Help bike running funny.

[fireworrior]

Ok I took my 99 warrior out for a ride. Was cutting out on topend.. I have a unifilter and a 152.5 main jet along whith a R4 white bros full exhaust.. It ran fine a month ago Northern california... I took the plug out and it was white, so I put a 160 main jet in it!!!! I did a compression check it's 100psi with throttle closed and 130psi with throttle fully open.. I don't know where to look to make it run right??? I'm about ready to put a wiseco piston in and a web .390 cam along whith a z400 carb!!! But I took it for a ride 3 hrs with a friend it ran fine till 3/4 throttle and above, cuts out!!!! No leaks at carb or manifold.. What em I missing?????? I want to get it running just right before I upgrade everything!!! Could it be a bad feul petcock????

Help anyboby give me a place to look!!!

 

[yamarider]

The first thing I would check is the fuel height in the bowl. If the fuel height is set too low it'll get starved for fuel during hard throttle. I can't remember the exact height on the warrior, but with most carbs you want the level to be right around the crease where the bowl meets the carb body. Quickest way to check the fuel height is with a small piece of clear hose from the drain/vent line on the bowl, and hold it up beside the carb so the fuel doesn't run out the end, then crack open the drain screw. The fuel will fill that tube up to the level it is in the bowl, if it is lower than that crease i'd raise the height and check it again. Just have to bend the small metal tab on the float/needle assembly to change the height.

 

[fireworrior]

Thanks thats a easy way to check the fuel level!!!!
But my fuel level is just a little above the seem. Petcock flows pleanty of fresh fuel.. Runs good down low but cuts out in upper rpms.. Pipe is black but plug is clean and very little color.. I would read it as lean.. Valves are adjusted right.. With the 152 it did'nt cut out at all. I guess I'll get a 150 main ant try it.. If anybody as any other idea's I could try PLEASE let me know????

 

[beastlywarrior228]

reading plugs does not work theres so many additives in modern gas if it ran best with the 152 then thats probably the right jet

 

[bomber315]

reading plugs does not work theres so many additives in modern gas if it ran best with the 152 then thats probably the right jet

yeah i beginning to think this also... i takes forever to get a plug to show any color.... but instead of additives i think you mean detergents specifically

i thought i chimed in on this question before but i guess i didnt.... im confused by the "northern california" part you randomly threw in there... is that where you were or where you are now?? is there an elevation change in this equation? you said it ran good before... what has changed? if all it was was the jet then put the original back in

 

[fireworrior]

Thanks guys.
Northern Califonia is where I live, I have been riding in the same area for 6 months since I've had the bike.
Bike has been in the garage for a few months, I start it every few weeks.. I changed the jet because it just seemed to be lacking power in the upper rpms.. It didn't do that before, last time I rode it. Carb was clean inside, put new gas in it. I checked the fuel level and using the plastic tube and it was about a 1/4 inch above the fuel bowl top. I check the other warrior i have and it was right on the line. I have another warrior I let my son ride and it feels so much more powerful than mine.. Carb on that one is stock jetted, I broke the accellrator plunger in the fuel bowl, it's frozen in bowl.. It has a K&N filter and a doma slip on exhaust.. I mean that bike gets it really good, other than it will slip from 3rd to 2nd gear on it's own in bumpy area's.. I did a re-ring on that engine and thats it..

I'm just trying to dial this bike back in... I put in a new needle and seat an reset the fuel level and it still just above the gasket surface... I put the 152.5 jet back in... It cuts out and surges at the topend.. Maybe I'm confusing valve float..

I'm going to rebuild the engine this winter as follows..
1) Wiseco 83.5mm piston 10.25 ( I already have the piston and cyclinder to go on it)
2) web cams .390 cam, kibblewhite valve springs.
3) z400 carb
4) another head i'm going to do valve lapping & new seals on..

I just didn't want to put together a new engine, having problems that i'm chasing down now as to be more complcated..

Anyway this is the way I'm going to build it.
The above mentioned stuff plus the way the bike is now..
White Brothers R4 full exhaust!!!!!
Uni-filter
Rad carrier
EBC dirt racers full clutch kit
Raptor 350 clutch mod..
all new bushings & tires...

Other Than a JR piston anything I mentioned I should not do?????

Thanks

 

[jasonp]

sounds like you are running rich to me. Go down on the main one size at a time until the miss goes away and will rev cleanly to the top of the RPM range at wide open throttle.

 

[fireworrior]

Ok I just got everthing adjusted and took it out.. I have the full whitebros R4 exhaust with sprark arrester screen in... I have the Uni Filter and have a 150 main jet in it.... I've had a 152 and 155 jet in their... Bike had a stock jet in it with just the exhaust on it.. the carb boot had a split in it but ran great.. So I replaced the boot put uni filter and put a 152 jet in it.. So it runs good but I have no color on the plug... I,ve checked for a leak on the intake with carb cleaner but can not find one... The plug looks like it's lean white no color and spots like ditenation, little beads... Exhaust looks rich with little oil residue on tip... Compresion is 115psi with carb closed and 135psi With throttle open... I rebuilt carb and cleaned it but I'm worried.... I have a wiseco 10.25 piston and a chiose of a elde z400 carb, the yfz 39mm or z400 carb..... I Love both bikes and the z400 runs great so the elde or the fcr 39*mm carb could be on the warrior !! Anybody have any thoughts on this!!!!!!
Even though the warrior runs lean I can keep on my bodies 06 z400 tail.... Sure in a straight drag race he'll beat me though never run away unless heavy wooded and twisty i can loose he.. But if I'm in front I can loose him in the same area...

Thanks in advance..
I love this site and have tried to reasearch this...
Jerry