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Chris

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Jun 5, 2006
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111
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Ontario Canada
Hey guys i have a 440 exciter and i have 1987 exciter carbs on it , they originaly had 135 main jets and the phazer had 125 , i have it jetted now ive tried from 125 down to 100s and still when i give it throttle about half you can see gas spitting out the jets ? any ideas what i should do ?
Thanx
 

Chris

do you mean you see fuel mist at the inlet side of the carbs ? i.e. where the airbox attaches to the carbs . if so this would be normal as without the airbox attached the pressure at the inlet is higher . the restiction from the airbox creates a lower atmospheric pressure at the inlet of the carb allowing fuel to be delivered more easily thru the jets . start with the stock jetting and tune with the airbox installed . dont worry about the fuel mist you are seeing it just part of the normal fuel atomization
Kevin
 
Like where the gas comes out from the bowl its rather large drops spitting out , i am running K&N filters insted of a air box and there is no stock jetting realy they came with a single carb and single pipe , i put twin pipe from a GPX and twin carb from a 570 exciter on my 440 EX
 
Chris

I ran foam pod filters and 44 round slides 420 mains on my 81 SRX and they were allways wet from fuel but my plug color was good , best to start rich and jet down from there find stock jetting for something close to your application displacement and rpm and start there but watch your plug color
better rich than a burndown
 
well the phazer is the closest i can find , it runs 120s i think with 36 mm i think my carbs are 38s, pretty much the same type of carbs tho , it will sit and idol perfect with the 120-115 but when i give it throttle it bogs down ?
 
well your putting twin carbs on a engine that had a single right? are you sure its rich and not lean? because a old piston port motor likes to have lots of low speed fuel. does it take the throttle any better if you barely touch the choke enrichening lever? not open but barely cracked up? if its worse then its rich, if it revs right up your lean on the pilot jet. The hint a main jet is way too big is it will idle and run decent till about 5/8 throttle then when you go wide open it will lose rpm and seem extemely flat sounding??? the needle settings control the mid range fuel flow. Is the float level correct?/ high float levels are rich running low and part mid range , low float levels will be lean and will pop out the carbs usually. Does it rev up and return to the idle speed right away or kinda hang up then slowly drop down?
 
yes the machine is ment for a single carbs , but i put twin pipe witch would lean it out so i decided to put the twin carb on it too , The machine i put them on is a Exciter and the moter is a SS433 with reeds , it sits and idles good but when i get to about half throttle it loses RPM and bogs , right when it starts bogging down you can see the gas spitting out of the hole going down th the bowl where the jets are , i cheaked the plugs tho and they are looking good just about half throttle it bogs ,putting the enritcher on a little does not help at all at half but when the enricher is on full it dies down too , so is it some thing to do with the float level should i try putting the floats lower ? to lean it out , but what i dont get is that the plugs look real good for idle and up to half throttle then it bogs down ? any ideas ?
 
HAve you checked your compression? Also what type of fuel pump are you using? I had a 78 440 and I purchased a dual carb conv.kit. I never put mine together, I sold the majority of it already but there are several options as far as your fuel pumps. I talked to osme people about this when I purchased my stuff and here are some of the options: A dual pump should be enough but a modern dual racing pump would be another option for a little bit more gas. You can also use two single pumps or I have even heard of using a fuel pump for a tripple to get more gas. Make sure that the pump you are using is supplying your engine with enough fuel at wide open throttle. There is a way to check this, I am sure someone on here can tell you how. Another option is to drop your needle jets one notch. Your plugs are the right color from idling but not at full throttle. The reason I sold off my stuff was that I heard it would be a nightmare to jet and I found a good deal on 78 SRX that I am looking at possibly buying. Good luck and if you need any parts for that thing, let me know. I might be able to help you out.
 
It seems to be getting plenty gas i am just using a round mikuni pump the carbs i am using are butterfly mikunies , i am going to try the float position for mid range ?
 
I guess I am not following the story correctly then I thought you said you had exciter carbs on it now and the 570 exciters came with twin roundslides, thats where I assumed you meant you had those installed on it.

on the butterfly carbs the only way to enrichen or lean the midrange circuit is by drilling the carb body, they were notorius for burning down hopped up phazers, because you couldnt adjust the mid range circuit unless you drilled the carb body and used insane big pilot jets(110 size pilots) and then it would still burn down and very tempermental, like someone suggested ditch the butterfly's and get a set of 34-36mm roundslide carbs, they are very cheap on ebay.
 
mrviper700 said:
I guess I am not following the story correctly then I thought you said you had exciter carbs on it now and the 570 exciters came with twin roundslides, thats where I assumed you meant you had those installed on it.

on the butterfly carbs the only way to enrichen or lean the midrange circuit is by drilling the carb body, they were notorius for burning down hopped up phazers, because you couldnt adjust the mid range circuit unless you drilled the carb body and used insane big pilot jets(110 size pilots) and then it would still burn down and very tempermental, like someone suggested ditch the butterfly's and get a set of 34-36mm roundslide carbs, they are very cheap on ebay.
Click to expand...

The stock 1987 Exciter 570 did come new from the factory with Mic butterfly carbs. Yamaha offered 1987 Exciter owners free updates to rounds to try and fix burn downs....and it didn't help.
 
That is what I was planning on using when I had my exciter. Definately a much easier carb to tune. Good luck and keep us informed...
 
Ya i figured it would be but a mechanic said to go with them ones ( of course the guy i bought them from ) im not to happy with him , got them home and the float bowl was stripped , after i got new needles seates , filters chokes, cables , and Filters , might have to pay him a visit im not impressed with him at all
 
Would i have to jet if i kept the stock GPX pipes and used the stock single carb ? Im just wondering for the time being suppose to get 20-25 CM tonight ?
 
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