Author Topic: Weber carb set-up (Read 151732 times)

scottly · « **Reply #250 on:** April 18, 2013, 05:18:37 PM »

Quote from: Tintop on April 18, 2013, 09:37:08 AM

Progression holes in my 40DCOE 149's. Notice that they are different sizes and pattern is staggered. The first (big one) is uncovered with with hardly any shaft movement (1 1/2 turns of idle screw),

Here is a picture of an 18. I found that the first hole is also uncovered at about 1 1/2 turns from fully closed plates. I looked at another 18, and the holes were in the same position. Both carbs had other differences; one has an un-drilled boss where yours has the sync port, while the other one doesn't. Also, the tipo font is slightly different. Neither carb has a proper serial number; one has 2F stamped into the pad, and the other is completely blank. I'm wondering if only the carbs used by the OEMs have serial numbers, and the ones sent to the aftermarket did not?

scottly · « **Reply #251 on:** April 18, 2013, 05:29:16 PM »

Quote from: Tintop on April 18, 2013, 02:52:07 PM

Figure this thread is becoming a Weber FAQ scotty so bare with me

Fine with me! I started this thread so information about these wonderful carburetors could be shared. Hell, I'm learning a lot lately myself!!

Tintop · « **Reply #252 on:** April 18, 2013, 08:12:20 PM »

Humm....interesting photo scotty. The hole pattern in your 18 looks the same as my 149, wonder if they are the same sizes?? I wouldn't doubt Weber reused progression hole patterns over the years, with different engines to solve a similar transition issue. That 18 also doesn't have the sync hole (between the cold start & idle holes), and because there's no provision, the air corrector hole that is in my photo. Also interesting that one '18' would have the sync hole & one wouldn't.

Not sure about the numbers. Don't think they ever had 'serial numbers', just size, type & version eg 40 (size) / DCOE (type) / version (18). Not sure about the second set of numbers eg 2F. Was once told that the letter stood for the manufacturer eg F (Fiat / Ford / Ferrari??), so you could be right about one without being aftermarket.

scottly · « **Reply #253 on:** April 18, 2013, 08:26:29 PM »

The carbs on my bike have proper serial numbers stamped into the pad below the one with 40DCOExx. The serial numbers are close, so I believe they came from the same car, perhaps an Alfa? Since it ain't broke, and I have a road trip coming up soon, I'm not going to pull my carbs and compare the progression holes.

I do suspect that they probably have the same as the others.

scottly · « **Reply #254 on:** April 26, 2013, 08:48:01 PM »

I woke my bike up from it's long slumber and paid particular attention to the exhaust: whacking open the throttle produced a puff of black smoke. Playing with the throttle, I could somewhat duplicate the loading-up I have experienced in stop-and-go traffic. I believe this confirms that I need to use larger discharge jets. The question is how much larger than the 55s?

Tintop · « **Reply #255 on:** April 27, 2013, 12:19:24 PM »

Quote from: scottly on April 26, 2013, 08:48:01 PM

I woke my bike up from it's long slumber and paid particular attention to the exhaust: whacking open the throttle produced a puff of black smoke. Playing with the throttle, I could somewhat duplicate the loading-up I have experienced in stop-and-go traffic. I believe this confirms that I need to use larger discharge jets. The question is how much larger than the 55s?
[/quote

Do you know what the throttle plate position is when the loading up occurs??? Maybe the loading is related more to the progression holes than the accel pump.

scottly · « **Reply #256 on:** April 27, 2013, 07:46:28 PM »

The loading up occurs when the throttle is being opened and closed repeatedly, without revving more than 3K RPM. It has occurred with both the 40 and 45 idle jets. It's not a major problem, but a niggling bother that I think I've finally figured out. I'm not going to change anything until I hear how your new set-up works.

BPellerine · « **Reply #257 on:** May 04, 2013, 05:52:51 PM »

Here are some pics of the weber setup that I bought .They are 38dcoes off of a 750.I am happy to be getting them.any thoughts comments would be welcome guys.Wont know full details until they come in the mailbox.What have I gotten myself into now!ha ha bill

http://i2.photobucket.com/albums/y33/pellersw/750motor.jpg
http://i2.photobucket.com/albums/y33/pellersw/750motor037.jpg

scottly · « **Reply #258 on:** May 04, 2013, 06:18:00 PM »

38DCOEs are very rare! Those were used on some Ferrari's.

scottly · « **Reply #259 on:** May 04, 2013, 06:29:42 PM »

Bill, those pics are a bit small. Anyway you could enlarge them?

