Gas in my bottom end! Need some help please.

[1979XS4002-F]

OK, So a few weeks ago I decided after two 2 seasons of riding my bobber that I'd fire up my bone stock 79' xs4002-f.. After draining the gas, removing the carbs/bench syncing, full carb cleaning and new plugs she was up and running. After hot lapping it in fron of my house for 5 minutes it stalled.. i couldnt for the life of me get it started again, that is until it cooled down..After 20 minutes or so she fired right back up again, but then stalled after heating up..During this time I noticed a weak spark so I cleaned/gapped the points and verified the connections but no help..So I threw my meter on the battery to find it very low(obviously after sitting so long) I then charged it fully only to learn the battery was toast(wouldnt stay charged even after running at 5 to 10min intervals before getting warm and stalling/sputtering. So, i then replaced the battery...After installing a brand new fully charged battery the bike continued to sputter and stall after it was warmed up..It was then that I learned my voltage reg wasnt doing it job(via multimeter). And this brings us to today, installed my new volt reg from OregonCycles and she fired right up..after warming it up I noticed you couldnt give it any throttle without it popping and farting, so I figured I'd verify timing with a light and file/gap points if needed. But, when I the stator cover off thinned out oil/gas began POURING out from the stator./magneto area,, as in a gallon or so??? SO if my rings are bad this will happen right? and iI've read that this is typical of a bike sitting also, true? My mileage is low with only 8500 original miles but she she did smoke when I parked it and both cyl read 140PSI with the comp. tester...SO, my question is, should I move forawrd with an oil change/warm up to see if rings seat or should I just repalce rings knowing they are at minimum spec(140psi) according to the book? Thank you in advance. Travis K

 

[Travis]

Gas in your ass?

Anyway, you get gas in your engine by having the floats stick in your carbs and they overflow. Gas goes into the intake and leaks down past the rings. That doesn't mean you have bad rings. You need to change the oil and maybe change the needle and seat in your carbs so it doesn't happen again. 140psi is fine. The smoking could be from a bad valve seal. Do you have a manual petcock? If so, be sure to turn it off when storing the bike.

 

[1979XS4002-F]

Travis, Nice name by the way , No gas in this ass...for now..lol Anywhoot, I just went back out to my garage to drain/change the oil, put some cheap oil back into her and kicked it oover 4x only to snap my kick starter off...FML!! So, being the economy model with kick only im screwed until I get a replacement..lol regarding my petcock, its a vac operated with no OFF position..but I'm picking up what your putting down, probably filled full of gas during the initial start-up period before I did the carb cleaning and such...SO, I'm hitting up Ebay now to find a kicker and I'll be back at it again, thanks for the prompt response and the help, tis greatly appreciated Sir!
Oh, and one last thoguht...do these bike pop and fart like crazy if test running with my airboxes removed? She did not want to run at all...
Travis K.

Gas in your ass?

Anyway, you get gas in your engine by having the floats stick in your carbs and they overflow. Gas goes into the intake and leaks down past the rings. That doesn't mean you have bad rings. You need to change the oil and maybe change the needle and seat in your carbs so it doesn't happen again. 140psi is fine. The smoking could be from a bad valve seal. Do you have a manual petcock? If so, be sure to turn it off when storing the bike.

 

[bcware]

My xs400 does not like dramatic changes to the air box/filters without re-jetting. Stock to no filters is a big change.

Be happy the kick start snapped while you're comfortable at home and not on the road.

Stay on the forums here and ask lot of questions when you run into a problem. I don't want you tearing down your engine because you're flooding

 

[dO-bOy]

You can run start it? Lol

 

[Goldwing 86]

make sure petcock turned to open, not prime.
don't leave bike on side stand, tipped sideways for long time.
P.S, the bottom end will be nice and clean ready for new oil change

 

[Goldwing 86]

Broke my kick starter also.
Found one that fit at cycle bone yard,
it was larger then stock but same size at bolt end.
Bike will run rough with airbox filters off, jetting gets screwed up.
Kick over first with key "off" and petcock to prime. This helps to cold starting.

 

[1979XS4002-F]

My xs400 does not like dramatic changes to the air box/filters without re-jetting. Stock to no filters is a big change.

Be happy the kick start snapped while you're comfortable at home and not on the road.

Stay on the forums here and ask lot of questions when you run into a problem. I don't want you tearing down your engine because you're flooding

I gotcha BC Thanks for the info, no all I have to do is wait for my new/old kicker to arrive...sigh*

 

[1979XS4002-F]

You can run start it? Lol

Yeah, yeah...lol I like riding it, but not that much..lol

 

[1979XS4002-F]

Broke my kick starter also.
Found one that fit at cycle bone yard,
it was larger then stock but same size at bolt end.
Bike will run rough with airbox filters off, jetting gets screwed up.
Kick over first with key "off" and petcock to prime. This helps to cold starting.

Scored a 77 xs360 kicker on ebay last night..23bucks Thanks for the carb info..actually a bit soothing to know it isnt something else "wrong"...yet that is..Thanks again.

