Barksavon
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| posted on 8/6/10 at 08:59 PM |
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Twin Side Draughts or Motorbike Carbs???
Ive got a 2L pinto on twin Dellorto 40 DHLA's in a Tiger. I'm getting a bit P'd off trying to get it run consistently well, it was
running reasonably but bogging down on acceleration so opened up the idle screws 1 1/2 turns and it got better but went out in it few days ago....ran
like a pig for about 4 miles then cleared itself, been out tonight and running like 2 pigs, plugs black and wet so presume running way too rich now,
wound the screws bak in and wire brushed the plugs, only a bit better...aaaaaargh!!!!! Thinking about bike carbs are they easy to fit and maintain do
they stay in tune once set up unlike the carbs ive got on at moment...Any comments/views/advice welcome.
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whitestu
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| posted on 8/6/10 at 09:03 PM |
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Dell'ortos in good condition and set up well shouldn't go out of tune. I've had several Alfas with them on and they consistently
worked well.
Having said that the bike carbs on my Zetec were dead easy to set up, and cost less than a service kit for a set of Dell'ortos.
Stu
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55ant
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| posted on 8/6/10 at 09:04 PM |
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couldnt be happier after changing from a 38 dgas to bike carbs, changed the car completely.
away from cars, now cycling and building TT bikes
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jacko
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| posted on 8/6/10 at 09:04 PM |
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Bike carb all the way
I fitted zx9r carbs and it was the best thing i have done
They stay in tune easy to fit and never bog down
I made my own manifold
look in my photo archives under zx9r / manifold
Jacko
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norfolkluego
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| posted on 8/6/10 at 09:05 PM |
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Only just fitted ours so can't give a long term view but they're certainly much cheaper to buy and seem easier to maintain (change jets
etc.)
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dlatch
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| posted on 8/6/10 at 09:08 PM |
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throttle bodies 
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b16mts
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| posted on 8/6/10 at 09:15 PM |
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I built my pinto tiger with twin weber 45's. gave up even before SVA, flogged them as nearly new, but a set of gsxr600 carbs inc manifold, and
pockets the £300 change!!
plus it now make 119bhp at the flywheel with nothing but a lumpier cam.
happy days!
Martin
who says you can't drive a kit car when you're 6'5"?
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Paul TigerB6
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| posted on 8/6/10 at 09:16 PM |
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Neither - get it to a rolling road and set up properly.
If starting from scratch i'd say bike carbs but have you actually had the DHLA's properly set up on a rolling road?? If not then its
highly unlikely to have the right main or idle jets for the fueling so you can mess about with the idle screws till the cows come home - you'll
never get anywhere.
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RichardK
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| posted on 8/6/10 at 09:25 PM |
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Bike Carbs everytime.
Cheers
Rich
Gallery updated 11/01/2011
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Barksavon
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| posted on 8/6/10 at 09:43 PM |
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Bike Carbs definately come out on top here then....Paul thanks for the reply, ive had the car on a rolling road, nice guy but he specialised in
MG's and didnt alter the jetting at all, he did get the car running better than it was but it still wasnt as good as it could be. I'm
thinking bike carbs are the way forward, i could spend a fortune with what ive got on (which i bough off e bay!!) and still get nowhere.
Thanks for the other replies as well guys much appreciated.
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Paul TigerB6
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| posted on 8/6/10 at 09:56 PM |
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Bit of a difference between a set of twin SU's that MG's generally have and a pair of DHLA's. You'd really need them set up by
a decent rolling road who know DCOE's and DHLA's as they take some knowledge to get right - especially around the progression between the
two sets of jets.
Anyway, you'll generally get a good price for the DHLA's on ebay - twin sidedraughts still seem to sell really well even with the bike
carb phenomena. If fitting bike carbs then it'll be a wise move to also fit a bike pump at the rear below the tank (they work more efficiently
pushing fuel). Do you have a Facet or similar electric pump, or the standard mechanical one under the carbs?
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madteg
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| posted on 8/6/10 at 09:59 PM |
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Fitted twin fourties to mine when first built couldn't afford the petrol. Getting more to the gallon now with turbo.
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jimgiblett
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| posted on 8/6/10 at 10:08 PM |
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quote:
Originally posted by whitestu
Dell'ortos in good condition and set up well shouldn't go out of tune. I've had several Alfas with them on and they consistently
worked well.
