Hard acceleration, fuel spewing out gas cap?

[Brad]

Ok..not that I go around ridding at high rates of speed(ok..well yes I do) but when I hit around 5 or 6 thousand RPM under hard acceleration,  gas comes spewing out the gas cap  This was quite a shocker the first time it happened, as it sprayed all over my face and the front of my jacket. 
The bike has been a little of a basket case, and I will try to look up some pictures of how things should be routed but maybe I have something hooked up wrong? It runs killer at the higher RPM's...when I go from 7 to 9K it is like hitting a shot of NOS.  But the downfall..it the fuel shooting out everywhere. 
Any ideas?

Thanks
Brad

[fj11.5]

Leaking fuel from the cap was the reason I changed mine over to the flush mounted cap tank, and prefer it anyway,, mainly leaked when full or close too, but was either the gasket was f@##cked or because they vent from the cap

[Brad]

Leaking fuel from the cap was the reason I changed mine over to the flush mounted cap tank, and prefer it anyway,, mainly leaked when full or close too, but was either the gasket was f@##cked or because they vent from the cap

Where would I find one of those?  
And...is that an option for the 84?

[fj11.5]

Bike pictured is an 84, or at least the frame and engine still are   ,the early 1200 tank with vaccume tap fit with no mods, fuel pump ect,,  does your cap still have a gasket  

[Brad]

Does this answer the question?

Gotta love the Portland rain. 

[fintip]

You have to get a new tank or be damn handy with welding equipment.

The 86 and on tanks featured flush gas caps. The 86/87 tanks, at least, are a bolt-on option for the 84/85 bikes. You lose a little capacity.

So: ebay. craigslist. junkyard.

[fintip]

You say yours hits really hard from 7-9... But from what I've read/heard, above 8 in top gear the FJ is a bit weak in stock form. But also, the bike pulls so hard everywhere else in its nearly-unlimited powerband, that I wonder if your bike is under-performing below 7?

XJ's are known for hitting a sweet spot at 6 or 7 and then pulling hard. They are also a mid-range bike. I've never heard an FJ described as having a powerband like that.

[Brad]

You have to get a new tank or be damn handy with welding equipment.

The 86 and on tanks featured flush gas caps. The 86/87 tanks, at least, are a bolt-on option for the 84/85 bikes. You lose a little capacity.

So: ebay. craigslist. junkyard.

Well...I have this thing about welding on a gastank...lol
So Ebay.CL . junkyard..it is..

[Brad]

You say yours hits really hard from 7-9... But from what I've read/heard, above 8 in top gear the FJ is a bit weak in stock form. But also, the bike pulls so hard everywhere else in its nearly-unlimited powerband, that I wonder if your bike is under-performing below 7?

XJ's are known for hitting a sweet spot at 6 or 7 and then pulling hard. They are also a mid-range bike. I've never heard an FJ described as having a powerband like that.

I am sure that the condensation this bike is in..I should not really even be ridding it..but..hey..that is the kind of biker I am. 
From what I can tell the last however many PO's this FJ has had there is sure to be more and more wrong with it. At least I have the wiring under control now. 
I keep thinking that I am going to make it over to Mr. Bean's to check out the carbs...mine has nothing uner say..4k.
When I got the bike it had 17/42 gears..and I think I know why.
It is a work in progress, I did place my first of many orders with RPM.
I will just deal with the tank for now, my next order with be anew cooler, I get stuck in traffic a lot and tend to overheat.
Also it is quite ugly right now, but looks will just have to wait.
I had to rebuild my clutch master cylinder while I was at work today, as it didn't hold enough fluid to get me all the way here.
When I get home I plan on putting on the 18 tooth gear and the spin-on oilfilter(I hope that gets rid of my oil leak.)
I cashed in some stock today so I could get some more work done on it, so I should be able to order some more stuff in the next week or so. 

[RichBaker]

You say yours hits really hard from 7-9... But from what I've read/heard, above 8 in top gear the FJ is a bit weak in stock form. But also, the bike pulls so hard everywhere else in its nearly-unlimited powerband, that I wonder if your bike is under-performing below 7?

XJ's are known for hitting a sweet spot at 6 or 7 and then pulling hard. They are also a mid-range bike. I've never heard an FJ described as having a powerband like that.

The FJ is NOT weak over 8k..... Maybe the Jap market ones were, but NO USA/UK/rest o' the world FJ was ever considered "weak", even over 9k....  Mine doesn't stop pulling 'til the rev limiter kicks in.

Looks to me like the cap gasket is nonexistant from those pics. Does the cap still have the flaps in it, do you know?

[Brad]

You say yours hits really hard from 7-9... But from what I've read/heard, above 8 in top gear the FJ is a bit weak in stock form. But also, the bike pulls so hard everywhere else in its nearly-unlimited powerband, that I wonder if your bike is under-performing below 7?

XJ's are known for hitting a sweet spot at 6 or 7 and then pulling hard. They are also a mid-range bike. I've never heard an FJ described as having a powerband like that.

The FJ is NOT weak over 8k..... Maybe the Jap market ones were, but NO USA/UK/rest o' the world FJ was ever considered "weak", even over 9k....  Mine doesn't stop pulling 'til the rev limiter kicks in.

Looks to me like the cap gasket is nonexistant from those pics. Does the cap still have the flaps in it, do you know?

I don't know...that is one of the other reasons I was hoping to hook up with someone else, I have no idea what a stock one looks like.
Almost of of my wire routing has been done from pictures on this site.  
I would love to see a "real" one so I can have something to compair to.
I am afraid that mine is so butchered that they may just wonder why I am ridding it..lol

Wiat...there is a rev-limiter I can hit?
I thought my oil light was my rev limiter!

[Pat Conlon]

Put a large gas resistant rubber washer on that cap and your problem will go away.
At least that problem anyway....
The large rubber washer seals against the lip of the tank opening.