Multi carb setups

[UTERUS]

So i have had this idea floating about in the back of my mind for a few years now.....

I want to use single (40mm?) motorbike carbs on a 2 litre 6 cylinder motor, for no other reason than for shits n giggles. They will not be joined by a plenum, just filters on each carb for sifting out bugs and the like, what i really want is a colour tune spark plug but my chances of finding one are pretty slim.

Has anyone had experience with multi carb setups and would be so kind as to shed some light on this dark art and to reccomend a good carb tuning and setup book.

Thanks,
Simon

[d1 mule]

YUSS multi carbs sound amazing . thats all i have to say lol sorry i cant help

[fangsport]

the hardest part would be finding 2 matching sets, without it costing heaps.
may be cheaper to get 3 Weber DCOE or Dell'orto DHLA

[Ae92typeX]

... what i really want is a colour tune spark plug but my chances of finding one are pretty slim...

Can still purchase them new & come up on trademe every so often. Chances should be better than slim

[atmosports]

Make sure you get 6 carbs exactly the same as bike carbs even from the same make/model & looking the same can vary inside quite a bit. Also be prepared to get looked at strangely when buying jets as you'll probably end up with odd sizes compared to what bikes run. The hardest part will be making a decent manifold & getting all six throttles to open/close at the same time. It can be done & we've tuned stuff like this before but it's not an everyday occurence. I know for a fact that it's impossible to get jets for some Mikuni/Keihins here in NZ as we've tried before for some of the STAR CAR carbs & ending up either changing carbs to another make/model or else making jets in the end & I've got a big bag of made up Keihin jets at work for a road bike one of the guys I worked with had, same thing we couldn't get any jets even though they were listed in the book & on the computer, no one here had ever imported them.

As for the Weber/Dellorto suggestion, I'd either go for Weber's or if the money allowed a new set of OER's a they are slightly better again than a weber. I don't really recommend Dellorto's as it's getting damn hard to get a lot of the jets/tubes these days & we've got a pretty good stock & are slowly starting to mnake more & more of this stuff as we can no longer source it.

[UTERUS]

Make sure you get 6 carbs exactly the same as bike carbs even from the same make/model & looking the same can vary inside quite a bit. Also be prepared to get looked at strangely when buying jets as you'll probably end up with odd sizes compared to what bikes run. The hardest part will be making a decent manifold & getting all six throttles to open/close at the same time. It can be done & we've tuned stuff like this before but it's not an everyday occurence. I know for a fact that it's impossible to get jets for some Mikuni/Keihins here in NZ as we've tried before for some of the STAR CAR carbs & ending up either changing carbs to another make/model or else making jets in the end & I've got a big bag of made up Keihin jets at work for a road bike one of the guys I worked with had, same thing we couldn't get any jets even though they were listed in the book & on the computer, no one here had ever imported them.

As for the Weber/Dellorto suggestion, I'd either go for Weber's or if the money allowed a new set of OER's a they are slightly better again than a weber. I don't really recommend Dellorto's as it's getting damn hard to get a lot of the jets/tubes these days & we've got a pretty good stock & are slowly starting to mnake more & more of this stuff as we can no longer source it.

Thanks for the advice, i was looking at bike carbs since they are fairly cheap to get a hold of, is there a particular make i should stick with if i went that way?. Will triple sidedraft webers be easier to tune and keep running if i went with them?


Thanks again.
Simon

[atmosports]

If you going to go bike carbs which are probably heaps cheaper, stick with a Keihin/Mikuni that is fairly common & one you can easily get jets for, possibly something similar to what they run on Harley's as I know way back we did a fair bit of dyno work on a motor with bike carbs & in the end the guys went with a set of either keihin's or mikuni's that would normally get used on a Harley as it was the easiest way of getting the same carbs & also easy to get jets for them.

I don't honestly think running weber's or any other carb setup would make it any easier to setup,adjust & tune & keep in a constant state of tune.

[atmosports]

If you going to go bike carbs which are probably heaps cheaper, stick with a Keihin/Mikuni that is fairly common & one you can easily get jets for, possibly something similar to what they run on Harley's as I know way back we did a fair bit of dyno work on a motor with bike carbs & in the end the guys went with a set of either keihin's or mikuni's that would normally get used on a Harley as it was the easiest way of getting the same carbs & also easy to get jets for them.

I don't honestly think running weber's or any other carb setup would make it any easier to setup,adjust & tune & keep in a constant state of tune.

[UTERUS]

Awsome, i really appreciate the info.

Will it really be that hard to keep them all in tune once they are sorted and i had it running well?

At the end of the day, should i actually bother with carbs at all and stick with the standard injection system. It is a map sensor motor so maybe it would be more sensible to go with 6 throttles from a 20v, nothing is definate at the moment and i am open to ideas about what to do.