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View Full Version : Tri-z fills exhaust with gas after 7 days



Karhu
09-23-2016, 12:04 PM
Been riding my tri-z and decided to check up on the spark plug on how its running (rich or not) after having it pushed back into the garage last week.

Noticed it was rather rich so figured needed to readjust. Funny thing is I found out by accident that over this week the trike has filled up the engine and the bottom end of the exhaust!

Now my question for you guys is, how could this be possible..... Its not just a little gas but more like 1liter!!

edizzle89
09-23-2016, 01:53 PM
the float in the carb might be stuck open letting fuel to keep flowing into the carb when the engine is off then going into the engine and exhaust, might try tapping on the carb to try to get the float loose.

atc007
09-23-2016, 02:52 PM
Unless you know it has been replaced. Get a new float needle and seat,and verify your float level is right. A tiny piece of dirt,seed or anything can do this. But with a 2 stroke that old,a new needle and seat will assure you that it doesn't happen again unless debris is introduced into the carb.

yaegerb
09-23-2016, 03:00 PM
x3, float seat isn't or needle isn't working properly. Make sure after you rebuild the carb (or before) that you pop the spark plug and kick the bike over to try and get the gas out. You may also have to tip it over to get it out of the crank case or suck it out with a mightyvac brake bleeder. That's a surefire way to blow out seals or blow you off the bike.

oldskool83
09-23-2016, 03:07 PM
float off or bad. If you cant fix this any motorcycle shop can. Not hard.

NeverLift
09-23-2016, 03:25 PM
Because of the fuel pump fuel cant flow like a gravity feed carb. So i'm not so sure it's the float needle. There could be a hole in the diaphragm of the fuel pump. Causing fuel to flow thru the pulse line into your cases and exhaust. It might also explain why you had to push it back last time.

Karhu
09-23-2016, 06:45 PM
Thanks for alll rhe replies guys!

Yes exactly, that's why I currently got all the fuellines of to see if its leaking somewhere... Im starting to suspect the line to the fuel pomp that connects on the bottom of the cilinder indeed..... If so would this be an easy fix?

Will take the carb apart and clean it all. Did cleaned all the gass already away.

Weird question, it only seems to do this when it has a full fuel tank. Not when there is just one gallon in the fuel tank.... Came to my mind that this happened before ones or twice but then it would fire up and just push it all out of the exhaust.

Red Rider
09-23-2016, 08:28 PM
Weird question, it only seems to do this when it has a full fuel tank. Not when there is just one gallon in the fuel tank...Is it possible, that when the tank is full, it is able to gravity feed through a leaking float valve seat? I'm not all that familiar with the Tri-Z's fuel system, other than knowing it has the fuel tank under the seat & requires a fuel pump, so forgive my ignorance. But, when the tank is topped off, is a portion of the fuel above the carburetor, thus allowing gravity feed?

NeverLift
09-23-2016, 09:00 PM
Pull the hose off the cylinder and apply pressure or vacuum to the line(6 or so psi) and it should hold. Rebuild kits are still available.
Could still be the needle and seat though. And you test this the same way. Pull the carb, then the float bowl, flip upside down and apply pressure or vacuum to the fuel line and you should have no leak.

Sent from my XT1080 using Tapatalk

yaegerb
09-23-2016, 09:36 PM
Is it possible, that when the tank is full, it is able to gravity feed through a leaking float valve seat? I'm not all that familiar with the Tri-Z's fuel system, other than knowing it has the fuel tank under the seat & requires a fuel pump, so forgive my ignorance. But, when the tank is topped off, is a portion of the fuel above the carburetor, thus allowing gravity feed?

You beat me to it. I have little knowledge with the fuel delivery system on a z but your logic is the only way I could come up with the symptom when the tank is full.

350xtrike.rider
09-23-2016, 11:14 PM
I've had it happen too because I left the fuel petcock on for a day or two. At $9 a gallon I can't afford to many of those "accidents" :lol:

Karhu
09-24-2016, 08:03 AM
This morning I checked all the hoses I pulled off yesterday. The one hose that has fuel leakage is the one coming from the pump to the cylinder. So the one that makes the pump work.

Could it be just the gravity of the full fuel tank making the fuel rise in the lines flooding the pump and making it go out reeves of the pump into the cylinder?

