PLUGS

Can I have an expert opinion please.
this is after 1 hour running, problems encountered were: slight backfiring when accelerating hard, it would idle fast, turn the screw out and it would idle fine then die, turn screw in and repeat process.
thanks guys.

 

I'm no expert, but I've been messing with mine for 4 weeks.
I would say #1 is right on 2 and 4 need to be leaned out.
#3 looks close to fouled.
Maybe it dies when you turn the idle down because you're running rich.

 

How many turns out were you on all of them is sequence?1-4?

 

1 is too lean

2 looks ok

3 is too rich

4 looks ok

 

set all at 2&3/4 turns at carb sync, was getting a poppety popping, so turned all 4 to 3 turns, no real thought other than to enrich.
some history here, when i got the bike there were caps on all 4 carb boot spiggots and the petcock was on prime, i had an idea that something was amiss. my very first post on this site was asking about pipes to the petcock.
now when you look at the state of # 3 plug, you must think there is some connection, is there a problem with the petcock?

 

simple test: set petcock on PRI, block off the vacuum nipple on #3 just like the others. clean or replace #3 plug. go for a ride.

...see if anything changes.

if the diaphragm in the petcock is damaged, I suppose you might be pulling in some fuel through the vacuum line.

 

i have cleaned the plugs and connected the vacuum line to # 4, will ride later and post results, cheers, 2brains.

 

Have set 2-3&4 to match 1 using Ricks fuse method, hardly moved a hair, vacuum tube is now on # 4, this is the result after riding for 3/4 hour.

 

#3 still loooks a bit lean

Might verify that the petcock diaphram is not letting fuel pulled into #4 through the vac line. I've only had one do it where the PO had installed a diaphram and had a hole in it near center.

 

looks like the petcock might need some further investigation...

 

x2

1&2 look good, besides the blurryness. Might wanna get that chked

 

wow, that's amazingly similar to my 1982 SECA.
plug#3 is black soot & I have been assuming that it's float issues...until I swear by moving the petcock to something other than RUN, it seems to alter how it runs..as in better
hmmm

 

today I will ride on prime with the vac' line clamped.
will post results.

 

Cheers Ass. I forgot to turn on the MACRO!

 

by moving the vac line from carb to carb & the fouled plug following faithfully behind, I yanked the petcock, sure enough, pinhole.
Problem now is, to get over this without spending too much.

 

What is Rick's fuse method? Did I miss an excellent read?

 

Sadly, I did the petcock test on my 82' SECA, which is exhibiting the same plug fouling: BUT mine passed the test.
Petcock seems fine.

The sad part, is now I'm pulling the carbs I guess to look at floats..
I'd rather have worked on the petcock...
Rich

 

Rick's Fuse Method: Find a plug that you like, that carb is set-up right.
Drop a glass tube fuse into the pilot screw hole, and mark a line on the fuse, now using the fuse as a ruler, adjust the other 3 pilot screws.

This would still just be a base-line setting; finish dialing in using plug reads, as Rick says, in 3 degree increments, because you're almost home at this point.

This method assumes that you will be able to precisely read your own mark with carbs on the bike, and that all carburetor components are machined identically.

 

I moved the vac' line from 3 to 4 & the fouling followed the vac (clue)
you might just be rich on that one pot. Let us know how it turns out .Wiz.

 

If the fouling follows the placement of the Petcock Vacuum Line ... that is a sure indication that the Vacuum Membrane is punctures and allowing Fuel to be sucked in through the Manifold under vacuum.

Take off the Vacuum Line from the Manifold Fitting.
Place the Vacuum Line to your lips and draw a vacuum on the hose.
If you taste Fuel ...
Your Petcock is to blame ... the Vacuum side is leaking.