View Full Version : Lt80 Help

01-09-2007, 02:57 AM
Hello again,

I had idle problems with my lt80 about a month ago, stripped carb and cleaned pilot jet again and idled perfect, i then sold the bike to a local guy who is picking it up in April, i have been doing a bit of work on the bike in the garage and it has sat for a fortnight with a carb full of fuel, i took it out today and ran it for ten minutes parked it up and let it idle, it then started to die and i just presumed it needed adjustment with it getting upto temp, tried adjusting and nothing, still dies with idle screw nearly all the way in and is now a pig to start (needs choke), do you think the pilot could have clogged again, what is the procedure for setting the idle correctly?, thanks in advance and happy new year.


01-09-2007, 08:29 AM
Clean the carb again.Deff a chunk of something plugging a jet IMO.
Once running properly, adjust the idle.

01-09-2007, 09:19 AM
Thankyou LT80,

These carbs are a pain, i had the thing absolutely immaculate and it has hardly moved since then, can i clean it properly without carb cleaner as i can't get any near me, do the pilots deteriorate with time?, how should i clean it?.


01-09-2007, 09:41 AM
Just take the jets out and blow thru them. Should do it no problemo. Wash it out w/a lil gas if you feel the need. :)
A uni-filter #101 on the carb VENT line is the cure. ;)

01-09-2007, 11:34 AM
is plugged jets due to dirt a common problem with lt's?

01-09-2007, 01:20 PM
Yes. Most don't know that it comes from the vent line.

01-10-2007, 12:58 AM
LT80 thanks again for your reply you are a wealth of LT knowledge, i just can't understand how this could have happened again, when i rebuilt the lt the gas tank was cleaned the reeds were cleaned all the lines were cleaned and the carb was immaculate, since i got it running the bike has only idled in the garage and ran up the road for a total of ten minutes, it has never been in the field or in any dusty conditions, so i can't understand how the jets have plugged, when we got the bike new in 1994 we used it for 4 years and never removed the carb or cleaned anything fuel related and it never missed a beat and now it's all clean it acts up, when i installed the piston i ran some oil in with the fuel aswell as the oil pump, could this be causing any problems, as i don't want to deliver it with any problems, i want it perfect.


01-10-2007, 08:39 AM
You didn't do anything wrong.
Just one of those "S**t happens" things. :D :D
Happy to help. :)

01-10-2007, 10:35 AM
Cheers LT80,

i have ordered a new pilot and main jet, for the price they are it seems worth it to prevent any more problems, one last question, do i need to install the little black rubber that goes in the carb bowl and covers the botton of the jets, i'm sure i read somewhere you can leave it out (stock motor)?.

Thanks again

01-10-2007, 04:01 PM
You can leave that out. :)

01-13-2007, 10:06 AM
hey LT80,

I have rebuilt the carb again and fit new pilot and main jets, i now can't get the thing to start, it has fired a few times and ran for about 2 seconds gave it gas and it died, i'm thinking that i've just flooded it, could i have adjusted the needle valve by accident when cleaning(the bit with the Y shaped clip that i removed, i think it's needle valve) or has it no adjustment, i'll leave it overnight and try it 2moro, hopefully just flooded,


01-13-2007, 10:50 AM
Could be flooded. Check the plug and see if it's wet.
There is no float adjustment so you didn't mess that up :)
The O-ring didn't fall out/mis-align did it?

01-14-2007, 10:44 AM
Finally got it running, tried it this morning and nothing, plug was soaking wet, removed it and hit the starter and fuel spitted out of the plug hole, left it to dry up for a while tried it again nothing, removed and stripped carb, checked everything, still alright, put the little black rubber in under the jets as i had fit it without, rebuilt it and tried again, held the starter on for about 25-30 seconds she coughed and spluttered fuel from exhaust and then fired up, ran it for ten minutes and it seems perfect, so i presume it was just badly flooded or could it have something to do with the black rubber?, also when i removed the fuel line it had a steady stream of fuel through it when the tap was on reserve, it didn't come through like it does on prime but i thought it was only drawn through when the motors running?, last thing is when i start it up from cold there is a noticeable ticking/tapping noise from the engine somewhere, it's hard to pinpoint where it's from, after around ten seconds it stops, it doesn't increase when revved up, is this common with lt's i hope so.


