Ask the experts

 I am looking for an inexpensive way to monitor the air fuel ratio while on the dyno and possibly in the field on a 2 stroke snowmobile. I have been reading up on the available O2 gauges and the ones that even mention a 2 stroke say that either they won't work or they will be inaccurate. On some of the other forums, it sounds like guys are using them on 2 strokes. Any input would be appreciated.

we use them on the efi cat sleds ,it is best to preheat the sensor before using on 2 stroke machines they should work on most anything as long as they are installed correctly and in the right location.KOSO ,autometer, glow gauge if you need any help let me know,thanks todd. 

You have to have a pre-heated O2 for a sled which means you need a 12volt source. That is no big deal because you probably need one for your data acquisition too. The issue is that O2 sensors do not like leaded fuel or oil, two strikes against us.  Those two problems mean that the life expectancy of your O2 sensor is going to be dramatically shortened compared to an unleaded 4 stroke, but once you have some data you should be able to correlate it and adjust accordingly.

Todd, i have bought one of this and planning to play with it in the dyno, what will be the correct location on 4 stroke and 2 stroke  sleds?

The right way to preheat them on 2 strokes?

Please use more than 10 words in your answer :))

On the 2 stroke sleds they go in the muffler where the stinger enters the can,and on a four stroke i would put it into the collector where all the head pipes meet.34

Thanks to you. 3

buy a a/f ratio gauge and ill buy it from you when you are done with it

DW, I CAN GET YOU ONE FOR A REAL GOOD PRICE!!

i gave you all of my money this year.Im gonna loose my house,my wife lost 20 lbs cause i can't buy food,the baby has had the same diaper on for 3 weeks but i did sleep at the marriot and ride a firecat

i spoke directly with KOSO tech and they say DO NOT  put the a/f sensor in the can on a 2 stroke. they like it in the pipe just before the large portion of the expansion chamber or as far away from the y pipe or manifoold as possible but not in the large portion of the pipe either. they also offer an adapter for 2 stroke sleds which helps protect the tip of the sensor from contamination. tunig is recommended without the adapter and then for riding purposes put the adapter in.hope this helps. any questions feel free to give me a call.

Freddie Jacobs

Jacobs Motorsports 315-724-1695 ask for Freddie Jr.

Thanks, good info !!!