Low end bogging?

[adam833]

I have an 86 trx250r with an esr trx6 low to mid pipe. CArb is brand new 38 a/s and jetted about 2 months ago to 172/50/1.5. Idles great. Lately I have noticed that I am almost bogging in the low to mid power range usually right before the power band...I gun it and I have to blip it a lil cause nothing happens..The only changes I have made is I put NEW stock 450r rims and tires on and I put in a new br8es plug and gapped it at .20...Prior to this plug I never gapped the plugs when I bought them and the tires were not as tall and the rear was an 8 in rim and its now a stock 9. Engine has about 2 hrs on complete stock rebuild. oil and mixture are the same at 32:1. Anyone know what can be causing this? Wasnt like this before..
tia

[86 Quad R]

try playing around with your needle position and main jet.

[trx-r#34]

low to mid range bog, I would try adjusting the air screw.