Stu
My Dellortos on my Alfa havent caused any problems either.
- Jim
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atspeed racing
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| posted on 8/6/10 at 10:21 PM |
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A correctly set up fuel system, EFI or carbs should never need to be reset up. If it needs to be redone, it was either not set up correctly in the
first place, or something on the car has made a change for you.
Having said that, a CD type carb like an SU, Stromberg or bike carb would be far more tolerant to low carb air speed due to a performance camshaft ,
large ports, scavenging exhaust or a big valve head being fitted. This is exaggerated on a very light car such as a kit car and would feel that the
car has a serious running problem (misfire).
This is why the bike carbs are so good, they dampen the irregularities brilliantly, but then so would SU carbs.
A pair of DCOE's or DHLA's set up correctly should not need to be adjusted ever, and as an earlier poster has said, the problem is down to
getting the progression correct between the idle and where the main circuit takes over. This is the hardest thing to get correct and this is an area
that most tuners fall down on. They spend all there time trying to get the big number and dont concentrate on the cars drivability
Hope my input helps.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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r1_pete
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| posted on 9/6/10 at 06:59 AM |
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I see you're in Derbyshire, anywhere near Chesterfield?
If you can get the car to Eike Wellhausen at Chatsworth Motor spares, hes a weber / delorto specialist, and will sort them for you, he's just
done the triple webers on my Jag.
He also Races a Lister Replica with triple dcoe's, and had 2 other E's in when I took mine, he is THE man for Webers.
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Barksavon
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| posted on 9/6/10 at 04:57 PM |
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paul yes ive got a facet pump mounted very close to the bottom of the fuel tank, would that be okay for bike carbs or would i def need a bike fuel
pump. Other replies thanks a lot, i know Chatsworth motor spares as i live Alfreton and got my cable linkage from him so may give him a call, i think
it is a progression issue...its how much cash and patience i want to spend sorting it out
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Paul TigerB6
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| posted on 9/6/10 at 07:19 PM |
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Some have used the Facet succesfully but personally i'm not a fan. The bike carbs only need about 1.5psi so probably just over half what your
current carbs use. A bike pump is designed to pump the volume at the low pressure and self regulates. Regulate a Facet down to 1.5psi and i'd
personally worry about fuel starvation under hard acceleration. There's enough people swapped from a Facet to bike pump and cured their running
problems to convince me its the better long term option.
Probably worth looking for a bike pump on ebay - most bikes of 600cc plus will have a near identical pump so most will work with any bike carbs (which
will probably be Mikuni or Keihin regardless of bike make) and then sell on the Facet and regulator with or without the carbs.
Bike pumps are cheap enough and are very reliable.
http://cgi.ebay.co.uk/Honda-CBR-900-Fireblade-Fuel-Petrol-Pump-And-Filter-/250643915996?cmd=ViewItem&pt=UK_Motorcycle_Parts&hash=item3a5b8aa4d
c#ht_515wt_1137
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Barksavon
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| posted on 9/6/10 at 07:29 PM |
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nice one mate thanks.....rang Bogg Bros today, £600 for carbs, manifold, pump etc, bit more than i hoped but still might take the plunge, are bike
carbs less thirsty with the petrol than the side draughts, i think ive read somewhere that they are...ive not measured my mpg but dont seem to get
much
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prawnabie
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| posted on 9/6/10 at 07:38 PM |
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Get the sidedraughts set up on a rolling road you wont look back! I think too many people jump on the "webers etc dont stay in tune for
long" bandwagon which in my opinnion is an old wives tale.
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tul214
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| posted on 9/6/10 at 07:45 PM |
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I swapped from Bogg Bros set up DHLA's to CBR 600 carbs on a home made manifold and took the car back to Boggs.
Both set ups made the same power BUT the bike carbs are SO much smoother and do not bog down coming on to power from low revs/speed.
I sold my Dellorto's and facet pump and regulator for £300, the bike carbs were £50, the bike fuel pump about £20 and the manifold cost me
about £50 all in.
NTDWM but FASTDAN on here is selling manifolds cheaper than Boggs and then just find some carbs on e-bay. Should cost you no more than £200 plus a RR
session to jet them.
Mark
1.6 Raw Super6 sold
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