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And a word of caution, when the engine gets that hot, best to back off on that throttle or, better yet, stop and let it cool down for a while (and hopefully traffic will dissipate too). Otherwise, you risk heat distortion and other bad things. Not just advice for air cooled, either. My liquid cooled (and E.F.I.) Yamaha R1 drops about 20 HP and runs like a bag of cow dung when it gets really hot (in city traffic), even with the radiator fans going.

I am surprised that the R1 drops that much power? Anyway we all seem to agree that drilling is not the best option. Suzuki got around this by injecting the oil onto the pistons from the bottom, that seemed to work but the Kawasaki oil pumps would not be up to the task with their low pressure.
The extra oil cooling will solve most problems but I don't believe that a standard big block would dissipate the heat quick enough into the oil.
Jberger, I wish you luck at solving this issue. Maybe just keep the revs below 3,000rpm

No eBay APP ID and/or Cert ID defined in Kunena configurationI guess the problem with any big bore kit is the reduced liner thickness and cooling space between the cylinders, with the inner pots running hotter on all aircooled four anyway. The big Suzukis and some Kawis had differing carb jetting for the inner pots - maybe you could tune this into the EFI for slightly richer fuelling on the inner pots?

If you have to back everything off to make it reliable for street use you might just be getting an 1170 kit and nailing it to the max. What might work great for about 9.5 seconds on a drag strip might not be so good as a daily driver.

I am also running dual plug and will cut back the ignition advance to avoid heat and detonation.

Interesting, the zephyr ZR1100 had a dual plug head too. Can these be fitted to a gpz11? ( The ZR550 block and head also had larger fins, even though a lot less than GPz550 power)

Something I really don't like to see on bikes is wrapped headers, it is supposed to reduce underbonnet temperatures in cars and it is claimed that keeping the headers really hot is good for performance. Whether it works on a bike I don't know but you might be shifting a bit more heat from the front of the head to the back and out of the exhaust if you can tolerate the look of wrapped headers.



Good thread, keep it coming

Zeph 1100 head won't fit . Not even close and Stainless steel headers are the way to go for max gas flow.

i searched for awhile yesterday to find the pics to illustrate what i'm talking about but couldn't.
i have seen pics from the vintage motorcycle scene in japan and noticed that some of the more race oriented looking bikes would sometimes have these aluminum looking clothes pin type deals clipped onto all of the fins ,side by side everywhere they could fit them.
seems like it would make sense that you are adding area but maybe disrupting the air more than necessary.

leon

edit : found some pics.

wow, crocodile clips, and not even painted matt black. But the idea is there, just badly executed. Could be worthy of an experiment with an infra red thermometer, to see if it makes any appreciable difference.

I love the Japs engineering and a lot of their culture , but some parts of the custom bike scene in Japan is goofy beyond belief.

How much proportion of heat is removed from the head by the oil? Cooling the oil further, even a liquid cooled intercooler and adding extra capacity is do-able but I wonder what effect it would have.

Bozo wrote: And a word of caution, when the engine gets that hot, best to back off on that throttle or, better yet, stop and let it cool down for a while (and hopefully traffic will dissipate too). Otherwise, you risk heat distortion and other bad things. Not just advice for air cooled, either. My liquid cooled (and E.F.I.) Yamaha R1 drops about 20 HP and runs like a bag of cow dung when it gets really hot (in city traffic), even with the radiator fans going.

I am surprised that the R1 drops that much power?:

My mint, low mileage, and bone stock R1 willingly power wheelies in second, sometimes even third, when it is running at coolant temps of 76 - 80 degrees C. I've had it "lift off" at 120 mph before on a cold day . Power drops rapidly after 80 deg. C. Above 90 deg. C, it won't pull the front wheel up in first gear. Over 98 deg. C and it starts to bog and wants to stall leaving a stop. I can smell hot / near boiling antifreeze, too. So I would say there is a major power loss .

Recently, I bought another R1 identical to the first except it has an aftermarket exhaust system, but haven't had it out on the road yet (too busy with KZ projects). I'm curious if it will behave the same way...

Fascinating project. I look forward to more

dry fitted engine just for looks and mocking up some parts. heres what she looks like.

Engine is currently being put together and bottom end is already complete. Head and jugs will be on later in the week.

Just curious, has the MTC block got larger fins than standard, basically what makes it different?

What a sexy view! I love that matte paint on the engine parts too! Is it powder coated?

Devin

The difference between the mtc block and stock block is the size of the sleeves. You ca only go up to about 1200cc in the stock block, this is 1394cc. The fins are wider as well but the main difference is obviously the sleeves.

And no it isn't powder coated. Cases and head are plastikote gloss black engine enamel, covers are textured black and block is just high heat clear coated

Bozo wrote: Just curious, has the MTC block got larger fins than standard, basically what makes it different?

- the big blocks (MTC, FBG, Wiseco, etc.) all are solid; there is no cooling air passages between the cylinders that the stock block has. One of the reasons jberger has put so much effort into "oil cooling" this monster. The BB cooling fins are thicker, and there are considerably less fins, and less cooling surface area (ironically). On the 1325 - 1500 cc cylinder blocks, boring the top crankcase to clear the cylinder liners leaves only about 5 mm of top case aluminum left between the cylinders, and the gaping holes get really close to the center cylinder studs. Anything bigger than 1500 cc, and the four center cylinder studs (nearest the cam chain tunnel) have to be moved outward.

I'll post some pics of the amount of material removed from upper case boring and the front and top views of the stock and 1395 cc blocks this weekend....I also am machining the billet oil cooler and oil main gallery adapter for jberger's build this weekend...