Jets and Carbs

[Wild Dog]

Lately, a lot people been having issues with their carbs either being way too lean or way too rich...
People been asking for jet size, but there is something that people is not asking.
Jet for whom? A Mikuni 102.5 Main jet will flow way more fuel than a Keihin 110 Main jet.

Now in an ideal (Or original) world this should not be a problem, because Mikuni carbs will use Mikuni jets, Keihin will use their own jets and so on....
But this is not the case with most of the chinese carbs, so you may have a PZ30 that use keihin jets or a PZ30 that use mikuni jets..

Let's say that someone post that their motorcycle runs great with a PZ30 115 MJ and 40 PJ (Both Keihin) if try to replicate that with a PZ30 that uses mikunis jets and we put a 115 mikuni main and 40 mikuni Pilot, we are going to be way too rich!.


If we are going to replicate someone else jetting is very important to know what brand of jets their carbs takes

[dirtbkr188]

Originally Posted by Wild Dog

If we are going to replicate someone else jetting is very important to know what brand of jets their carbs takes

That is something that is easier said than done, as long as the Chinese carbs are going to be sold with unmarked jet sizes, this problem will continue to prevail. Some carb manufacturers put some half-assed copy of a Keihin or Mikuni logo on the jet, which narrows the guessing game down some.



This issue is the main reason why I ask people to post some pictures of the jets they are working with, along with some dimensions, that way I can browse through the JetsRus website and try to match the unbranded jet with a genuine Keihin or Mikuni jet.

[Wild Dog]

Originally Posted by dirtbkr188

That is something that is easier said than done, as long as the Chinese carbs are going to be sold with unmarked jet sizes, this problem will continue to prevail. Some carb manufacturers put some half-assed copy of a Keihin or Mikuni logo on the jet, which narrows the guessing game down some.

Those unmarked jets are a nightmare i just use them to find out what kind of jets i need to buy and then i get real ones...

[nij_tp]

So Wild Dog, following on from your comment, if you are new to carbs and you buy one marked PZ30, how as a total novice do you know what knock off jets are in your carb if as you state above

.......with most of the chinese carbs, so you may have a PZ30 that use keihin jets or a PZ30 that use mikuni jets..

Thanks in advance

[Bruces]

Dirtbiker answered it above ,get a picture of your actual jets and take some measurements then start searching

[Goob]

Originally Posted by Bruces

Dirtbiker answered it above ,get a picture of your actual jets and take some measurements then start searching

Send those photos and measurements to Jetsrus and work with Mike to figure out what they are. Explain you situation in your initial e-mail, and let him know what you think the carb is a clone of. He is not snobby about figuring out what you need.

If you have the time for your bike to be down, then you might be able to just send what you have to him and then he could match. I would try photos & measurements first and order one of each suggested. Then if those work order more, if not, then ask if you can send in.

You will get your jets in 2-days after ordering (based on the 6 orders I have made).

[Wild Dog]

Originally Posted by nij_tp

S
.......with most of the chinese carbs, so you may have a PZ30 that use keihin jets or a PZ30 that use mikuni jets..

Thanks in advance

Not only that bu sometimes you may have a Mikuni main jet and a Keihin Pilot jet and the other way around...

Down the road buying cheap chinese carbs is a lottery, the only brand that i can say actually comes ready to be use with little tuning are the Nibbi Carbs.
They use keihin type jets, their jetsare marked with their branding so no fake keihin jets but you know they are keihin types, the needle jet has a # for Keihin needles, even the slide has #. So pretty much you have all the # you need to tune it.


Also OEM carbs are a cheaper option than Original carbs.. For example an OEM PE26 for a Kawasaki KX85 can be found on Kawasaki dealers for 120 bucks more or less. The same Carb but from the aftermarket channel is around 200 usd.

Both PE26 are made by Keihin but the OEM are cheaper because reasons....

[nij_tp]

thank you everyone. I totally missed Dirtbikers comment so thank you