Register Login
Lamps by Post - For all your lighting needs
Reply
 
Thread Tools
Old 1 Week Ago   #31
Join Date: Mar 2017
Posts: 14
Thanks: 0
Trader Rating: 0
USA 
Re: weber 26 carb rebuild / tuning

Carb is indeed bend at the bottom flange and the top cover.
I saw the posting about straightening thing out but am just looking at other options too.
As mentioned, the car came with the 26 IBM 3 carb (have the 004 sport engine) What other carbs could I use. Can I use the 28 mill carb from the 126 for example?
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

reneb is offline Reply With Quote Quote 
Old 1 Week Ago   #32
Join Date: Jun 2009
Posts: 488
Thanks: 42
Trader Rating: 0
United Kingdom 
Re: weber 26 carb rebuild / tuning

I guess that it comes down to how much you want to retain the original parts and engine specification. You could fit any of the other 26IMB carbs from the 500 range which would be a slight detune on a 500 sport engine but look original. The 28IMB carbs from the 126 have a Venturi 1mm larger than the 500 Sport carb and with the right jetting may give a tune up but it is a straight bolt on and would probably benefit from a modified Bakelite spacer.
Personally I would do my utmost to revive the original carb as the bottom flange can be sorted with care. Top cover can be replaced if necessary. The Venturi size is machined into the main body so cannot be exchanged. Some standard size carbs have been refurbished and the body bored out to match the 500 Sport carb but I do not know if there are any available at the moment.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

Toshi 975 is offline Reply With Quote Quote 
Old 1 Week Ago   #33
Join Date: Mar 2017
Posts: 14
Thanks: 0
Trader Rating: 0
USA 
Re: weber 26 carb rebuild / tuning

Thanks for the info. I am learning a lot about these weber carbs through this forum. I did not realize that these 26 IMB 3 are "rare" and as such I will try to repair this carb. and keep the car original.
If that fails I am considering the 28 IMB carb since I definitely do not want to reduce power by going to a standard 26 IMB 10 which are readily available! This car is new to me and I am finding out more about it every day. Compression for example is higher than original at about 125 PSI so I trust that a former owner did some work to the engine.
I guess it is therefore safe to assume that the car may benefit from a little more carb.
If you have more suggestion on jet sizing I would welcome the info or any other suggestions you may have.
Thanks again
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

reneb is offline Reply With Quote Quote 
Old 1 Week Ago   #34
Join Date: Jun 2009
Posts: 488
Thanks: 42
Trader Rating: 0
United Kingdom 
Re: weber 26 carb rebuild / tuning

I have never had the opportunity to work on a 500 Sport engine so they are a bit of an unknown to me. I did see in the manual that the engine had an 8.6-1 compression ratio compared with the 7.1-1 on the D models. The Fiat workshop manual only shows drawings of the standard engine but at a guess I would say that they ran high compression Pistons. I do not know if an illustrated parts book exists for the Sport as it would be most interesting.
The early 126 carbs shared a lot of the same jet sizes with the Weber 26IMB3.
Likes fiat500 liked this post
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

Toshi 975 is offline Reply With Quote Quote 
Old 1 Week Ago   #35
Join Date: Mar 2017
Posts: 14
Thanks: 0
Trader Rating: 0
USA 
Re: weber 26 carb rebuild / tuning

Thanks Toshi,
So my plan is to revive the 26 IMB3 carb. If that fails I'll install the 28 IMB which is probably a better match to my engine than a standard 26 IMB 10.

I'll give you guys an update after I am done. Can't wait to have this Autobianchi Bianchina Transformabile back on the road.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

reneb is offline Reply With Quote Quote 
Old 3 Days Ago   #36
Join Date: Mar 2017
Posts: 14
Thanks: 0
Trader Rating: 0
USA 
Re: weber 26 carb rebuild / tuning

I was able to sort out my Weber carb 26 IMB 3
The bottom flange was severely bend as was the to cover.
I was able to get most of that corrected by squeezing them in a vice between 2 smooth metal plates.
I ended machining the bottom flange to get it perfectly straight.
New gasket did the rest.

Glad you guys convinced me to save this carb which is irreplaceable and original to the car.

The information on this forum was very helpful in the process.

