Should I go Backwards or Forwards???

Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
Mile9c1 said:
I'd try 115 pilots, 120 mains, and 30psi popoff. Low screw about 1.125 turns out and high screw between 1 and 1.25 turns out.

I bet it would work well...
Click to expand...



:biggthumpup: I agree.
 
9

93SJ760

X-H
Location
Timmins, Ontario
Alright,

I've received my jets and they're installed. Heading out in a few minutes to go tuning. I've changed my pop-off to 25psi, just because after reading the Mikuni manual it suggests using the smallest needle valve possible for the pop-off you require. So I put a 2.0 in and kept my 95g springs. I threw in 130 pilots and 100 mains as that's what I had on order. We'll see where I can get with this.

I should have a full case load of new jets that I ordered by tomorrow night. At which point I'll have a little more flexibility in jetting. Hopefully after today I'll just have my B-pipe to tune. I have the middle screw closed, the bottom opened just to say it is opened and the top is opened 1/8 - 1/4 turn.

Is there a setting on these pipes that always seems to work for all engines or should I just follow the FPP tuning guidelines but with-out the sizzle as I don't want steam inside my engine compartment.

Thanks again,
Tyler
 
Legdragger

Legdragger

Bringing it back
Location
New Hampshire
If you have WSM crank seals I wouldn't trust them if you are still thinking you have an air leak. I went through musical jetting problems last year until I lightly siezed m SJ and figure out my WSM crank seals were the cause of my problems. Later I found out they were notorious to leak.
 
W

waxhead

wannabe backflipper
Location
gold coast
i only ever use oem crank seals
but i think the prox come from the same factory as they look identical
wsm
what a joke i would never use any of there parts on my boat
they are built to a price not to a quality std
 
9

93SJ760

X-H
Location
Timmins, Ontario
Legdragger,
I'm not too concerned about air leaks anymore. Must of just had a leak between the carb and intake manifold. I did a leak down test and it held 9psi for 1/2 hr.
I'm now back from trying to tune and it didn't go all that great.

I could get a nice smooth idle but only at a high idle speed. As soon as I would try and turn the idle down it wouldn't hold a good idle. So I'm not sure what's going on there but I got it so it was idling smooth just a little higher than I'd like.

Then I drove around at 1/8 to 1/2 throttle for a while checking response. The majority of the time it would hit good but occasionally seem to load up and lose all power almost like running on 1 cyl. I adjusted the pop-off to about 32 psi instead of 25. This cleaned things up a lot. I would say 90% of the time it accelerates clean and doesn't hesitate or load up.

When applying full throttle at 1 turn out on the high speed adjuster it would hesitate so I turned the screw to 2 turns out. Got rid of hesitation but on a ful throttle run even at 2.5 turns out the plugs are very white.

I think my next step is to try a larger main and possibly smaller pilots and reduce my pop-off back to 25.
 
9

93SJ760

X-H
Location
Timmins, Ontario
Checking my high speed jet using a tach sounds like a good plan but this I have a hard enough time just keeping it upright never mind trying to read a tack at the same time.

This is only my third time out on a round nose. I've ridden squares for the last few yrs.

I will try the smaller pilot once I get one.

Tyler
 
W

waxhead

wannabe backflipper
Location
gold coast
I tape them up on my pad
facing backwards
that way i look over it on a high speed run ( down low and off the back)
and just a quick clance is all thats needed
i always use a tiny tach
it holds it reading for about 2 secs
so you get chane to read it with out fluctaing numbers
 
9

93SJ760

X-H
Location
Timmins, Ontario
I think I found my loading up issue off take-off. I've gotta find a ride to the river to go check it out. (my truck was lent out for the wknd). I pulled my plug caps off last night and it appears my plug wires are falling apart. I was able to pull the wires out one little piece at a time. It seems the wires are broken into about 1/4" pieces all the way through. I'm hoping this could be part of my problem. The elec box is from a square nose so older stuff.
 
9

93SJ760

X-H
Location
Timmins, Ontario
Another Contributing Factor

My plug wires didn't seem to solve the issue so I pulled the flywheel cover off to inspect stator/flywheel/key and what looked to be a cup of gas flowed out.
Trail of gas/oil looks like it's coming from crank seal.
Tear it down
Put new mag side seal and re-do entire case with 1211
Leak-down test - Failed again, air rushing out from behind flywheel.
Pull flywheel and do another leak down.
Find pinhole leak right through casing. Kind of like porosity in the casting so I smeared JB Weld over the hole.
Will try another leakdown tomorrow. Would have never thought my flywheel cover/starter o-ring and rubber grommet would hold 10psi for 1/2hr. At least I know I did a good job of sealing that up.
Hopefully this little hole affected the tuning and now it goes smoother.
Got my jets in. Bought over 250 jets off an ex-racer... woo-hoo
 
9

93SJ760

X-H
Location
Timmins, Ontario
I can't get the 130 pilot and 100 main to work. I went down to a 125 pilot and tried 20 - 32 psi pop-off with both the 130 and 125 pilot. I cannot get a clean low end and I keep getting fuel dribbling in the carbs. I've changed my Needle and seat and then put new seats in and still get tons of fuel dribbling even when it's not running. Can there be a problem with these carbs? They look like they have very low hours and the mods I've done are: doubled up the plastic valve as well as drilled out the internal restriction and put a 60 main jet in the return line in order to ensure the pressure in each is even. I'm running dual pulse with dual pumps so I figured my dribbling problem was due to too much fuel pressure and figured if I drilled out the restrictions it may help this.

I don't know where to go next. I figure I'll try raising my pop-off as high as possible (Aprox 32psi) with a 2.0 N+S and take Matt E and Mile's advice now that all my jets came in.

This is really getting irritating. I've had my carbs apart almost a dozen times already.
 
9

93SJ760

X-H
Location
Timmins, Ontario
I changed the needles (I meant to say needles in the last post) out with brand new ones already and had the same dribbling problem with 2 different sets of needle and seats. I feel it must be either vibrations or too high of a fuel pressure. I've also made sure my carbs are synchronized to try and smoothen out the engine although I didn't even find it vibrated that much to begin with.
 
W

waxhead

wannabe backflipper
Location
gold coast
ok well then your not going to like my next suggestion
the only other reason i have seen then leak thi sbad was from excesive vibration
turned out to be a bent crank
 
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