phbg carb size - how to chose?

I am looking at phbg carbs for my maxi. I have a malossi 60 kit, wondering what the optimal size would be. 19mm phbg's seem to be a pretty common choice, but I wonder if this is too large for my kit.

What changes when the id of the carb changes? Is fuel efficiency compromised when it gets larger? Torque?

are dellorto 17, 18, 19 phbg identical besides the bore?

Thanks.

Re: phbg carb size - how to chose?

Kevin Bishop /

There is a formula, but I would say 15mm is big enough.

Re: phbg carb size - how to chose?

Read my last two posts here:

https://www.mopedarmy.com/forums/read.php?7,3692448

Also, the search function works wonders. Have you tried using it? Have you looked in the wiki?

Here.

Re: phbg carb size - how to chose?

Matt Mahloch -- MBM Customs /

Measure the intake on your cylinder and match it.

Re: phbg carb size - how to chose?

Derek Vanasse Wrote:

-------------------------------------------------------

> Read my last two posts here:

> https://www.mopedarmy.com/forums/read.php?7,3692448

>

>

> Also, the search function works wonders. Have you

> tried using it? Have you looked in the wiki?

>

> Here.

Your last two posts are helpful but did not give an idea of optimal size of carb to cylinder. The wiki does not give a formula. Search function did not give a formula. Just looking for insight from people who have tried stuff. Thanks for the Google link, pretty clever.

Re: phbg carb size - how to chose?

Overpriced Parts /

14mm bing will go just as fast because the pipe will be the limiting factor.

14 mm will have more low end because the revs will need to spin up more for the 19+mm carb to be efficient.

Hope your not planning to make a hi rev setup with stock unrebuilt e50

Re: phbg carb size - how to chose?

#CrazyWayne™ rocks. #CrazyWayne /

If you can tune 12mm carbs can do 50mph and 60mph with a 15mm carb.

You will lern more a bought flow matching power tuning with small carb setups.

Re: phbg carb size - how to chose?

Crazy Wayne™ rocks your Mom's sister's niece's daughter's grandma Wrote:

-------------------------------------------------------

> You will lern more a bought flow matching power

> tuning with small carb setups.

This is very true, good point Wayne.

Re: phbg carb size - how to chose?

Patrick - I love this website:

http://gearing.martysgarage.info/

You'll probably be in the ball park of 40-50mph, so take a look at your current gearing and use it in the gearing calculator to get a rough RPM estimate of where you'll be.

Take that RPM range over to the carb calculator and it will give you a min/max size carb. You'll probably see something like "14-24mm", so the world is your oyster. Pick a carb in that range and be done with it.

Re: phbg carb size - how to chose?

Thanks, very cool site. I think I will try the smaller phbg. I am rebuilding the internals, just got a rito in the mail. I am looking for reliable over power/speed so the rpms should stay down I think

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