Freestyle piston wash, plug color etc

[Brian_216]

After riding I like to pull my plugs and have a look at them and use a bore scope to look down inside. Both plugs were black and wet, tops of pistons are dark brown and wet with oil. no real burn pattern, just a solid color across the pistons. I havent really spent much time tuning this yet, or burned more than 5 gallons of fuel- ( we have been super busy building hulls.) Im running T/L and a PFP on an 8mm dasa with 46mm sbns. Still jetted for b pipe. My lows are at 1/2 turn and highs at 1 full turn out. It dosent seem as crisp as it could be. Any pics of what the piston wash should look like?

 

[subhard]

 

[Brian_216]

Darker one is the front

 

[Brian_216]

And to make it even more interesting, I reached inside the exhaust port and the lighter colored cylinder had a stuck power valve. Stuck in the down position, would not budge. Fixed now and even sounds better when I fire it up.

 

[Brian_216]

Ok, we made some changes today:
low screw. 1/4 turn. Not changed
High screw. 2 full turns. Was 1 turn
120 low Not changed
140 high. Was 110
Pop off at 18psi. (was at 12)
2.3 n/s. Not changed

I cleaned the pistons off very well, had shiny aluminum. Went out and ran about 1.5 gallons through it and have this now.


Can someone give me some direction?

 

[shepster]

Looks very rich still to me! Maybe go somewhere between the two settings?

 

[Brian_216]

Ok, from the last pics, I went all silly like and ran the high adjuster into 1/2 turn and have this...and the front is still the leaner of the 2. I'll be pulling carbs, and reeds and spacers to make sure there is no air leak causing the front to be leaner. This is the same jetting as the earlier pics, only change was the high adjuster went from 2 full turns open to 1/2 turn. The lighter colored piston seems to be starting to show some wash around the ports, but nothing like what I'm after. I'll be making a call to DASA tomorrow and see if I can get some better answers as to where to start.

 

[D-Roc]

Try front carb at 1 1/4 and rear carb at 1 turn out. My screws are staggered a bit. Front and rear have different loads on them and need seperate adjustment. Hence the dual carbs.

Personally I think your lean.

 

[Freakrider]

Try front carb at 1 1/4 and rear carb at 1 turn out. My screws are staggered a bit. Front and rear have different loads on them and need seperate adjustment. Hence the dual carbs.

Personally I think your lean.

X2 darker piston need a little more fuel than the other.

 

[Brian_216]

Do you guys feel the lighter colored one looks closer to being correct or is that still lean?

 

[Freakrider]

Should have at least a thumb wide clean area from cyl wall inward.Better to be safe and run a little rich.

 

[Brian_216]

I spoke with Kyle at DASA today. He said go to a 130 pilot and around a 140 main. 2.3 ns and 95 gr spring. I had all but the 130, so I tried 135s until I can get my hands on a pair of 130s. I tried to find the lean spot on the bottom tonight, she just loaded up and had a blubber to it all the way in to an 8th turn from closed. I'll let it sit until I get the 130s to try.

I also pulled the intake and sealed everything with three bond to insure there was no air leak.

 

[CARBONX2]

Generally, a '10' change to jetting is equal to 1 full turn on hi-screws

 

[Christian_83]

Brian you might try this jetting, im running it now. And we jetted a friends DASA 8mm PV cast stroker with the same, he is running ATP TL, B pipe, dual 48mm Riva
Power Bombs. He havent changed it since.
My specs is in my sig.
High speed jet 125, 0.5 turn out
Low speed jet 135 1 turn out
needle and seat 2.0. spring 80 grams giving a pop off in 21 psi area.

 

[Christian_83]

Brian, btw. you cant rely on adding three bond, to insure no air leaks, if you a chasing one or worried about if you have one.
Best option is to make a pressure test, block off intake and exhuast ports. put 10psi in the engine and see if it holds up, if not spray with soapy water on all gasket surfaces to find the spot the bobles and lets air out.
or you can use a simlple and not so good method, start the engine and with engine runing spray starting fluid (or something highly flameble) on gasket surface on carbs, intake and cases, frist on cylinder 1 then cylinder 2.
If the engine rises RPM when you spray on a certain place you got a airleak.

 

[Brian_216]

I'll have to do a better test for leaks. Hopefully what is in there now is going to be pretty close. I just need to quit my day job so I can go put the time in and tune and ride!