Tunning dual Weber's

Engine, Transmission and related drivetrain.
NunoTT
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Joined: 09 Oct 2018 06:34

Re: Tunning dual Weber's

Post by NunoTT » 25 Oct 2019 01:10

icehouse wrote:
24 Oct 2019 13:12
This is how I tune them. I find the orginal box and packing material. Box them up real nice just like they came out. Then I load the box into my car, drive down to the river and chuck them in! haha That's a Heinz joke if you guys don't remember it :)
Joke all you want, but I was planning all installing a set of Weber on my classic Mini in a 7 port head, but after having all these problems with the Datsun I will most certainly go with fuel injection :lol:

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bertvorgon
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Re: Tunning dual Weber's

Post by bertvorgon » 25 Oct 2019 08:54

HA...you may laugh..but...when the Alien invasion comes and they send a massive EMP blast to stop all electronics, I will be driving in my carburetted 510.

We have a local carb guru here who is from Portugal, he is a whiz with tuning.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

Keith Law
1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

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cartel
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Re: Tunning dual Weber's

Post by cartel » 25 Oct 2019 18:21

that must be Paul? hes been at work a few times and done tuning on some vintage race cars-- theres a chassis dyno here
Mike Gibson
Datsun: 71 dime; 73 Z ; GT3 240
Other: 65 + 67 Mustang ; 03 murcie

NunoTT
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Joined: 09 Oct 2018 06:34

Re: Tunning dual Weber's

Post by NunoTT » 28 Oct 2019 14:09

bertvorgon wrote:
25 Oct 2019 08:54
HA...you may laugh..but...when the Alien invasion comes and they send a massive EMP blast to stop all electronics, I will be driving in my carburetted 510.

We have a local carb guru here who is from Portugal, he is a whiz with tuning.
Who is the carb guru?

NunoTT
Posts: 22
Joined: 09 Oct 2018 06:34

Re: Tunning dual Weber's

Post by NunoTT » 28 Oct 2019 14:18

UPDATE:

I removed the covers of the Webers this afternoon, ajusted the fuel level closer to 7.5mm closed. It was around 4-5mm. No wonder I had too much gas :lol: I also changed a gasket since I had brand new set here.

If all goes according to plan, I will reeinstall the covers tomorrow and hopefully the car will run a bit better.

Ps: I haven't tested the fuel pressure yet. I'm still trying to get a fuel pressure gauge.

yenpit
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Re: Tunning dual Weber's

Post by yenpit » 28 Oct 2019 16:31

NunoTT wrote:
23 Oct 2019 00:22
yenpit wrote:
22 Oct 2019 13:33
There are NUMEROUS factors involved, so you can try to narrow it down, but in the end you will either use your "butt dyno" with trial & error, swap jets, drive, diagnose, swap jets, drive, diagnose etc etc...........that's what I did as a kid. The other option is to find a local dyno AND pay somebody with dyno AND Weber experience to help you.....or just let them do their thing!

Where are you located........sea level or altitude? What engine? What specs? What cam? What compression ratio? What ignition system? Based on some of this, most Weber manuals/books have charts with BASIC starting points for your jetting.........BASIC. Then you buy a range of jets based on this & either try your butt dyno OR pay somebody to do it.

Another way that sometimes works is to use an exhaust gas analyzer up the tailpipe OR a simple air fuel ratio GAUGE. These are a good first step & can sometimes get you really close............but running the car on a dyno with a specialist is THE way to go.
I've been trying to find someone with Weber experience, but it's not easy (I don't know why). I could try to tune it on the dyno... I'll try to find one local to me.

I'm located at sea level amd the engine is a stock SSS L16.

I would like to buy an AFR gauge, but I haven't found any that is affordable
Where are you located?? Maybe someone here can help you find a Weber specialist relatively close to where you are...........!! 8)
72 510 4dr
1965 Mustang GT Coupe
2003 Saturn LW300 - wow!
LOTS of 510 parts!

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icehouse
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Location: Everett Wa

Re: Tunning dual Weber's

Post by icehouse » 28 Oct 2019 16:59

510rob wrote:
25 Oct 2019 00:57
That is good humor. Where is H.P. these days anyway?
He stopped by the other day. He seems to be in good spirits. Sold his yellow convertable 510 and his two stroke motor bikes he might have kept one. His girlfriend also lives with him!!!!
"People don't like it when shit doesn't match their rule of thumb." Sam

iceD
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Location: Richmond, B.C.

