Hello everyone, really needing help on this one I have an upcoming enduro event on my rt1 and it’s acting up. Here’s what I got vape ignition with timing set at 2.8mm btdc, clean carb with 220 main and 30 slow jet, needle clip on 4 down. Bike Revs to the moon on the stand but under load I cannot get above 5k rpm in any gear. Pulls strong right up to it then it spits and sputters no matter how much or little throttle is applied. I recall seeing someone else with a 175 have to same problems on here but I think he blew a plug out of the head before finding the cure. Any input would be greatly appreciated 

I think a similar problem on this board turned out to be an over oiled foam air filter. Hope it's something simple like that.

Awesome I’ll take a look. I vaguely remember putting filter on heavy.

Welcome from NZ. My first thought is a semi blocked spark arrestor Deep down in the end of the exhaust & if original it'll be a fixed item spot welded in. Second thought it the small Oring on the jet setter if original carb. Think it's always #7 on partzilla or cmsl. Video link to youtube might help if possible. Cheers.

I cleaned the oil from the filter and I can tell a big difference it will get up around 6k now, I’m running the uni yellow filter and it’s brand new. What’s a safe redline for these bikes? Thanks for the suggestion, I do have a new oring on the jet setter, not sure how clogged the pipe is I’ll try to burn it out. I am running a silencer in the pipe. Would that cause a noticeable restriction?

HP peak is 6,000 RPM and drops like a rock after that.

Two strokes need some restriction in the exhaust.  Stock silencer is fine.

Take that Yellow Uni air filter completely out and see how it runs. I have had the same issue's with that filter on many Yamaha 250's and 360's in the past.
I use the Green Uni filter foam part # UFI-BF-1 and make my own to fit the stock cage or the uni cage. easy to cut and glue together with a glue gun or other fast drying adhesive. Weather strip adhesive works.
Make sure to cut it long enough to just butt up to the filter lid when installed. 
lightly oil the filter and grease both ends for a good seal and your good to go.