Cracked tank - side effects

14 replies to this topic
  • holeshot

Posted July 25, 2002 - 04:38 PM


I was at a moto track recently (Elsinore) and noticed that my gas tank was leaking when I stopped back in the pits. During that day and the also during the previous ride, my bike developed an intermittent misfiring problem. When an intermittent problem develops, it's usually ignition/electrical, but when I pulled the hot start out while it was still running, the problem cleared up temporarily, which would indicate a carburetor/jetting problem. I was soooo confused. :D

Thinking that the cracked tank and misfiring at the same time were no coincidence, I decided to soak the coil with gas while the bike was running, to see if I could recreate the problem. Nope, that wasn't it. I was going through the electrical/ignition with a meter looking for the problem and was almost resigned to buying a new CDI, when it hit me like a sack of bricks (not the CDI, a revelation).

The gas tank was cracked at the far rear, near the air box, and raw gas was dribbling onto the filter whenever I squished the tank while riding (causing a rich condition). Just another classic religious experience revealed here on TT. :D

Good thing it didn't cut out when I went for that third gear jump..... :)

[ July 25, 2002: Message edited by: holeshot ]

  • Scott_F

Posted July 25, 2002 - 05:29 PM


I went through the same revelation years ago with my YZ400's. Yamaha called it the auto-enrichening circuit. :)

  • sirthumpalot

Posted July 26, 2002 - 02:35 AM


Good find, though I'm glad you weren't parked next to my truck when you were pouring gas on the coil while the engine is running. :)

  • Uncle_Rich

Posted July 26, 2002 - 03:33 AM


If the coil was the problem, when you soaked it with gas you would have found out how good gas burns
Please don't do that again

  • Shawn_Mc

Posted July 26, 2002 - 07:33 AM


Those 909 guys are too funny. Im really glad you didnt burn down. You may have another scenario, gas in the filter will mobilize the filter oil, allowing dirt to pass into the carb, more than likley into the primary air jet. You might want to clean your carb.

  • holeshot

Posted July 26, 2002 - 09:10 PM


Originally posted by sirthumpalot:
.......I'm glad you weren't parked next to my truck when you were pouring gas on the coil while the engine is running. :D

I was wondering what kind of reaction that would get. :D Actually, gas was running all over the coil while I was riding, and it didn't ignite.

Don't try this at home folks. :)

[ July 26, 2002: Message edited by: holeshot ]

  • mxerhale

Posted July 26, 2002 - 09:12 PM


So I guess when my tank cracked on my '00 426 it wasn't the first one to do so. I must say I was a little disappointed that a three year old tank would develop a crack without even a crash to blame it on.

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  • holeshot

Posted July 26, 2002 - 09:17 PM


Originally posted by Shawn Mc:
.....You may have another scenario, gas in the filter will mobilize the filter oil, allowing dirt to pass into the carb, more than likley into the primary air jet. You might want to clean your carb.

The filter was "cleaned" a little in one spot on the lip. I'll make sure there's no grunge in the air jet.

Yamaha added auto-enrichening and auto-filter cleaning. Nice touch.

  • dezthumper

Posted July 30, 2002 - 06:11 PM


I experienced the EXACT same thing. However, only six rides on the 01 stock tank. I race desert and the tank came off before my first ride and the Acerbis dez tank went on. Recently, a new track opened up near my home. Thus the switch to the tiny little tank. On my sixth time out (just over 15 hrs of practice time on the track) and it cracked at the back.

I think the problem is due to the rubber bungee like piece that holds the rear of the tank down. That piece rubbed in two where it folds over the bottom bracket where the bottom piece slides over. I looked for a long time trying to replicate the impact possibilities of the tank and bike. The only place I could see contact was at that point. I was so disappointed in Yamaha. I bought a new "used" tank, a new bungee thingy and replaced the foam that sits on the frame to support the stock tank. It swelled up due to gas leaking on it and sitting for a day while I searched for time to fix it. I am now looking for a company that does plastic welding to fix it. The gas did the same thing yours did. It leaked onto the airfilter attracting A LOT of dirt and causing the bike to run like crap. I pulled over to look at the carb due to it running like crap. Viola, gas streaks everywhere. D@mn... anyway, fresh air filter etc and the bike is like new again. Anyone in AZ know of a company that welds plastic. I know of people who weld plastic, but I'm looking for a place that really knows what their doing.

  • Shawn_Mc

Posted July 31, 2002 - 07:12 AM


Dezthumper, I thought the same thing once. It didnt crack because of the rubber strap. It breaks from body wieght. Mine broke,and I took the strap off to avoid the crack. As just about 80% of the rest. A while back I theroized that the bigger the guy, the quicker the tank would break. I was wrong. What happens, the seat crushes the tank and folds the very rear most corner, and it just work hardens and cracks. I bought a Clarke tank. Fit perfectly, seems thicker.

  • John_Lorenz

Posted July 31, 2002 - 07:16 AM


Gad Durn

You from the Ozarks or Sum-Pin

Geez Poured GAS :) on my coil while running

I have nothing to say I cant believe it I actually cant respond to that one

  • CJ_Baran

Posted July 31, 2002 - 08:28 AM

#12 least he did not pour the gas on a burning cat! :)

Who started the burning cat thing...

  • holeshot

Posted July 31, 2002 - 09:05 PM


Yes, I like living on the edge. :) I was almost hoping that it would burst into flames at that point. But seriously, no one should ever pour gas on their bike while it's running (it just don't make no sense). You could get blowed up real good. :D

With the stock tank, there's about a 3/8" gap between the rear of the tank and the subframe (where the long bolt goes through). It's possible to compress the rubber cushion (under the the tank) and flex the tank enough so that it comes in contact with the subframe, eventually cracking the tank. The Clarke tank has a slightly different design at the back which gives a good 3/4" gap or more. If anyone hits hard enough to close that gap, they'll have much bigger problems than a cracked tank.

Only time will tell if the Clarke tank hold up...

[ July 31, 2002: Message edited by: holeshot ]

  • John_Lorenz

Posted July 31, 2002 - 09:33 PM



I knew you were fro the Ozarks
You Wrote

Yessuh, ah like livin' on th' edge. ah was almost hopin' thet it'd bust into flames at thet point. But seriously, no one sh'd evah pour gas on their bike while it's runnin' (it jest doesn't make no sense). Yo' c'd git blowed up real fine.

Wif th' stock tank, thar's about a 3/8" gap between th' rear of th' tank an' th' subframe (whar th' long bolt goes through). It's postible t'compress th' rubber cushion (unner th' th' tank) an' flex th' tank inough so thet it comes in corntack wif th' subframe, eventually crackin' th' tank. Shet mah mouth! Th' Clarke tank has a slightly diffrunt design at th' back which gives a fine 3/4" gap o' mo'e. Eff'n ennyone hits hard inough t'close thet gap, they'll haf much mo' trimenjus problems than a cracked tank. Shet mah mouth!

Only time will tell eff'n th' Clarke tank hold up...

:D :) :D

  • holeshot

Posted July 31, 2002 - 03:39 PM


I doen kno ware yer gittin that from, cuz ya cant here acsents on the innernet.

Sum peepl call me a Rednek, cuz I boht my (ex)wife a Shop Vac fer her birtday. I dont see nuthin wrong wit that..... :)

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