Fri Oct 22, 2021 6:07 am

Enthusiast
Rally 200
Joined: 11 Apr 2021
Posts: 87
Location: Altrincham
 
Enthusiast
Rally 200
Joined: 11 Apr 2021
Posts: 87
Location: Altrincham
Fri Oct 22, 2021 6:07 am linkquote
Hi folks

Is a BE4 mixer tube richer than a BE3 please?

Thanks for any help

Cgt75b
Fri Oct 22, 2021 6:22 am

Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 4244
Location: Nashville
 
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 4244
Location: Nashville
Fri Oct 22, 2021 6:22 am linkquote
Yes, the BE4 is the richest.

This has been discussed in great detail in the past.

What's the problem you're trying to solve?



Fri Oct 22, 2021 6:50 am

Enthusiast
Rally 200
Joined: 11 Apr 2021
Posts: 87
Location: Altrincham
 
Enthusiast
Rally 200
Joined: 11 Apr 2021
Posts: 87
Location: Altrincham
Fri Oct 22, 2021 6:50 am linkquote
chandlerman wrote:
Yes, the BE4 is the richest.

This has been discussed in great detail in the past.

What's the problem you're trying to solve?
Thanks man, a wee flat spot.
Fri Oct 22, 2021 6:52 am

Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 4244
Location: Nashville
 
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 4244
Location: Nashville
Fri Oct 22, 2021 6:52 am linkquote
did you change anything to cause it, i.e. install a different exhaust or top end?

If not, you've probably developed an air leak and will only be able to jet around it for so long before you seize it and kill the piston & rings, if not the whole top end.

(hence why I asked about context)
Fri Oct 22, 2021 10:51 am

Enthusiast
Rally 200
Joined: 11 Apr 2021
Posts: 87
Location: Altrincham
 
Enthusiast
Rally 200
Joined: 11 Apr 2021
Posts: 87
Location: Altrincham
Fri Oct 22, 2021 10:51 am linkquote
chandlerman wrote:
did you change anything to cause it, i.e. install a different exhaust or top end?

If not, you've probably developed an air leak and will only be able to jet around it for so long before you seize it and kill the piston & rings, if not the whole top end.

(hence why I asked about context)
It's a stock motor with an Sip road 2
Fri Oct 22, 2021 11:04 am

Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 4244
Location: Nashville
 
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 4244
Location: Nashville
Fri Oct 22, 2021 11:04 am linkquote
If you haven't changed anything, then I'd start by cleaning the jets, but you may have a seal failing causing an air leak.

What's your current jetting? Somewhere in the neighborhood of 160/BE3/112, I'll guess?

If you don't have a leak, but do have a bit of a flat spot, then you probably want to bump up to a BE1 or BE6. You shouldn't need much richer with just a SIP Road on an otherwise stock 150.

And your main may also be too weak, which could also cause a flat spot as it fails to transition from the atomizer to the main.

Can you post a video of it running on the stand, blip the throttle a few times, rev it out a bit more? That will help diagnose things.
Fri Oct 22, 2021 5:25 pm

Hooked
1959 Allstate w PX Engine
Joined: 29 Nov 2020
Posts: 382
Location: Los Angeles
 
Hooked
1959 Allstate w PX Engine
Joined: 29 Nov 2020
Posts: 382
Location: Los Angeles
Fri Oct 22, 2021 5:25 pm linkquote
Cgt75b wrote:
It's a stock motor with an Sip road 2
Did you upsize the main jet when you installed the Road 2?
Should be 2 to 4 higher on a stock setup with that box.
Fri Oct 22, 2021 9:08 pm

Enthusiast
Rally 200
Joined: 11 Apr 2021
Posts: 87
Location: Altrincham
 
Enthusiast
Rally 200
Joined: 11 Apr 2021
Posts: 87
Location: Altrincham
Fri Oct 22, 2021 9:08 pm linkquote
Ray8 wrote:
Did you upsize the main jet when you installed the Road 2?
Should be 2 to 4 higher on a stock setup with that box.
I did Ray8 I'm gonna go up another 2

I'll report back when I get one and get out for a ride.

Thanks 😎
Sat Oct 23, 2021 3:57 am

Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8630
Location: Atlanta, GA
 
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8630
Location: Atlanta, GA
Sat Oct 23, 2021 3:57 am linkquote
Yeah don't underestimate the main jet needs of the Road 2. Start high and work down. Even a shop underestimated it with mine and I soft seized pretty bad when I was pushing it. Running a bit higher than the usual "sito+" recipe and it's a bulletproof machine now at all speeds
⬆️    About 1 month elapsed between posts    ⬇️
Sun Nov 21, 2021 12:14 pm

Enthusiast
Rally 200
Joined: 11 Apr 2021
Posts: 87
Location: Altrincham
 
Enthusiast
Rally 200
Joined: 11 Apr 2021
Posts: 87
Location: Altrincham
Sun Nov 21, 2021 12:14 pm linkquote
Bit of an update

ATM I'm on a 122 main but think it could go upto 123/124 but I don't have these to hand just yet, most British dealers are out of stock.

Just recently I've had what was like an over fueling issue bogging down and stalling, anyway spoke to a tuner here, and he suggested checking a few things one of which was the mixture screw.

Checked this and it was 2.5 turns out he recommended 1.5 turns out which I did, and low and behold things are sweet as a nut now, no flat spot no bogging down, just need to make sure the MJ is correct which I'll get too once I've scoured those jets.

Anyway thanks for all advice given

It's much appreciated

Cgt75b
Sun Nov 21, 2021 2:10 pm

Ossessionato
2 matching N.Z. '69 VBC Super, 177cc Racer, VespaCross Bodge, Puch SRA150, Piaggio Zip 100! & others
Joined: 26 May 2013
Posts: 4189
Location: That bushfire place
 
Ossessionato
2 matching N.Z. '69 VBC Super, 177cc Racer, VespaCross Bodge, Puch SRA150, Piaggio Zip 100! & others
Joined: 26 May 2013
Posts: 4189
Location: That bushfire place
Sun Nov 21, 2021 2:10 pm linkquote
Something I was told many moons ago (but cannot confirm if it is true, but seems to work & I understand spray nozzle dynamics) is;
The higher the hole (up the mixer as shown in the prior drawing), the higher the revs that it is affecting.
The bigger the hole, the richer at those specific revs (ie. more mix can come out the hole at the same pressure)
THEREFORE
If you have a lean spot low down in the range, then make a pair of holes slightly larger to richen it up in that rev range.
Can also ADD holes at a rev-range if needed

if you suspect one is a bit damaged or has a burr or sharp edge (take closeup pic on phone) by something getting stuck or whatever:

Model shops sell packs of teeny precision drills
OR
Poke a thin bit of wire (single strand is ok, but multiple strands of very thin wire twisted together can be better as they k8nda work like a teensy saw) thru hole & spin the tube to smooth the edge off.
It can make the mix "spray" thru the hole "cleaner" (better spray pattern).
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