I'm not real sure what you mean by wet, dry, or WOT. It has fuel and oil getting to the piston, so I'm assuming it would be wet..?
As far as mods, such as restrictor plate and jets, everything is completely stock. All the restrictors are still in place and both jets are still there.
I'm thinking my compression is alright because I had to hold the guage tight in the plug hole with one hand and pull the start rope with the other, and it still showed 90lbs. Everything I've read shows it should be somewhere around 120. So I'm thinking even if mine is alittle low, it should still run.

This little machine ran perfectly all last summer, and then one day it just decided to not start...and hasn't ran since.

Thanks for the link, I had read that one before I think. I've searched almost every forum on the net trying to find a solution. The only thing close has been a thread on this forum by "moomba99". Here's the link to his problem and solution. His problem was bad gas and a leaky base gasket...that doesn't appear to be the same problem I'm having. Well, we have the same problem..just not the same solutions..LOL
LTA50 problems - moomba99
I've sent a private message to him but haven't received a reply back yet.

Surely someone out there has found a solution to this Suzuki problem. Every forum I've read has people complaining about the exact same issues that I'm having..but I've yet to read a solution posted. Trust me, when we get this resolved....I'm calling CNN, ESPN, New York Times, The Outdoor Channel....LOL.

 

Dry is just a compression test as is...pull out the plug and test. That gets you one value. Then add a bit of oil thru the spark plug hole, and do another test. This is referred to as wet test. If this increases the compression, more than a few percent, the rings probably arent sealing very good.
WOT is wide open throttle. All compression tests are done at WOT. If not, the results will be low.

 

I'd get a good comp tester (screw in). Hold the throttle wide open and turn engine over till the gauge peaks. Put a few drops of oil in hole and try again. If the comp reading increases alot, it's pointing toward a new bore/piston.
Lack of air shouldn't be a problem as it's the air that brings the fuel in. If fuel can be brought thru a pin hole, air will travel freely thru a 16mm opening. Does that motor have a reed?? (I'm no 50 guru)LOL
Yes I have seen a dirty flywheel/stator be the problem.
The plug is grounded in the head. The piston hitting the plug would only close the gap.
I'd run a separate ground wire from the frame to the motor...
And just how much longer is your pull arm now?? [img]i/expressions/face-icon-small-happy.gif[/img] [img]i/expressions/face-icon-small-happy.gif[/img] [img]i/expressions/face-icon-small-happy.gif[/img]

 

Thanks....I'll try to get a better comp tester next week.
I'm wondering....Do you think it's possible that I'm not getting enough spark to ignite the fuel under compression? I had someone mention to me that maybe the amount of fuel is too much for a poor spark. The spark appears to be fine to me, mainly because it bites the snickers out of me if I get my hand too close. So, I really don't think it's a poor ground issue because it is sparking.

As far as the reed...it doesn't have one.

What if the rings are bad? Would it cause the motor to not hit at all? The real puzzling part to me is the plug ignites the fuel when I unbolt the head from the cylinder and leave a gap to allow more air.....very confusing!

And yes, much more of this and I'll be special ordering my shirts with one sleeve longer! [img]i/expressions/face-icon-small-happy.gif[/img]

 

"Do you think it's possible that I'm not getting enough spark to ignite the fuel"
yes, we mentioned the dirty stator/flywheel.

"I had someone mention to me that maybe the amount of fuel is too much for a poor spark."
ya, read above again. It's not too much fuel, it's the proper amount that's being sucked in that won't ignite. Low comp will suck in less fuel.

"I really don't think it's a poor ground issue because it is sparking."
So after messing around for hours you don't want to try a 1 minute fix.....ever think that when you loosen the head it's somehow getting a ground thus spark? The "more air it's sparking" thing,,,nah.

"What if the rings are bad?"
Probably, a dbl check on the compression will tell.

 

OK guys...I'm back needing more help unfortunately..LOL.

Here's the problem I'm having now. The ATV has started, but only with the fuel valve in the "on" position and the thumb throttle in the wide open position. Once it's started, it does idle, and even appears to run half-way decent for a short time. Sometimes you can give it throttle, and other times it just kills the motor. I then let it sit for a few seconds and it will start back up. I'm assuming during this wait period the carb is filling back up.?.? The whole process seems to be depending on the carb getting enough fuel, which I know...it's supposed to.

