I have had my 2000 trailboss since August of 2000.Like most of the folkes here I would rather not pay my local dealer $78.00 per hour to do repairs. I have a 71 Mach1 and 86 IROC which I have rebuilt the motors in myself so doing the mechanical repairs on my toys is something I have always done myself.

To get to the problem , my trailboss stays at 45 acres I own in the country and get to visit about once or twice a month.It has always stayed inside a storage building since it was new. About one year ago I noticed it getting harder to start and taking more choke each time to start. For the last three months I have had to use starting fluid to get it to crank the first time . After that it would start right up usually with no choke but for the last month it would require the choke to be used when restarted. The last time it was started was two weeks ago and I had to take the air filter out and use a gas soaked rag over the carb intake before it fired up.Then it seem to run fine. I parked it inside that night as normal and the next morning the same thing again, accept this time the motor would not start so I tried the gas rag again,that didnt work and now it is backfiring thru the carb.

My only experience with working on a ATV has been the basic oil changes and lube jobs on this one. I have pulled the spark plug and it looks fine just the basic black carbon coating "looks like it has been running rich" but other wise ok.To me the orginal symptoms would indicate a fule flow problem.When I hold my hand over carb and crank the motor and crank it over it doesn't seem to draw more fule into it as you would expect. I'm sure its got spark because its backfiring. Would this indicate a out of timming condition or maybe a intake valve not closing all the way. I haven't tore into it yet but I guess tracing the fule flow down to the carb would be a good start. Can the bottom of the fule bowl be taken off to check for contaminants?

I'm sorry for such a long post. Just not sure which problem to address first. Thanks[img]i/expressions/face-icon-small-sad.gif[/img]

 

Since my orginal post for help I have run a compression check which comes out to be 90 psi, with the plug out and grounded it fires like crazy while being cranked over. The cold clearance on the exaust and intake valves both measure .008 but my owner supplement does not give me a spec. for the valve clearance. My best guess now is something stopped up or corroded in the carb. Maybe some one can help me from here!!!!![img]i/expressions/face-icon-small-disgusted.gif[/img]

 

90 psi is really low. Sounds like a rebuild or the valve seats might be gunked up. It should still fire up but will have some trouble doing so. Did you ever put in a fuel stabilizer? The fuel might be bad also. But your compression is still way to low.

 

i know on car engines anything below about 120 psi is getting to be to low on compression. A trick the old timers use to use to find out if the rings or cyl. wall were the problem was to squirt some motor oil in the plug hole and recheck the compression. if it went up a lot thats where the problem is. This bike has a total of less than 100 hours on it since it was new and has never been abused !!! Never used stabil but am tearing the carb. down right now.[img]i/expressions/face-icon-small-happy.gif[/img]

 

Heavyhook,

the 325 engine in your trailboss has an auto compression release to make it easier to start with the pull starter...(also fuctions with the electric starter...the release disengages after the engine reaches a certain rpm, so it will resume normal compression again at running speed).i beleive this is why your compression reading is only showing 90 psi. I'm pretty sure the valve specs are .006" on both intake and exhaust vavles. Yours are a tad loose, but i don't beleive that would cause hard starting. I think cleaning the carb was a good spot to start[img]i/expressions/face-icon-small-smile.gif[/img] Also try a new plug..certainly can't hurt. Goodluck!

 

Well I took the carb of yesterday and sprayed it with carb cleaner. I was able to get it to start and let it run for about 30 minutes.It seemed to have good power and run fine. I restarted it several times loaded it up and went too the car wash for a good cleanup. When I returned it started fine again.There was no smoke or anything that would cause me to think the motor has a internal problem.
Now comes the bad part, I try too start the bike this morning and for 3-4 seconds it ran for a couple of different times but would die and now doesn't even try to fire up.
Too me its acting like theres not enough choke too richen the fule mix. checked the choke cable adjustment but its to specs.
Thanks for the info on the valve specs and the compresson release, that this motor has. That part has me wondering. If the compression release is not work right it could explain the symptoms I am seeing. Can anyone tell me more about that. Thanks[img]i/expressions/face-icon-small-confused.gif[/img]

 

Water in the gas could be the problem. You might want to drain your tank and gas lines. Check the fuel filter too.

 

I would agree with predator and check for water next. Water can cause lots of weird intermitant problems....we see this a lot at work. Drain the tank, the carb, and fill it up with some fresh gas...and add some drygas too. May take a bit of riding to get any residual water out of the bottom of the tank after you drain it...but the drygas should help with that. I would put a lil drygas in the tank everytime you fill with fresh gas...its cheap reasurance on a quad that isn't used daily. Also some Stabil might not be a bad idea either.[img]i/expressions/face-icon-small-smile.gif[/img]


Shaun

 

Well guys I want to thank everyone for the help with my trailboss.
I took the gas tank off yesterday drained it and the carb, fule pump and lines. I even used my air compressor to blow out the inside of the tank just to make sure it was completely dry. I filled it up with fresh fule and opened the drain on the bottom of the fule bowl on the card and let about a quart of gas flush through the system just to make sure anything inside would be flushed out. Then I tried to start the motor ,dead not even a burp out of it. The same symptom I started with. So I pulled the plug out again to check for fire ( yall will note in my orginal post I described how good the spark had been as I started trying to find out why the motor would not start) no spark between the electrode and the plug tip while it was grounded to the motor and being cranked over but as I ungrounded it sparks came from the threads to the motor I was using for the ground.The next step was going to the local auto zone and picking up a bosch spark plug($1.07 w/tax) and replacing the orginal JNK plug. The bike fired up at once and is running great. That was about 24 hours ago and I went out too the garage a few minutes ago and it fired right back up.
So I guess it gets down to what conclusions are to be draw from this repair. It is apparent now that the cost of a new plug would have been a good investment in the begining even though the orginal showed to be working fine. Ain't hind site great. When I cleaned out the fule system I did add some chemtool B-12 to help clean out any crud that could still be in the system since this bike has sat a lot for the 2-1/2 years since it was new. The chemtool claims to help dry in moisture that is is left in the fule system.
Total cost $2.54 for the chemtool, $1.07 for a new plug and about 5 hours labor. Beats the heck out of $78.00 per hour for help from my local dealer. By the way the dealer wanted $6.50 for a plug, is that mark up or what.

Thanks again everyone for the help

 

Heavyhook,

I am a novice and I have a similar problem with my sons trailboss 325. I don't have the mechanical knowledge that you have so I'm a little afraid to go digging. This atv has sat a few months without being started and it has a tank full of gas that I assume is bad. I'm going to try and drain the tank this weekend and then put in some fresh gas. I was wondering also how hard it is to get into the carb and look for debris.