TOPIC:

Oh, it will build pressure, alright!  I ballooned my tank sealing it up.  Luckily Nessism had a great idea to bend the tank back into shape (close, but not perfect).  You have to leave a pressure relief or you will hate yourself afterwards.

wrote:

Oh, it will build pressure, alright!  I ballooned my tank sealing it up.  Luckily Nessism had a great idea to bend the tank back into shape (close, but not perfect).  You have to leave a pressure relief or you will hate yourself afterwards.

Mikaw post=866111
I would not completely seal the tank. Set it upright on the bench in its normal orientation and fill to the top and not close the fuel cap. The couple times I used this technique it was bubbling and I’m sure if sealed would build pressure. Did you toss in a handful of screws into the dry tank and shake shake shake, it’s helps break up the rust. 

Thanks for the tip guys. As the vinegar is in a sealed plastic jug, it never occured to me that the rust would cause it to swell & bubble up. Good catch. I appreciate it. 

Anyways. Turns out the fittings to plug the petcock location were the wrong size... dammit...   I should have known better than to try to measure it with the end of a chinese tape measure and take it's word for it. For reference, its M22 x 1.0 threads. $33 for an official Pingel fitting? or $.29 for a cork?

In the end, I ended up using a $.59 cork from Ace Hardware to seal the petcock location. All in all I had a positive experience with the vinegar treatment.

No chain, nuts or ball bearings, just vinegar all the way to the top of the tank for about 24 hours. Shaken a couple of times during the day for agitation. I want to borrow the borescope from work to check the deep part, but based on the pictures, the vinegar works great.

After looking into the tank:


Not horrible, but this was the "floating" debris out of the bucket.

I saved the vinegar for a second wash if needed, and filtered through a shop towel...
First pour out of the 5 gallon bucket:



After a couple more pours:


and the bottom of the bucket after poring it all out!



 

I should have mentioned that I used a half a pound of baking soda in a gallon of water as a first rinse.
Plain water as a second rinse, and the shop vac running in reverse to "blow dry" the interior.

After most of the moisture was removed a solid squirt of WD-40 in the tank, until I ran out of WD-40.
Next best option was some 2 stroke gas to try to "protect" the inside of the tank.

Be safe guys.

That's a significant amount of crud you've pulled out of there Slayer, certainly a worthwhile exercise 

Pay a close eye on fuel seeping.  Some of your tank walls are probably getting mighty thin around now.  I used denatured alcohol for leak testing.  With water it showed no leak, but with the alcohol, which is much thinner, it showed where the repairs were needed.

Great success story. Quick thinking on the reversal of a shop vac to speed drying. 

It's good to know people....
   I have access to a very high tech bore scope at the plant where I work. I had one of the mechanics fire it up so we could take a look inside the tank for "peace of mind".

It looks fantastic inside! 24 hours of vinegar with out any agitation or nuts or chain and it came out clean as a whistle!
I can now feel much better about re-installing the tank & getting the old girl back on the road!

I have successfully brought my Wife's GPz 1100 back to life!
   The vinegar rinse of the gas tank was 100% successful, cleaning old rust from the carbs was also 100% successful! I got the old girl back together Saturday morning & got Christopher to follow me... just in case and because the tags are still 6 years expired    We rode up a country road to the next town & back down the hiway and the bike performed flawlessly but for a minor clutch cable adjustment. Huzzah!

Read through this entire thread.  If memory serves me,  in 2014 when I stopped by you had recently picked up this GPZ.
All of your hard work and persistence has paid off!  I know Mrs. Slayer must be very happy.  Please post photos when you can of her and the bike together.  I can just see a huge smile.!
Congrats! 

BTW, how many teeth on that rear sprocket?  Looks like this could be a wheelie machine!  

AND, if I read correctly and see in the pics, you converted from FI to Carbs?!!!  Amazing work!  Two thumbs up!

Well thanks Forest! The intent was to get some pictures this past weekend. It was going to be their "maiden voyage" back together again. Ride the 20ish miles out to the delta and have lunch. My old bike let us down, however. It was puking gas out of the #1 carb. Gentle tap with screwdriver to "fix" the stuck float, and we're good to go, right? Wrong   Now I think the float is stuck shut! She's only running on 3 cylinders! Dammit!   Count on this, though... we WILL try again sometime soon.

Be safe Forest!

PS: the rear sprocket is a 50 off the top of my head. This change was made when I swapped from 630 to 530 chains.