Hello to all, this is another great site.looks like great community of fellow ATV'rs helping one another.If you can help me I truley would appreciate it.

Hi from Bend Oregon (central Or.,high desert)
I did try searching info first.My boys 05 LT80 I bought new,it has no more than 10hrs running time,recently i noticed it wont idle with choke off,never hard to start,I removed fuel bowl and float and sprayed carb cleaner all through it.No fuel varnish or build up,very clean when it came apart.Reassembled with same issue,i did compression check,got 95psi.I removed top end,all clean,bore looks fine piston too,pulled top ring slid in bore very tight clearence,gasket sealing looks ok.I read that the piston has an arrow on it pointing backwards(towards rearend) so thats ok ,I would appreciate anything you can help with.Thank you .GonzLT80

 

Sounds like a dirty idle jet. When you cleaned the carb did you remove the idle jet and seat and clean them thoroughly? Did it run ok last season? Fresh gas and plug? Check the easy stuff first, there's probably not much at all wrong with it.

 

thanks for taking the time to respond, yep new plug new gas, no i didnt pull idle circuit,yes did run tip top last season.I plan at this time to have head cut replace head and base gasket re-ring oem std

what say you?

 

You need to remove both jets plus the float needle seat and clean all well.
I think you should bore it to .5 over instead of re-ring.

 

Welcome!

 

I agree with LT.....spraying cleaner thru a carb without removing all the bits isnt "cleaning" a carb.....and wont get all the gunk out.

.....Im betting that fixes your problem.

 

Thanks to all whos responded to this post,really appreciate it,im hesitant to bore it as the cyl bore and piston is so clean and smooth, have .010 ring gap, top ring in bore.Mentioned earlier I bought this new and has less than 10 hrs on it.Was it said here an option to shaving the head ,to install head metal to metal no head gasket?,Now doubt I can do a better carb cleaning,but it has zero signs of varnish or contamination,although it only takes a spec to foul things up. again thanks to all.

 

You guys here are A1 in my book,thanks again to all that responded.It went back together leaving out the head gasket, fired it up,sightly different tone with more compression,choke off them same thing acted like it was running out of gas and would die,as suggested,I pulled carb,benched it for a complete disassebly,back together and she purrs,one of these days I will take LTjacks recipes and do some the things he shares for performance.Thanks for the warm welcome and all the help.Gonzo Bend Or.

 

so you put it together with no head gasket for higher compression?

I think your problem was a partially plugged pilot jet since the get go. it's very common. I had it on two bikes that were sitting a while. and when I don't get idle and have to run with the choke, that is the sign... I just clean mine with a small needle never bothered to boil an entire carb yet. interested to see if it will do anything more than make it function like a plugged jet.

 

Let me tell you some things abou tsmall bore machines, carbs and gasoline in general. First of all, these little carbs have very small orifices, and it doesn't take much to clog them. I agree, you need to take the jets out and clean them. We wil lmake an ssumption here that you have re-assembled everything correctly. Not sure what that head gasket thing is all about... but let's concentrate on the carbs. First of all, the gas we buy today has a certain percentage of corn based alcohol in it. The gas seperated after very little time and the corn alcohol accelerates the gum and varnish buildup. The first thing I would do once you get it running again is to make sure you ALWAYS turn the fuel petcock off and let the bike run out of gas. That helps keep the crud from forming. Secondly, always shake the fuel up in the tank prior to turning on the gas when you start it up again. This mixes the gas and Alcohol again. Third, change your fuel filters regularly. They actually will melt as a result of the alcohol.
It sounds like you have a classic gummed up carb. You may need to nuy a carb kit and replace the needles. Lastly, I know people love using chemicals, but the BEST way to clean a carb is with an ultrasonic machine. If you have never used one, you will think it is BS, but if you have, then you know what I am talking about, and your will never go back to using carb cleaner or brake cleaner etc.