bore up Yamaha Jupiter-Z hingga 200cc

Pasca bore up liner silinder Yamaha Jupiter-Z hingga 200cc ke atas, kendalanya diameter lubang exhaust justru menyempit. Apalagi jika pasang payung klep aftermarket yang rata-rata diameter 34/28 atau 34/30. Akibatnya aliran gas buang nggak lancar akibat tercekik.

“Itu karena diameter lubang exhaust standar Jupiter-Z cuma 20mm. Kalaupun bisa diporting, paling gede diameternya cuma sampai 25mm. Sebab lingkar luar pipa knalpot aftermarket rata-rata berdiameter 28mm,” ucap Chandra Soepandi pemilik bengkel bubut Master Tjendana.

Biar aliran sisa gas bakar makin lancar dilepas knalpot mesin kapasitas besar, Chandra kini punya solusi. Yang dilakukan membesarkan diameter lubang dudukan knalpot asli. Sehingga pipa knalpot besar bisa dipasang. Juga bisa bikin gede diameter exhaust.

Keuntungan bore up pakai metode ini karena sisa gas bakar dilepas sempurna. “Apalagi menurut buku panduan korek karangan Abraham Bell, biar nggak ada hambatan aliran di ruang bakar mestinya lubang knalpot harus lebih besar dari diameter lubang exhaust,” imbuh si necis.

Atas dasar itu, Chandra coba modifikasi seputar lubang dudukan knalpot di head Jupiter-Z. Lubang asli diameter kecil, dibantu mesin bubut jadi lebih besar.

Pembesaran lubang dudukan knalpot tetap pada posisi lingkar asli. Tidak miring kanan, kiri, atas atau bawah. Saat pasang knalpot aftermarket pipa lebih besar, kedua baut bisa dipasang mengikat penjepit pipa knalpot tanpa ragu.

“Besarnya lingkar luar bisa untuk knalpot diameter 32mm, sehingga lubang exhaust bisa diporting mulai diameter 25mm hingga 28mm. Ukuran menyesuaikan mau mekanik peracik mesin,” lanjut Chandra yang patok harga modifikasi ini Rp 300 sudah termasuk paking albronze.

Selain ubah lubang dudukan knalpot, Chandra juga punya knalpot aftermarket dimeter 32mm. Wah!

Albronze Kurangi Turbulensi
Mengurangi turbulensi di antara lubang exhaust dan pipa knalpot pasca pembesaran lubang dudukan knalpot, Chandra juga melengkapi ubahan ini dengan memasang paking tambahan yang bukan dari material biasanya. Sehingga sisa gas bakar yang dialiran melalui lubang exhaust. Benar-benar lancar tanpa tekanan berarti.

Kali ini meterial dasar paking atau penutup celah agar tidak bocor yang tepat adalah bahan albronze. Sehingga meski sudah terjepit oleh knalpot, namun kondisi paking masih tepat alias tidak bergeser pada posisinya. Sehingga diyakini tidak ada lekukan pada paking yang bisa menyebabkan turbulensi.

“Kalau gunakan paking biasa, takutnya saat dijepit knalpot malah jadi gepeng hingga meneyebabkan terjadi penyempitan. Aliran gas buang pun malah bisa nggak lancar,” wanti Chadra dari Jl. Pagarsih. No. 146, Bandung.  


  (motorplus-online.com)

BOUR UP HARIAN MIO

OTOMOTIFNET - For daily, do not need a large bore up. Origin of power up, the motor with a capital ngibrit quite economical. For, the user Yamaha Mio, please copy Utomo, mechanic Tom's Racing in Pondok Benda, Pamulang. "Take advantage of the Suzuki Smash piston, rising 53.5 mm bore so. Not cost much, but the maximum power, "explained the mechanics with dyed red hair.

Originally it bore x stroke Mio = 50 x 57.9 mm. So, in person, change the bore to be 53.5 mm, the capacity to be increased more than 120 cc. But, of course not directly plug. First, it must gedein block with liner first lathe to 53.5 mm piston can go. No need to replace the boring, quite dikorter.

Then, lathe pin hole of 1 mm. Because, the piston has a pin Mio's 15 mm. Meanwhile, Smash piston congenital punyalubang only 14 mm. "Do not forget to ask also to make a turner to create a clip or spi got the piston," this little light-bodied men.
Also do not forget to ask that the piston height adjustable. Originally, the piston Smash distance from the third to the bottom piston ring 31 mm. "Well, Papas bottom until almost smooth. The distance to the ring at the bottom would only 22.5 mm, "said the mechanic who still oprek 2-stroke racing engine is. Finished it, put deh. Baseball needs to the person who tinkers piston head or a dome, also change the cylinder head. "Because the diameter of the piston squish Smash approximately 44.7 mm. Well, the original head Mio to 50 mm. So mendem, deh. Going to hit a baseball, "said mechanical rada this dark-skinned. Now talking about the cost? Smash the following piston ring set free in the price range of $ 98 thousand. At least not until the lathe cost Rp 100 thousand. "What's done so well there. "Priced $ 300 thousand," said Utomo ready dikontek at (021) 923-32-976. Hello, capa ya?

High piston and pin holes are also adjusted

source: www.otomotifnet.com

PROMOSI WISATA 2012

Ministry of Tourism and Creative Economy (Kemenparekraf) establish three tourism promotion strategy in the country for 2012. "The strategy that we apply a promotional tour for next year has not undergone many changes, we have set three strategies," said Director of Domestic Promotion Kemenparekraf, Muhammad Faried in Jakarta, Friday (12/16/2011). Faried said, three things ...







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