Thanks again
Likes F123C, BambinoClassic liked this post
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

reneb is offline Reply With Quote Quote 
Old 2 Days Ago   #37
Join Date: Jun 2009
Posts: 488
Thanks: 42
Trader Rating: 0
United Kingdom 
Re: weber 26 carb rebuild / tuning

That is great news
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

Toshi 975 is offline Reply With Quote Quote 
Old 2 Days Ago   #38
Join Date: Jul 2012
Posts: 1,328
Thanks: 98
Trader Rating: 0
United Kingdom 
Re: weber 26 carb rebuild / tuning

Out of the blue, I have just (today!) been given a copy of the early 'Haynes' workshop manual for the 500--which includes the '500 Sport'. Would you like me to go through it and see if I can come up with any relevant info regarding the car, and particularly the carb?
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

the hobbler is offline Reply With Quote Quote 
Old 2 Days Ago   #39
Join Date: Apr 2013
Location: Athens
Posts: 354
Thanks: 10
Trader Rating: 0
Greece 
Re: weber 26 carb rebuild / tuning

Quote Originally Posted by JakeF View Post
Any gasket or o-ring etc(red arrow)?
Unfortunately my repair kit didn't include this little seal. So i have put epoxy glue all around to seal it. Is this part avail?
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

gordinir8 is offline Reply With Quote Quote 
Old 2 Days Ago   #40
Join Date: Jan 2014
Location: SE Ireland
Posts: 419
Thanks: 46
Trader Rating: 0
Ireland 
Re: weber 26 carb rebuild / tuning

Quote Originally Posted by gordinir8 View Post
Unfortunately my repair kit didn't include this little seal. So i have put epoxy glue all around to seal it. Is this part avail?
You could use an 'o' ring from one of those inexpensive selection boxes but it's likely to be made from a type of rubber (Butyl?) that not Ethanol resistant. I think you ideally need the Viton type? But in this application, you might get away with the cheap type?

Another source of small rubber type 'o' rings is motorcycles, especially older Japanese ones, they supply lots of O rings in engine gaskets sets and carb kits

Al.
__________________
The more you know, the less you need.

If what I write is helpful please click on the 'thanks' button, (smiley face on lower right).
F123C is offline Reply With Quote Quote 
Old 1 Day Ago   #41
Join Date: Apr 2013
Location: Athens
Posts: 354
Thanks: 10
Trader Rating: 0
Greece 
Re: weber 26 carb rebuild / tuning

If it is just an o ring then no problem I will find one, I thought it was square or something. Thank you
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

gordinir8 is offline Reply With Quote Quote 
Old 1 Day Ago   #42
Patinated Peter
 
fiat500's Avatar
Join Date: Mar 2005
Location: Nairn
Posts: 3,352
Thanks: 155
Trader Rating: 0
fiat500 has donated!
United Kingdom 
Re: weber 26 carb rebuild / tuning

Thomas, you're correct, it is a thick nylon washer and squarish in section.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

fiat500 is online now Reply With Quote Quote 
Old 1 Day Ago   #43
Join Date: Jan 2014
Location: SE Ireland
Posts: 419
Thanks: 46
Trader Rating: 0
Ireland 
Re: weber 26 carb rebuild / tuning

Quote Originally Posted by fiat500 View Post
Thomas, you're correct, it is a thick nylon washer and squarish in section.
Hi Peter,

I don't remember any nylon washers being used on Weber carbs fitted to Fiats back in the day. Copper? yes, Aluminium? yes, rubber 'O' rings? yes (depending on location). Are you sure the thick nylon washer is not a later alternative to a rubber 'O' ring, possibly to withstand attack from Ethanol fuel?

I'm not contradicting you, just curious.

Al.
__________________
The more you know, the less you need.

If what I write is helpful please click on the 'thanks' button, (smiley face on lower right).
F123C is offline Reply With Quote Quote 
Old 23 Hours Ago   #44
Patinated Peter
 
fiat500's Avatar
Join Date: Mar 2005
Location: Nairn
Posts: 3,352
Thanks: 155
Trader Rating: 0
fiat500 has donated!
United Kingdom 
Re: weber 26 carb rebuild / tuning

Al, I have never separated the washer but this question has come come up before. I'm away from home so can't check, but it's not metallic or rubber and it's not thick and hard . I'm talking about the 26IMB4.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

fiat500 is online now Reply With Quote Quote 
Old 15 Hours Ago   #45
Patinated Peter
 
fiat500's Avatar
Join Date: Mar 2005
Location: Nairn
Posts: 3,352
Thanks: 155
Trader Rating: 0
fiat500 has donated!
United Kingdom 
Re: weber 26 carb rebuild / tuning

I meant to say the washer is quite thick and a hard plastic type material and relatively square in section....this annoying phone types it's own words for me.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

fiat500 is online now Reply With Quote Quote 
Reply
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump
Similar Threads
Thread Thread Starter Forum Replies Last Post
(G) weber carb info panda racer Panda (Classic) 2 17-03-2017 17:08
(T) Weber Rebuild Giacosa Panda (Classic) 13 11-01-2011 01:01
(T) Weber 28 Carb Dos2 500 (Classic) 2 21-03-2010 13:17
(T) Weber carb INsantiy Tipo (Classic) 9 19-06-2006 13:18