Re: Tunning dual Weber's

Post by iceD » 28 Oct 2019 21:22

Miguelsss is in Portugal and has some 510 experience

ice D

NunoTT
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Re: Tunning dual Weber's

Post by NunoTT » 29 Oct 2019 00:39

yenpit wrote:
28 Oct 2019 16:31
NunoTT wrote:
23 Oct 2019 00:22
yenpit wrote:
22 Oct 2019 13:33
There are NUMEROUS factors involved, so you can try to narrow it down, but in the end you will either use your "butt dyno" with trial & error, swap jets, drive, diagnose, swap jets, drive, diagnose etc etc...........that's what I did as a kid. The other option is to find a local dyno AND pay somebody with dyno AND Weber experience to help you.....or just let them do their thing!

Where are you located........sea level or altitude? What engine? What specs? What cam? What compression ratio? What ignition system? Based on some of this, most Weber manuals/books have charts with BASIC starting points for your jetting.........BASIC. Then you buy a range of jets based on this & either try your butt dyno OR pay somebody to do it.

Another way that sometimes works is to use an exhaust gas analyzer up the tailpipe OR a simple air fuel ratio GAUGE. These are a good first step & can sometimes get you really close............but running the car on a dyno with a specialist is THE way to go.
I've been trying to find someone with Weber experience, but it's not easy (I don't know why). I could try to tune it on the dyno... I'll try to find one local to me.

I'm located at sea level amd the engine is a stock SSS L16.

I would like to buy an AFR gauge, but I haven't found any that is affordable
Where are you located?? Maybe someone here can help you find a Weber specialist relatively close to where you are...........!! 8)
I'm from Porto, Portugal

NunoTT
Posts: 22
Joined: 09 Oct 2018 06:34

Re: Tunning dual Weber's

Post by NunoTT » 29 Oct 2019 00:41

iceD wrote:
28 Oct 2019 21:22
Miguelsss is in Portugal and has some 510 experience

ice D
Thanks! I'll try to get in touch with him

yenpit
Posts: 1366
Joined: 07 Jul 2006 20:14
Location: Denver Colorado

Re: Tunning dual Weber's

Post by yenpit » 29 Oct 2019 15:23

Well, Portugal would have had quite a few classic European cars that would have run Webers, so focus on finding a classic European shop...........it really doesn't matter that you have a Datsun, cuz Webers are Webers! Wish you luck!

TJ
72 510 4dr
1965 Mustang GT Coupe
2003 Saturn LW300 - wow!
LOTS of 510 parts!

NunoTT
Posts: 22
Joined: 09 Oct 2018 06:34

Re: Tunning dual Weber's

Post by NunoTT » 30 Oct 2019 03:54

yenpit wrote:
29 Oct 2019 15:23
Well, Portugal would have had quite a few classic European cars that would have run Webers, so focus on finding a classic European shop...........it really doesn't matter that you have a Datsun, cuz Webers are Webers! Wish you luck!

TJ

True... I haven't thought of that. Thanks!!

NunoTT
Posts: 22
Joined: 09 Oct 2018 06:34

Re: Tunning dual Weber's

Post by NunoTT » 30 Oct 2019 04:07

UPDATE:

I reinstalled the carb covers yesterday and the car started right up. It now runs MUCH better! No gas dripping out, but it still backfires a bit through the carbs. But I would have to guess that is timming related and/or possibly incorrect valve clearance?

I still have some work to do, but adjusting the fuel level was a HUGE improvement!

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bertvorgon
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Re: Tunning dual Weber's

Post by bertvorgon » 30 Oct 2019 09:46

You are on the right track now.....TUNING....

It goes without saying that the timing needs to be correct and for sure check the valve lash. You cannot begin to jet the carb till you have made sure those are all correct ( you still need to check fuel pressure)

A back fire out of the carb means...it might be a bit lean as you transition from idle to the main circuit.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

Keith Law
1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

NunoTT
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Joined: 09 Oct 2018 06:34

Re: Tunning dual Weber's

Post by NunoTT » 02 Nov 2019 15:41

bertvorgon wrote:
30 Oct 2019 09:46
You are on the right track now.....TUNING....

It goes without saying that the timing needs to be correct and for sure check the valve lash. You cannot begin to jet the carb till you have made sure those are all correct ( you still need to check fuel pressure)

A back fire out of the carb means...it might be a bit lean as you transition from idle to the main circuit.
What timing should I aim for? 10-12 degrees advanced?

I was going to adjust the valve lash and I encountered a rather worrying problem... I was not able to adjust the intake valve lash to 0.20mm (cold engine) because I wasn't able to loosen up the lock nuts. I also almost broke a wrench while trying to loosen it. The lock nuts had a mark of a spanner jumping out, so I assumed the previous owner had the same problem. However I did check the lash and it was spot on 0.25mm, so every valve (intake and exhaust) are set at 0.25mm of lash.

My question is: can this incorrect valve lash contribute to the back fire through the carbs?

Also, if it's lean on the transition from idle to the main circuit, the the problem lies in the progression circuit, correct? But what should I change? Idle jet size? Or just adjust the idle mix screw?

Anyway, many thanks for your help!!

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