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PostPosted: Mon Mar 26, 2012 10:07 am 
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Can anybody give me a run down of how the accelerator pump rod on a Dellorto DHLA should be set?

This information is curiously absent from my Tuning manual, so I've been setting it by trial and error. I'd be interested to know whether I can determine if my accelerator pump jet is too big/small based on where the pump rod is adjusted to get it running right. :?:


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PostPosted: Mon Mar 26, 2012 10:21 am 
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The more you screw the nuts on the rod, the more effective pump stroke you get.
I think mine has around 6mm length of thread sticking out, I'll try and measure it.
What size pump jets are you running- I think mine are 50.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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PostPosted: Mon Mar 26, 2012 10:30 am 
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I think I'm running 55 jets but I'll need to double check

The way I had it set up there wasn't a great deal of pump stroke. When I increased the pump stroke (by quite a bit, admittedly) it ran really bad. I reckon I would be better to run smaller pump jets with a greater stroke on the pump rod, so I might experiment on that one.


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PostPosted: Mon Mar 26, 2012 11:42 am 
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Regardless of the pump jet size, IMO you can't stomp on the throttle at idle and expect it not to bog down. Even on my 1412... :lol:
Once it's around 2500 rpm+, different story.
People that want to use the throttle like a light switch should stick to SUs... or maybe fit injection. :wink:

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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PostPosted: Mon Mar 26, 2012 11:57 am 
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Bog down? With a 286 cam and a Dellorto? Never :lol:

Car is running okay in general, but uses a lot of petrol. Getting it running well is one thing, getting it running well with (reasonable) economy is another ;)


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PostPosted: Mon Mar 26, 2012 1:14 pm 
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Don't be afraid to lean off the main jet size a bit for general running about. It helps economy a lot.
I use 168s for general use (170s were NLA), 175 or 180 for dyno runs etc.
[edit] I have 36mm chokes in it.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


Last edited by drmini in aust on Mon Mar 26, 2012 2:33 pm, edited 2 times in total.

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PostPosted: Mon Mar 26, 2012 1:46 pm 
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I'm currently running 34 chokes with 155 main jets. Thinking of dropping it back to 150s or 145s. If it still goes hard with the smaller jets then I'm happy :D


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PostPosted: Mon Mar 26, 2012 2:34 pm 
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Anto wrote:
I'm currently running 34 chokes with 155 main jets. Thinking of dropping it back to 150s or 145s. If it still goes hard with the smaller jets then I'm happy :D

I ran 34 chokes and 145 mains for years in my 1310S. Should be fine.
Air correctors are 180, always seems to be about right in a Dellorto.

[edit] Anto, re the rod adjustment, it feels to be about 5 or 6mm but I cannot see the bugger in the car.. :x

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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