754 · « **Reply #260 on:** May 04, 2013, 06:42:14 PM »

Thatisamysteryma ifold,not what you thought. I have one on a display motor. May be the. Same one I saw at Drag Bike Eng in Calif in the eighties.
The nice part, you can mount linkage to. Rod ends on those two tapped bosses..with rod endsto carbs..be easy to adjust.. Get the aircleaners just in case.

Welcome to the Italian Squirter club..

scottly · « **Reply #261 on:** May 04, 2013, 06:46:29 PM »

Almost looks like an MPD manifold, but with the carb mounting face straight across, like an RC? Hard to tell from those pics.

Tintop · « **Reply #262 on:** May 04, 2013, 06:51:47 PM »

I had 38's on a built 1275 in a Mk2 Sprifire. Great carb, should work very well an a 750. Definitely replace the bushings with rod ends for the throttle shaft.

+1 on it looks like am MPD.

754 · « **Reply #263 on:** May 04, 2013, 06:59:51 PM »

Tis straight,and has the two tapped bosses.. I have that one..

BPellerine · « **Reply #264 on:** May 04, 2013, 07:06:16 PM »

thanks guys those are sellers pics will get better ones when they get here.even with my limited knowledge I too did not think it was rc looks like single cable pull but I cannot see that well.going to get filters if seller can get them in the box nice guy to talk to .thanks guys I feel like a kid again !bill

scottly · « **Reply #265 on:** May 04, 2013, 07:14:59 PM »

I'm guessing the 38s take different chokes, auxiliary chokes, and stacks than the 40's, but the jets etc would interchange with those in 40s?

754 · « **Reply #266 on:** May 04, 2013, 07:21:46 PM »

I did some research on them a while back..i think alot of40 parts fit. ..i think they are pretty rare.

Tintop · « **Reply #267 on:** May 04, 2013, 07:32:49 PM »

Quote from: scottly on May 04, 2013, 07:14:59 PM

I'm guessing the 38s take different chokes, auxiliary chokes, and stacks than the 40's, but the jets etc would interchange with those in 40s?

+1 Those maybe the hard stuff to find, if changes are needed.

scottly · « **Reply #268 on:** May 04, 2013, 07:35:51 PM »

According to the Haynes book (take that with a grain of salt, as I never would have come to my settings, had it been my resource at the time) the 38s were used on the Ferrari 365 GTC/4 and 400 GT.

Tintop · « **Reply #269 on:** May 04, 2013, 07:47:54 PM »

BPellerine - Try giving these guys a call regarding a rebuild kit, your going to need one. http://www.piercemanifolds.com/

Very helpful, better pricing than you'll get from a Canadian source (even with shipping USPS).

754 · « **Reply #270 on:** May 04, 2013, 09:32:16 PM »

Must be a common one, look at this..lol

BPellerine · « **Reply #271 on:** May 05, 2013, 04:43:46 PM »

Thanks for the pic frank that is the manifold in the pictures I have I can zoom on the pictures he sent me and there are no markings on it.I too did a little digging around and it seems that most removable parts fit the 40s so I may be okay in that regard.where are these guys located tintop? another question frank what mounting rubbers do these use? Scottly I will be asking a lot of questions so I hope you have patience.ha ha.bill

754 · « **Reply #272 on:** May 05, 2013, 05:14:06 PM »

I have the right hose to cut the rubbers..wait till you fit them ..probably 1.25 - 1.5 length.

scottly · « **Reply #273 on:** May 05, 2013, 05:35:48 PM »

What sort of hose are you using, Frank? The fuel pump hose I'm using is a tight fit on the MPD manifold, and requires two horses and some cussing to get on.

754 · « **Reply #274 on:** May 05, 2013, 05:47:32 PM »

It is a blue silicone hose like used on turbos.. But they usually sell a min of 4 feet.

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Author Topic: Weber carb set-up (Read 151732 times)