01-15-2007, 08:17 AM
more problems today, went to start it today after draining the carb last night and it just turned over and over and fired once, when i was turning it over the starter motor started to make a horrible grinding noise as if it wasn't meshing, checked the gear on the crank and it seems ok, but i cannot get the starter off, i have loosened the footpegs and removed the carb but i can't get it free, can u please tell me the technique so i can hopefully overhaul it and get this sodding thing running, what do u think could be wrong with the starter, maybe just holding it on too long caused it to be stupid, could it now be damaged?. could it possibly be the battery also getting low on charge,

What is the best way to start them when you have an empty carb bowl, prime till it starts?


01-15-2007, 10:29 AM
I sence your pain. :(
Clicking noise. Usually piston slap, which means a wore pistom/bore. This could explain why it's starting so hard with the excaetion of the motor being full of fuel. FYI: when starting a flooded motor, hold throttle wide open to allow more air to mix.

The petcock should be up and down to run and prime to get the bowl full. Up and down works on vaccum. If there is a problem, simply get a on/off valve at the lawn mower place and run on prime. :)
FYI: we/ve been running carbs w/o the black rubber for 10+ years, I doubt that's a problem or fix.

Certainly it could be a low battery. You've not tried charging?
Starter removal (if needed)::I take it you/ve removed the 2 starter bolts. I figure you've also popped it out of the case with a slight tap. Now thw fun. :D :D
It does come out! Possibly stand the machine on end to remove from the bottom. OR,,You may have to lift the motor (remove the long bolt) slightly. They are tight. I think I remember getting it out w/o lifting the motor tho.
Use jumper cables/battery charger. Ground the starter and touch the positive to where the cable attached. If it spins and sopunds ok, it proly is. You may have burnt it up. I don't know what parts are available for the starter. Maybe go to http://www.nrys.com/fiche_select.asp

FYI::Cut those footpegs in 1/2 (middle of the machine) and make a rod to re-join them. This allows both footpegs to be removed and out of the way. It also is a giant help when servicing the clutchs to just be able to remove the left footpeg.
Ebay has them.
Lemme know how it turns out.

My 2 fingers hurt...j/k :D :D :devil:

01-15-2007, 10:40 AM
Thanks LT80,

It has only been hard to start since i replaced the pilot and main, before that it was perfect, i've just fitted new piston and rings, it's a stock motor, the old piston still felt tight in the bore so i checked the ring gap with a feeler gauge in three places down the bore and it was all perfect, hope the starter is ok, just needs battery charge, tho it is a newish battery.


01-15-2007, 10:55 AM
How about a broke reed?
I still think it's in the carb seeins the compression should be good.

01-15-2007, 10:59 AM
would a broke reed mean too much gas to motor and lack of compression? i will look tommorow, LT80 thanks for all your input, sorry for being a pain in the ***, if only you lived nextdoor.:)

01-15-2007, 11:09 AM
A broke reed will push fuel/air back thru. (they always push a lil).
Shouldn't effect too much fuel or compression. It was just a thought since the carb is off.
Happy to help. :)

01-19-2007, 09:57 AM
Hi again,

I finally got the starter removed by lifting the motor slightly, overhauled it and is now working perfect unlike the motor, when i was removing the starter i removed the carb for access, as you suggested i checked the reeds and they were in good shape as far as i could see, refit reeds and carb and sealed up the reeds and carb spacer with gasket sealant to eliminate any air leaks, primed carb with fuel and just turned over and over with or without choke, giving it gas never helped and then for some reason i started rocking the bike side to side whilst sitting on it with my feet on the ground (probably releasing a bit of anger) and it started up, i kept it running by giving it a bit of gas and then took it up the road, got back to garage and set the idle and it ticked over perfect, stopped it and started it right up with no probs, left it for 24 hours and tried it again, hit the starter and it ran for 2 to 3 seconds and died and then wouldn't fire up again, rocked it side to side and it fired a few times and then i got it going, took it up road and ran perfect and idled perfect, what do u think is the problem, could there be excess gas swimming around in the crank from it being flooded? seems strange it starts when u dance with it.


01-19-2007, 10:34 AM
So ya gotta do the "rock-a-doodle" with it eh...LOL
I would think this would point to the carb. It sounds like the vent is plugged???? Suck on the vent line. :D :D...Suck twice~spit once..LMAO!!
If you leave the petcock on prime is it OK (vaccum working?)??

