So I've been hesitant to dive into the carb ever since the end of last year when I had pipes and BAK put on at dealer. Since then the bike has not run well, but not horrible either.

Finally did the WOT which led me to think I was a little lean on the main. Tonight I used the guide here to jump into the carb. Saw I had the 172.5 mikuni main in, left it. PMS was 3 turns out so I went another 1/2 turn. Barons needle was on the 4th clip so I moved it to the 5th as recommended here. Put everything back together and she started ... then coughed out. It helps when you reconnect the fuel pump to the tank So then I went out for a ride and what a difference. Power as soon as I goosed the throttle, no backfiring on decel, noticeably less knocking (although still some.) Just all around sounds and feels better.

So thanks to everyone here who has put out a guide and offered help, it gave me the confidence to fix the problem myself and now I have no problem going into the carb if I need to do more adjustments.

Cool, glad you go it all worked out. This place is good for helping to give you the confidence to tear into these bikes. I know it has helped me a bunch.

Paul

My opinion is you have an air leak and compensating with richer settings. Suggest you go thru a couple of tanks and check mpg's. MY test for cruise mpg's is similar to what Mikuni uses, 65mph and I go for a solid 100 mile + ride, you should be in the upper 40's, city low 40's. The manifold to jug connection is a common spot for leaks, I find wd40 does not find leaks as well as carb cleaner does.

I agree with Erbman .5th groove sounds rich. I found mine on the 5th clip from the dealer and 3 1/2 on the pms and my plugs were black and sooty. about 33 mpg at best. Now I'm setting on 3rd clip w/1 washer and 2 1/2 turns on the pms. It is running great . I havn't checked the mileage yet (just got it to this point yesterday) but I'm guessing that it will greatly improve.

Ride it for a while and see what your plugs look like. I am at 400 ft above sea level and am running a 172.5 with the needle at 3 with two silver washers. Don't know what your elevation is so you could be right on the money. Seems kinda rich but the needle is where you are running most of the time so you may see poor mileage. I can get 50 mpg on a good 300 mile run most of the time.

At one point, I found that one of the pipes was not bolted tight to the engine. I tightened up all the bolts and that didn't seem to make much (if any) difference.

Mileage when the bike was running funky was well over 50 for a long ride.

Hopefully this weekend I will have the chance to ride through a full tank of gas and see what it's like.

When I did the WOT with the old settings (172.5, 4th clip, PMS 3 turns out), it felt like she held the rate of acceleration when I backed off the throttle (that's what made me change the clip to 5th.) She also backfired like a mofo when I would come totally off the throttle.

Is the general consensus that it's better to run a little rich versus a little lean? I thought I read somewhere that running lean puts more strain on the engine and could lead to cylinder/piston issues (after I read that the engine knocking made me paranoid.)

Oh and BTW, I left all the stock washers in place on the needle (two silver, one white), what difference do these make?

Run it for a while and see what the mpg is and what the plugs look like as all of these scoots are different. I have an 06 at sea level, with a 170 main, 2 1/2 turns out on the PMS and needle in the 4th groove. Plugs have always been clean around the electrode and ceramic cone with some black soot on the underside of the threads indicating a somewhat rich idle circuit, but if I back the PMS down for that I get a lot of popping. I have run this set up for about 23,000 miles and she runs strong. I get occaissional light knocking on hard acceleration depending on the gas I use. Happens more with Chevron than with Mobil or Shell the common name brands around here.

Each silver washer is equal to half a step between the slots. Do you still have the AIS on? It is known for cusing backfiring.

Curt wrote:
Each silver washer is equal to half a step between the slots. Do you still have the AIS on? It is known for cusing backfiring. Curt :I was reading your jetting and your on the 3rd slot w/ 2 washers wouldn't that be the same as the 4th slot?

Nope it is 3 1/2 I was lean in the RPM range of 2000 to 3000 when I had the clip on 4 with one washer.By moving the clip to 3 and adding another washer(2 washers)it is like 3 1/2 instead of 4. There also is a gold washer but I am not sure how much it is Doc told me one time but my old mind has forgotten. The silver washer is equel to half a slot.