[Tonck1]

Why are you wasting your money on a piece of junk, for $500 or $600 you can buy a good used real Euro bike. That carb is not going to help you from breaking down all the time. How are you going to tune something you know nothing about. You are going to spend all your time tuning, every 10 degrees up or down you need to change jets. You do what ever you want, but don't come back here and complain later. My C1 is a big pain in the the azz, if its not one thing its another, lol. A Walbro carb is a no brainer.

I’m happy with what I’m doing mate. I’m asking questions, trying to learn. You don’t have to help me. When something goes properly wrong I will rebuild the whole thing with quality parts and I’ll have a good time doing it. Thanks.

 

[Chrisi]

First picture is fuel line from the tank, the screw below is the air mixture, turn clockwise = ritch/ turn the other side = lean.
The second picture is for an vacuum fuel tap. The blocked of is for extra oil line when you don't run on mix gas.
Blue is from the production, there is one cast for different carbs.

And don't worry, there are thousands of Europeans who use "normal" carburettors without any problems. I usually only have to rejet from summer to winter and only the main jet.

So I’m still unsure what to run into the second red circle. I was told I don’t need a fuel tap, shall I just run the two into a T piece connector and then up to the tank? Or should I just block that off?

Nothing, block it off!!
If you don't believe me ask Ian Harris from m4 Karting he will tell you the same thing. This connection is for a vacuum fuel tap if the carburetor is installed in a moped or scooter.

You do not have to install a fuel tap, but it would be recommended because if something is broken on the carburetor and it overflows, you can cut off the fuel supply.

 

[Tonck1]

So I’m still unsure what to run into the second red circle. I was told I don’t need a fuel tap, shall I just run the two into a T piece connector and then up to the tank? Or should I just block that off?

Nothing, block it off!!
If you don't believe me ask Ian Harris from m4 Karting he will tell you the same thing. This connection is for a vacuum fuel tap if the carburetor is installed in a moped or scooter.

You do not have to install a fuel tap, but it would be recommended because if something is broken on the carburetor and it overflows, you can cut off the fuel supply.[/QUOTE]
Thanks mate, have ordered a block off cap set for it.

 

[CAM2]

Thank you for the straight answer Chrisi! I’ve bought a spare china manifold atm and I’m gonna see how I get on doctoring that to get this new carb to fit.

I’ve received the 17.5 dellorto phva now and was just wondering what goes where. First picture is where I think the fuel line to the tank goes and then the second picture I think the red circle is an overflow nipple so just route lines leading down to the floor? I’m stuck for what the blue circle is though. It’s a threaded hole but it’s blocked off at the end. Is this redundant or am I missing something? Thanks a lot.

The blue circle is a left-hand provision for the air / fuel mixture screw as those carbs come lefthanded aswell as right handed...

The factory setting for the a/f mixture screw is 3 5/8 turns out from fully turned in..

Idle screw is 4 turns out

Needle clip is center position

The fuel inlet is next to the choke and don't unblock ant inlets that come blocked off..

The only time you block that fitting on the opposite side off is in karting as kart engines run off of an external vacuum activated fuel pump to feed the carbs when not running a pumper carb and if they didn't run a pump they ran a pressurized fueltank...

We cut out the middleman and went with carbs with pumps built-in and used case pressure to control them..They were finetuned by adjusting pop-off pressure...………..

This kart is a vintage 60's model and the engine is a 137cc IAME engine that runs on methanol...I raced this in the early 80's and still have it.......LOL

I also have a Jr Kart w/100cc engine too

Your gonna have problems if you don't give that fitting 6-7 inches of hose and just let it hang as it also helps put gravity on the float to balance it when the carb is gravity fed....

Good Luck

 

[Tonck1]

The blue circle is a left-hand provision for the air / fuel mixture screw as those carbs come lefthanded aswell as right handed...

The factory setting for the a/f mixture screw is 3 5/8 turns out from fully turned in..

