MAKUNI Carby

[short.y]

hey,
ive got a genuine thumpstar 110cc 2005 model which has a genuine MAKUNI carby in it. Does anyone know the size of them??
eg.25mm
i dont know how to measure them, therefore it would be easier to be told the answer or if someone can tell me how to measure the carbys?
thanks.

sorry i spelt the brand wrong, i meant to write MIKUNI

 

[wogtaz ryder]

22mm id be guessing?

only one way to find out measure it..... dont ask me how to measure it tho ...

do some searches of thumpstar specs in google.

 

[Cactus Jack]

You measure the area thru the venturi (smallest part just in front of and behind the slide) ... A true 26 mm carb will measure 26 mm in diameter thru those areas ... ie 26 mm in height and 26 mm in width ...
The two Mikunis which come supplied on most China engines are:

The 22 mm Mikuni oval bore carb (25 mm out of the rear and the venturi is 25 mm high x 18 mm wide) ...

The 26 mm Mikuni oval bore carb ... (30 mm out of the rear and the venturi is 30 mm high x 22 mm wide) ...

Now if you picture a cross placed inside the venturi ... you'd get one that's 26 mm wide and 26 mm high in a round bore 26 mm carb ... in the oval bore 26 mm carb the cross is 30 mm high and 22 mm wide ... if you take 4 mm off the 30 mm height and add it to the 22 mm width you get !!!!!! .... 26 x 26 ... the same as the round bore carb ... so they are both equal in peak air flow capability ... The reason for using an oval bore is to minimise the rate of vacuum and air speed drop as the slide is lifted ... The 26 mm oval bore carb acts like a 22 mm carb off idle to give better low down response and pulling power under load ... then morphs into a 26 mm carb at full throttle ... The 26 mm round bore carb acts like a 26 mm carb right off idle and can be easily bogged under load at lower revs ... But on a worked engine which is geared to allow it to increase its revs quickly , the round bore carb gives quicker response with less twist of the throttle ... and that helps for racing ... An oval bore carb is better for trail riding , hill climbing and stunting ... There is a carb that looks like a copy of a Honda XR200 26 mm oval bore carb and they work really well everywhere on stock chinese engines ...

 

[headsmess]

llǝʍ sɐ sɹnoʎ ɟo ʇouʇooɟ ǝlʇʇıl ʇɐɥʇ pɐǝɹ ı lıʇun ıunʞɐɯ ǝuınuǝƃ ɹnoʎ ʇnoqɐ ƃuıɥʇǝɯos ʎɐs oʇ ƃuıoƃ sɐʍ ı ʇǝʎ pɹɐǝɥ ǝʌı sǝɹoq lɐʌo ɹoɟ uoıʇɐuɐldxǝ ʇsǝq ǝɥʇ ǝq oʇ sɐɥ ʇɐɥʇ 'llǝʍ

 

[Cactus Jack]

I see you've played Slack Babbath at 87 speed headsmess ... LOL ...

 

[headsmess]

"ɐuɐnɾıɹɐɯ ǝɹoɯ ǝʞoɯs u doɥɔ" ǝʞıl spunos ʇı 'spɹɐʍʞɔɐq "ʇsnp ǝɥʇ sǝʇıq ǝuo ɹǝɥʇouɐ" suǝǝnb ʎɐld noʎ ɟı 'lllǝʍ