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Author Topic: Spark plug signs  (Read 15488 times)

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Offline flybox1

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Re: Spark plug signs
« Reply #75 on: September 26, 2016, 06:35:12 AM »
Quote from: jebon on September 25, 2016, 11:24:33 PM
Ok, I'll leave it then. Mostly town riding. It spits a little at idle. I think maybe because my new float seat is one step up from original. Don't remember the number.

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Dont leave it.  get it right.
Those deposits are from your average throttle position.  If its spitting at idle, then its not correct at idle. 
You have idle mixture screws to adjust for this reason.
Do an idle plug chop. See what color your plugs are, and adjust as needed.  Its the easiest one to do.  No reason not to do it.
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Offline jebon

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Re: Spark plug signs
« Reply #76 on: September 26, 2016, 01:02:45 PM »
You're right, thank you! Believe me, I want to get it right.

Also I'm learning all the time. I thought the mixture screws were general mixture. Not idle only. There you go.

I'm one turn out. Could it be that the float seat is 2.5 and not 2.0?

My problem right now is that there are some variables in the equation that are difficult and I need to fix these first to get it right.

1. There IS a chance I have a small leak in the rubber manifolds. I tried spraying them with brake cleaner and the idle changed a bit. But it could have sucked in fumes via the air box. What is a bulletproof way of checking for leaks? I want to change the manifolds and the straps but this kit will set me back $230.- which I don't have right now. I need to change these to tick off that one.

2. I tried synchronizing the carbs with the kit I bought but I suspect the kit to be broken because one gauge gives me very low reading to no reading and when I switch the tubes around it reads the same. I've contacted them to see if they'll replace it.

Also as you can see in some of the previous pictures, the carb  cylinder slides are pretty scratched and I don't if that will influence reading and/or performance.

So, I which order would you tackle these things? The manifolds are a no-brainer but can I do anything before these things are fixed?

Thank you for your patience with me!
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Offline flybox1

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Re: Spark plug signs
« Reply #77 on: September 26, 2016, 01:25:16 PM »
Quote from: jebon on September 26, 2016, 01:02:45 PM
You're right, thank you! Believe me, I want to get it right.

Also I'm learning all the time. I thought the mixture screws were general mixture. Not idle only. There you go.

I'm one turn out. Could it be that the float seat is 2.5 and not 2.0?  If they shut off fuel from overflowing out your bowls, i think youre ok.

My problem right now is that there are some variables in the equation that are difficult and I need to fix these first to get it right.

1. There IS a chance I have a small leak in the rubber manifolds. I tried spraying them with brake cleaner and the idle changed a bit. But it could have sucked in fumes via the air box. What is a bulletproof way of checking for leaks? I want to change the manifolds and the straps but this kit will set me back $230.- which I don't have right now. I need to change these to tick off that one. $230?!?!? post a link to what thsi is.  might be able to find a better option

2. I tried synchronizing the carbs with the kit I bought but I suspect the kit to be broken because one gauge gives me very low reading to no reading and when I switch the tubes around it reads the same. I've contacted them to see if they'll replace it. Sounds more like your bench sync of your slides is off, or possibly that slide is installed backwards..

Also as you can see in some of the previous pictures, the carb  cylinder slides are pretty scratched and I don't if that will influence reading and/or performance.  No, its fine.

So, I which order would you tackle these things? The manifolds are a no-brainer but can I do anything before these things are fixed?

Thank you for your patience with me!
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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

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Offline jebon

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Re: Spark plug signs
« Reply #78 on: September 26, 2016, 02:03:18 PM »
I forgot. It has left a puddle once in this setup. I was on the reserve tank and was filling it up when it happened. Prices for rubber manifolds (OEM) are from davidsilverspares.co.uk and cmsnl.com My problem is that unless I order from within the EU, I have to pay +25% of the goods including shipping plus a $25 fee. The slides have a small tab. I believe they can only be installed one way. How can it be something on the carbs when I tried putting a different carb on that gauge and it behaves the same?
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Offline flybox1

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Re: Spark plug signs
« Reply #79 on: September 26, 2016, 02:06:01 PM »
What type sync gauges do you have?  Liquid or dial?
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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline jebon

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Re: Spark plug signs
« Reply #80 on: September 26, 2016, 02:06:59 PM »
Quote from: flybox1 on September 26, 2016, 02:06:01 PM
What type sync gauges do you have?  Liquid or dial?
Dial
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Offline flybox1

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Re: Spark plug signs
« Reply #81 on: September 26, 2016, 02:12:37 PM »
So youve got 3 working dials and one not working.  There might be a brass dial screw on the face of your gauges.
If there is....
Take the reading for carb #1 vacuum with any of the working dials.....write the # down.
Put the non-working carb hose on #1 carb, remove the dial cover, and turn the dial sync screw to see if it was too far out to get a reading.
If it starts to move, set it the same as the # you wrote down.
Do this to the other 2 good dials so all four read the same vacuum off your #1 carb.

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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline flybox1

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Re: Spark plug signs
« Reply #82 on: September 26, 2016, 02:16:04 PM »
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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline jebon

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Re: Spark plug signs
« Reply #83 on: September 26, 2016, 02:16:54 PM »
Thank you. I'll try this. But I need to rule out a possible manifold leak first, right?
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Offline jebon

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Re: Spark plug signs
« Reply #84 on: September 26, 2016, 02:21:05 PM »
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Offline flybox1

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Re: Spark plug signs
« Reply #85 on: September 26, 2016, 02:23:56 PM »
No.  Its not necessary as the actual value of each carb vacuum is irrelevant (unless zero). 
Only that all carbs have the same vacuum is important. 
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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline jebon

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Re: Spark plug signs
« Reply #86 on: September 26, 2016, 02:31:35 PM »
Quote from: flybox1 on September 26, 2016, 02:23:56 PM
No.  Its not necessary as the actual value of each carb vacuum is irrelevant (unless zero). 
Only that all carbs have the same vacuum is important.
Do you recommend cooling it with a fan when syncing? It's idling higher when I have the dials on it
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Offline flybox1

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Re: Spark plug signs
« Reply #87 on: September 26, 2016, 02:35:34 PM »
Yes, fan on always.
If the idle goes up, just turn it down to normal levels with the idle set screw.
I have good friends from Solrod Strand.....its late night there. lol
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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline jebon

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Re: Spark plug signs
« Reply #88 on: September 26, 2016, 02:43:39 PM »
I'll get a fan. Solrød strand is about 3 hours from where I live (that's actually considered far by Danish measures :)
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Offline jebon

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Re: Spark plug signs
« Reply #89 on: May 07, 2017, 07:53:07 AM »
Hi guys. Just want to say thanks and close this one as I'm taking it to a mechanic. I don't want to spend a whole other season troubleshooting this. However, I ran into an electrical problem yesterday but I'll start a new thread on this.
/Jess
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Offline jebon

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Re: Spark plug signs
« Reply #90 on: April 14, 2018, 12:35:10 PM »
Just for the record, I can not recommend these.
18 months and they're cracked.
Gonna buy originals  ;)
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