleeves like these

I don't have the valve cover back on yet but I've got those little sleeves on both the bottom of the valve cover and in the top of the head, around the same studs. I think the extra pair came from the bottom of the head and I reinstalled them in the top so now I've got four sleeves for between the head and valve cover. I need to pull the head back off and put them in the holes on the cylinder don't I?

 

[CalsXS2]

Go to boats.net and see what it looks like.

Also. I hope you're going to clean that piston.

 

[Rexxis]

There they are, #2. I was pretty sure that they needed to be there. I already pulled the head off and put em where they were supposed to be.

Thank you though, having diagrams like on boats.net can be very useful and I never knew that they were there.

Yes. Already done.

 

[cobrasneverdie]

sorry to hijack this thread, where did you get that x fuel line? I like that set up.

 

[Rexxis]

sorry to hijack this thread, where did you get that x fuel line? I like that set up.

eBay

Now I know I messed up. Bigtime.
Snapped the little bolt at the back of the head. The rest of it is in the cylinder block. Yes I was using a torque wrench set at 16 ft/lbs.

What do I do?

 

[CalsXS2]

Is it broke off down in that hole your index finger is pointing to.

I've had great success with left handed drill bit's. You can get a complete set at harbor freight for $14, instead of $14 for one at the hardware store.

 

[Rexxis]

Yes it is. About and inch or more down in there.

 

[TwoManyXS1Bs]

Hey, rexxis, I see you're making ...progress?

Hoo boy, broken bolt removal...

There are several methods going from easy/simple to difficult/expensive
First, pull off the head and cover the cylinder well.
In order:
If any of the threads are grabbable, try removing with pliers
If stiff, try vicegrips
If enuff threads, threadon a nut, flashweld inside nut (heat can help), turn nut
If broken at surface, can try gently tapping around edge of screw with sharp/small punch, when hi enuff, use pliers
If still stuck, carefully/precisely center punch, start with bit 1/2 dia of bolt, drill about 1/4", use ease-out.
If still stuck, drill with left-hand drillbit.
Still stuck, drill to bottom of screw (careful), to reduce bottoming lockup, ease-out again.
If still stuckdrill larger to just below thread tap size, ease-out.
Still stuck, drill to tap size, work-out threads like spring.
Still stuck, drill-out for heli-coil, then heli-coil.

These are not all the tricks, just a simple progression from ahhh to yikes!

I feel like I'm writing an essay for an A&P test...

 

[CalsXS2]

Is it this bolt?

Before you do anything, start soaking it with pb blaster.


Do you have room to get a drill in there. Maybe if you use an extension.

I was going to say the same thing as TwoMany. But I might have to try and leave the head on if possible.

If you can take the head off with out ruing anything,, like a head gasket,,, then take the head off.

I broke every easy out I ever tried. Then your really screwed

I just drilled out a broken crankshaft bolt with a left handed drill bit. Drilled a smaller hole first. Then stepped up a few sizes and the bolt screwed right out.

If you do take the head off, like TwoMany said,,, if there's enough nub left, you can weld a nut on it. I've don a lot like that too.

 

[CalsXS2]

Stick something down in there to tell how deep it is. Then post a pic showing where it's at.