A while back I made a post about the 90 being very cold blooded. It runs terrible until it is warmed up, then runs great. The concensus was that the factory jets lean to meet emissions standards, and that was the cause. The dealership said this was the case also, so it is probably true.

Last weekend we were at Ocotillo Wells (see the Suzuki Ozark article on this sites main page for some pics of the area), much of which is BELOW SEA LEVEL. So, the bike should be running EVEN LEANER! I had put in a fresh plug just before the trip, but when I get home I pull out the plug, and it is BLACK like the thing is running way RICH!! And, this happens to both bikes, so it isn't just a one bike specific thing. So what is going on??? The dealership suggested not messing with it if it runs OK when warm, and just change the plug real often. Thing is, I don't want to carbon up the valves and combustion chamber. Anybody have any ideas? Maybe the thing is lean on the bottom, and rich on the top??? I am running a UNI two stage air filter, so I don't think it is a restrictive air intake.

Also, there is a vacume tube in the air box. This thing has a small filter (about the size of a short pencil) on it that has to be cleaned. It goes from the air box to the head of the engine. There is a sticker showing the routing of the tube, and it talks about CALIFORNIA EMISSIONS. Is this something that only Calif bikes have, or do those of you in the rest of the country have the same thing?? If not, could it be related to the problem???

 

I'm 99% sure that our TRX90 does not have that small filter that you mentioned in the airbox. Our 90, like yours and probably everyone elses out there is cold blooded. That was one reason the guy I bought it from sold it, he got a Yamaha Breeze with electric start because he was over not being able to start the Honda and was over all the fouled plugs. He said he was constantly changing plugs and in fact, the bike came with a couple of extra ones.

However, I put a new plug in it when I bought it two years ago and it's still in there. The TRX almost always starts on the first pull. True, once it does start you really need to baby the choke and throttle. I usually have to hover over it for at least two minutes, then I or one of my boys will do a simple no load 2nd gear ride around the parking lot or yard for a few more until it warms up.

We live at about 900 ft above sea level and frequently ride 1500-2000 above that.

Jaybee