Routing fuel lines on DOHC cb750 and engine number.

[barnett468]

I don't have access to a welder unfortunately. Why do you suggest not heating the bolt? Just curious.

because aluminum melts at a fairly low temp and if i remember correctly, the housing is aluminum and it will not give you any warning before it melts because it wont turn red when its hot like steel will and it might take quite a bit of heat to break any bond of junk between the bolt and the housing.

 

[halftide45]

Ah. That makes sense.
If I can't get it to budge is there a way to cut off the head of the bolt and get the cover off that way? I'm not optimistic about just prying at it.


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[barnett468]

Ah. That makes sense.
If I can't get it to budge is there a way to cut off the head of the bolt and get the cover off that way? I'm not optimistic about just prying at it.

no, prying is definitely a bad idea . . you can drill the center with increasingly larger bits until the hole is the same size as the id of the bolt shank then go with a drill that is around .020 - .040" bigger and drill in just 1/2" from the head of the bolt . . then take a drift and whack the head of the bolt and it will break off part way . . then just grab it with pliers etc and break it off . . you might have to use a round file inside the bolt at a 45 degree angle to get any edges off . . the housing should come off fairly easily after that especially is you spray wd40 or something between the bolt shank and the housing . . warming it up with a little butane torch or hair dryer on high might help.

 

[Tune-A-Fish]

The biggest thing with the whole hot mess is to not damage the case or motor side of things, the filter housings are a dime a dozen on eBay and come with the bolt usually... if you get to struggling to much, I would get out the cut wheel and cut the head right off "warm" it up good with a propane torch and shoot PB blaster inside... grab the housing with a rag and twist back and forth until it slides off.

 

[halftide45]

update:

I took a peek inside the spark plug holes and saw rust. Not a huge amount, the 3rd piston is only dull, but they're not clean. So, per BrosMSU's advice I pulled the valve cover just to make sure that the cam chain hadn't lodged itself anywhere. Luckily it was sparkly clean in there! I mean really clean, not a speck of rust anywhere. The thing looked brand new. Then I went and bought some PB blaster and soaked the pistons. I also shot some on the oil filter bolt. My plan is to continuously douse the oil filter bolt with penetrating oil and not try to wrench on it again until the motor is unseized. No reason to get ahead of my self.

Do you guys think I absolutely have to pull the motor to get it back up and running? Since the rest of the engine looks so plausible (the carbs are clean and the generator was spotless), I'm hoping I can unfreeze it before it needs disassembling.

 

[halftide45]

Annnnd the photos are upside-down....

 

[barnett468]

.
The rust by the plugs is nothing.

if your rings are rusted to the cylinder you should pull the top end and check it out before running . . hone the cyls if they are good and install new rings . . the engine can stay in for this.

oiling the bolt is a waste of time.

 

[halftide45]

It's possible to pull the head without pulling the engine?

 

[barnett468]

It's possible to pull the head without pulling the engine?

ok, well its been a while but i think it will come off in the frame if you remove the studs.

 

[cxman]

it is possible to get the head off in frame how ever its a bear working on the motor around the frame

way easier to just pull the motor and have total access and can touch up the frame and paint the motor

i had a engine just like yours rust on one jug

i got it free and ran it i got 1200 miles out of it before that same cylinder started smoking and has low compression

i am now doing a engine out repair

 

[Tune-A-Fish]

Yeah! Just mix up 4 oz's of Acme engine rebuild and divide into 4 equal portions, pour one portion in each spark plug hole and wait 30 minutes... wha la!! instant motor refresh... The Acme engine rebuild is in the fairy section at Walmart right next to the Pixie Dust no heat powder coat kit ;D

 

[barnett468]

Yeah! Just mix up 4 oz's of Acme engine rebuild and divide into 4 equal portions, pour one portion in each spark plug hole and wait 30 minutes... wha la!! instant motor refresh...

That's a ridiculous suggestion...it will take st least 8 oz's . . plus another type comes in different colors in aerosol cans.