Amal throttle valves
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Piero
According to the Amal website
"Throttle Slides
Throttles Slides are stamped with their identifying size on the bottom surface. Typical markings will be either 622 for a 600 Series slide, 928 for a 900 Series slide, an MB number which is a foundry mark, and a stamped number from 2 to 5 indicating the height of the cutaway on the inlet side of the slide."
A "Foundry" is a facility where the slide would have been cast or machined.
Peter
According to the Amal website
"Throttle Slides
Throttles Slides are stamped with their identifying size on the bottom surface. Typical markings will be either 622 for a 600 Series slide, 928 for a 900 Series slide, an MB number which is a foundry mark, and a stamped number from 2 to 5 indicating the height of the cutaway on the inlet side of the slide."
A "Foundry" is a facility where the slide would have been cast or machined.
Peter
Hi Peter,
I mean, but my 928 cut 3 MB3 and 928 cut 3 MB 4 have difference each other .
The arc of MB4 finish in plane both side, the midle of the arc is a little bit higher.
If you put both at the end of the carb there is not the same measure.
Thank yiu
Piero
I mean, but my 928 cut 3 MB3 and 928 cut 3 MB 4 have difference each other .
The arc of MB4 finish in plane both side, the midle of the arc is a little bit higher.
If you put both at the end of the carb there is not the same measure.
Thank yiu
Piero
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- Feb 14, 2013
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Piero
I think I understand the question now.
I would not expect the cutaway(arc) to be different between your two slides.
The MB number indicates that the slides were cast at two different foundries(factories), but the cutaway profile should be described by the number stamped 3 on your slides.?
Of course, the accuracy of many parts from the suppliers is often not good, perhaps the slide cutaway has been wrongly marked as a 3?
Could a previous owner have modified the slide?
I think you would be better to have each slide with the same cutaway(arc), so you may have to buy another slide.
If you search for "Throttle slides" on the forum you will see the question was asked before, in 2004, but not really answered.
Peter
I think I understand the question now.
I would not expect the cutaway(arc) to be different between your two slides.
The MB number indicates that the slides were cast at two different foundries(factories), but the cutaway profile should be described by the number stamped 3 on your slides.?
Of course, the accuracy of many parts from the suppliers is often not good, perhaps the slide cutaway has been wrongly marked as a 3?
Could a previous owner have modified the slide?
I think you would be better to have each slide with the same cutaway(arc), so you may have to buy another slide.
If you search for "Throttle slides" on the forum you will see the question was asked before, in 2004, but not really answered.
Peter
Hi Peter,
I completely agree with you.
In fact i askwd to my supplier to send me two cut 3 eirh the same cut way from the same factory.
But believe me, i have two theottle 928 3 (nothing else stamped on) that have differences in the cut and also at the bottom eith different cast.
Ciao
Piero
I completely agree with you.
In fact i askwd to my supplier to send me two cut 3 eirh the same cut way from the same factory.
But believe me, i have two theottle 928 3 (nothing else stamped on) that have differences in the cut and also at the bottom eith different cast.
Ciao
Piero
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Very common to ' tune ' with file , slides once - 1950s .
Carving to get both as larger cutout no trouble .
check the other dimensions first - if all other same , match cutouts .
http://triumphbonneville120.co.uk/amal.php
http://www.jba.bc.ca/Bushmans%20Carb%20Tuning.html
tho these are two stroke fitment . Fine tune to suit . Saves throwing them out .
Carving to get both as larger cutout no trouble .
check the other dimensions first - if all other same , match cutouts .
http://triumphbonneville120.co.uk/amal.php
http://www.jba.bc.ca/Bushmans%20Carb%20Tuning.html
tho these are two stroke fitment . Fine tune to suit . Saves throwing them out .
- Joined
- Nov 20, 2004
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- 21,112
Old Bloke said:
Not necessarily from different foundries I think, just a different casting pattern was used for each, presumably because the slides are cast using multiple patterns and not from one individual pattern.
Piero,
The 'MB' number has northing whatsoever to do with the slide specification so it can be ignored completely.
Slides that I have bought directly from Amal (Burlen) often have different MB numbers.
Just joking. Part number fits both left and right. Universal.Yes, I see the difference in slides. On one the cut-away starts at notch and on the other it starts about 2 or 3mm after the notch. The cutaway height seems equal and I don't know the differences shown would matter but I would want them both the same. I looked at the supply of Amal slides I have collected over the years and they all have a cut-away that starts at the notch.
Did not mean the total cut-away does not make any difference, I meant the slope of the cut-away is what may make no difference. The slide cut-away is measured from up the side of the slide down to the surface the slide is sitting on. That measurement is 3, 3 1/2, 4, or whatever the cut-away may be. The number following MB means nothing here. Within reason, where the cut-away starts probably makes no difference. As best I can tell from your photo with two slides facing each other cut-away to cut-away they are the same. Both # 3.
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