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Dragbike Engine 22 Apr 2019 20:45 #802660

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I think you don't see enough pictures of racing engine internals on here, and since I don't compete, I thought I would share some.

I had the top end off the bike and figured you guys might like to see a few pictures. The engine is effectively a 1600 J model. Not just a J model head on a KZ, but an actual J model engine. It's a 1500 with a 70mm (4mm over) Falicon billet stroker crank. Head was ported and machine work done by Paul Gast's shop. Has 42mm titanium intakes and 34 mm titanium exhausts.
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Dragbike Engine 22 Apr 2019 20:49 #802662

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It has 44mm welded on spigots, and the 2 outside spigots are moved about 1/4" to the outside in an effort to straighten the port, as the 2 outside ports have the largest curve. The floors are epoxied to maintain velocity. The ports are very large for a stock head casting.
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Dragbike Engine 22 Apr 2019 20:53 #802663

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The pistons were matched to the combustion chambers, which were re configured extensively, as you can see the squish is very small for a 1500 with a stock head casting. The chambers were opened up quite a lot. You can also see how much the head was milled.
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Dragbike Engine 22 Apr 2019 20:55 #802664

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The spacer under the block for the stroker. The pistons are as close to zero down in the bores as we can get them; They are about .002 below deck height. We run a .043 copper head gasket.
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Dragbike Engine 22 Apr 2019 20:58 #802665

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The crank
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Dragbike Engine 22 Apr 2019 22:04 #802667

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A clearer picture of the ports. You can see how far #4 has been moved int this picture.
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Dragbike Engine 22 Apr 2019 22:18 #802668

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How long does that epoxy last?
Steve

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Dragbike Engine 22 Apr 2019 22:24 #802669

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The head was done 6 years ago, and who knows how many heat cycles. It's Marine-Tex, and should last a very long time.
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Dragbike Engine 23 Apr 2019 03:20 #802671

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well done, what sort of camshafts are you using and is there forced induction ?
First Permanent ride the Z1R since Dec1977 (220,000km) as of June 2015
Second permanent bike 1989 FJ1200 dyno'd 140RWH, great bike.
Third ride is now the Frankenstein 1981 GPZ1100B1, getting new/ refurbished 83-84 motor soon
Forth my work bike FJ1200 1989 (same type as above)

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Dragbike Engine 23 Apr 2019 06:37 #802681

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No, the bike has 44mm Lectrons. The intake is a little over .500 lift, and the exhaust is a .480.

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Dragbike Engine 23 Apr 2019 11:29 #802698

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Man, those are a great series of pics - thanks for sharing those, sparcuser - very cool! Maybe you could provide additional details/pics of the entire bike in a different post? Obviously a car tire chassis . I'm going to guess mid to high 7's in 1/4 mi?

Unusual to see J/GPz cases used for an ultimate build like that, I think mainly because you lose the bottom rear motor mount with the J-cases. It can be done, though, as proven by Steve Rice with his funnybike, back in the day.

Looks like some Falicon knife rods hanging on the crank? And, looks as though the multiplate cam chain is still being used - interesting! The porting on the cylinder head is rather intense - but there's no way around it when trying to generate big HP numbers with normally aspirated motor..

Other details that I see - the gas ports drilled into the circumference of the piston crowns to backload the top compression ring - nice. And check out the top of the cylinder flange - I remember taking a Dremel to my cyl head locating dowels to fit what is now a three quarter moon at the top of the cylinder flange.

All part of the million and one details when building high output race motors (although I took the easy way out by using turbo power :) )

Thanks again for posting those pics - brings back a lot of great memories - greatly appreciate it!

Mike
Presently - 1980 KZ1000B4 LTD w/mild ported head, Megacycle cams, 1015cc Wiseco, Falicon Supercrank, R&D undercut trans
In a former life - KZ-based dragbike - CrMo car tire chassis, 1395cc, Hahn Racecraft turbo system, VP C16, Orient Express 3-spd auto, 7.80's @ 165-170.
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Dragbike Engine 23 Apr 2019 13:23 #802710

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Thanks Mike. I thought some people might find it interesting, although honestly I have mixed feelings about putting this stuff out there. Guess I'm secretive at heart.

Anyway, it's a Koenig pro mod chassis with a 10" rear and 10" pro stock tire. You can see some nice pictures of the bike when it's together by just doing an image search in Google for "kawi dragbike". It's the first result. You can't miss it.

I chose to build a J engine because the transmission is stronger, I feel the 2 front mounts are better than the old KZ setup, and I never believed all the talk about the silent chain being weak. Tsubaki's own technical information makes it clear that silent chains are stronger than a standard chain of the same size. As long as they have lube, they are fine. I run a 2 link longer chain for the stroker. It's actually for a Honda.

It currently has a multi stage lockup in it, and I have a slider I don't use because I usually race alone. I currently run it 1/8 mile, although life has gotten in the way, and I have done little racing the past few years. It has a Robinson 3 speed full auto in it for the 1/8th. When it was run in the 1/4 it had a 4 speed. It can run the 1/4 in the 160's with me on it at about 2000 ft. above sea level. I weigh around 210 suited.

The blue bike below had the same engine as now, but no stroker - it was a 1500, was back-halfed, and the bike was very heavy. That nifty rear wheel Sandy Kosman sold me looked cool, but was billet, and weighed a ton. I was also 20 lbs. heavier. I liked the small tire bike, but it was always badly overpowered, and could be tough to ride. Used to run in the mid - high 150's with that setup.

Curtiss
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