bike running lean

I recently got an 81 Seca 750 that was barely running. I have been able to get it into rideable condition. I found a used 4 into 2 exhaust to replace the obnoxious cobbled together unit that was on it. Checked the plugs and the condition shows it is running very lean. My question is will I do any harm to the engine riding it until I can get the carbs tuned and synched?

 

I'd like to know a little more info. What type of exhaust is on the bike now? Is it a 4 into 1? If so that may be why it is running lean if the po didn't rejet. Is it running lean at idle or running speed? To find the diference do plug shop at speed. This is done by killing the bike with the kill switch at around 5k RPM and coasting to the side of the road. Then you pull the plugs and read them. If you idled your bike into your garage and pulled the plugs even after a long ride the time at idle will make the plugs read the idle mixture.
Important difference is that the colortune only sets the idle mixture which is good to about 3-4k RPM. After that the main jet takes the bulk of the fuel to the cylinders. So a rich or lean idle may not be a factor at highway speeds. If the bike is lean at these speeds then it could over time burn a valve.

 

Here it is what I have observed; Previous exhaust was original headers and crossover joint with after market slip ons. It leaked lots of air even after i patched some of the holes in the rusty exhaust joint and was obnoxiously loud. I found a used 4 into 2 exhaust, it looks like a Mac. It idles okay, I don,t feel any hesitation on acceleration even hard acceleration up to 8 or 9k rpm.
I do hear some back firing until the bike is really warm on acceleration and some back firing(not every time) on deceleration. The new pipes have been on for about 100 miles, I have checked the color of the plugs twice both times right after a 30 minute expressway speed ride. Drove it into the yard shut it off waited a little so i didn't burn my fingers. Plugs in cylinders 1 and 2 look tan,normal from the pictures I have seen, plugs in 3and 4 look white, too lean I am assuming

 

Your going to have to jet up to compensate for the lack of backpressure with the new exhaust. Odd that the right bank is lean and the left good. Usually the two outside cylinders will be lean. Sounds like someone was messing with the carbs. Pull the carbs and verify your jet sizes and so on, something may be out of wack.

 

It wouldn't hurt to check the valve clearences. Screwed up valves can mimic carb problems.

 

thanks for the suggestions, I will check them out.