Author Topic: Tank liner failed...crystals in float bowls?  (Read 1607 times)

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Offline going4speed

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Tank liner failed...crystals in float bowls?
« on: November 19, 2010, 09:00:12 AM »
I had a new liner fail and I just pulled the carbs to adjust the needle down a notch.  The carbs have had gas in them for about a month.

When I pulled the carbs and drained them the gas was brown and the bottom of the bowls have what looks like sugar crystals  :o

Any ideas that this may be?

Offline flybox1

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Re: Tank liner failed...crystals in float bowls?
« Reply #1 on: November 19, 2010, 09:10:40 AM »
your bike sat for a month.....thats what happened :P
gas will do that if left to sit w/o some sort of stabilizer.  try seafoam or stabil for times when you'll be storing the bike. better yet, RIDE YOUR BIKE!!!!
worst case....drain your bowls and top off your tank and include some stabil.

on another note... how do you know your liner failed? did your tank leak?
get liner bits in your bowls?

'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

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Offline going4speed

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Re: Tank liner failed...crystals in float bowls?
« Reply #2 on: November 19, 2010, 09:46:17 AM »
Yea its not ready to ride I just wanted to get it started after I rebuilt the carbs.  Lesson learned.  Need to drain the bowls!!

I looked in the tank yesterday and the liner on top of the tunnel was sloughing off.  I called kbs and they said it was due to lack of good prep...dammit.

The tank had stabil in the gas but the whole liner looks like its bubbling from heat or something its weird.

There was no liner in the carbs as the liner had not started falling into the fuel...the fuel in the tank seemed weird though like it was thicker than normal and brown/yellow.  Perhaps from the rust that is now started under where the tank liner is starting to fall off.  :o

your bike sat for a month.....thats what happened :P
gas will do that if left to sit w/o some sort of stabilizer.  try seafoam or stabil for times when you'll be storing the bike. better yet, RIDE YOUR BIKE!!!!
worst case....drain your bowls and top off your tank and include some stabil.

on another note... how do you know your liner failed? did your tank leak?
get liner bits in your bowls?



Offline Really?

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Re: Tank liner failed...crystals in float bowls?
« Reply #3 on: November 19, 2010, 09:58:13 AM »
The underneath of the topside of the tank may not see as much cleaning as everywhere else.  Get your self one of the mirrors on a stick (HF has them cheap) and check it out while you are cleaning to make sure you got it all.  You will need a flashlight to shine into the mirror to see good.
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline dave500

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Re: Tank liner failed...crystals in float bowls?
« Reply #4 on: November 19, 2010, 12:07:12 PM »
the inside has to be dryer than a very dry thing!if its done in winter it might not have been fully bone dry?

Offline Really?

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Re: Tank liner failed...crystals in float bowls?
« Reply #5 on: November 19, 2010, 12:21:09 PM »
the inside has to be dryer than a very dry thing!if its done in winter it might not have been fully bone dry?

I let mine sit for days to make sure it was dry, using a blow dryer too.  I didn't wait long the first time and it all caved in.  Getting POR15 out, even with their stuff was massive biotch!  So, I purposely went overboard.  I was not going to do this for a third time!
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline dave500

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Re: Tank liner failed...crystals in float bowls?
« Reply #6 on: November 19, 2010, 12:28:39 PM »
i dried mine for three days in our hot sun and randomly blowing air through it,before i applied the sealant i stuck a vacuum cleaner in the fill hole and let it run for 45 minutes.its a glass like finish inside.

Offline going4speed

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Re: Tank liner failed...crystals in float bowls?
« Reply #7 on: November 19, 2010, 03:05:32 PM »
I let mine sit for five days before the coating.  Mine does not look like glass but a dull gray.

What coating did you use?

i dried mine for three days in our hot sun and randomly blowing air through it,before i applied the sealant i stuck a vacuum cleaner in the fill hole and let it run for 45 minutes.its a glass like finish inside.

Offline dave500

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Re: Tank liner failed...crystals in float bowls?
« Reply #8 on: November 19, 2010, 03:26:57 PM »
por,its a silver metalic grey and as hard as glass.

Offline Really?

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Re: Tank liner failed...crystals in float bowls?
« Reply #9 on: November 19, 2010, 06:22:12 PM »
I let mine sit for five days before the coating.  Mine does not look like glass but a dull gray.

What coating did you use?

i dried mine for three days in our hot sun and randomly blowing air through it,before i applied the sealant i stuck a vacuum cleaner in the fill hole and let it run for 45 minutes.its a glass like finish inside.

There are quite a few steps with POR15 - I spent two days on the strip, two days on the rust removal step and prolly about the same on the prep wash before I got to the liner.  I skipped the degrease step on the second time around.

I would rather lick my exhaust clean than do this again.
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline dave500

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Re: Tank liner failed...crystals in float bowls?
« Reply #10 on: November 19, 2010, 08:23:49 PM »
hey tipper ill do your tank if you lick my exhaust clean,deal?

Offline Really?

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Re: Tank liner failed...crystals in float bowls?
« Reply #11 on: November 19, 2010, 08:35:21 PM »
hey tipper ill do your tank if you lick my exhaust clean,deal?

ROFLMMFAO!
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline dave500

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Re: Tank liner failed...crystals in float bowls?
« Reply #12 on: November 19, 2010, 08:47:29 PM »
do you want it hot or cold?

Offline Gaither

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Re: Tank liner failed...crystals in float bowls?
« Reply #13 on: November 19, 2010, 09:19:21 PM »
'Sounds like Dave got an excellent job on his tank.

FWIW -

Of course, there are numerous ways to clean/line a tank.

As we know, new rusts can form during the drying process - preventing a successful lining job. High humidity can cause this. Clean metal can begin to rust in a few minutes.

If you are gonna do it the hard way, at home, you might find an aircraft shop at your local airport. All planes, after a certain number of hours, are required by the FAA to have the tanks cleaned and lined. So, these guys usually buy 50 gallons of quality liner at a time. They will sell you a quart or two (or a gallon) cheap - and it is required to be good stuff. Go to a paint store, get some new cans/lids before you go to the airport. (You might even get 'em to do the whole job for you.)

If you don't care about the paint on the tank, take it to a reputable radiator shop. They'll clean and line the tank reasonably. They have all the right stuff. In my antique car days, I used this method many times with 100% success. Takes all the guess work and aggravation out of it.

Yeah, most prefer to do it at home.
Gaither ('77 CB550F)

Offline dave500

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Re: Tank liner failed...crystals in float bowls?
« Reply #14 on: November 19, 2010, 11:48:49 PM »
the por and the aussie made kbs tank kits both come with a prep acid stuff that prevents that flash rusting,i think the kbs prep was slightly better than the por one,they both have a good hard finish,the por one looks more metalic though.
http://www.kbs-coatings.com.au/KBS-MotorCycle-Tank-Sealer-Kit_p_13.html

Offline going4speed

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Re: Tank liner failed...crystals in float bowls?
« Reply #15 on: November 20, 2010, 05:28:32 PM »
I used this.  90% of it is good.  The rest is .... hmmm crap. :-\

the por and the aussie made kbs tank kits both come with a prep acid stuff that prevents that flash rusting,i think the kbs prep was slightly better than the por one,they both have a good hard finish,the por one looks more metalic though.
http://www.kbs-coatings.com.au/KBS-MotorCycle-Tank-Sealer-Kit_p_13.html