Yamaha TRX850 Enthusiasts Forum

can any one give me a clew as to why my fcr41s run rich at 2000rpm its ony at that revs it dose it i have adjusted the slow air screw and the fuel screw ,its ok every were else its just goes rich at 2000 rpm (i have no tps ) any ideas ????

2000RPM? Do you use that part of the rev range much then?

No i don't but it bugs me that it does it

steve speed wrote:No i don't but it bugs me that it does it

steve speed wrote:can any one give me a clew as to why my fcr41s run rich at 2000rpm its ony at that revs it dose it i have adjusted the slow air screw and the fuel screw ,its ok every were else its just goes rich at 2000 rpm (i have no tps ) any ideas ????

I went down one size on the slow jet and upped the fuel screws, helped me anyway.....in polarbear country....

went down one size on slow jet , its better but not right so i will give 40s a try and if its still rich it has to be the needle jet , , yes they do ware out , it runs ok on tick over then it hits 2000rpm and its like the choke has come on, it then clears its throat by 3000 rpm and run sweet (needle jets are not cheap) bugger

steve speed wrote:went down one size on slow jet , its better but not right so i will give 40s a try and if its still rich it has to be the needle jet , , yes they do ware out , it runs ok on tick over then it hits 2000rpm and its like the choke has come on, it then clears its throat by 3000 rpm and run sweet (needle jets are not cheap) bugger

How many turns on the fuel screws??

one turn on fuel screw but when i tried them at half a turn it was not right on tickover and was still as rich at 2000rpm slow air is at 1.5 turns, its looking more like needle jets the more i think of it and as steve at alans said its the only thing it can be now ,,,,I WILL HAVE IT RIGHT

steve speed wrote:one turn on fuel screw but when i tried them at half a turn it was not right on tickover and was still as rich at 2000rpm slow air is at 1.5 turns, its looking more like needle jets the more i think of it and as steve at alans said its the only thing it can be now ,,,,I WILL HAVE IT RIGHT

If under 1 turn out...smaller slow jet and same on top IIRC...
Mine where better when i locked the AccPump arm so it don´t rely on the spring....might add that i use the boyesen quick shot though.

...also, mine has a REALLY nasty lean spike at 3k....see pic:

$81us a bit expensive ,,,,well i tried 40s slow jet and it was rubbish so i have new needles and now on there way is new needle jets we will see tomorrow what happens

new needle jets,, new needles this time the right ones OCEMP not T ,,48 slow jet ,gone down on main jet to 165 but fitted smaller main air jet 180 runs a LOT better on the stand i will give it a test ride once it stops persisting down

runs a lot better at WOT with 180 maj in ,,,,dyno time

steve speed wrote:runs a lot better at WOT with 180 maj in ,,,,dyno time

Wonder why you don´t have the standard MAJ in yours?

the 200 maj was just making it go lean at wot,, it was ok up to 8000 rpm then it would start to go lean ,so this points to the maj is too big ,,,i think !

steve speed wrote:the 200 maj was just making it go lean at wot,, it was ok up to 8000 rpm then it would start to go lean ,so this points to the maj is too big ,,,i think !

There you go how different they are, mine goes fat on the top!
....not that it matters much coz then i´m already over max HP...