Once started and run, there is no fuel residue in the motor.:)

Instead of rocking it, try hand choking the carb with 2 fingers and see what it does.:confused:

01-19-2007, 10:45 AM
hey LT80,

The vent line is clear i can blow through it, the motor gets fuel ok on reserve and on and it flows perfect on prime, what is the 2 fingered choke trick and what does it show ya, could i have installed the needle valve wrong or can u not, thats the only thing i can think of in the carb that could cause a problem, so you've heard of people dancing with LT's to get them going?


01-20-2007, 08:02 AM
I've seen ppll do alot of things w/them. LOL
The rocking would seem to be moving something. Where and what is the problem now eh!
When a machine won't fire, I push the rubber off the front of the carb, stick 2 fingers in front and hand choke it. I donno why but it opens things up sometimes.:)
I don't know what could happen to the needle, maybe the seat is wore. That's rare.
:confused: :confused: :confused:

01-28-2007, 09:29 AM
I think i've finally got it running right, yet another carb clean seems to have done the job, i'll try it in the morning and make sure she cold starts, how many turns should the idle screw be out roughly?.


01-28-2007, 01:03 PM
The idle screw is adjusted to the proper idle when hot.
It's a screw to adjust the slide, not a air/fuel mixture screw like some have. :)

02-04-2007, 09:15 AM
The LT has been standing in a cold damp garage for a week, went to start it and it fired straight up with choke on and then died after about 3 seconds, tried again and same thing, rocked it from side to side with choke on and it fired up, kept rocking it with a bit of gas until it would idle, ran it for 5 minutes and it ran good and idled good, shut it off and tried again and it fired straight up and ran good, could there have been crystalized fuel in the pilot when i tried to start it which then cleared when i got it running, cos surely the pilot has to be clear for it to idle as good as it did, the fuel in it is 5-6 weeks old, can it detiriorate in this time, are LT's known for being cold blooded, should i start the thing up more often with it not getting properly used, i know LT80 mentioned a filter on the vent line but it has just been sitting in the garage since it last ran good, where should the vent line be routed, can u fit a fatter pipe? sorry for all the questions, thanks in advance for the help :confused:

02-04-2007, 09:25 AM
Yes they are a lil cold blooded.
The rocking thing sure is weird.
Gas can go bad that soon but I doubt that's it.
The vent line isn't the problem either this time (as you stated, it's been sitting).
This is a tough one.

02-04-2007, 12:26 PM

I'll try it in a few days when it's cold, if it's still no good i'll borrow a compression tester just out of interest to see what it's at, what is the procedure for checking it?, i can't see it being the fault as this thing used to fire straight up until i replaced jets and she's now a pig to start. surely it can't lose compression that fast?, i'll let u know what happens, have a good week.


02-05-2007, 08:55 AM
Comp test:: hold throttle wide open and crank till the gauge peaks. :)

02-10-2007, 09:48 AM
hi LT80,

I just tried the lt again and the same thing, would only run for a few seconds with choke on, removed the vent line from the carb and it started fine and ticked over fine, i can blow through the vent line ok, i borrowed an air compressor for the weekend so i'll blow through the vent with it 2moro and remove and clean the carb again with compressed air, i have been using a john deere carb cleaner spray while i've had this problem and wondered if it wasn't suitable for the carb, how do i remove the needle valve seat to clean it and the brass piece below the main jet as i havn't yet whilst cleaning the carb as this will be the last time it's apart hopefully, where do u route the vent line?, mines routed up the frame with the starter cable and earth etc.

I removed head and piston today and found there was movement on the big end from side to side, there is non up and down or forwards and back, when u hold the top of the rod u can move it at least 1mm side to side, it was all tight when assembled and now it has play in it, what is the big end tolerence?, what do u think LT80?. is it still serviceable? as i've now sold it and don't want to spend more money on it.

02-11-2007, 01:59 PM
Slight movement of the piston is normal, alot means it's piston/bore time. It sounds like it may be alot.
1mm movement on the rod/crank is OK, I think the rod/crank is fine from what you've explained.
Any carb cleaner should work fine. To remove the needle seat there is a tiny phillips head screw. Only screw in there, should be a easy find. :D
I don't mess with that brass tube under the jet.

02-11-2007, 02:24 PM
LT80 u have made me feel a thousand times better, i was dreading your reply about the big end but i am seriously pleased with what you've said, the piston has very little movement in the bore, i'll reassemble, clean that damn carb and she should be good to go.

LT80 thanks again, i can sleep well tonight:) :) :) :) :)

02-11-2007, 02:50 PM
Any more problems and you may have to fly me over to the UK to have me fix it. :D :D