Bah, tri-z fuel delivery issue "Calling Raffa"

[factoryX]

I tore apart the fuel pump looks okay, doesn't have any pin holes. The trailprotrailprotrailprotrailprotrailprotrailprotr ailpro will start occasionally and then die and won't fire back up(Cleaned up the carb). Plug looks okay as well? I put my thumb over fuel pump hose coming from the cylinder and I'm not getting any pressure? Its also backfiring, I switched coils to little to no effect. Any ideas would be great.

[90guy]

Doing this to subscribe. I am also having the exact same problems!

[volfan537240]

Got spark?

Backfiring.... Flywheel key sheared?

[Bryan Raffa]

man thats pretty vague .. it is hard to feel the pulse off the cyl ... vacuum gage? .. hows the Rings?? what shape is it in? what carb.. ect... very difficult to pin point your prob .. with out actually seeing it ..had a guy call me at the shop today... wanted me to tell him what was wrong with his car ... by making the noise with his mouth...:lol:

[90guy]

man thats pretty vague .. it is hard to feel the pulse off the cyl ... vacuum gage? .. hows the Rings?? what shape is it in? what carb.. ect... very difficult to pin point your prob .. with out actually seeing it ..had a guy call me at the shop today... wanted me to tell him what was wrong with his car ... by making the noise with his mouth...:lol:
Sounds like its one of your days to be a mind reader and to know what is exactly going on!

[factoryX]

The symptoms are very vague, but here are the details. The bike sat in a field for 7 years under a tree after this guy's brother died(Possibly longer..). I thought it would be a complete utter basket case but the dry climate with no salt here in the high desert of central oregon does wonders and everything looks to be in decent shape. I need to replace motor seals, but so far its not sucking transmission fluid, its holding coolant and runs great when it does. Everything on the bike other than the boyseen reeds and answer silencer is stock. I'm just confused really as by all means it sounds like it just needs a pump rebuild, but it doesn't explain the backfire? Has about 160-170psi, and I'm running a br8eg plug. Has spark, but a little on the weak side? Either timing is way off or both my coils are probably crap which is a possibility.

[volfan537240]

Sheared flywheel key = timing way off

[Bryan Raffa]

pull the fly wheel cover and the fly wheel ,, see where the stator is set to the hash mark.. put it in the middle if not.. inspect keyway and key..

[ATC-Eric]

Agreed on some sort of timing issue. Also, if you want to eliminate the fuel delivery theory, put some fuel directly into the carb, bypass the pump.

[barnett468]

Hello


Looks like you have lot’s of help and the tri z expert is here but just wondering.

Can’t you take the plug out ground it then kick or push it in gear to check “idle” timing with lite?

If it’s firing on time the key is obviously good.

Have you tried what post 9 says?

You say you have weak spark. Some bikes just look that way Bryan or another will be able to tell you if it’s correct or not. OHM test coils per manual anyway and voltage output while kicking bike over if possible. Post results. If that’s all good then it’s a good chance it’s your CDI box. I would pull the flywheel, if it’s since it’s been sitting in a field it’s possible the magnets or coli ends might be rusty and not creating good magnetism.

Was the pump diaphragm dried up or still EASILY pliable.

Electronics do NOT like to sit outside in a field for 7 years even in Oregon.

[atc300r]

Have you tried a new plug.

[El Camexican]

My $0.02 is to put a hose with nice clean cut ends on that vacuum elbow on the cylinder, lick your finger, put it over the end of the hose, close your eyes and with the spark plug installed and the ignition switch off have a buddy kick it over hard a few times. You should feel a pulsation on your finger. If not it is plugged somehow as your cylinder pressure indicates a pretty good ring seal. The only other thing I can think of that would cause a lack of a pulse in the line with good compression is a broken reed, but I think you would hear air coming back through the carb if that was the case.

Rebuild the fuel pump. Good or not it can’t hurt and it’s less than $30.00 bucks, so why be left wondering if it’s a problem.

Only after this would I start looking at electronics.

Remember, you get what you pay for and this advice was free

[Dirtcrasher]

^ That in itself is good inexpensive proactive maintenance.

The pumps are know to fail. IDK where your fuel filter is but I always remove them and put an inline filer in.

When it dies, shut off the gas petcock immediately. If your carb has a drain screw, loosen it and see if the bowl is near dry.

[factoryX]

It does get a little gas, but next to nothing and even more so now. I've actually ridden it(No bottom end) but after a few minutes it won't start again and the plug is dry. I have the flywheel cover off, little to no corrosion. Don't get me wrong, it needs work, but its still in great shape for sitting for so long. Its even more unbelievable that it even started. El Camexican, I did that yesterday before I even posted, no dice.

[El Camexican]

^ That in itself is good inexpensive proactive maintenance.

The pumps are know to fail. IDK where your fuel filter is but I always remove them and put an inline filer in.

When it dies, shut off the gas petcock immediately. If your carb has a drain screw, loosen it and see if the bowl is near dry.

Good point, that gasket could have chunked up and clogged something

[El Camexican]

El Camexican, I did that yesterday before I even posted, no dice.

I just tested mine. There is definitely a pulse that can be felt. It won’t give your finger a hickey, but it is there. If you have good compression, but no pulse from the elbow I would guess that either your reeds aren’t sealing, your base gasket is leaking, or your left side crank seal is blown.

[volfan537240]

Leak down tests are most important on 2 strokes

[Bryan Raffa]

did you take the bowl off the pump with a 10mm ,, look up in there ..with needle nose pull the screen out and clean it.. maybe you dont know there is a screen in it..

[Rigaman]

Hey Raffa. Can you take a picture of where the stator is supposed to be lined up? I have the mark on the stator lined up with the mark on the case. You said put it in the middle. I would like to see where you set it.

[Bryan Raffa]

center mark... and dam I just put it back together! 20 min ago!

[MTS]

I would suggest you pull the carb off, stick your hand over the intake and have a buddy give it a good couple kicks, should be a very strong suction on your hand, short of doing a proper leakdown/vac test this will point you in the right direction, no bottom end power, no fuel,backfires when trying to start? Sounds like a air leak to me, they will start up and run pretty good if your stator mark is +- a couple thou, ie eyeball centerd,

[Rigaman]

I had this same problem with a z I bought a little while back. The guy who sold it to me couldnt get it to run for more than a few minutes. He didnt have the fuel return hose hooked up. I hooked the return line up, and it was doing what yours is doing. First thing I thought was the flywheel key sheared. But it didnt. I never figured out what the problem was. I just swapped bottom ends out, and it was fixed. So it either was a bad air leak at the base of the cylinder, or the timing wasn't set right. Probably timing. It was backfiring like crazy. and would just die out.


Raffa. I think I figured it out. The manual doesnt say much about timing. Especially if you want to retard or advance it. Just says line up the marks, and at 1.66 btdc the flywheel center mark should line up with the stator mark, and case.

[Bryan Raffa]

correct.. forward is advanced, back is obvious retard .. i'll probley get :banned: for sayin that :rolleyes:

[muthey]

no no Bryan you used proper terminology for that, and I am a parent of a disabled child and find no offense with what you said, it is funny when my daughter calls people that while we a driving. Just brings a big smile to my face.

[Mosh]

And in my experience, the Tri Z likes a little retard in the timing when you start building them up. It also takes a smidge of stress off the kicker and sidecover.

As to the original issue of the thread , has all the tank and all fuel lines been checked to be clear? Generally when something sits outside for year's on end like that things tend to get clogged up.