Dellorto PHBG replacement Jet

RLorange · #1 06-24-2008, 06:37 AM

Is everybody here aware that the jet in carby is replaceable? By chance I discovered that Dellorto PHBG main jets are a perfect fit! The 70cc's really need a bigger jet. I am using an 0.85mm jet which compares to 0.70-something for the stock. I raised the pin clip to the highest (leanest setting) and then dropped it back by a 1/2 using a tiny washer.

That is another great tip: To get an in-between clip setting simply use a tiny washer.

Bigger jet is a massive improvement with the leaner clip setting needed for compensation. Now my engine is very smooth during the mid range and no longer starves for fuel at full throttle. I feel that idle may be a little lean however because it idles very high now.

Dellorto PHBG jets are cheap mine cost $5.

Bikeguy Joe · #2 06-24-2008, 01:55 PM

I posted your other post about the delortos in "Classic Posts". It's permanent.

**Dave31** · #3 06-24-2008, 02:58 PM

Thank's for that tip RLorange...good info

Pablo · #4 06-24-2008, 03:05 PM

GREAT post. I'm familiar with the tiny washer trick - but I had no idea Dellorto PHBG main jets are a perfect fit......where did you get yours?

Bikeguy Joe · #5 06-24-2008, 05:40 PM

See the classic post section, there's a link to several places as low as 2.11.

RLorange · #6 06-24-2008, 07:32 PM

Lots of places sell them try a minimoto dealer 'cos they use Dellorto's for pocket bikes.

Next experiment is to try fitting a Dellorto PHBG 19mm Carby to my engine!!

19mm might be too big but I got it very cheap (its a replica) and they do use them on mini bikes with sucess.

Pablo · #7 06-24-2008, 10:50 PM

I was looking at the 19mm as well.....keep us posted.

I ALMOST ordered an 80,83 and 85 from DELLORTO Direct - but $10 for shipping - yikes....

RLorange · #8 06-25-2008, 06:20 AM

Well I can tell you that the Throttle cable fits but you have to remove the cable guide at the carby.

The carby slips OVER the manifold snugly which is an amazing coincidence unfortunately this doesn't work for long because liquid fuel quickly gathers at the 'Step' down to the smaller diameter intake tube so it runs rich as ****.

I did get it going tho briefly. These PHBG's have THREE jets! an idle circuit, main jet pre-mix circuit and a choke circuit. There is an idle mixture screw but no main jet mix screw cos it doesn't need one being a pin/clip design like the stock NT's

All I need is my custom 19mm manifold made up.

I am drooling in anticipation

Pablo · #9 06-25-2008, 06:22 AM

Please post picts of the manifold when you rig it....you da man!!

RLorange · #10 06-25-2008, 06:40 AM

Will do for sure. My Dellorto Repllica cost me $40 AU! Hope it is good working order.

I've got an expansion chamber muffler coming soon too, I'm going to get the same guy to make me up a header pipe. really wanted to get the one from Easy Rider but postage to Australia... I'm looking at $200+

Being lazy I'll have to post some pics soon