Kawasaki VN750 Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
113 Posts
Discussion Starter #1
what causes gas to leak out exhaust??? Or , what is the fix for gas leaking out exhaust pipe.?
 

·
Premium Member
Joined
·
4,054 Posts
Wow, you are probably going to have to elaborate on this for any of us to understand the problem. You have gas leaking out the exhaust pipe? Just sitting there, or running or what? Are you positive it is gasoline? If it's doing this just sitting there not running, your oil is probably full of gas and you don't want to start up the bike until you have changed oil and fixed this!

Give more information if you can.
 

·
Registered
Joined
·
113 Posts
Discussion Starter #3 (Edited)
gas / exhaust

OK, I just bought the bike . It had 3200 mi and is a 1996 vn750.I had a gas leak at the petcock diaphram and fixed it. It has been very hard to start or would not start. I finally got it started and rode to fill up and had to push it home (just died).So this morning would not start and finally backfired (scary),some smoke. So I said "enough" loaded bike on trailer and gas flowed out of tail pipe. I don't as of yet have a manual of any sort and know nothing about this model bike. So I hauled into repair shop. What is your diagnoses???What is this going to cost to fix..Bound to be some carb prob eh? Let me know what you think. Thanx
 

·
and the Adventure Cycle
Joined
·
6,141 Posts
Sounds like you were getting some major flooding.
You don't hold the throttle open while trying to start it, do you ??

Possibly carb problems, but like Fergy said, check to be sure there's no gas in the oil too.


Good luck with the fix !!
 

·
Registered
Joined
·
165 Posts
bilyum said:
what causes gas to leak out exhaust??? Or , what is the fix for gas leaking out exhaust pipe.?
I had the same exact problem with my '97... I pulled all the vent lines from tank and blew them out along with the small vent at cap. Pulled and cleaned the carbs and petcock. And definitely change the oil because it does have gas in it. I filled it up and rode 150 miles yesterday with no problems, stopping and restarting several times just to be sure. I turn my petcock to off every time I let it sit at all now. Before I left it on all the time. I never did find a definite problem but the bike is running now.:confused:
 

·
Registered
Joined
·
130 Posts
Yeah sounds like flooding, had it happen with my 440, spewed gas out of a cylinder into the exhaust pipe, big puff of flame, rousing laugh, and rebuilt carbs a total of 12 times now. So i got the 750. =)
 

·
Registered
Joined
·
165 Posts
artman said:
Did the bike smoke when you rode it? If so, black or white?
The overflow of gas diluted the oil and flooded rear cylinder with oil and smoke was white until plug fouled. Cleaned up and excess gas burned black smoke until flooded and flaming backfire. Cleaned carbs and all vent hoses and lines from tank and bike is back running.
 

·
Premium Member
Joined
·
4,054 Posts
Years ago when my CJ7 shorted and caught fire and burned up in my driveway one night, and when the volunteer fire cheif, who lived across the street and was on vacation at the time, but the firetruck which was still parked in his yard wouldn't start, and while the volunteer crew and I waited for another firetruck to arrive, while we watched my cherry red Jeep/bonfire as we could hear the siren in the distance... the old firetruck finally came rolling round the corner, sputtering like it was about out of gas, and then it backfired, and a four foot ball of flame shot out and rolled down the street behind it...

At the time, it wasn't very funny but now it kinda is.
 

·
Registered
Joined
·
165 Posts
bilyum said:
what causes gas to leak out exhaust??? Or , what is the fix for gas leaking out exhaust pipe.?
I had the very same problem...
I did not relate the two but my problems started when I installed the Scootworks degoat. A retired Kawasaki mechanic (8 Years ago) told me that on late '96 to early '97 models that a back pressure problem existed due to a small vent line oriphice in the vent lines to the tank and/or carbs and/or gas petcock. This caused back pressure problems and did not allow gas to flow properly through the running engine creating the flood out situation and way too much gas. He couldn't remember which vent tube it was or where it was exactly.

Rather than pull tank and carbs again I chose to Regoat (since I didn't have the funds for V&H) to see if it would clear up flood out problem. Guess what??? No problems at all since regoat. The mechanic also said that the custom exhausts removed the problem as well and that whatever was changed and made smaller was corrected on the later '97 models and at least up to early '99 that he knew of. I figure removing the baffle plate from the Kaw mufflers with degoat would also relieve the back pressure problem as well.
 
1 - 11 of 11 Posts
Top