That would mean the pump has had its best time......correct? Where would I be able to order a new pump or revision kit for the old one?

atc007
09-24-2016, 08:50 AM
You will need a new diaphragm/rebuild kit,or a new pump. Most any single cylinder sled uses the same type pump. It sounds like you found your problem,but if your tanks breather hose is plugged,the tank can build pressure and push gas through the carb also. Rebuild the pump,clean the vent and see if it solves it. If not then the float needle for the carb :).

Karhu
09-24-2016, 12:21 PM
Youre spot on! Carb is good with no leakage or what so ever, cleaned it but wasn't dirty at all.

The issue is the pump, it leaks fuel into the line to the cylinder when its turned off, and thus doesnt have any pressure going into the pump. Yet ive still no idea how it exactly suppose to work, but think that with a rebuild kit it all be solved. Does anyone have a diagram of the pump and perhaps an explanation of the darn thing ��

All lines are open yet I indeed think that with a full fuel tank it just builds up more pressure n start filling up the engine slowly.

Does anyone know where I could order a kit for the pump?

atc007
09-24-2016, 01:29 PM
Here is the Yamaha part # for in America, 38W-W1391-01-00,,,,,$46,,,Might be different over there. Again, it won't mount up exactly the same,but any single cylinder snowmobile fuel pump will work.Most likely less than $12 on ebay.That's the way I would go..

Karhu
09-24-2016, 03:01 PM
I cant figure out how this pump actually work....

Did find that on the back end of the pump the round foil was cracked so perhaps that would be the issue of the gass leaking?

Rob Canadian
09-24-2016, 11:59 PM
If my memory serves me correct.
3 lines to the pump.
1 fuel in
2 fuel out
3 pulse from the engine.

Pulse from the engine will move the diaphram in and out. Fuel in and out are on a 1 way valve controlled in the pump via springs of what have you. All 3 circuits are isolated from each other by gaskets.

Sounds like a gasket is leaking into the pulse line. I ran gocarts with this type of system. Post up pics of the pump. And what you are seeing. I am only guessing

Karhu
09-25-2016, 08:13 AM
Problem turned out to be a cracked (brown part) in the fuel pump on the rear side going to the cylinder. This is probably why the Z had extensive smoke. Just replaced the brown part (paper/plasticish) by a new one and she drives like a champ without smoke nor is she spilling any gas into the engine/exhaust.

Thanks for all you guys help! I learned a lot this weekend ;)

atc007
09-25-2016, 09:51 AM
The extra pressure of a full tank would have pushed it easier :). Thanx for reporting back. Glad you can enjoy her now. That must be a rare bike over there? I imported a John deere harvester from the Netherlands many many years ago.

Karhu
09-25-2016, 10:19 AM
Well I figured out that when the tank is full or filled over 4 liters there is indeed enough gravity to make the bike run without an actual fuel pump. So that explained why it has happened before but never as much as last time as I usually fill up tthe bike before a ride and this time I filled her up after.

Yes its indeed a rear bike, here aren't many trike enthusiast and many machines has been used damaged and destroyed. Therefor im really happy to have such a great machine. This one was actually sold in Argentina in 1987 then imported to the netherlands and after a ride on a field a local farmer parked it in the barn and havent seen a lot of action ever since ;)

Oh, wasn't that a hustle to import? Expensive shipment? Etc? Do you still own the John Deere, great machines :)

atc007
09-25-2016, 02:10 PM
It actually cost more to truck it from Baltimore to my State Pennsylvania,than it did to ship it from your port to Baltimore. I was gonna play more with my import license,then the dollar went in the toilet. I do still have it,but need to sell it as I have no use for it anymore.

Red Rider
09-25-2016, 04:39 PM
Well I figured out that when the tank is full or filled over 4 liters there is indeed enough gravity to make the bike run without an actual fuel pump.I figured that must be the case. Since I don't have a Tri-Z to look at, I went out to the garage, looked at my 250R, and envisioned an underseat fuel tank on it, and a portion of the tank would definitely be above the carburetor. So, the Tri-Z only needs the fuel pump to make all of the fuel usable, and without it, a portion would be unusable. I'm glad you got it figured out & taken care of, now go enjoy it.

Karhu
09-26-2016, 07:55 AM
Yes most definitely enjoy it, like the fact that it has way better power now too and that it doesn't smoke anymore. Will readjust the carb later on if needed. But the fuel pump is an interesting part on the Z i must say. I like the fact the Z has its fuel tank low under the seat so it keeps the overall weight low. Hate the fact it has a fuel pump that can brake ;)

Rob Canadian
09-26-2016, 11:02 PM
Glad it is up and running well. :)