View Full Version : LT80 Hard start

08-05-2007, 01:57 PM
New to forum. Found it searching for advice on my son's 2003 LT80. It is difficult to start. More so when warm. It cranks great and sounds like it wants to fire every few seconds but takes a long time to finally start. When it starts, it runs great. Any advice?

08-05-2007, 02:04 PM
Also, it just about will NOT start without the choke. Even when it is warm. It is still very difficult even with the choke on, but basically impossible with the chok off. It is a RARE occasion that this quad will ever start without the choke on. I just tried the petcock (put it on prime) to see if it was easier and didnt really notice much difference. Still impossible without choke and difficult with. Any advice would be helpful.

08-06-2007, 05:07 PM
Sounds like a plugged Pilot jet.
Have you cleaned the carb?

08-06-2007, 07:57 PM
I tried that with no change. It has kind of been difficult since it was new but gradually gotten worse since as it got older. Maybe I'll try a larger pilot jet. Do you know what size is in there and how much I can go up without going TOO far?

08-07-2007, 06:27 AM
The Main jet is too big as is. 92.5 is stock and a 90 or 87.5 is OK.

Do a compression test please. :)
If that's fine, we will look at a posible stator/coil problem.

08-10-2007, 05:26 PM
You mentioned the man jet is too big but isnt the pilot jet the one responsible for starting?

Just did a compression check and she is about 155psi.


08-10-2007, 07:27 PM
Yes the pilot is for starting.
Sorry. I read it wrong. I saw main not pilot. LOL
You don't need to adjust the pilot. it's a 17.5 and is fine.

Have you done anything to the motor? 155 seems high for a stock motor (fine but high).

Starting w/o the choke rarely works on any LT80. I understand that yours isn't correct.
The LT80's usually fire right up.

Some thoughts...
Clean air filter, remove and make sure the lil holes are open in the pilot jet, spark plug cap conected to spark plug (the stock caps suck), spark plug cap on the coil wire correctly (not loose),
Ground wire on motor (I make a extra)..
Removing the flywheel and sanding the stator has helped alot if you think it's been thru enough mud and such.
Cracked reed or a carb o-ring not there..
The coil could be bad.

At this point, I'd check all the above but for what I know of this thread, I think it's in the carb. :)

08-10-2007, 09:07 PM
Air filter is cleaned regularly and nothing changes. Everything is completely stock except for my homemade kill switch which I will remove but it always had the problem before I made the switch. Which o'romg are you referring to? I have taken the carb off in the past to clean it out when it was hard to start and could have lost it or something butlogically, I only ever took it apart to see if there was an issue because of the starting. (but ill try again)

08-11-2007, 07:34 AM
There is a o-ring that sits in the lil black plastic piece behind the carb. :)

08-12-2007, 12:28 PM
Checked the air filter, it was still clean (only one ride on it). Cleaed the carb with a fine tooth comb and allwere clear. Removed my home made kill switch (auto fuse drilled and attached to a clip to my sons chest protecotr that would kill the ground to the coil if he fell off). Still requires choke before it will start even when is warm but it seems a little better. I still keep thinking I should try a larger pilot since the choke makes such a difference)

08-12-2007, 07:26 PM
I suppose it wouldn't hurt to try. 20 is the next bigger.

08-13-2007, 06:12 PM
I know this is a long shot but are you still running oil injection? my son's 05 was hard to start would not run without the choke on, I had read a thread about removing the oil pump drive, i did this and started running premix and wow what a difference no more choke i think it was loading the cyl up with oil, what do you think Jack? maybe or maybe not.

08-13-2007, 08:34 PM
I am still running the injector?

08-14-2007, 08:25 AM
Surely a possibility. :)

I'm still wondering if it's a cracked reed. That happens.

08-14-2007, 09:02 PM
put a #30 pilot in it and it starts without choke wen warm. Still needs choke when it sits for a few minutes but its better.

Reed was ok

08-18-2007, 09:07 AM
OK. After some longer riding it is still doing it. The pilot jet helped when it was warmed up around the house but after a good long ride, it was still VERY difficult to start even with the choke. After trying to start it and checking the plug, it seemed like the plug was dry. Now I just had the carb apart, cleaned, and the new pilot put in it. Starting to get really frazzled on this one.

08-19-2007, 12:59 AM
What do you mean by the plug was dry? does it look like it is not getting gas or what, maybe it is a problem with the fuel valve and not the carb? does the plug have alot of oil deposit on it? I have heard of people having probs with the fuel petcock maybe the vaccum line has a small crack in it, check that out cause the engine has to be running to create the vaccum to pull the fuel out of the tank.

08-20-2007, 11:07 AM
Presuming there is no electrical issues (poor spark from ststor or CDI), Carbs go bad sometimes. I think trying another carb will help diagnose the problem.

08-20-2007, 04:35 PM
Been thinking about doing one of the instake upgrade kits available. Air filter, carb, and reed kits.

08-21-2007, 06:47 AM
I think we should fix the problem before doing much.

*** far as what you want to do,a reed is fine. I prefer the stock air filter, and I do not recommend the 20mm carb.It's just a waste, not to mention 100 bucks more than a new stock carb.

How about I send you a carb to try?
If you want to do that, email me your address.

08-23-2007, 05:46 PM
PM Sent

old school lt
05-29-2012, 06:54 PM
I was curious if the new carb worked for the LT 80 or not. I have one and it is extremly hard to start as well. Most of the time the battery drains before it starts. I have taken the carb apart completly, installed an in line filter so I know that the carb is getting gas, but it is still hard to start. Sometimes it fired right before the battery is drained but it takes a long time. Have noticed that I can usually get it to start every time after I remove the carb, clean it and reinstall. My next thing that i plan on trying is to check to see if all my fuel lines are in good shape and not creating any vaccuum problems.

05-30-2012, 07:49 AM
I'm thinking the carb could be bad as it sounds like it could be flooding.
I'd do a compression test.

old school lt
05-31-2012, 11:21 PM
I have purchased a carb rebuild kit, reeds and a new petcock from midwest mini. when they come in I will try that. Wish me luck as I love this machine when it is running but I am getting way frustrated.

old school lt
05-31-2012, 11:24 PM
I will check the compression as well. it will be about a week before I get back to it though as I am going out of town.

06-27-2012, 11:02 PM
I just picked up 2 lt80s today, the one that I got to run has been sitting for a season and is doing the same thing it seems, I'm thinking its a vacuum leak and its having to build a suction to get fuel, also cuts out down low ( I think that's related to a dirty Carb) but I did notice Carb cleaner was coming out of the front intake tube like it maybe cracked, I left the Carb on and was just seeing if it would start, but it started easier when I put my finger over the crack intake boot

07-03-2012, 09:43 AM
I would throw some crank seals at these bikes with the hard starting issues. I know it seems like a big job but it fixed more than one LT 80 I had this issue with. Jack says stay away from the aftermarket seals, so I did. Problem fixed. Check the crank bearings for up-n-down play or looseness while you have the seals out. They'll still run but a vacuum leak from the crank seal area makes 'em real difficult to start.