I'm stumped...combined milage around town(80%) and freeway(10-20%) I get 20 MPG. Freeway 25-33 mpg at best if I hold down the speed at 65-70MPH. Yeah I ride it like a stole it...a lot of the time, but if the wifes with me I slow down a lot.

Dealer just did Trans Recall so new rings. Top of pistons are totally black with buildup of carbon, dealer said it was running to rich...so mechanic leaned out PMS. Plugs show white insulator now, black soot on metal base of plug. Runs great, but I get popping on medium to hard decel ( not that big of a deal). Flips me out when I have to stop at 88 miles to put in 4.1 gallons of gas in the tank. Especially when I hear some getting 40 to 50 with similar jetting etc.

JETTING: Pilot jet 35, main jet 170, Starter Jet blocked, needle 5th notch from top with white donut type washer and one thin metal washer underneath. PMS 3.00 - 3.5. I measured the jets with jet drills in MM and I have a Dyno Jet kit that I thought was used...but it doesn't look like they actually changed the jets...(previous owner said he had it rejetted).

I've seen the jet chart that shows Mikuni jets (CC's flowed) and Dynojet (mm's) and note the comparisons. I think my main jet is the stock jet it looks different than the jets in the Dynojet kits (much bigger jet than the jets in the Dynojet kit.).

Running Barons BAK with Power Cone, Hard Krome Short Shot pipes 2.625 diameter, Stock Carb.

Stock intake manifold (not ported) shows some cracks in the rubber outer cover on top...I thought this wasn't a big deal because it was aluminum underneath??? True. I am going to put carb back together and start and do an intake leak test...dealer wanted to replace manifold but didn't have it in stock...so put the old one back on.

Anybody see a problem? Shouldn't the plug insulators show tan?

If it's the stock main jet in there it will have a number on top of it. It will also have an R with a little square next to it. If you have the Dynojet main and it is a 170 it's too small IMO. 5th groove is too rich. A good starting point for the PMS is 2 to 2 1/2. If the cracks go all the way through the manifold you will have air leaks.

You need to find out for sure who's jets and needle you have. After you know that we can work on it. Also check for air leaks on the manifold.

I agree with Musky. Figure out the identity of that main jet , or just be safe and replace it with a Mikuni 170 , and put the needle on the 4th groove (which drops the needle into the carb a hair deeper, thus leaning it out). BB

Musky and BigBear...it is the stock 170 jet...it has the R and the square on it. My PMS is definitely 3-3.5...that was adjusted by the dealer. I will put that in at least one turn.

So now I come to the needle... its on the 5th out of 6 slots and it has a plastic washer under the clip which effectively raises the needle two or three more slots...so I would assume a richer mixture. But, the insulators on the plugs are white, not tan. But there is black soot around the metal outer base of the plug where it surrounds the insulator and electrode.

I have to determine if my manifold has a crack in it...I check it tonight and it appears that the crack in the rubber doesn't go all the way through. I am going to put some liquid electrical tape on it and that should seal it up to test if that makes a difference.

The 170 Mik isn't stock. The 1600's had a 165 and the 1700's have a 182.5. But the 170 Mik is a good place to start. The white spacer doesn't raise it 2 or 3 slots. It doesn't raise it at all. The stock needle set up from the top is washer, clip, white spacer, washer. You should always have that no matter what. You can move the clip up or down or you can add washers under the spacer but you should keep the stock stack intact. Adding a washer under the spacer makes you 1/2 groove richer. Your clip is in the 5th groove from the blunt end of the needle?

You should go to the tech articles and read through the carb section to familiarize yourself with the where, what, and why.

"trans recall" means you have a 1600 ... possibly with some miles. There is definitely something wrong as your carb settings would not result is such poor mileage.

I'd check the float level
Inspect and replace (maybe just replace) the float needle valve
Inspect and check out the main for rounding of the centre hole

Doc

Musky and Big Bear,

Yes it is a 1600...sorry I was not specific. 20,000 miles on motor but very easy, mostly highway miles...when the motor was apart for the recall, there was no ridge on the cylinders and you could still see hatch marks from the original honing done at the factory when the motor was assembled. Piston skirts had very little wear. So with new rings from the recall, I won't have as much compression as I had until they fully seat.

Ok well if the 170 isn't stock then thats what was changed to richen up the bike when the BAK and the short shots were put on and the clip was moved to the 5th slot with one metal washer underneath.

Ok since the white spacer is stock (didn't know that, thought it was added which would raise the needle as apposed to not having it in there) then probably I'm going back to the 165 and moving clip to the 3rd slot. That will be the starting point. I'll also make sure that I have no intake leaks which would give me a leaner mixture. I'll clean my air fliter, check the float level and start moving in increments from there.

On the Dynojet package it says Stage 1 settings: use a 160 jet if you are using stock mufflers, and 165 if you have stock mufflers and a free flow baffle.

On the Dynojet package it says, State 2 settings: when using the K&N style filter to use the 190 jet with stock mufflers, and use the 195 if you have free flow baffles.

Dynojet also says to use the 3rd slot for the clip as a starting point...consistent with most of what I'm hearing form you guys.

I now have five main jets to use: 160, 165, 170, 190 & 195. I measured all the jets with a Weber jetting drill set that I have that had drills from 40-235 jet size. I had this from prior years when jetting 4 two barrel weber carbs (48 IDA's) on a Chevy V8. I use to start with the smallest jet as a starting point and kept drilling out until the motor wasn't running lean...but there were three circuits to deal with low, mid and high speed circuits. Talk about a lot of work with disassembly and assembly. The Mikuni should be a piece of cake now that I know where stock is.

You guys have been great helping me figure out where to start and what the heck I have...it sucks when you buy a used bike and you don't know what they put in it. Looks like I'll be working on the carb most the day. Thanks again!

For the DJ main, folks have had the most luck with 175 or 180.

3rd groove from the top and 2 silver washers or 4th with one silver washers will put you in the ball park for midrange.

Doc

Doc...if most are having luck with a 175-180 main...wouldn't that give me worse milage that what I have...worst being last weekend 89 miles on 4.2 gallons (21MPG) best being 33 mpg. I'm running a 170 now?

That's why in my original response I suggested you check some other things.

Your settings are not unusual and would not suggest such poor mileage.

I need to ask but are you sure you're calculating it correctly.

Doc