From Fatties to PT Mids.

[Trick2stroke]

I switched out my Fatties for some PT mids recently, and it seemed to run ok after the swap ( I had planned to rejet but not right away since it seemed to run fine although alittle rich) , but then the weather warmed up a good 20-30 degree's and now it sputters out and won't accelerate then fouls the plugs.

 

I'm running 260 mains (unsure of the needle at this point, the dickhead who owned it before me striped the screws in the slide out), air screw 1 1/4 turn from seated, and what I'm guessing is the stock pilot, I haven't checked.

 

My question is, if anyone has experimented with jetting on the PT mids, what needle and pilot did you have the most success with? I figured I'd go down a size at a time on the main till I get it cleared up but was curious to see if anyone had some insight on the needle and pilot sizes.

 

Thanks.

[bigboybanshee]

I'm not sure of the needle, but my pilot is a 27.5, mains are 320's and a tad rich. I'm also running an airbox w/ the lid removed...mildy ported cylinders. On stock cylinders, I ran a 280 main, 27.5 pilot

 

I'm about 400 ft above sea level, 50 to 60 degrees outside

[Trick2stroke]

I'm almost directly at sea level (something like 47 feet above), the temp is around 70-85 right now and the air box lid is removed, I was surprised to see 260's in it actually, being that it's running so rich.

 

I'm going to pick up some 230's, 40's, and 50's today and work my way down.

 

Thanks for the reference BBB, anyone else have any idea as to what needle/range of needle to use? (I have no idea what the diffrent sizes or order of sizes for the needle are.)

[LiftdT4R]

I'm almost directly at sea level (something like 47 feet above), the temp is around 70-85 right now and the air box lid is removed, I was surprised to see 260's in it actually, being that it's running so rich.

 

I'm going to pick up some 230's, 40's, and 50's today and work my way down.

 

Thanks for the reference BBB, anyone else have any idea as to what needle/range of needle to use? (I have no idea what the diffrent sizes or order of sizes for the needle are.)

Whoa! 260s are going to be too low for that setup. I run 260s with FMFs and a full air box, and it's on spot. Do not go any smaller! My guess is that he probably fucked around with the needles, and they are on the wrong clip, they should be on the middle one, I'd check that first. You probably want to be at around a 280 or so. Going from PTs to FMFs or vice versa should not require any major jetting changes, seeing how as they are similar pipes, you shouldnt be changing mains, thats for sure. Should be 25 pilots also, and then a turn or so out on the air screw.

[Banchetta]

I highly doubt your too rich at all, I think you have other problems, is the choke tube in place between the carbs? I was running 300 mains, needle 5th clip, stock pilot, on stock cylinders, 165psi compression, boysen petals......fmf pipes usually run leaner than pt mids. Also make sure you disconnect the tors brain, you could have hit something during installation and if tors acts up, then it'll feel like a rich jetting.

[Trick2stroke]

The TORS is removed, the needle was on the 3'rd clip, choke tube is in place, everything seems to be in order.

 

I've gone as low as 240 on the mains, put the air box lid back on, and it runs seemingly good now ( seemed to be rich even before the swap with the fmf's and 260's).

 

Still seems to studder about half throttle just before I get into the PB. I've yet to do a plug chop though to confirm any of my adjustments. The last time I changed the needle to postition to see if I could clear up the studder (was going to try it on the 4'th clip from the bottom) the slides don't seem to be getting stuck but it just revs wide open when I start it up. I gave up on it for today. I got tired of fucking with it. I have a short temper and didn't want to break something.

 

I'll take the carbs off to be sure the slide isn't sticking somewhere tomorrow sometime.

[Banchetta]

When you say the tors is removed, are you talking about the carb tops or the little black box? Disconnect the clutch switch on the handlebars? Your mains are way too small, like I said earlier, your not running rich, you have other problems...slides in backwards? Cutaway facing the airbox. If you removed the carb tops, did you install the new idle screws? If so, did one of them fall out?

[Trick2stroke]

The slides are in correctly, the tops of the carbs are removed. I never drilled or tapped for an idle adjustment screw though, I was just using the threaded adjustment on the thumb throttle. :: It seemed to work fine before I changed the needle position and started having slide problems.

 

I must just be jetting illiterate, I always seem to have trouble with it.

[Banchetta]

Did you disconnect the little black box above the left exhaust w/ the 3-wire plug? Disconnect the clutch switch on the handlebars as well?

[Trick2stroke]

No, but I bridged the two TORS wires that pluged into the harness.

 

Would not disconnecting those make it run like that?

 

I'll give it a shot, but it started doing this before I evern touched the TORS. I just removed it when I had the carbs off to jet.

[bigboybanshee]

Just for the sake of knowing, what's your compression?

[Trick2stroke]

I don't have a compression tester. It should be fine, the top end is relatively new and the bike still runs strong, it just recently developed this rich condition.

[Banchetta]

the tors system is more than just the carb tops...the little black box is the central brain, you have a clutch switch which should be disconnect at a connection towards the radiator. There is also a switch in the thumb throttle which is only on some years and doesn't matter when you disconnect the black box....but if the black box isn't disconnected, then it will still be active and they fail all the time...they will create symptoms like rich jetting and when they fail, its at any point of time....The tors affects spark and I've seen it cut the spark off completely or sometimes make the shee act like a rev limiter, it'll mess w/ you and drive you insane, so try that first.

[Trick2stroke]

Alright, thank you so much, I'll check into that and disconnect the box and see what happens.