Montreal Manchild with an '81 Honda CB750K
- Thread starter Jimbonaut
- Start date
MEK is strong stuff. Also can be used to remove Red Kote and possibly other tank liners. Don't breathe it in.
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Jesus Murphy you're not wrong. Opened up a can of that MEK stuff and saw stars for an hour.
Looks like the tank needs it - drained out as much of the lacquer thinner as I could and wicked out as much as possible - the varnish had melted into a thick brown sludge but nowhere near dissolved. Thinking this varnish situation may be worse than I thought, but will leave that MEK in over the weekend and see what gives.
Looks like the tank needs it - drained out as much of the lacquer thinner as I could and wicked out as much as possible - the varnish had melted into a thick brown sludge but nowhere near dissolved. Thinking this varnish situation may be worse than I thought, but will leave that MEK in over the weekend and see what gives.
CarbsAndCylinders
Careful With That Axe Eugene
Be careful with that stuff, I was just diagnosed with cancer in my kidney and it was removed. One of the causes of this type of cancer is exposure to chemicals.
My prognosis is good and in a month or so I will be able to get back to working on my bikes.
Brian
My prognosis is good and in a month or so I will be able to get back to working on my bikes.
Brian
Both sorry and happy to hear that Brian - cancer sucks balls but very glad to hear you beat the thing. Here's to you getting back to getting mucky with your bikes soon.
Yeah, that MEK stuff is intense - I'm gonna pick up a decent respirator mask for when I work on getting it out of the tank. And even though it's well into minus Celsius here I'll be leaving the garage door open too...
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Yeah, that MEK stuff is intense - I'm gonna pick up a decent respirator mask for when I work on getting it out of the tank. And even though it's well into minus Celsius here I'll be leaving the garage door open too...
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CarbsAndCylinders
Careful With That Axe Eugene
I will still probably have to have chemo, oh well.
Ya, make sure you keep protected from the nasties.
Brian
Ya, make sure you keep protected from the nasties.
Brian
What I've learnt about de-varnishing and de-rusting '81 CB750 gas tanks so far...
1. More or less every step pretty much sucks balls
2. See 1
3. See 2
4. Don't use lacquer thinner to dissolve the varnish, totally didn't work. Softened it but that's it
5. Use MEK - that shit not only melted the varnish it melted my eyeballs and made inroads into my soul
6. With that in mind, handle MEK with a respirator (I did) and in a well ventilated area (I did. In -15 Celsius)
7. MEK will destroy petcock gaskets - no biggy as I'm replacing mine anyway. But know that, otherwise your garage floor will end up wearing some highly flammable shit
8. Be patient - I let the MEK sit in the tank for a few days, moving it around so it got everywhere. But I had a serious varnish situation happening
9. MEK (in Canadian Tire anyway) comes in small, 1 litre cans. I used 4. Don't do what I did, which is to try draining the used MEK back into separate cans. It's a highly combustible ball ache. Get a larger 5 litre can and drain it all in one go.
10. Once drained, chuck in a couple bottles of alcohol to mop everything up. Don't get impatient and try to speed up the drying process by blowing your shop vac in there. Like I did. And blew a bunch of shit/wire/crap into the tank. Big - and massively irritating - fail there.
11. Go the Metal Rescue, got 2 gallons of that mofo in the tank now and - if you're freezing your balls off in The Great White North - point your heater at the tank to keep things as warm as possible. Like all good things (except beer and snowball fights) it's better toasty.
12. Use a good length of chain (with a piece of thin wire coming out of the gas tank cap to make for easy removal) in the tank to knock off any big rust
13. Find something else to do while the whole thing does it thing - takes days. I've degreased the engine and frame, and now plan on starting a brewery.
Oh, and the whole process sucks balls
1. More or less every step pretty much sucks balls
2. See 1
3. See 2
4. Don't use lacquer thinner to dissolve the varnish, totally didn't work. Softened it but that's it
5. Use MEK - that shit not only melted the varnish it melted my eyeballs and made inroads into my soul
6. With that in mind, handle MEK with a respirator (I did) and in a well ventilated area (I did. In -15 Celsius)
7. MEK will destroy petcock gaskets - no biggy as I'm replacing mine anyway. But know that, otherwise your garage floor will end up wearing some highly flammable shit
8. Be patient - I let the MEK sit in the tank for a few days, moving it around so it got everywhere. But I had a serious varnish situation happening
9. MEK (in Canadian Tire anyway) comes in small, 1 litre cans. I used 4. Don't do what I did, which is to try draining the used MEK back into separate cans. It's a highly combustible ball ache. Get a larger 5 litre can and drain it all in one go.
10. Once drained, chuck in a couple bottles of alcohol to mop everything up. Don't get impatient and try to speed up the drying process by blowing your shop vac in there. Like I did. And blew a bunch of shit/wire/crap into the tank. Big - and massively irritating - fail there.
11. Go the Metal Rescue, got 2 gallons of that mofo in the tank now and - if you're freezing your balls off in The Great White North - point your heater at the tank to keep things as warm as possible. Like all good things (except beer and snowball fights) it's better toasty.
12. Use a good length of chain (with a piece of thin wire coming out of the gas tank cap to make for easy removal) in the tank to knock off any big rust
13. Find something else to do while the whole thing does it thing - takes days. I've degreased the engine and frame, and now plan on starting a brewery.
Oh, and the whole process sucks balls
At least it's clean. The process gets quicker every time though. Does it need to be sealed or ya just gonna run it bare? If you're gonna run it bare swish some premix around the tank and get everything coated to prevent any flash rust before using it.
