{"id":12007,"date":"2024-08-23T20:52:24","date_gmt":"2024-08-23T11:52:24","guid":{"rendered":"https:\/\/www.decoboco.info\/en\/?p=12007"},"modified":"2026-09-24T13:46:24","modified_gmt":"2026-09-24T04:46:24","slug":"whoa-65-horsepower-air-cooled-4-cylinder-last-monster-gpz550","status":"publish","type":"post","link":"https:\/\/www.decoboco.info\/en\/20240823\/decoboco-cars\/zephyr550zr550\/whoa-65-horsepower-air-cooled-4-cylinder-last-monster-gpz550","title":{"rendered":"Whoa? “65 horsepower?” Air-cooled 4-cylinder last monster? I’m getting the feeling that GPZ550 might actually be a hidden gem (*\u00b4\u03c9\uff40*)"},"content":{"rendered":"\n
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Lately I’ve been fixating on 550cc displacement bikes.
Among them, I’ve been diving deeper into the GPZ 550, which has caught my attention for a while now.

It has an engine similar to my Zephyr 550 that I own.
The price is also very reasonable, which suits my taste.
I got the manual in PDF and when I read it, I discovered it has 65 horsepower.
I’d like to ride one if I get the chance.

Why don’t you get fooled into buying one too? <\/p>\n\n\n\n\n\n\n\n

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Choose a model with high parts compatibility <\/h2>\n\n\n\n
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The GPZ550 apparently existed from 1984 to 1988 in versions A1 through A5.
Since I haven’t received the service manual yet, the details are unclear, but
if you’re buying one, a later model year would be better. <\/p>\n\n\n\n

Somehow, the fact that it was made until 1988 gives older guys a lot of peace of mind, right?

Since the engine is basically similar to the Zephyr, you can feel somewhat reassured, right?
There was also a GPZ 400 that existed in domestic and export versions, so there are slight differences, but the peace of mind factor is pretty high.
Compared to the Zephyr 400\/550, there might be fewer parts available, admittedly. <\/p>\n\n\n\n

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At 10,500 RPM it produces 65 PS. You gotta rev it… <\/p>\n\n\n\n

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Anyway! This orange gradient is the deciding factor <\/h2>\n\n\n\n
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This paint job is extremely simple and is basically accomplished with decals.
*Just black with decals applied, that’s the design <\/span><\/strong>of it.
Basically, the paint cost can be kept super reasonable.

Since reproduction decals also exist, you can easily recreate it even if you repaint later, so you can buy any color. <\/p>\n\n\n\n

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Up to A3, I’ve never seen the “TK carb?” which is the predecessor to CVK <\/h2>\n\n\n\n
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At first glance, it looks similar to CVK\u2014the “TK carb?” is apparently equipped on models up to A3.
Old vacuum carbs are a bit scary when considering compatibility, so it’s better to go with a later model if possible. <\/strong>

Alternatively, it might be interesting to use the stock carb from a Zephyr 550 or similar. <\/p>\n\n\n\n

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I found a service manual floating around, so feel free to reference it <\/h2>\n\n\n\n

GPZ550 Manual <\/a><\/strong>

This covers up to A2, but the data is extremely helpful as a reference.
I got one covering up to A5 on eBay, so I’m looking forward to it (*\u00b4\u03c9\uff40*) <\/p>\n\n\n\n

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Front fork is 35mm! Anti-dive equipped <\/h2>\n\n\n\n

The GPZ-specific left-right connected pipes are equipped without exception.
Honestly, this feature isn’t necessary and I’d like a simpler setup.

However, with the front fork being 35mm, the options are somewhat limited.
I could replace the entire front end, but
it seems more fun to do subtle tuning while keeping the budget down.
<\/p>\n\n\n\n

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\u3010Pre-order Now!\u3011GPz550\/320mm Rotor Brake KIT <\/figcaption><\/figure>\n\n\n\n

A terrifying product is about to be released from the Speed Shop Itoh that I admire.
\u3010Pre-order Now!\u3011GPz550\/320mm Rotor Brake KIT <\/a><\/span><\/strong>

With this, you can brake with confidence.
But to develop a brake kit for such a niche vehicle\u2014that’s Itoh for you.
That’s some serious passion. <\/p>\n\n\n\n

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In the end, is just lusting after it without buying the best deal? <\/h2>\n\n\n\n

If I buy it, fix it, and sell it, that’s fine, so there’s no problem with purchasing.
But I also have my own bikes that need fixing, so
I’m questioning whether adding another one here is the right move.

Somehow, on Yahoo Auctions they’re trading for around 400,000-600,000 yen, which is a very affordable price range.
If you want an air-cooled 4-cylinder that’s a bit different from what others have, it might actually be a good recommendation? <\/p>\n\n\n\t\t

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\n\t\t\t\t\t\n\t\t\t\t\t\t\"\"\/\t\t\t\t\t<\/a>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t
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\n\t\t\t\t\t\n\t\t\t\t\t\tZephyr 400\/550 CP2696 Support Speed Shop Ito Kit\t\t\t\t\t<\/a>\n\t\t\t\t<\/div>\n\n\t\t\t\t\t\t\t\t\t
\u30a6\u30a7\u30d3\u30c3\u30af\u3000\u697d\u5929\u5e02\u5834\u5e97<\/div>\n\t\t\t\t\n\t\t\t\t\t\t\t\t\t
\n\t\t\t\t\t\t\u00a534,666\t\t\t\t\t\t\uff082026\/09\/22 19:35\u6642\u70b9 | \u697d\u5929\u5e02\u5834\u8abf\u3079\uff09<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t\t
\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\n\t\t\t\t\t\tAmazon\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t<\/div>\n\t\t\t\t\t\t\t
\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\n\t\t\t\t\t\tRakuten\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t
\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\n\t\t\t\t\t\tYahoo!\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t
\n\t\t\t\t\t\"\"\n\t\t\t\t\t\u30dd\u30c1\u30c3\u30d7<\/span>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\n\n\t\t
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\n\t\t\t\t\t\n\t\t\t\t\t\t\"\"\/\t\t\t\t\t<\/a>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t
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\n\t\t\t\t\t\n\t\t\t\t\t\tZephyr 400\/550 Preload Adjuster Black 22671101 Hyper Pro (HYPER PRO)\t\t\t\t\t<\/a>\n\t\t\t\t<\/div>\n\n\t\t\t\t\t\t\t\t\t
\u30cf\u30a4\u30d1\u30fc\u30d7\u30ed(HYPER PRO)<\/div>\n\t\t\t\t\n\t\t\t\t\t\t\t\t\t
\n\t\t\t\t\t\t\u00a523,016\t\t\t\t\t\t\uff082026\/09\/20 15:33\u6642\u70b9 | Amazon\u8abf\u3079\uff09<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\t\t\t\t\t
\n\t\t\t\t\t\t\n\t\t\t\t\t\t\t\"\"\n\t\t\t\t\t\t\t\u53e3\u30b3\u30df\u3092\u898b\u308b<\/span>\n\t\t\t\t\t\t<\/a>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t
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\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\n\t\t\t\t\t\tAmazon\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t<\/div>\n\t\t\t\t\t\t\t
\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\n\t\t\t\t\t\tRakuten\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t
\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\n\t\t\t\t\t\tYahoo!\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t
\n\t\t\t\t\t\"\"\n\t\t\t\t\t\u30dd\u30c1\u30c3\u30d7<\/span>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\n\n