I have a 99 xcsp 700 and i was wondering about jetting and possible gains and risks. People have been telling me to go with 180 / 185 mains and so on. i know stock is PTO-185 / MAG-190 but what do these #'s (and letters) mean? why is there 2 #'s? i'm kinda new and want to know learn more about what i ride. Any help would be great.

Also I was looking into new air filters to get rid of the big air box. But there are vent lines from the carbs that go into the air box. Do these need to be connected to the air box? with filters since there is no air box what do they connect to (if anything)? And do filters actually help or just a waste?

Thanx for reading and thanx for helping if u can.

Jetting down will lean the motor out. I still have stock jetting in my 99700. I don't want a melt down. The reason for the different jetting between PTO and MAG is the MAG side runs hotter than the PTO side.

If you race then get rid of the airbox. The lines that come from the air box to the carbs are for vacume. The motor will run at low rpm's without the lines. Mid/top end will be gone if you remove them.

Do you have any mods to your 700?? If not I suggest SLP power packs and a boost bottle to start. This will clean up the low/mid bog.

Shoot me an email if you would like to know all the mods I've done to my 700.

If your not a experenced tunner save yourself a lot of money and stay stock, the chances of engine failure are very high. I believe the lines fron the carbs to the air box are to keep the proper air pressure in the float bowls. Most engines can be jetted down from stock ast they are jetted safe for all conditions such as extreme cold, if its warm use the mfg. recomended jetting.

I jetted my wifes XCR 600 three jet sizes and had no problems(adjusted air screw accordingly) with any melt downs. Most manufactures like to jet themhigher to reduce chance of engine failures.
just my .02

FZ700