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Tru dat. Not Roland-Sands-checking-out-the-brocolli-stuck-in-his-teeth-in-his-clutch-cover-clean but clean enough I hope. Plan was to the let the Metal Rescue do its thing for a few days, dump it out, swish a few bottles of alcohol around to mop everything up and then pour in some WD40 to coat the inside. Think that'll do it?
Was planning on leaving it like that until I fill the tank up with gas, but that won't be for months at this rate. Keep coating the inside with WD40 every fortnight or so until it gets filled with gas?
Was planning on leaving it like that until I fill the tank up with gas, but that won't be for months at this rate. Keep coating the inside with WD40 every fortnight or so until it gets filled with gas?
The Jimbonaut said:
WD-40 works fine. I find its easier to pour enough pre-mix in to swish it around, but oil is oil. Once you've coated it, it'll be good to go. Just be sure not to store it for extended periods of time when low on fuel or you'll have to do it all over again.
Another day, another excuse to duck out of work and get into the garage.
While I'm waiting for the Metal Rescue to do its thing I'll be degreasing the engine with a view to having a look at the top end. Now this really will be unknown territory, and I'm wondering what kind of bite I'm taking for a very novice mechanic. From what I can tell in the Clymers, I need to remove both overhead cams and move the timing chains out of the way - does anyone have a video of the process they can hook me me up with? Or have any advice on the job before I get started? A step by step would be asking a lot, but very gratefully received =)
The main objective is to clean out the carbon from the cylinders, and to replace the piston rings. Cylinder #1 has low compression, so figured this would be a good place to start. Plus I like the adventure - this will be a steep but scenic learning curve.
While I'm waiting for the Metal Rescue to do its thing I'll be degreasing the engine with a view to having a look at the top end. Now this really will be unknown territory, and I'm wondering what kind of bite I'm taking for a very novice mechanic. From what I can tell in the Clymers, I need to remove both overhead cams and move the timing chains out of the way - does anyone have a video of the process they can hook me me up with? Or have any advice on the job before I get started? A step by step would be asking a lot, but very gratefully received =)
The main objective is to clean out the carbon from the cylinders, and to replace the piston rings. Cylinder #1 has low compression, so figured this would be a good place to start. Plus I like the adventure - this will be a steep but scenic learning curve.
The Jimbonaut said:
Back up a bit. You should only be looking at taking the head off as a last option. Have you checked valve clearances on the low comp cylinder? Have you tested the compression when the motor is hot? Have you run the motor though a bunch of heat cycles in case it's just stuck rings?
You'll be up for a couple of hundred bucks just in gaskets and other stuff taking the head off, so do everything else before you jump down that rabbit hole.....
Getting that tank clean was a heck of a job - turns out I had a major rust and varnish situation so it was a bit of a battle. Not sure how much crap is still in there but flushed as much as I could out with a few alcohol rinses. For my first tank overhaul, I'll take it.
Thanks for the engine advice. I have checked and re-shimmed the valves across all cylinders, but have not checked the clearances on a hot engine, nor run it through a few heat cycles either. The bike is new (to me) and in fact I've never ridden it - it was a non starter when I bought it in November and pushed it home.
So, think I should leave delving into the head for now? If - once I've got the whole bike put back together again and run it through a few cycles - the compression is still low then take the engine out again and then consider removing the head?
I'm ok with that, have a lot to do on the bike as it is and I'm definitely open to advice on any engine work.
Working on cleaning up the engine, the front looks like this -
(and that's after I cleaned up a lot of oil/crap from around the cam chain tensioner bolt). There's oil everywhere, it's a mess. My thinking is that the cam chain tensioner bolt (the hole for which is totally stripped - it sits in the hole rather than threads into it) is a possible cause of this oil spill - the oil could be leaking out of that hole and spraying over the engine front. Could that be it? If so, while the engine is out of the frame, now would be the time to helicoil that little bugger?
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Thanks for the engine advice. I have checked and re-shimmed the valves across all cylinders, but have not checked the clearances on a hot engine, nor run it through a few heat cycles either. The bike is new (to me) and in fact I've never ridden it - it was a non starter when I bought it in November and pushed it home.
So, think I should leave delving into the head for now? If - once I've got the whole bike put back together again and run it through a few cycles - the compression is still low then take the engine out again and then consider removing the head?
I'm ok with that, have a lot to do on the bike as it is and I'm definitely open to advice on any engine work.
Working on cleaning up the engine, the front looks like this -
(and that's after I cleaned up a lot of oil/crap from around the cam chain tensioner bolt). There's oil everywhere, it's a mess. My thinking is that the cam chain tensioner bolt (the hole for which is totally stripped - it sits in the hole rather than threads into it) is a possible cause of this oil spill - the oil could be leaking out of that hole and spraying over the engine front. Could that be it? If so, while the engine is out of the frame, now would be the time to helicoil that little bugger?
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Maritime
Over 10,000 Posts
Did you put some penetrating oil or sea-foam into the cylinder with the low compression to try and un-stick/free the rings? Do that before you pull the head and jugs, let some sit for a few days or even a week then turn the motor over with plugs out to get rid of whats left, then do another comp test and you may be fine. you can do the comp test on the bench with a battery and some booster cables. ground the neg to the motor then touch the pos to the starter terminal and it will turn over for you. As for the tensioner bolt, I'd look at the parts fiche and see how it's supposed to work, or the manual and if it is supposed to be tight and it's not, it is your leak and should be fixed, also you don't want the cam chain flopping around and grinding your head metal away. Does your oil have any fine bits of aluminum in it? that's a sure sign the cam chain has been lose and wearing on the cases.