Idle screw is 4 turns out

Needle clip is center position

The fuel inlet is next to the choke and don't unblock ant inlets that come blocked off..

The only time you block that fitting on the opposite side off is in karting as kart engines run off of an external vacuum activated fuel pump to feed the carbs when not running a pumper carb and if they didn't run a pump they ran a pressurized fueltank...

We cut out the middleman and went with carbs with pumps built-in and used case pressure to control them..They were finetuned by adjusting pop-off pressure...………..

This kart is a vintage 60's model and the engine is a 137cc IAME engine that runs on methanol...I raced this in the early 80's and still have it.......LOL

I also have a Jr Kart w/100cc engine too

Your gonna have problems if you don't give that fitting 6-7 inches of hose and just let it hang as it also helps put gravity on the float to balance it when the carb is gravity fed....

Good Luck

Thanks CAM2! Nice kart aswell mate, you love your little engines. Fair play to you! So you’re saying don’t block this nipple off I have circled? Should I just run a hose straight out and hang down similar to an overflow or should I loop it back over the carb itself? I’ve done that before on MX bikes but to be honest don’t understand the reasoning of it lol.
I’ll make sure all set screws are like you say and go from there. Hopefully my air filter lands by the weekend and I can fit it ready for the track. Cheers lad!

 

[Chrisi]

You have to close this connection, otherwise the engine sucks in false air and the mixture becomes too lean.

 

[Tonck1]

You have to close this connection, otherwise the engine sucks in false air and the mixture becomes too lean.

I do have a block off set coming but I’m confused about it now lol!

 

[CAM2]

I do have a block off set coming but I’m confused about it now lol!

Read this......It should clear up some confusion....

https://s776.photobucket.com/user/barretlo/media/17_5mmDellortoWorksheet_zpsc5bd5902.jpg.html

http://www.thisoldtractor.com/mg_manuals/dellorto_manual.pdf


https://www.google.com/url?sa=t&sou...Vaw1dkCBvg2QAV54QAfTUFlXD&cshid=1583860192685

DELLORTO 17 5 MANUAL | sso.homage.com

 

[Tonck1]

I do have a block off set coming but I’m confused about it now lol!

Read this......It should clear up some confusion....

http://www.thisoldtractor.com/mg_manuals/dellorto_manual.pdf


https://www.google.com/url?sa=t&sou...Vaw1dkCBvg2QAV54QAfTUFlXD&cshid=1583860192685

http://sso.homage.com/dellorto_17_5_manual.pdf

CAM2 you absolute legend! I will read them tomorrow as soon as I get chance!

 

[Tonck1]

Finally got round to fitting the carb. Had the air/fuel screw set to stock along with the idle screw but it would not tick over at all. I messaged m4 karting about that vacuum hose nipple and they told me to block it off so I done this. The bike would not tick over even after trying all combinations of air/fuel mixture and idle screw. I took the carb off and upjetted from the stock 90 to a 94. Problem persisted. I then unblocked the vacuum hose fitting as suggested by cam2 but it seemed much worse then. The original spark plug fouled when trying to get it to fire but put in a fresh plug and after that it seemed to be a bit lean if anything. Will I go a higher main jet again or does anybody have any other suggestions? Maybe re block the vacuum hose fitting? I’m at a loss. Lost the head and just packed up lol.

 

[Tonck1]

Also fitted that stuffer into the reed block. I’m not sure if that has affected things. I might try taking it out aswell. See how it runs. I wasn’t sure if it actually sat flush inside the reed so maybe it’s affected the seal between the carb and the reed?

