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peterjameswalker
50cc nipper
Joined: 13 Sep 2008
Posts: 28
Location: maitland
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 Posted: Thu Feb 19, 2009 12:33 pm Post subject: twin dellortos on raptor 660? |
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hi guys, my next door neighbour just bought a 660 which is supposed to have had work done, although we cant seem to track down what exactly.
It has a white bros pipe, a twist throttle and twin 40mm dellortos with pod filters. I figure if someone has gone to the trouble of buying the adaptors and fitting them then they must be there for a reason?!
When he got it it was running like a pig, which is how he managed to get it rather cheap, and we found that one of the main jests was sitting in the bottom of the bowl (left side carb if it makes any difference) we also found that the left one has a 170 jet and the right has a 155, when you twist the throttle the one on the right squirt sfuel but the left one doesn't.
Would one be set up as a primary with a accelerator pump (which i have never seen on a bike carb) and the other a secondary??? Or should they both be pumping?
We were contemplating some standard carbs but i cant help but think that they are on there for a reason, if they weren't better than standard you would just change them back i reckon! |
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4stroker
Joined: 15 Jan 2007
Posts: 1420
Location: North Queensland
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| Posted: Thu Feb 19, 2009 12:40 pm Post subject: |
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on the raptor one carb feeds one inlet valve and the other feeds 2 doesn't it? this would explain the difference in mainjets. the carb feeding one valve is probably a smaller bore too?
sorry cant offer anything other than that!
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2002 SE Banshee |
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peterjameswalker
50cc nipper
Joined: 13 Sep 2008
Posts: 28
Location: maitland
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| Posted: Thu Feb 19, 2009 4:18 pm Post subject: |
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| i'm fairly sure that the raptors are only a four valve head? |
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4stroker
Joined: 15 Jan 2007
Posts: 1420
Location: North Queensland
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| Posted: Fri Feb 20, 2009 8:15 am Post subject: |
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i think you will find it is indeed a 5 valver...
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2002 SE Banshee |
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peterjameswalker
50cc nipper
Joined: 13 Sep 2008
Posts: 28
Location: maitland
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| Posted: Fri Feb 20, 2009 12:11 pm Post subject: |
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i stand corrected, i looked it up and it is indeed a five valve head.
I'm not used to working on yamahahahas. 
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KFX400,
Loncin 250,
Suzuki LTF 250 |
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PeteW
Moderator
Joined: 09 Feb 2006
Posts: 1877
Location: Doreen, Vic
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| Posted: Sat Feb 21, 2009 9:06 am Post subject: |
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unless there has been other major work done requiring bigger carbs I'd just change them back to stock. or I believe that there were adaptor kits around to be able to put an FCR single carb on....
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www.thumbpump.com
www.dirtcomp.com.au |
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SpecialEd_05
50cc nipper
Joined: 15 Jan 2009
Posts: 30
Location: Perth, Western Australia
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| Posted: Mon Feb 23, 2009 6:20 pm Post subject: Re: twin dellortos on raptor 660? |
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| peterjameswalker wrote: | | Would one be set up as a primary with a accelerator pump (which i have never seen on a bike carb) and the other a secondary??? Or should they both be pumping? |
The Yamaha XT550 (around '90 model) had a two stage twin throat carby. One throat was primary and the other was secondary so they opened in stages. Both machines being Yamaha's they are most likely very similar in design with the Raptor 660 engine being loosely based around the XT I would think.
But yeah for simplicity's sake try and pick up the stock carb setup or a better aftermarket setup.
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2005 Banshee Special Edition
-Toomey TR6 pipes
-V-Force3 Reeds
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-BKT X-driv Tyres
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peg_leg686
90cc 2 stroke / 110 4 stroke
Joined: 23 Feb 2008
Posts: 77
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| Posted: Sat Feb 28, 2009 10:50 am Post subject: |
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best to throw it on a dyno. Twin 40mm carbys are pretty big for a raptor 660 probably too big unless its had some massive work done as the standards are twin 33mm carbys. Mine is making about 55rwhp on the standard carbys but i had to get custom jets made for mine as they are about 210/215 jets in it which keihin dont make. atleast if you throw it on a dyno you can see if its running lean/rich and try and adjust carbys to suit. alternatively you could go out and buy some 35mm fcr carbys for it but the are pretty expensive to set up but really good. id love a set for mine.
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01 RAPTOR 660. 55RWHP |
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wa5
Big Bore, Stroked & Bling +
Joined: 06 Nov 2007
Posts: 446
Location: Port Stephens
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| Posted: Sat Feb 28, 2009 11:12 am Post subject: |
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I just want to clear something up. When you say it has "twin 40 mm Del'Ortos, Do you mean that it has TWO seperate 40 mm twin choke carburettors (giving a total of four throats) or , do you mean that it has ONE 40 mm twin choke carburettor (giving a total of two throats) which I would consider far more likely.
This may sound like a dumb question, but when I hear mention of twin or triple Webers or Del'Ortos, I think of two or three seperate carburettors. Not twin or triple throat carburettors (and Weber did make a triple throat downdraft to suit Fords' Capri V6 BTW). |
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