Is my carb upgrade logic sound?

[patthesoundguy]

I'm going to upgrade the carb on my express because I put a 70cc kit on it and the stock carb is not cutting it. It going to get a new intake to match the carb. So here is my logic every one tell me if this makes sense... if my kit is 40% larger than stock then would a 40% upsize in carb make sense. So if the stock carb is 12mm then add 40% I get 16.8mm or round up to 17mm. My gut tells me a 19mm would be perfect but I have know Idea why. I need some guidance or I'm gonna go nuts trying to decide what to buy.

[abreen89]

Go with the 19mm i put it on my 48mm bbk and worked great had great throttle response. If you get the 19mm from a hona aero 125 you can keep the bystarter set up as well

[patthesoundguy]

Go with the 19mm i put it on my 48mm bbk and worked great had great throttle response. If you get the 19mm from a hona aero 125 you can keep the bystarter set up as well

Thanks that's the kind of epearience I was looking for 19mm delorto phbg carb is going on the list. throttle response is what I'm looking for.

[abreen89]

does the express have electric choke? if so go with something like this http://www.ebay.com/itm/Honda-Scooter-N ... 9f&vxp=mtr

[patthesoundguy]

It has a manual cable choke. I ordered the delorto to match . The carb has replacable jets for the starter enrichment, idle pilot and main jet. I also ordered the racing float bowl with the drain plug that grants access to the main jet with out having to remove the carb or the bowl that bike should work right with all of the goodies. It has 70cc kit on it now with boysen 2stage reeds stock carb with non removable main jet drillled. The bike works but its not breathing right through the tiny stock carb. There is the new intake, carb and filter assembly on the way.

[LMH]

Nice Im glad ya got to use the reeds I sent ya, a 19mm is the smallest Id use on the 70cc. I ended up taking off my Arechi 19mm for the OKO 24mm, but its was for top end more than throttle response.

[martynkim]

Go with the 19mm i put it on my 48mm bbk and worked great had great throttle response. If you get the 19mm from a hona aero 125 you can keep the bystarter set up as well

As I have done the BBK on the express 24 mm is the only way to go. That deltoro will hit just right then.

[abreen89]

Go with the 19mm i put it on my 48mm bbk and worked great had great throttle response. If you get the 19mm from a hona aero 125 you can keep the bystarter set up as well

As I have done the BBK on the express 24 mm is the only way to go. That deltoro will hit just right then.

Listen to Marty he has the experience with the express but hey trying something different isnt out of line either. You never know what different carbs will do.

[DaylightDies]

I ran a 19mm on a 70cc kit, was awesome! Alot more fuel consumption though
I think a 17.5mm might be better, and it seems eliteguy50 is trying to test that out.

[abreen89]

I ran a 19mm on a 70cc kit, was awesome! Alot more fuel consumption though
I think a 17.5mm might be better, and it seems eliteguy50 is trying to test that out.

yea thats what im saying 19mm is good for up to 90cc. going any bigger would just be a waste of fuel

[patthesoundguy]

Intake, carb and new air filter arrived yesterday. all I can say is wow I'm so very glad I bought the trail tech CHT gauge, it makes setting up a new carb so much easier.


A plug chop or two and a larger pilot jet and I'm laughin