Topic: 73 CB500 Boston Cafe

[Restoration Fan]

HOLD ON A SECOND!

You should be aware of something:  viewing this as giving up is one thing...but you need to know something.
When we broke off an engine case bolt in our build, I took it to a machine shop to get it out.  I described what I had done and how I had stopped when I thought I had better bring it to the machine shop.  It ended up only costing me $25 and that was because $25 was their minimum charge.  He told me, "Had you gone further, it would have very likely cost you between $100 and $200 to fix the same thing because you didn't get it down to an unmanageable state."

So just be forewarned that if you end up breaking it one more time, you can almost assuredly count on more $$ out of your pocket when/if you do end up going to the machine shop.

[lajos]

@iron_worker: Thanks for the great step by step! We have another day of rain coming in Boston, so the stud is now soaking until I can work on it outside. There's still material left for another couple rounds of nut welding and I got a oxy-map torch so I'll try to heat the area more before I get to drilling.

@restoration fan: Thanks for the warning! This is the first stuck bolt on this project, I got hundreds of screws out mostly with the impact screwdriver from HF (best $9 I spent on a tool). Obviously money doesn't grow on trees, but the reason I want to keep trying instead of going to a shop is not because this would put me over budget. This will happen again in the future and I want to know how to deal with it.

Thanks again for everyone's help and advice and sorry that this silly bolt hijacked the thread

[SOHC4 Cafe Racer Fan]

@iron_worker: Thanks for the great step by step! We have another day of rain coming in Boston, so the stud is now soaking until I can work on it outside. There's still material left for another couple rounds of nut welding and I got a oxy-map torch so I'll try to heat the area more before I get to drilling.

@restoration fan: Thanks for the warning! This is the first stuck bolt on this project, I got hundreds of screws out mostly with the impact screwdriver from HF (best $9 I spent on a tool). Obviously money doesn't grow on trees, but the reason I want to keep trying instead of going to a shop is not because this would put me over budget. This will happen again in the future and I want to know how to deal with it.

Thanks again for everyone's help and advice and sorry that this silly bolt hijacked the thread

Well, it was your bolt, so technically no hijack. 

I admire your perseverance.  I personally would pay $25 to have a machinist take out the stud, rather than risk having to pay more OR possibly have to buy new crankcases if things go south (with those possibly having multiple stuck studs).  You got heart!!

[iron_worker]

I had sent my cases in to a machinist that snapped a bit above flush. They also TIG welded and fixed one of my points cover bolt holes. Total bill: $500. 

IW

[SOHC4 Cafe Racer Fan]

I had sent my cases in to a machinist that snapped a bit above flush. They also TIG welded and fixed one of my points cover bolt holes. Total bill: $500. 
IW

You obviously pissed somebody off...

Did they use any lube before reaming you?  That's nucking futs!

[iron_worker]

That's what happens around here when all the shops are used to getting work from a thriving mining industry.

IW

[SOHC4 Cafe Racer Fan]

That's what happens around here when all the shops are used to getting work from a thriving mining industry.

IW

Where's that?

[iron_worker]

Saskatoon, Sk, Canada

[Doctorlumen]

Hey lajos!
The Iron Worker method does work. You have super heated that stud, and mostly ended its structural life, so perhaps the welded nut (also super heating the stud) aint the way. Not to mention you have been whaling on that F***ker until now, so if it hasn't budged yet, you are probably not seeing the stud twist out on its own.

I have been where you are on a sad little Suzuki T350. The drill-and-tap method, if you are careful, is a sure fire way to success. But you have to be careful and slow. There should be no brute force involved...but tons of patience. Proper drilling and hand tapping holes is not something to shy away from when it comes to these old bikes. Its becoming a lost art of sorts, but still necessary to achieve professional results. Good luck with your project!   

[lajos]

!!!!!!!!!!!!!!!!!!! yay !!!!!!!!!!!!!!!!!!!

Got this sucker out! Thanks for everyone's help!

So looks like I just needed more heat. I've been soaking it for days, even mixed up some atf-acetone, didn't budge.

I welded another washer to the stud, then a nut to the washer. I got an oxy-mapp torch at home dippers and started heating the stud until it glowed red. I did this a couple times, still didn't go. I was getting ready to give up.

Then I used the oxy-mapp torch in one hand for the stud and my mapp torch in the other to heat the crank case. Whacked it with a hammer and the sucker just started turning with hardly any force!

I had to wiggle it back and forth a bit, soaked it with liquid wrench (that was the only thing that didn't instantly evaporate in the heat) and it slowly turned out in one piece.

Thanks again for all the help! Now on to more fun stuff. Or fun stuff after I clean up the mess I baked on there.

