Thanks for the compliments on the pipe.
Been riding today, so away from the computer.
Jeff,I did TIG weld it. Wire, or stick with a small rod would work fine but I LOVE to TIG so I try to do that whenever I can. I capped it off and purge welded it so the inside would be better.
Tom,an O2 meter would be sweet! I know a guy that has one I may be able to borrow later but don't know much about it.
As for the jetting,it's getting much better. When I took it apart to clean it originally it had a 136 (stamped) main, 45 (stamped) pilot and a needle of unknown origin. I say what size the jets were stamped because someone had been inside and I didn't measure the jets to verify the actual size. I figured I would measure later if needed to see if they had been drilled. I started by installing a KLX needle,142 main and 40 pilot. When I installed the carb and ran it it had a bad slump when the pump kicked in on hard acceleration. I put the original parts back in to start from scratch. It ran much better and I could tell when the squirt hit which was wonderful.
It was better but still not right. Even though it ran better it was using to much gas. It was weird because of the drastic change with the jets not being a whole lot different. I hadn't paid much attention to them,but just out of curiosity I measured the needle jets. They were the same size on the small end but the one in the pumper was about .008" larger diameter and about .010" deeper on the large end. I looked on the microfiche and they do have different numbers listed. I didn't think it was a big deal but it was. I put the KLR needle jet in the pumper and went back with the KLX needle and things got better. Been back and forth getting the idle better and today I was able to do another test run. My test runs are usually about 200-225 miles,with different types of riding with fill ups in between to check gas mileage. I pay attention to performance, but fuel mileage is more important to me. A lot of my trips are in the boonies and I don't like to think about looking for gas stations every few hours. Miles per tank mean more to me than something that is a bit quicker that sucks gas. 50 mpg(no camping gear) is my reference and I don't want to go a lot less than that. Early on in the project I was in the mid to low 40s which wasn't going to work for me. Today's results were the best so far. I have a 142 main,42 pilot,KLX needle(2nd slot from top) and the KLR needle jet. Going up on the highway I got 47 mpg.,not thrilled but could be worse. Flogging it like a rented mule through twisties, FS roads,jeep trails was 45 mpg, still not worth the improved throttle response for what I do. My last fuel stop I pulled out one 1inch plug from my air box and slabbed it home. This time I got 53 mpg. Gas quality varies a lot around here so I need to try this set up a while longer but at least I am getting better results on the MPGs. The improved throttle response is still there and most rewarding in twisties, curvy FS roads and jeep trails. On the slab I haven't done a whole lot but don't really care to see how fast it goes wide open.
While I was in the carb I had another idea that may or may not be needed and may or may not work. IF there seems to be too much fuel flowing from the pump for this size engine to efficiently utilize, I may make a restrictor bushing to reduce the amount of fuel that the pump delivers. I haven't thought about it much to see what may the best route but this is a possible option. There is a place that I can install a brass bushing about .100" O.D. x.080" O.A.L. with a hole about .015"-.020"" dia. through the middle. These numbers are just a guess at this point but a possible option if needed. If it helps I can make different size bushings to tune it in.
Sorry about the novel length answer,just wanted to give an idea of what I found inside and what I have experienced during this process. There were a couple times that I thought this project was a wash but as I weed through things,it gets better as I go. Even if it doesn't suit my type riding,I've had fun going through the process.
Thanks again guys for the nice words on the pipe,that was the easy part of this ordeal.