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frankd_nm
11-22-2008, 06:24 PM
I've never worked on a Dell'Orto carburetor before and I have a couple questions.

1) I assume that the mixture screw on this carb is a fuel mixture screw and allows more fuel in when you back the screw out. Is that correct?

2) If I can screw the mixture screw all the way in and the bike doesn't die then I should install a smaller pilot jet. Correct?

3) What's the best way to get more air into the stock airbox? Modify the snorkel? Drill the top of the airbox? Will it be effective?

4) Where's a good source for jets and parts for the stock 28mm Dell'Orto?

HONDARACER
11-22-2008, 08:47 PM
Are you trying to install the 34mm carb? I think we only need a few larger jets than what they come with for the stock 28mm carb. What is the stock main in your bike? Mine has a 175 so I am looking to get some right up to 190. Also I want a larger pilot jet. Mine has an S40 and I want a S45 as Aoe recomends.

I have been looking on Ebay UK for a jet kit but mothing has come up yet. I got all winter to watch.

random0082
11-23-2008, 05:52 AM
to mod the airbox for the 34mm carb, take the snorkel out of the airbox, cut off the 2 round intakes that were on the outside, turn it around n fit it the other way round, so you now have 2 larger square intakes on the outside n nothing on the inside. no need to drill anything. Thats assuming youve got the same snorkel for the 28mm carb that we get

for carb parts try Eurocarb, do a internet search. theyve had every Dellorto part in stock that ive ever needed

frankd_nm
11-23-2008, 05:33 PM
I'm working with the stock 28mm carb. I'm do my riding between 3500 and 5000 feet elevation most of the time and I'm running rich with the stock jetting. So, I figure I need to get more air into the airbox or go with smaller jetting, or maybe both.

I'll try the snorkel modification to start with and try adjusting the mixture screw again, but I think I'll still have to go with a smaller pilot jet.

williamr
11-24-2008, 09:23 AM
I think the idle mixture screw is an air bleed on this carb.

Rob

HONDARACER
11-24-2008, 02:01 PM
Is you spark plug black in color? Also if you do have the carb apart would you mind noting what main and pilot jets are in the carb? THanks in advance.

frankd_nm
11-25-2008, 12:17 AM
An air bleed?! Then adjusting the screw inward would restrict air and make it richer?

I thought if the screw was on the engine side of the carb it was usually a fuel screw?

Plug is black and oily now. Not too bad, but needs adjustment. The powervalve didn't seem too bad when I pulled it for inspection/cleaning at 600 mi, but it's the first time I saw one out of a bike, so I don't really have much to compare it to.

It may be a couple of weeks before I get around to opening the carb to check the jets, but I'll jet you know what size they are.

random0082
11-25-2008, 07:58 AM
fuel mixture screw on the 28mm, its an air screw on the 34mm. Try Eurocarb for Dellorto parts unless you can find somewhere in the US, they should have a distributor over there too tho.

Steve / AF1 Racing
11-26-2008, 11:01 PM
Yeah, we're a Dell Orto Dealer.

Mains can be ordered online here: (you need the 6mm)

http://www.af1racing.com/store/Scripts/prodView.asp?idproduct=1623

Just put what sizes you need in the comments box.

We can get all the internals as well, pilots, needles, slides, et cetera.

Also have the 34mm carb incoming...

The 34mm manifolds showed up earlier today:

http://www.af1racing.com/store/Scripts/prodView.asp?idproduct=6875

There may be a Keihin option as well

ThisEndUp
11-27-2008, 11:39 AM
$111.00 for the manifold!!???

Yikes.

Steve / AF1 Racing
11-27-2008, 01:19 PM
$111.00 for the manifold!!???

Yikes.

We're working on it.

ThisEndUp
11-27-2008, 06:22 PM
Apologies for rubbing the "forum powers that be" the wrong way...but geez, I can't imagine how much the 34mm carbs are going to cost if the manifolds are at that price point.

O.K, I'm done criticizing your product pricing.

HONDARACER
11-27-2008, 08:07 PM
I bought a spare carb and am going to bore it out to 30mm. I am with the scholl that 34mm is going to be to big for anything but all out racing. They get away with huge carbs on the 125 motocrossers only becasue they have very steep geraing and spend 90% of the time at full throttle.

I checked my fuel mileage and I am getting 55MPG Imperial gallons too, so I am not willing to sacrifice any fuel milage for a bit more top end. Especially if it will casue tuning grief where it only runs good in midrange or wide open.

random0082
11-28-2008, 08:29 AM
In the UK the manifold is about 35 - 40, the 34mm Dellorto carb about 130 new. dunno how it compares

Steve / AF1 Racing
11-28-2008, 12:53 PM
In the UK the manifold is about 35 - 40, the 34mm Dellorto carb about 130 new. dunno how it compares

There are just too many middlemen to get the manifold to the US, but when I go direct, exchange rates and shipping do about the same thing to pricing as using all those middlemen.

You wouldn't be willing to get me in touch with a distributor would you?

Steve / AF1 Racing
12-03-2008, 04:06 PM
Our stock carb came with a 175 as others have noted.

Not sure about the pilot, as we haven't dropped the bowl.

---

We did get this little gem in today:

http://www.af1racing.com/store/ProdImages/st2/pivhsb349784.jpg




It can be ordered online here:

http://www.af1racing.com/store/Scripts/prodView.asp?idProduct=6888

frankd_nm
12-03-2008, 05:07 PM
Steve,

Does the boot from the airbox fit over the bell on the 34mm?