But here's the real kicker....We pulled the carb once again and completely cleaned every inch of it. Used cleaner, wire, and compressed air. Started it back up, and the exact same results. So we started adjusting the fuel and air adjustment screws. (the two screws on the outside, one with a flat-head, and one with phillip). They made absolutely no change. I even screwed them both completely in and it didn't kill the motor. Any ideas? When we opened the choke, it kills the motor.

Could my problem just be a wore out carb? What about the diaphram in the fuel ****? I'm not sure how it works anyway. There's no fuel flowing when in the "on" position, so does the compression work the diaphram in the fuel **** to release fuel? Can the fuel **** be rebuilt?

BTW, when it dies, the spark plug is completely dry. I tested the compression again with the same tester cause that's all I have....it shows 90 dry, wet, and WOT.

 

<div class="FTQUOTE"><begin quote>Could my problem just be a wore out carb? What about the diaphram in the fuel ****? I'm not sure how it works anyway. There's no fuel flowing when in the "on" position, so does the compression work the diaphram in the fuel **** to release fuel? Can the fuel **** be rebuilt?</end quote></div>

If you're still having problems, here's a couple of things to check that I haven't seen mentioned yet:

1) Disconnect the fuel line from the carb and set the fuel valve to PRI (prime). Fuel should flow out by itself. This will confirm that your fuel lines aren't restricted.

2) Have you disassembled and cleaned the fuel valve? Even if it flows fuel in the PRI position you don't know how it behaves in the ON position. If it can't be disassembled and cleaned, clean it as an assembled unit and blow it out with compressed air in all positions.

3) Adjust the carb float. I recently cleaned and rebuilt the carb on my son's LT-A50 and had a hard time getting it to work properly. I adjusted the carb float according to the manual, and noticed that it was WAY out of spec. Once reassembled, it wouldn't run properly. As a last resort, I put the float back to the "out of spec" position - and it started working again! That float has more impact than you'd think. I don't know how it would have "suddenly" gotten out of adjustment but it's something to check.

4) Have you replaced (not just cleaned) the jets and needle/seat? IIRC the needle on that carb doesn't have a return spring, so it relies solely on gravity. Perhaps it got bounced around enough to damage the needle/seat during transport. Who knows. Replacements aren't that expensive - a lot less than the time that you've spent on this problem so far.

Report back!

 

i would agree on checking the float.

 

if i remember correctly, the lt50 has a prime, and an on position. the reason for this is it is a vacuum fed system. there has to be enough vacuum to pull the fuel from the tank. what alot of guys with the same basic set-ups (such as my z400) have changed the petcock out to a full flow unit, whre there is no prime, or on position. its either on, or off...gravity fed.
either way....the one thing i have noticed nobody mention to check...is the reeds. the reeds act as the intake valves on this engine, if the reeds are bad...broken, warped, etc...its not going to run no matter how many compression tests you do. if theres enough compression to pop your finger off the plug hole..theres plenty enough for the engine to run.

 

Hi,
I am almost a ditto to your profile and problem. I have many machines work on them all etc. etc.

I am experiencing the exact same symtoms with one of my LTA's. EXACT.

While trying to diagnose the issue I installed a vacuum gauge in the intake port. There was absolutely NO vacuum. I have seen this beore on 2 strokes and in the past have resolved with correcting reed valve issues (No Reeds on this machine)or a top end overhaul.


Since the cylider did have very slight scoring I bored 1mm over and added new piston and rings and reassembled.

Exact same symtom. Absolutely no vacuum at intake. I have the luxury of having 2 identical machines. So I tested intake vacuum on runing machine. It has measurable vacuum at the intake port.

What I have just (last night) noticed is that whe I pull the start cord I can feel what seems like pulsating air coming out of the hole where the pull cord comes out of. I am at a bit of a loss where to go next. I guess I will rip the crank case apart and look for a problem there???? I once had a breech on a case gasket that allowed the engine to suck transmission oil into the combustion chamber. The bike looked like a crop duster and left the stench of burning gear oil. Tis was my strategy to win the heat ....LOL. It still ran fine but smoked like a Bi..XX%#ch

Anyway just wondering if you ever resolved your issue.

Thanks J