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ball bearing float needles

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Bobbieslandy
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Postby Bobbieslandy » 14 Sep 2010 14:13

Cheers Stag, so i guess after 3k they should be fine[:D] i'll concentrate on those fuel levels first.

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Beans
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Postby Beans » 14 Sep 2010 16:23

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Bobbieslandy</i>

... after 3k they should be fine ...<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
Not if the plastic notch is worn away, closing the gap almost completely.
I had that happen in approximate 5000 km.
(yes I did have the lubricating foam fitted to the cam lobe [:p])

Got fed up with adjusting them and put a Luminition kit in ...

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<font color="blue"><i>1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)</font id="blue">
<b>[url="http://www.tr7beans.blogspot.com/"]<u><b><font size="2"><font color="red">My Weblog</font id="red"></font id="size2"></b></u>[/url]</b></i></center>

Bobbieslandy
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Postby Bobbieslandy » 14 Sep 2010 17:51

My luminition kit needs wiring back in badly, i fitted the new dizzy in a hurry without really checking anything. Another job to add to the list!

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saabfast
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Postby saabfast » 14 Sep 2010 19:22

Not sure about the Sprint dizzy (they are different to the 8 valve aren't they?), but the standard one would probably need adjusting after 3k, and its a pig to do! Thats why I changed to electronic.

Alan
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Bobbieslandy
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Postby Bobbieslandy » 18 Sep 2010 11:57

Hi,

Right, i've fitted the leccy ignition at last! I didn't bother setting the gaps but the contacts did look a bit black and didn't look as if they were closing square to each other if that makes any sense. Access to it is actually really good on the sprint, it could of only gone horribly wrong if i dropped one of the screws into the depths of the dizzy housing. it's running a lot smoother now but the fuel levels aren't right. I've taken measurements from the top of the bowl at the three points where the lid bolts down and they are.....

Left hand carb, starting at bolt hole nearest bulkhead and working clockwise...

23.8mm
22mm
29.7mm

Right hand carb (nearest rad) starting from bolt hole nearest air cleaner...

27.5mm
26.2mm
32mm

Perhaps averaging them might help to make things clearer

Left hand carb

25.2

Right hand carb

28.6

When i removed the piston and damper assembly i could see a fuel level at the needle seat (bridge??) on the right hand carb, there was no fuel to be seen on the left hand carb though which is strange.

I have done a search with regards to the correct fuel level but couldn't find anything, ditto my haynes manual and Triumph workshop manual. It has to be there somewhere i just can't find it!

Any thoughts / recomendations on the fuel levels? the grose jet on the left hand carb is now without washers. If i need to raise the fuel level will i have to cut and re thread the jet to make it sit higher? or is there an easier way?

I've been given a carb tuning kit for SUs, came in a little blue pouch with a small spanner, 3 pins, one small round metal something or other which i can't work out what it's for and 3 metal pipes with a slot in one end, ovalled at the other (for setting float hights i believe). even the instructions aren't that great!

Many thanks!!

Rob.




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steve_1360
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Postby steve_1360 » 18 Sep 2010 14:15

I've read a bit of stuff about fuel levels on slant fours on the dolomite forum. On my 1850 i put a washer under the front float value to lower the fuel level a bit as i was getting fuel at the bridge as you describe. No washer on the back one. Another thing is the over run values, they can cause all sorts of carb set up problems. I've just soldered mine up.
Luckily my TR7 is running well at the moment so not messed with it yet[8D]

Cheers Steve

Hasbeen
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Postby Hasbeen » 18 Sep 2010 14:44

Rob, you won't find a level for the fuel in the jets, as Triumph could not give one.

See my earlier post re float level, & you will see that their cheapskate carb instillation means that it can not be right without some machining to alter the carb.

On SUs they give a measurement for the distance between the float, & the top of the float bowl, when held upside down. This will give a fuel level, but only in the float bowl. AS these bowls sit at different angles/heights in relationship to the choke tube of their carb, they must be different by about a 1/4", as installed in the car.

Study your carbs, & you will see the rear bowl is lower, [giving that lower fuel level], due to the angle of the engine.

Triumph, & probably SU, [who were owned by Leyland by then] reckoned that this would not matter in a road car for hair dressers, & grannies. A few flats richer of main jet adjusting nut of the rear carb & it would be good enough.

It probably is too, unless you like things to work properly.

In that post I mentioned that you can modify the spacer in the float bowl attachment to the body of the carb. Grinding them to a wedge shape, [suits a wedge] will allow you to lower the front bowl, & raise the rear bowl. Don't go too far as the faces won't sit right, & those spacers are hard to get.

I managed to find a clapped out HS6 SU to experiment with, & tried a few things as mentioned.

Hasbeen

Bobbieslandy
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Postby Bobbieslandy » 18 Sep 2010 15:38

Sorry Hasbeen, i forget things so quick! i re-read your earlier post and after pulling the carbs apart and having a proper look at them it does make more sense. You mention having the fuel level between 1 and 3/32" below the top of the jet and that this level should ideally be the same on both carbs. Mine are different, the front carb has fuel flush with the top of the jet whereas the rear carb does not. Should i lower the fuel level in the front to match that of the rear?

Thanks!

Rob.

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Hasbeen
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Postby Hasbeen » 18 Sep 2010 16:09

Yes Rob, lower it a bit, but not too far. An extra washer or 2 under the valve should do.

I run at about an 1/8" below the top of the jet, but then I'm a bit of a nut. This had to be lowered a little after the first tuning.

Probably around 3/16 would be better for normal road use.

Yes, although it is hard to do, due to that cheep design, ideally the float levels should be the same in each carb. Being close to the same is more important, for smooth operation, than the actual level.

Hasbeen

Bobbieslandy
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Postby Bobbieslandy » 20 Sep 2010 17:47

I must be doing something really stupid! The level in the carb nearest the rad is spot on, i cannot raise the level in the other carb to match it no matter what i try! i can bearly see the level in the jet, i fitted a standard float needle valve with no washers between the valve and the lid of the float chamber. I ran the engine for a few secs then removed the dashpot and piston and could just about see the fuel level about 3mm down!! I was expecting that after encouraging a "worst case scenario" i would have fuel practically peeing out of the jet.

I re-fitted the ballbearing valve without washer, ran it again and checked the level. No difference.

Time to put it in the garage until next year.

Rob.

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