Boggin' down in the cold.

[Wait4me]

OK, I know I should make sure my jetting has been checked since the addition of the new exhaust but I can't just let my TBlazer sit and stare at me. I took her out today for some jumpin' and scootin' around work and all was going great.....for about 20 minutes. All at once, the engine started bogging at about 1/2 to 2/3 throttle. When I let off it, it would cruise fine but I couldn't gas her past that point anymore. I took it inside and pulled the plug which was very dry with a bright white electrode base and a mild tan tip. I believe that means lean and that isn't good.......since it would have to be REAL lean to not combust at all at higher rpms.

What opinions do you folks have for me with these symptoms? Should I stay off her 'til I get the bigger main jet in? Please let me know so I can get her fixed for the weekend. I'm not sure how tricky pulling the carb off will be, or taking the bowl off, but I don't want to ruin my engine either. Do I have to have a new gasket set before I do anything?! I am alittle worried here. Thanks everybody.

[ubnpast]

Check your airfilter or air inlet. Is it packed full of snow?

When you run her lean, she'll run like a striped @ssed ape for a few mintutes before she sticks the piston to the cylinder wall.

[Weck]

Air temperature plays a pretty big part in the jetting and 2-strokes are a little more sensitive than a 4 stroke. You need to check what the main jet size is vs. what HSP says to run. There is a tiny number printed on the end of the jet.

From your plug description you are way lean!!! Not to sound like Mr. Scientist but cold air has a higher oxygen content than warmer air thus causing the lean burn condition and the need for different jet changes. In the long run all you will need to be concerned with is a jet size for winter riding and one for summer.

Here's what I recommend. Start it up and let it warm up all the way. (Running any motor at high RPM before being warmed up is asking for serious trouble.) Then take it out and verify it will cut out about 1/2 throttle. Then give it about 1/2 choke. If it runs better it is the main jet that is to small and causing your trouble. Take whatever you need to off to get to the carb. Loosen the clamps on the intake and airbox side of the carb and turn it at an angle so you can access that bowl plug you talked about previously and take out the main jet. Its a brass looking hex head thing in there. Get the number off of it and ref whatever HSP told you to run. If it is what HSP said to run call around to a shop (Pinnicle) and get a jet 3 sizes larger. I will PM you my phone numbers if you want to mess with this today or tomorrow.

All of the above assumes you checked the air filter like UBNPAST suggested.

Take it easy on this thing till you get it figured out. I'd hate to have you explain to the Mrs. why you need a new piston and bore job after slapping on this new pipe.

Later
Weck

[ubnpast]

I've been a fan of this site for years. VERY, VERY, informative site for 2 strokes. A lot of reading, but you will see how much of a science the 2 strokes can be.
macdizzy.com/2stroke.htm

There are some helpful links near the bottom of the page. Like plug reading, etc. Good luck.

[Wait4me]

I called Pinnacle Polaris yesterday about the jet swapping and he said it requires removal of the carb. I am not 100% sure he is familiar with every carb so that may be wrong as it looks like the main jet is installed directly above the bowl drain plug. I guess there is only way to find out.....Get out the wrenches!!

Ubn, the air filter and intake passage was perfectly clean as I have to remove the airbox top to get to the plug right after the bogging incident. I wish it was a simple fix like that though!! I goggle'd the web for how a striped @ss ape runs so I could compare it to my quad's performance.....but I didn't find anything ATV-related. Weird isn't it?! I will check your new websites for more info about 2 strokes as I have started to enjoy understanding the whole science. I just need to get the actual mechanical time in on the quad to round-out the whole thing. I just hate taking anything apart on it that isn't a simple procedure......like carbs and trannies. Those scare me.

[Weck]

You're in luck, carbs are easy and your bike really does'nt have a transmission.

[ubnpast]

If I remember correctly, your carb bowl wasn't too hard to get to. If you have that drain plug in the middle, pull it out and use a 6mm socket to remove the main jet. Jets run about a $2-3 each, so the more you have the finer tuned you could get it, but it can add up fast. Not to mention, all the time changing them to get the right one. But usually once it's done, it's done, for riding at the same elevation without additional mods.

A great place with excellent animation: www.atvriders.com/articles/twostroke.html

How to read a spark plug:
www.atvriders.com/articles/sparkplug.html

The Jetting guide:
www.atvriders.com/articles/jetting.html

I love my trusty ATVriders.com

[Wait4me]

Ubn, those are some great sites for the 2 stroke and plugs. According to the pics, my plug looks like everything is running right so that makes me feel good about the mix.

THANK YOU JAMIE for taking the time to come out and help me get the new main jet put in. With his help, it all seemed much easier than I was anticipating! The TBlazer ran great and the new plug says it is doing good so I hope my baby is back in tune. I will take it out tomorrow for a long ride (like the day it bogged) and see how she performs. I REALLY appreciate all the help, advice and information everyone gives me as I learn about my new toy. Take care.