Awful tempting...

Steve / AF1 Racing
12-03-2008, 05:33 PM
Does the boot from the airbox fit over the bell on the 34mm?



Yes it does. It is actually very close to the same diameter as the stock carb, but the internal bore diameter is greater.

Socket
12-07-2008, 04:11 PM
I have my 34mm fitted and the bike is running terrific so far, still breaking it in.

I opted for the pipercross cone filter as I have no need for the airbox. Going to need to order needles/jets here soon, anyone have that pic of the tuning guide for the 34mm?

the-heft
12-08-2008, 08:27 AM
Remember the 34mm carbs need a nipple adding on to run the vacuum fuel tap on these new shape bikes.

Socket
12-08-2008, 02:46 PM
Remember the 34mm carbs need a nipple adding on to run the vacuum fuel tap on these new shape bikes.


could you please post a picture? I have the bike together and it's running very nice. what am I missing?

edit: Nevermind, I read your reply slower.

My 34mm carb did have the nipple, right near the same spot as the 28mm for the fuel tap.

Steve / AF1 Racing
12-08-2008, 03:27 PM
could you please post a picture? I have the bike together and it's running very nice. what am I missing?

edit: Nevermind, I read your reply slower.

My 34mm carb did have the nipple, right near the same spot as the 28mm for the fuel tap.

Yeah, its a 90 degree on the 34mm (ours and PJengineering's have them) instead of a 0 degree fitting on the 28mm, but some 34s apparently don't have one at all.

Ebay deal seekers beware!

Socket
12-09-2008, 02:52 PM
Steve, do you have jets in stock for the 34mm del orto? I'd like the K58 needle, and 154, 156, 158 main jet for it. thanks!

Steve / AF1 Racing
12-09-2008, 03:56 PM
Steve, do you have jets in stock for the 34mm del orto? I'd like the K58 needle, and 154, 156, 158 main jet for it. thanks!

Yes on all the jets:

http://www.af1racing.com/store/ProdImages/st2/Dellortojet.jpg



http://www.af1racing.com/store/Scripts/prodView.asp?idproduct=1623

But no needles yet.

Socket
12-11-2008, 03:58 PM
Yes on all the jets:

http://www.af1racing.com/store/ProdImages/st2/Dellortojet.jpg



http://www.af1racing.com/store/Scripts/prodView.asp?idproduct=1623

But no needles yet.

Where can I find the K58 needle? have you put the 34mm on one of your bikes yet?

Steve / AF1 Racing
12-11-2008, 04:47 PM
Where can I find the K58 needle? have you put the 34mm on one of your bikes yet?

Not sure where to get the K58 needle, we could special order one, but you're probably not going to see anything until after the first of the year.

We haven't fitted the 34mm yet, and we may not anytime soon, local race club (CMRA) has homolgated the bike with stock carb only.

HONDARACER
12-11-2008, 06:12 PM
I had a 11KW needle in a carb I bought off Ebay. I just put it into a drill and resized it useing a block and some very fine sandpaper. Of course if you need a larger needle that wont work.

Max09rs
12-18-2008, 09:45 AM
I race a kart with rotax max 125.. visit your local kart race shop they will stock almost everything pistons jets ect.

kboe
01-02-2009, 12:59 PM
There are just too many middlemen to get the manifold to the US, but when I go direct, exchange rates and shipping do about the same thing to pricing as using all those middlemen.

You wouldn't be willing to get me in touch with a distributor would you?

Have you tried these guys as a US distributor?

http://www.gorotax.com/index.php?option=com_content&task=view&id=15&Itemid=39

There is also www.ssceast.com as an east coast Rotax distributor and ssc racing as a west coast distributor: http://www.sscracing.com/page.cfm?content=191

These are all kart racing shops, but it looks like we use the pretty much the same motors and carbs on the karts as you guys do with the motorcycles. They are great motors, very tunable, well built, and reliable. I just wish we could run the 2 stroke bikes legally on the streets out here in California.

I'd ride my rotax to work everyday, work on the rotax's all day, and ride back home (I'm a full time kart mechanic at Infineon raceway and spend 80% of my time maintaining a fleet of 24 rotax powered karts)!!

-ky

Steve / AF1 Racing
01-02-2009, 01:50 PM
Have you tried these guys as a US distributor?

http://www.gorotax.com/index.php?option=com_content&task=view&id=15&Itemid=39

There is also www.ssceast.com as an east coast Rotax distributor and ssc racing as a west coast distributor: http://www.sscracing.com/page.cfm?content=191

These are all kart racing shops, but it looks like we use the pretty much the same motors and carbs on the karts as you guys do with the motorcycles. They are great motors, very tunable, well built, and reliable. I just wish we could run the 2 stroke bikes legally on the streets out here in California.

I'd ride my rotax to work everyday, work on the rotax's all day, and ride back home (I'm a full time kart mechanic at Infineon raceway and spend 80% of my time maintaining a fleet of 24 rotax powered karts)!!

-ky

Thanks for the links, I'll check their catalog. The parts manuals might be helpful, too. Especially with regards to the Pneumatic powervalve assembly.

kboe
01-02-2009, 01:57 PM
you're welcome. feel free to pm me if you'd like more info on rotax parts and availability. I'd be happy to put you in touch with our parts manager who orders stuff for our fleet of rotax powered karts. He may have some good advice for you, or at least another resource.

-ky