[SOHC4 Cafe Racer Fan]

Success! Now you're ready for anything!

[lajos]

While I'm waiting for the cylinders to be big bored and the valves/seats recut, I started cleaning up the carbs.

I have a set of carbs where two of them look very nice and clean with no oxidation, but the other two have lots of white stuff in the float area. This is what one of them looks like after ultrasonic cleaned in simple green hd pro.

Is it worth cleaning this up, or should I replace the two oxidized carb bodies? I've read some threads that suggest using steel wool and elbow grease to clean the oxidation out, is that the best way to go?

[lajos]

Thanks Cal, I'll be gentle with it.

I've read somewhere that soaking it in pine sol can take it off. I might give that a try before scrubbing.

[lajos]

Thanks for the warning about pinesol, I've read about it changing the color of aluminum.

I have a perfect test case, a carb body that has a broken float tower that's buzzing away in the ultrasonic cleaner in pinesol now, we'll see what happens

[lajos]

Pinesol in the ultrasonic cleaner definitely ate all the white stuff off. It did darken the aluminum a bit, but if that's just aesthetic, I can live with it. Here's my test piece (with the broken float tower). The whole float area was covered with white oxidation.

[lajos]

Stripped the paint off the upper half of the crankcase (damn she looks ugly now) and cleaned off the remainder of the gaskets. Aircraft stripper is pretty insane stuff. Tomorrow I hope to strip the bottom half.

[lajos]

In the carb body under the throttle slide there is a tiny hole. It's closed up from gunk in some of the carbs. What does that little hole do? Is it ok to clean it out with a small drill bit?

[lajos]

Plastigaged the crankshaft last night, all of them are ~0.0015", one a tad bit smaller.

Tightening the case felt good, almost like putting things back together.

[MickB]

Lajos what's happening with the stud?

[lajos]

I managed to get it out in one piece ( the post is on previous page at http://forums.sohc4.net/index.php/topic,148166.msg1691159.html#msg1691159 ).

In the end I needed more heat- got an oxy/mapp torch that I used to heat the stud to red glowing, and a regular mapp torch to heat the case around it. After a couple tries of this, it started turning with hardly any torque. Then I wiggled it back and forth until it turned all the way out.

I got the APE heavy duty studs in the mail to replace the old ones.

I'm still waiting for my big bore job to be done, in the meantime I'm prepping for engine paint and cleaning carb bodies.

[MickB]

I takes a lot of heat that's for sure, I remember mine I was worried about the case being damaged, but it took the lot.

[lajos]

@MickB: Yes, I was also worried about melting the aluminum. But then I figured this cannot be pure aluminum but some sort of alloy, so it shouldn't melt that easy. I have an extra head that has super pitted unsavable valve seats, so I used that as a test piece with the oxy/mapp torch and I couldn't melt it even after heating it for a good couple minutes. But the oxy/mapp torch had a much tighter flame, so I could really heat the base of the stud (with the regular mapp torch I could get the welded nut glowing, but I guess the case sucked all the heat away from the screw part).

@Cal: Thanks for the suggestion for the small soda blaster. I was thinking about it myself, but at this point I have the carb bodies pretty clean having used simple green hd and pinesol in a small ultrasonic cleaner. Attached a picture below of the worst carb body I have. I can clean the small leftover alu oxide spots with a brush. The rest have no pitting or very little pitting. Is it worth using this carb body, or should I get a better one?

[lajos]

Picked up my bored cylinders along with decked and valve seat cut head from the machine shop today! There's definitely no rust spots left in the cylinders after taking out 3mm

[lajos]

I have the 61.5mm cruzinimage pistons from ebay. The cylinders were bored to those with 2 mil clearance.

[lajos]

Finally got the crank cases painted.

After stripping the paint with aircraft stripper I spent a bunch of time cleaning with wire brushes, filed and sanded off a lot bumps and whatnot from casting, scuffed with red scotchbrite pads and some 4" 180 grit drill brush from HF. Then acetone washed and masked.

Cutting the masking tape around the edges was challenging at first, but then I used a small flashlight as a backlight which made finding the edge and following the shape with a small xacto knife a lot easier.

We don't have a garage so I was going to paint in the basement landing, but I found an old tent and used it as a paint booth. Worked pretty well, natural light and the mesh kept dust out.

Lint is evil. I did the masking on a painters drop cloth and the edge of the masking tape picked up a whole bunch of lint. I didn't see it until I sprayed the primer, so I stopped after priming, redid the masking on plastic sheet and all went well after that.

Used VHT engine primer, VHT cast aluminum engine paint and VHT clear gloss.