 

[1979XS4002-F]

make sure petcock turned to open, not prime.
don't leave bike on side stand, tipped sideways for long time.
P.S, the bottom end will be nice and clean ready for new oil change

Yessir, no side stand on mine, removed it years ago(didnt want my baby to ever tip over..lol) and yes, i supposed the "glass is half full"

 

[XSLeo]

On a vaccum pet cock if the diaphram in the pet cock is bad the engine vaccum can pull fuel out of the petcock, bypassing the carbs. If your petcocks are working right, leaving them in the on position is what you do. The prime position bypasses the vaccum so fuel can get to the carbs with out the engine running.
When I get ready to start the bike, I put the petcocks in the prime position for a minute or so before I try starting. This way I know the carbs are full of fuel. I then start the bike, then turn the pet cock to on.
The float valves arenot designed to be fuel shut offs, If they were then they wouldn't put petcocks on. They are fuel metering devices. They keep the correct fuel level in the float bowls so the carbs don't run rich or lean.
The petcocks shut off the fuel flow.
If your pet cocks leak the weight of fuel in the tank can push the float valves open slightly and let fuel into the carbs. As this extra fuel gets in the carbs the bowls over fill and run out into the air boxes and into the engine.
You need to check your petcocks for leaking.
On the vaccum operated petcocks fuel can also leak through the vaccum diaphrams into the carb holders and into the engine.
So clean, rebuild or replace your petcoks to prevent this.
Or drain the fuel out of the tank and carb. With tidays Ethanol fuels, thius is a good idea anyeay. The Ethanol draws water and settles to the bottom of the tank causing rust. Better to drain and coat the inside of the tank with motor oil for storage.
Leo

 

[Travis]

Leo, nice post!

 

[1979XS4002-F]

On a vaccum pet cock if the diaphram in the pet cock is bad the engine vaccum can pull fuel out of the petcock, bypassing the carbs. If your petcocks are working right, leaving them in the on position is what you do. The prime position bypasses the vaccum so fuel can get to the carbs with out the engine running.
When I get ready to start the bike, I put the petcocks in the prime position for a minute or so before I try starting. This way I know the carbs are full of fuel. I then start the bike, then turn the pet cock to on.
The float valves arenot designed to be fuel shut offs, If they were then they wouldn't put petcocks on. They are fuel metering devices. They keep the correct fuel level in the float bowls so the carbs don't run rich or lean.
The petcocks shut off the fuel flow.
If your pet cocks leak the weight of fuel in the tank can push the float valves open slightly and let fuel into the carbs. As this extra fuel gets in the carbs the bowls over fill and run out into the air boxes and into the engine.
You need to check your petcocks for leaking.
On the vaccum operated petcocks fuel can also leak through the vaccum diaphrams into the carb holders and into the engine.
So clean, rebuild or replace your petcoks to prevent this.
Or drain the fuel out of the tank and carb. With tidays Ethanol fuels, thius is a good idea anyeay. The Ethanol draws water and settles to the bottom of the tank causing rust. Better to drain and coat the inside of the tank with motor oil for storage.
Leo

Thank you Leo,
I just recieved my new kickstarter on friday so this evening I began working on the ol'gem again. Once I had the new kicker-boss installed I removed the fuel line an confirmed there was now leaking of the carbs/cock,,all is operating at the should..Next I used a nail file(metal cross hatched style) to brush up the points just in case(i read here that emory is a no-no) then threw on the key and whammo, the key was already on ..Yup...left it on from the last session..SO I suffered an hour or so delay while charging the battery(meter read 12.6v)...my bad. Once charged I flipped her to prime, went to full choke and after 3 kicks she fired right up..kinda sputtering/farting but running worked it down to no choke in a matter of 30 seconds(it was 83deg. today!!)..I then double checked my advance...ended up a bit retarded so I bumped it ahead a little(@3500rpm) Then dropped the idle and confirmed my timing@1200rpm.. looked pretty good until It started getting a popping(backfire/no spark?) at idle..quick thinking I grabbed my multi meter and tested the battery..12.3v....12.2v......12.1v.....stalls...sigh...No charging!! Threw the charger back on it and kicked her over...vrooom takes right offf...revved it up with meter on the batt...12.4 steady...no increase!! WTF just bought a $45+ Oregon Volt reg after she failed the ohm test.... Did a quick rectifier test..all is well from a continuity/open stance(flipped pos/neg and went thru wht/red and blk red as detailed in manual..Looked over voltage reg. test method again in manual and debated silently tomyself how this non-OEM volt reg will not test out the same..and I was right..but I 'm confused as to what setting to put my multimeter on..thought 20ohms was good but i'm not savvy to the specifics on resistance readings/settings..any advice? Lastly I did clean the carbs earlier in the week while waiting for kicker and noticed my flots were set too low(25) vs manual specified for 2-f models 32..How did it run fine for the last 4k miles I owned it with the floats at 25 vs. 32? Anywhoot I made the adjust ment and not when I try to give it gas it immediatly stalls... FLoat height back to where it was everyone?..lol...Sorry for the scrambled posts...just dont feel good about a few things an want to capture them before I forget...

 

[1979XS4002-F]

bump....

 

[HoughMade]

The float height of 32mm is wrong- 25 to 26mm is right...many have confirmed this.

I don't know much about the charging particulars, but if you left the battery dead flat for the off season, it's probably toast. What else may be going on, I don't know.

 

[1979XS4002-F]

Ok Hough, thanks for the info...as for the battery..the key was left on over night only..charged and its holding fine .