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Discussion Starter · #1 ·
If you have triples , what model are they , do they have a welch (freeze) plug directly behind the idle mixture screw or do they have a threaded plug? If there is a threaded plug please remove it and tell me how many progression holes you see and the carb model # and any tunning troubles you may have had. I am chasing a bug please help.
 

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> If you have triples , what model are they ,
> do they have a welch (freeze) plug directly
> behind the idle mixture screw or do they
> have a threaded plug? If there is a threaded
> plug please remove it and tell me how many
> progression holes you see and the carb model
> # and any tunning troubles you may have had.
> I am chasing a bug please help.

45mm Webers (36chokes), I'll have to check about the welch plug. I do remember when installing them, that they had 4 progression holes. I bought these brand new 3 years ago. I believe the older DCOE's had 3 progression holes. No major tuning troubles, except for re-jetting. I found that the idle jet needs to be what seems like excessively rich. This is because of the large choke size, which prevents proper airflow at low rpms to draw fuel out the main circuit. Thus, the idle circuit needs to dump more fuel in order to have a somewhat 'linear' progression circuit. I'm running 65F9 idles w/ 155 mains. No major problems for me.

Dave
 

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Discussion Starter · #3 ·
> 45mm Webers (36chokes), I'll have to check
> about the welch plug. I do remember when
> installing them, that they had 4 progression
> holes. I bought these brand new 3 years ago.
> I believe the older DCOE's had 3 progression
> holes. No major tuning troubles, except for
> re-jetting. I found that the idle jet needs
> to be what seems like excessively rich. This
> is because of the large choke size, which
> prevents proper airflow at low rpms to draw
> fuel out the main circuit. Thus, the idle
> circuit needs to dump more fuel in order to
> have a somewhat 'linear' progression
> circuit. I'm running 65F9 idles w/ 155
> mains. No major problems for me.

> Dave
I have 40mm with 30mm chokes on daily driver stock w/header,tried F945-55 idles mains from 110-130,even tried 28mm chokes and still have popping and dogging during transition. Do I try smaller chokes? Is excessive richness unavoidable?
 

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Usually means sychronization problem

> I have 40mm with 30mm chokes on daily driver
> stock w/header,tried F945-55 idles mains
> from 110-130,even tried 28mm chokes and
> still have popping and dogging during
> transition. Do I try smaller chokes? Is
> excessive richness unavoidable?

Are you running a L28 or L24/26?? I ran 30 chokes in my 45's for about 3 weeks. I used 130mains, and 60-F8? idles. Car had much better response than my current setup, although it didn't like to go above 5500rpm. With my new cam (275 duration/.450), I needed the bigger chokes, and richer jets.

Sounds more like a sychronization problem, more than a jetting problem. I can't tell you how many times, someone has complained to me about a popping, and hesitation. Almost 95% of the time, this was a sychronization problem. Are your carbs old or new? If they are old, you may have bent throttle shafts. You might also want to try taking them apart, and blowing air through all the passages. These can become clogged over time. Remember, under 3000rpm, you are going to rely heavily on the idle circuit. It feeds the progression circuit, and is wholly responsible for off-idle transition. If your car runs fine from 3000 up, then you know where to concentrate your efforts. Your choke size sounds fine. Usually, guys run 26-30 for L24/L26, and 32-36 for L28. But anywhere along those lines will work well. Actually, the smaller chokes will help the main circuit come on sooner, due to the higher velocity at lower engine speeds. This is why my car made more low-end power with the 30 chokes, compared to the 36 chokes now.
 

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> I have 40mm with 30mm chokes on daily driver
> stock w/header,tried F945-55 idles mains
> from 110-130,even tried 28mm chokes and
> still have popping and dogging during
> transition. Do I try smaller chokes? Is
> excessive richness unavoidable?

I'm going to take a stab here also, I know with Mikuni carbs if the pilot jet is too small it can cause poping and backfire from 0-20% throttle.
The Idle jet in the weber does the same thing. Also I wonder what your using to sync the carbs. There is a far better way then using the airflow tool called the unisync gauge but you need to have a vacume access to each carb to use a Manometer and I'm not sure what your manifold is like but I'd get this tool and drill and tap some in if I had them and I'd get a Manometer to sync your carbs. You will be able to do a much better job of it and far less time. It's used at every motorcycle shop and cycle dealers sell them. Mikuni recomended them to me and it's been a life saver for my Mikuni's and I try to recomend them to any tripple or dual carb user on here. If the weber has a vacume port on the carb so much the better but I don't think they do so it has to be done at the manifold. The good thing is with these carb setups you only have to set up 3 access ports if need be, like cyl 1,3,5 or 2,4,6. it's nicer to have all 6 though so you can check each carb for individual throttle shaft sync, it's a good thing to check with old or used carbs, I had a nightmare syncing mine till I checked this and found a twisted shaft that kept one carb from syncing. It doesn't take much with these types of carbs either. This can also be checked with the unisync gauge, it's all I think that tool is good for personally.
 

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Discussion Starter · #6 ·
> I'm going to take a stab here also, I know
> with Mikuni carbs if the pilot jet is too
> small it can cause poping and backfire from
> 0-20% throttle.
> The Idle jet in the weber does the same
> thing. Also I wonder what your using to sync
> the carbs. There is a far better way then
> using the airflow tool called the unisync
> gauge but you need to have a vacume access
> to each carb to use a Manometer and I'm not
> sure what your manifold is like but I'd get
> this tool and drill and tap some in if I had
> them and I'd get a Manometer to sync your
> carbs. You will be able to do a much better
> job of it and far less time. It's used at
> every motorcycle shop and cycle dealers sell
> them. Mikuni recomended them to me and it's
> been a life saver for my Mikuni's and I try
> to recomend them to any tripple or dual carb
> user on here. If the weber has a vacume port
> on the carb so much the better but I don't
> think they do so it has to be done at the
> manifold. The good thing is with these carb
> setups you only have to set up 3 access
> ports if need be, like cyl 1,3,5 or 2,4,6.
> it's nicer to have all 6 though so you can
> check each carb for individual throttle
> shaft sync, it's a good thing to check with
> old or used carbs, I had a nightmare syncing
> mine till I checked this and found a twisted
> shaft that kept one carb from syncing. It
> doesn't take much with these types of carbs
> either. This can also be checked with the
> unisync gauge, it's all I think that tool is
> good for personally.

Dave and BW I really appreciate all of your help and I guess my next step is to sync sync sync. I have no vac. ports so I,ve been using
unisync and have noticed that the two throats
on each carb are not reading the same.
I can drill ports and sync with a manometer
but, what do I do if a throttle shaft is bent?
Must I replace it? Can it be tweaked back or
is that a no no?

Once again, thanks........I've been recieving
more help in the past few days here than on the telephone in the past six months!!!
 

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Discussion Starter · #7 ·
> Dave and BW I really appreciate all of your
> help and I guess my next step is to sync
> sync sync. I have no vac. ports so I,ve been
> using
> unisync and have noticed that the two
> throats
> on each carb are not reading the same.
> I can drill ports and sync with a manometer
> but, what do I do if a throttle shaft is
> bent?
> Must I replace it? Can it be tweaked back or
> is that a no no?

> Once again, thanks........I've been
> recieving
> more help in the past few days here than on
> the telephone in the past six months!!!

240 SIX PACK
 
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