Well, Mark, you were right. I removed the silencer and spent the entire evening cleaning and heating it. No doubt it was dirty. Then replaced the BR8ES with a non resister B8HS clone. Took it up a decent paved hill nearby my house. No measurable change. Then pulled off the air cleaner and rode it “raw dog” as you suggested. BAM! Instant difference! Thanks to all for the advice. Finally I can focus on cosmetic aspects!

Great news!  Congratulations!  I know how maddening that exact problem can be an I also understand why you didn't try it first.  The way she runs it just doesn't seem like it could be the filter. Actually seems to run good but doesn't have power.  Until you test run without it.

Just make sure you get a filter installed...  engine won't last long if you ride without one.

P.S.  The Uni filter the Yamaha dealer gave me was one of those clamp on foam pod filters.  Not a stock foam element.  Worked good but areas I rode were dry and dusty, not much water around.  I wish I still had the original LT2 filter housing, probably would be worth a fortune. 

If you call Uni filter, I believe they make a foam replacement element for the stock housing.  It may not be listed in their catalog. 

One puzzling thing is that LT3 came with a different air filter than the LT2 and Yamaha doesn't tend to make changes unless needed.  But there also has to be many stock LT2's out there that run fine. 

Yup, I have the stock housing And it’s in very good shape. Great advice on reaching out to uni directly. I was confused as to if the filter they show fitted with that housing. Even if they don’t have a figment I’d be ok to use their replacement and just hang on to the original for posterity. I didn’t have the NOS front fender and replaced with a DT100 fender bracket and black UFO fender for an ‘86 Honda CR80. I’m sure it’s nails on a chalkboard for NOS purists But I like the motor cross look. I’ll probably pickup the original at some point

Hey this is my first reply to a forum ever can’t type lol classic-cycles on eBay has a uni filter with cage for a Lt2 new I’ve used them before for my Ht1 and Ct1c and Rd350 AWESOME group here!!!

 from Salisbury, UK.

Now that you've learned to type  , how about teaching yourself how to upload photos  - we'd love to see some of your bikes!

Thanks Gr8uncleal ht1 added turn signals paint not the right shade  but it was free. Going to try the upload