Strange LT80 no start

[86Rrider]

Hey guys, looking for some help here with my daughter's LT80. A few years ago, LT80 himself turned me onto the carb boiling thing that got this machine running after setting many years.

Now I am dealing with the bike will not start. In the spring (April-ish) I got it out for her to ride and did the usual clean-up and prep. It started and ran all afternoon for her. A couple of weeks later we got it out and she rode again for several hours. Then, the first week-end in June, my riding group was doing their annual motocross track rent day and my daughter wanted to go. So I started to prep her machine, along with mine, the week prior to that event. That is when the LT80 decided to not start.

What I've done:
cleaned/boiled carb
replaced spark plug
removed air filter/intake
remove and inspected reeds
checked key on crank to flywheel
dumped gas tank, put in fresh new gas
re-checked float height

OK, I have spark, it has compression (only cranking with thumb over plug hole- don't have correct adaptor for my compression gauge to measure) and there is gas in the carb. The engine will not even sound like it is firing, even with starting fluid sprayed in the carb or spark plug hole. It acts as if the timing is off, which is why a pulled the cover to check the flywheel key. When cranking, I cannot feel air coming back out of the carb throat nor any moving out the tail pipe. The starter relay clicks when the starter button is pushed and the starter turns the motor with the normal sounding rhythm. The voltage rectifier seems to have power at the correct terminals, just not sure which terminal is which (did not down load that part of the manual).

I'm at a loss here! Anyone have any ideas what I could check or try next?

[yophilly]

How about clean the ground wire at the coil (and frame)and at the engine ground?

Dis-assemble the kill switch and clean up the contacts?

Remove the flywheel and clean the magnets as well as the corresponding side of the stator?

Those are the only things I can come up with…..

[Matt150]

Sounds like crank seals.

[LT80]

"nor any moving out the tail pipe"
Plugged pipe maybe. Should be able to feel some flow.

[86Rrider]

yophilly - thanks for the additional things to check. I'll probably look into those this week-end

Matt150 - is there a way to verify if it is blown crank seals? Do these little motors have a open crank case to transmisson like other 2-stroke atv engines? So like could I look for gas in the trans oil?

LT80 - to verify if the pipe might be plugged, could I remove the pipe from the cylinder and try starting it? Would it run without the expansion chamber? Or do you suspect the silencer is what is plugged, not the pipe/expansion chamber?

Thanks for the help guys!

[LT80]

Even tho it was running, you might as well check the pipe. You can try starting it by loosening the pipe and pulling it back some.
It's what you call the silencer is what is usually plugged. It has a lil hole inside it on the bottom going in and out. Thus the lil hole can get plugged by oil residue/etc. I stick them in my woodstove and get them red and blow compressed air thru it. Charcoal works I'm told.
The crank seals are behind the starter gear/front clutch and behind/under the fan/flywheel. About 3 bucks each at your local Suzuki dealer.
Ever so many carb related problems since ethanol. That's my story and I'm sticking with it!

Seeins you had a carb problem before, you may want to consider a new carb if all else fails. I been getting them off of ebay.

[86Rrider]

LT80- I would agree with you on the carb, since I have had it apart many times to clean the ethenol residue out of it, but even if I shoot gas, carb cleaner or ether in the carb throat or spark plug hole- nothing! Not even a pop. That is why I was thinking timing, because the plug has a good strong spark, engine has compression, so I figured the spark and gas just were not meeting up at the same time. But, as you point out, if the pipe is plugged, the back pressure could be "blowing -out" the flame, so to speak. Do you know of another method of cleaning out the pipe other than needed to go out back and build a fire to throw it in? Could it be heated with a torch? Or is that too much heat, too fast? Fill it with some kind of solvent?

[LT80]

A torch can work.

[86Rrider]

OK, took the pipe off and tried starting. Plenty of air movement out of the exhaust port, but still no start. Digging further, now with the pipe off, it seems to be flooding now. I just crank the engine for 2 seconds, then remove the plug and its soaking wet. blow it off, stick it on the plug wire and crank with the plug grounded to enigne and still nice thick blue spark. So I'm thinking LT80's advice of the new carb is looking like the route to go.

Looking at E-bay, there are several aftermarket carbs for sale. Most are by a brand name of EMSTD? Does anyone have experience with this brand? Or can anyone recommend a different brand/location to purchase one?

[yophilly]

The only problems i've had with a/m carbs is the choke knob pulls off.I just remove it and twist some safety wire around the stub of the choke plunger and make a 'tab' just so it's easier to grab w/ gloves on.