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Re: What are reed valves????
Posted: Fri Mar 04, 2016 7:00 pm
by Meds
dellorto PHBH 28, PM25 exhaust
Prior to the reed valve I had it dynod and done a few thousand miles with the following set up
Av266
X7 3rd clip down
Main 122
40 slide
Pilot 50
Choke 70
Had the reed fitted, inlet port matched and TS1 piston
I had to screw the air screw out to weaken the mixture, it ticks over ok
Initially the scoot wouldn't pull away, did the choke test and it killed it dead so diagnosed it was rich, raised the needle clip by 1 and it improved but still 4 stroked a lot.
Raised it to the top clip and it seems much better.
Plug chops are still showing oily ( not chocolate brown)
What I'm querying is why I'm having to weaken it all through the range when all the literature says richen it?
Re: What are reed valves????
Posted: Sat Mar 05, 2016 2:30 pm
by Minority
Meds wrote:dellorto PHBH 28, PM25 exhaust
Prior to the reed valve I had it dynod and done a few thousand miles with the following set up
Av266
X7 3rd clip down
Main 122
40 slide
Pilot 50
Choke 70
Had the reed fitted, inlet port matched and TS1 piston
I had to screw the air screw out to weaken the mixture, it ticks over ok
Initially the scoot wouldn't pull away, did the choke test and it killed it dead so diagnosed it was rich, raised the needle clip by 1 and it improved but still 4 stroked a lot.
Raised it to the top clip and it seems much better.
Plug chops are still showing oily ( not chocolate brown)
What I'm querying is why I'm having to weaken it all through the range when all the literature says richen it?
Pretty sure on the PHBH that if you screw the mixture screw out you will be making it richer not weaker.
Re: What are reed valves????
Posted: Sat Mar 05, 2016 2:52 pm
by Meds
Yes my mistake, deinately screwed it out
It's now at 3 1/4 turns out
Needle on top clip.
Took it for a good ride out and it's stopped 4 stroking but 1/2 throttle plug chop shows weak.
So start again, I'm obviously doing something wrong, or mis diagnosing.
Re: What are reed valves????
Posted: Sat Mar 05, 2016 3:36 pm
by coaster
Meds wrote:.......Needle on top clip......... but 1/2 throttle plug chop shows weak
mid range will be all about the needle/atomiser and the top clip is the leanest position so lowering the clip is the obvious next step as lowering the clip will lift the needle and that will allow more fuel into the mix
Re: What are reed valves????
Posted: Sat Mar 05, 2016 5:58 pm
by Meds
Cheers coaster.
I have dropped the needle one clip, I will have a go tomorrow morning at getting the mid range correct.
From stuff I have read it sounds like I need to richen the pilot and readjust the tick over.
It looks like I have diagnosed rich when it was really weak.
Re: What are reed valves????
Posted: Sat Mar 05, 2016 7:33 pm
by Chris in Margate
A bigga mistaka to maka !
Plug chops.
Re: What are reed valves????
Posted: Sun Mar 06, 2016 12:01 pm
by Meds
Oh yess, luckily it wasn't costly
So changed the pilot from a 50 to a 55
Air screw 1 3/4 out
Dropped the x7 needle from 2nd clip down to 3rd clip down.
125 main jet
What a difference
1/4 throttle plug, dark chocolate. ( my reading too rich)
1/2 throttle the darker side of milk chocolate ( again slightly rich)
3/4 light chocolate (weakening)
It seems to be weakening up the Rev range,
At 30mph 3rd gear it 4 strokes and feels lumpy, soon as you raise the revs it cleans up
so might go for a slightly smaller pilot.
I haven't given it a full throttle run as I'm still bedding the rings in.
At the moment the jetting a safe.
Re: What are reed valves????
Posted: Sun Mar 06, 2016 12:57 pm
by coaster
I doubt the pilot will be the issue, should be needle/atomser. What atomiser and needle have yougot?
Re: What are reed valves????
Posted: Sun Mar 06, 2016 4:28 pm
by Meds
Av266 and x7 needle
paul