 

[Chrisi]

Finally got round to fitting the carb. Had the air/fuel screw set to stock along with the idle screw but it would not tick over at all. I messaged m4 karting about that vacuum hose nipple and they told me to block it off so I done this. The bike would not tick over even after trying all combinations of air/fuel mixture and idle screw. I took the carb off and upjetted from the stock 90 to a 94. Problem persisted. I then unblocked the vacuum hose fitting as suggested by cam2 but it seemed much worse then. The original spark plug fouled when trying to get it to fire but put in a fresh plug and after that it seemed to be a bit lean if anything. Will I go a higher main jet again or does anybody have any other suggestions? Maybe re block the vacuum hose fitting? I’m at a loss. Lost the head and just packed up lol.

A few things to do.
- let the carb blocked at the engine
side
- did you tested the engine on air
leaks?
- what needel and position of needle
clip do you use?
- what lowjet do you use?
- check you squish gap, should be
lower than 0,9mm

Main jet depending on lowjet but 94 sounds a little bit to small always run 95-98 mainjet with a 34 lowjet and a A07 Needle.

When you have a other carb, try the other and see if it's better, when it's not better maybe there is a air leak at the engine, Reed valve do not close correctly or the ignition has a failure.

 

[Tonck1]

A few things to do.
- let the carb blocked at the engine
side
- did you tested the engine on air
leaks?
- what needel and position of needle
clip do you use?
- what lowjet do you use?
- check you squish gap, should be
lower than 0,9mm

Main jet depending on lowjet but 94 sounds a little bit to small always run 95-98 mainjet with a 34 lowjet and a A07 Needle.

When you have a other carb, try the other and see if it's better, when it's not better maybe there is a air leak at the engine, Reed valve do not close correctly or the ignition has a failure.

What to you mean let the carb blocked at the engine side? Are you saying to block the vacuum hose nipple again like you originally said?
I have no way of checking the engine for air leaks. I believe it’s the stock a07 needle with the clip in the middle position but I will double check. Not sure of the idle jet. Will have a look. I bought it from a blata dealer and was told it is sold with the stock settings for a blata b1. Thanks Chrisi!

 

[Chrisi]

A few things to do.
- let the carb blocked at the engine
side
- did you tested the engine on air
leaks?
- what needel and position of needle
clip do you use?
- what lowjet do you use?
- check you squish gap, should be
lower than 0,9mm

Main jet depending on lowjet but 94 sounds a little bit to small always run 95-98 mainjet with a 34 lowjet and a A07 Needle.

When you have a other carb, try the other and see if it's better, when it's not better maybe there is a air leak at the engine, Reed valve do not close correctly or the ignition has a failure.

What to you mean let the carb blocked at the engine side? Are you saying to block the vacuum hose nipple again like you originally said?
I have no way of checking the engine for air leaks. I believe it’s the stock a07 needle with the clip in the middle position but I will double check. Not sure of the idle jet. Will have a look. I bought it from a blata dealer and was told it is sold with the stock settings for a blata b1. Thanks Chrisi!

Yes Block it off/close it as I said in my first post.
You can start the engine, then take something like break cleaner and spray on the seals and oli seals when the engine run stable its ok, when it change the rpm then there is an air leak.
First all other parts at the engine should work correctly and then setup the carb.

 

[MrKitty]

Here is a way to do a leak down test https://youtu.be/lCFyxLPtu5E once you pump up the engine to about 7 psi spray a mix of soap and water dish soap all around the engine you will see bubbles where the leak is

 

[Tonck1]

Okay, I’ve sorted the problem. The needle was not in the correct position in the slide. I re blocked the vacuum hose nipple and am now running a 98 main jet. All other variables are standard. The bikes running great. I also took the head off and set the squish to 0.8-0.9 and the bike is quick! I’m very happy. Just need to get it back to track and try it out properly!

 

[Chrisi]

Good news 😬😬

 

[Tonck1]

Good news 😬😬

Thanks for your help mate! Just need the tracks open up now!

 

[Chrisi]

Good news 😬😬

Thanks for your help mate! Just need the tracks open up now!

With us it is on May 1st that the tracks open again🏍

 

[Tonck1]

With us it is on May 1st that the tracks open again🏍

Hopefully we ain’t far behind you lad!