Jetting/Plugs

[CASADEHUSKER]

Thoughts on these plugs?

1978 RD400 About 3700 original miles.

Top end....Chuck's cylinder porting, wiesco pistons, Daytona head. (about 100 miles on top end.)
SpecII F1 pipes
V Force YZ85 reeds with Chuck's spacers
VM30 carbs w/ Chuck's boost bottle
PJ 55
slide 2.5 (I have some 3.0)
AJ 2.0
Needle 6DH3  3rd notch
NJ 159-P2
MJ 300
AS 1.5

Uni filters
HPI iggy installed, timing 1.8 BTDC
Plugs B9EG
On the pump

Did re jetting after move from Colorado 6500 ft back to North Phoenix 2200 ft.

Starts right up, good throttle response.  Drops right back to idle.  Around neighborhood and a couple short 2 mile rides seems fine.  Rode it yesterday for about 15 miles, seems okay but at one point I was in 4th gear and doing say 50.......rolled throttle on and not much there....seemed weak, rolled out and was okay. 

Stopped at buddies house, let it cool checked plugs looked okay, raised the needle to 4th notch (richer) and rode home.  Started fine ran fine but seemed a little burbly at 4th-5th gear 55 mph.

Got home and here's the plugs.

Happy b-day Chuck

rob

[CASADEHUSKER]

Two more views

[1976RD400C]

55 pilot jets seems kinda big. I would try leaning the needle instead of making it richer and see if the mid range becomes more crisp. It's not going to want to rev if the needle circuit is too rich and as you lean it out the rpm's will want to take off and go instead of feeling burbly. Did you check the timing with a timing light and watch the curve to see if that's all good? My bike is similar with HPI, Uni's, ported, Wiseco's, but have 34mm carbs. 30 pilots, 159 P-2 needle jets, 300 mains. Getting the needle circuit right makes all the difference.

[CASADEHUSKER]

1976RD,

Hey nice to talk again.

I started with a 50 pilot and was good.  I typically go by how well it pulls away from a dead stop.  Tried a 47.5 and bogged trying to pull away, so went up to check.  Will go back to the 50 pilot.

I think I was just a little nervous about over heating so I went richer for the ride home and had a chance to get a look at the plugs.  Didn't have a lot of color so figured I would get some thoughts on here.

Easy enough to go the other way on the needle.

I did check the timing and the curve seemed fine, but I can recheck all that just to be safe.

[SUPERTUNE]

Too rich. Go to clip # 2
To keep a good idle with fat pilots, don't worry if you have to run the air screw out to 2 1/2 turns out.
What oil in the injector are you running? What is the pump shimming and is the timing mark just past the full open mark (about 4mm) at full throttle?
Chuck

[CASADEHUSKER]

Chuck,

I am using Bel Ray Si-7, synthetic ester.

I will have to go back and check the shimming.  Seems at some point I increased it from stock.  So I will check that and the re-check the timing.
Thanks

[CASADEHUSKER]

Pump minimum stroke is set at .010"

Check timing tomorrow.

[CASADEHUSKER]

Timing is good

[2steve]

I finally got more happiness in 2nd gear 6000 rpm roll-ons with a similar set up (boost bottle, Chuck update ported cylinders, FPP pipes), by going from P4 needle jets to P5.
My carbs are VM28s though.

[SUPERTUNE]

.010 should be fine.
BelRay SI7 is great also.

How does it pull to redline in 5th or 6th?
RD's when rich pull great in the lower gears then struggle in the upper gears to reach redline.
Chuck

[SUPERTUNE]

Try the 3.0 slides also...you may go in on the mixture screw a 1/4 turn if it seams lazy on the throttle response.
C

[CASADEHUSKER]

Chuck,

I have/had not made a run WOT in 5th or 6th.

I think I will change the slides back to the 3.0 which you had initially set up in these VM 30's for me, and go from there.  Report back this weekend.

Thanks

rob

[CASADEHUSKER]

Sorry for not getting back sooner.

Looking at a supermoto project.

Any way I went back to my 3.0 slides, AS out to 2 and put the needles back to the middle to get a baseline.

Pulling away from a stop I am happy.  Seems to be running very nice, 2nd gear wheelie with ease.  Will give have a look at the plugs after a bit more of riding and just check the needle one notch higher and lower to see how she feels.

Thanks guys.