I need to do a little venting here!

Lately nothing has been going right with my trailblazer. Initially it started when the carb ran dry for no apparent reason going up hill on a trail ride and burnt the top of my stock piston. It started, after a long wait, and was brought home for a teardown.

To make things better, or so I thought I would buy a wiseco piston, have the carb bored, cylinder ported and head machined through ritter. When the parts came back everything was washed out and lightly coated with oil for the rebuild. The engine went together well and started on the first try. Then the break-in with small spurts of low throttle every day began and went perfect.

Now I have problems, AGAIN! Riding up in the same region with my trailblazer I was having a good day. During a rest the plug was checked and was a perfect chocolate brown color running 170 main and 50 pilot jets. Then thing took a turn for the worse.....

During the day the machine had finished being broken in and was being ridden like normal, mostly under 1/2 throttle but opened up here and there to clear the carb. Suddenly with out warning the engine cuts out as if it is losing fuel again. As the day progresses this problem occurs more and more under varied-easy riding conditions. WHY? What would cause this!

At the end of the day I drove up to our truck/trailer and right before I turned the engine off it quits. Thinking nothing of it, I come back 5 minutes later to drive onto the trailer and it won't start so I push it up and take the ride home.


Now, I am trying to find out why the engine will not start. It has air, fuel and spark. The carb has been cleaned out numerous times with compressed air and once with wire to clear and blocked passages. The fuel line has been replaced and at one point fuel was pushed past the carb with a turkey baster type of tool. The gas is not more than 2 weeks old. The ignition system works with the plug grounded on the frame or head. The reverse ovveride has been disabled. The piston holds 45psi and does not appear to have a hole in it.

The only thing that leaves is spark, which is happening at the wrong time. Timing is near impossible to check with and without the pipe on, there just isn't any room to aim the timing light and see the mark. One step past that is removing the side cover which holds the pull start and then removing the flywheel.

When removing the flywheel, the flywheel pops off and breaks a magnet adding to the problem of not starting already. The exciter coil behind the flywheel has been tested with a volt meter and works fine. The only problem now is that the most up to date manual doesn't cover a 2001 TB, it only goes up to 1995!



Do you polaris guys have any ideas as to why this engine will not start? I need some help here!

 

if all else fails, start with the obvious. have you looked at your air filter? my scrambler didn't quit running but it ran like the plug was loaded all the time. regular cleanings with the k&n filter cleaner just wasn't doing the trick. i clean my filter about every other ride and it never seemed to turn the gauze white again like it should. finally i ended up soaking it in simple green over night and then washing it out with the hose. all is good now. if not that, have you checked the needle and seat? it may be worn. from what i've been told, the ignition either works or it doesn't but that doesn't say what shape the ignition wire or ends are like.
just trying to help
steve


oh yeah!
it never fouled a plug while running loaded. that's why it stumped me.

 

make sure the throttle cable is adjusted properly,and you should see over 100psi on a cold engine.

how did you break a magnet off removing the flywheel?

and undo the bowl drain on the carb to see if it is getting fuel.

 

When i would run out of gas on my scrambler it would not restart without getting a rag and soaking it in gas and put that rag where the airfilter is hooked up and that would give it enough gas to get the gas into the carb i dont no why but it always worked. And if that dont work try getting a spary bottle and maybe put gas in it and spary it through the carb while trying to get it started. I dont know if it will work on your 2 stroke but it worked on my 4 stroke> well good luck on figuring it out.

 

did the dealer or you filled oil into the gas tank after the rebuilt?
maybe the oil ratio is too rich (gas tank),but if you scratched something on the ignition system there is maybe the problem,if timing haven't been wrongly setted from the stock setting i don't see any troubles about that.

 

Put it back together and start from scratch. New gas, plug, and filter.
Check for air leaks around the carb and boot.
Make sure the plug boot is connected well to the plug wire.
Sounds like you did a lot with the carb. If you know a friend with a Tblazer borrow his carb and see if that fixes the problems.
If all else fails find a good dealer with a shop that has a good reputation. Let them figure it out.

 

Thanks for all of the suggestions guys.

It turns out my polaris is hungry for pistons, my new wiseco piston is shot. I didn't burn a hole in it this time, the rings in the front seem to have melted and left some material behind.

Can anyone say they've had this many problems with the fuji 244cc engine? This is the second piston in this summer, I've barely had a chance to ride the thing! Is it just a bad design of could I have a flaw in my engine? I'm sad to say it but I'm starting to lose faith in polaris, my dads used 1990 banshee hasn't had a single problem since we bought it and its over 12 years old.

 

The main problem seems to be that the engine is losing fuel for a short period of time and without fuel it gets no oil to lubricate the internals.

Has anyone else had a problem with a trailblazer cutting out to do loss of fuel?

 

There's only a few things that can cause your fuel starvation problem, clogged fuel fiter, pinched fuel line, clogged or pinched vent line on the fuel tank or something in the tank blocking the fuel valve. Also the carb should be diassembled, cleaned and inspected, remove the jets (pilot and main) and make certain nothing is in them. You need to find the problem and correct it before you ride it or you'll continue to loose pistons from the lean condition. It's not the fault of Polaris, any two-stroke can have these problems. If you don't find a problem in the fuel system then look for possible air leaks, have the engine leak tested after repairs are made to make sure it's tight and not leaking.

 

Powerslider, thanks for the info. All of your suggestions have been tended to at some extent.

Going through your post; the fuel filter and OE line have been replaced with a direct line from the tank since the first time the problem occured. Carb vent lines have been remove, cleaned and put back on w/o any difference. The tank doesn't appear to have aproblem but hasn't been checked. Although the fuel line runs very close to the head in stock configuration, but it has since been re-routed. Carb has been cleaned out with compressed air and a wire.


One question though, when breakin was finished on the new piston the plug was a perfect choclate brown showing proper rich fuel and oil mix. What could cause the perfect running engine to run so poorly and die? The one thing that comes to my mind is heat from the hills terrain but whenever possible I wicked the throllt open to get air flow going and clear the carb out.