Pumper carbs, Whats out there?

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These few words say it all when it comes to port size and intake runner lengths ...

Intake Port to Torque Peak

* Long Port Length: Improve low RPM range
* Short Port Length: Improve high RPM range
* Large Cross Section: Works better on larger CID and higher RPM
o Too large of a cross section can cause reversion and less power
* Small Cross Section: Works better on smaller CID and lower RPM
o Smallest cross section without losing HP is the best size
 
there are not many guys that have tried accel pumps carbs on these small engines, they do work extremely well if you have the room for them.
 
What happen to de guy who buy pump carb ? He is talking , talking saying I testing and keeping you posted. Then all gone silence of de lamb.
 
mattbombers said:
You need to work on your grammar a little bit mate;)
Click to expand...

What ? You no understand what I saying ? :confused: Englis teacher telling me I doing very well . Maybe I directly copy what other peoples are typing ?

Many people saying they gunna do dis and dat on forum , but never finishing ! I find strange that .
 
i can read Tai Chi's posts a damn sight easier than some of the OMG Fooly sik uleh wtf EMO POS IMO text speak some of the young fellas post.
Plus tai chi is using punctuation... not something you see every day on here..
Dont worry Tai Chi, we can read you fine.. :)
 
Tai Chi Chameleon said:
What happen to de guy who buy pump carb ? He is talking , talking saying I testing and keeping you posted. Then all gone silence of de lamb.
Click to expand...

Dis guy who buy pump carb is waiting waiting for jet for tuning an manifold fo fiting....

In all seriousness, just waiting on a few main jets and the manifold that i'll be using.
I have the adapter that fits it but now awaiting a manifold that'll fit the adapter.

I have temporarily mounted it on an old manifold with near the right bolt pattern but only has a 20mm port through it. I have tuned the slow jet but see no point in doing the main as it'll all change when the suitable manifold gets here and is mounted.
 
Thanking you ! So pump carb fits on bike and engine runs properly on bottom end with it on ? How it responds to throttle turn compared to normal carb ?
 
As said, i've only done the pilot jet. I don't want to waste my time on the main jet untill i have the manifold that i'll be using.
You must understand that these are very large carbs so they won't fit most bikes in the normal postition. I'll try and get a comparision photo this arvo between it, an OKO and a molkt.
 
Here we go, OKO 28 vs. Mikuni tm28-1

IMAG0044.jpg


IMAG0046.jpg
 
photos are pretty ordinary but you get the picture.

Molkt vs the TM pumper

IMAG0047.jpg


IMAG0045.jpg




As you can see they won't easily fit in most bikes and the TM pumper is currently mounted to a manifold to make the tuning easier since it requires removal of the bowl for jet changes and the mixture screw is in a pain of a spot.
 
De TM28-1 looking like 30mm or more bigger carb.......De 28mm OKO looking like 28mm.......De molkt looking only like small 24mm hehehe.........................................

Maybe you take de comparison picture between 26/28 molkt and 28 mm oko ? You have measure this carbs ?.............. Very great pictures.............. Thanking you for de effort.............
 
Tai Chi,
you are correct,
The Molkt is a 25mm version. I used this along with the OKO as a comparison against the pumper TM because they are fairly common. I would have used a VM Mikuni as well if i had one at my disposal.

However, the TM28-1 measures in at 32mm x 24mm giving it the appearance of being larger but it is indeed 28mm.
 
<a href="http://s625.photobucket.com/albums/tt334/96moto/?action=view&current=Image0182.jpg" target="_blank"><img src="http://i625.photobucket.com/albums/tt334/96moto/Image0182.jpg" border="0" alt="Photobucket"></a>
hope it worked
this carb looks crap compared to the one that 1 50 1 wheel has.
has anyone tried it?
i had it on a 50cc 2 stroke went really good [rejetted ]
also on std 125 4 stroke with out pumper hooked up went std
its of a 150cc road bike that goes crap.
 
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Aha ! ... The TM28-1 is an oval bore carb designed to maintain higher velocity (ie torque) at partial throttle settings and lower revs ... ie trail riding , hill climbing and low speed /hi load usage ... 32 + 24 = 56 divided by 2 = 28 mm diameter in venturi area ...

That carb should work excellent overall to broaden the torque curve since it has an accelerator pump ... but don't go twisting it and flooding things while the engine isn't running or when trying to start the bike ... And they work best if the throttle is rolled on to create a fuel injection type effect ... not whopped wide open in every gear so that the cylinder gets dumped with fuel which then sprays out the exhaust pipe unburnt ...

It's a pity the Japs have to jack the price up to a ridiculous level simply because it has a built in syringe ...

Have you modified your MOLKT's venturi ? ...

Every time I read where people say they are bigger than 24 mm I can't help it but pull out the dial gauge verniers and inside calipers and re-measure all of my MOLKTS just to be dead certain I'm correct ... 23.95 mm every time ... So you can drop a $1 coin into the venturi and it'll go right thru ? ... ( I wonder how many kids did the $1 coin test ) ... LOL ...


You are asking good questions Tai Chi Chameleon ... Welcome to Miniriders and Australia ... but work on your english and grammar and you'll be much betterer ... Cheers mate ! ...
 
You would be correct Cactus, the molkt is 24mm. I'm not sure why i wrote 25 in my previous post which states that Chameleon is correct. He had said 24mm.

Must have been a typo!

I'll definately be rolling the throttle on and not snapping it open with that one as it does squirt a fair volume!
 
Yes if you bang the throttle wide open on each shift like you're riding a two stroke you will actually lose power ... countless goons do that on 4 stroke MX bikes that have accelerator pump carbs ...

All you are doing is discharging the pump volume in one go at low revs so the extra fuel flies out the exhaust and maybe causes the engine to bog ... then the bike will run thru the gears just like any other with a normal non pump carb on it ... LOL ...

I've seen countless goons swearing and cursing trying to start accelerator pump carb'd bikes ... they twist the throttle as they kick and all they are doing is keeping an already flooded motor saturated with fuel ... When they learn to get their hand off the throttle , the bike starts instantly ...
 
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