Roger P.

Cut off the PAIR nubs, file flat, tap for 8mm hex bolt. Works fine but don't over torque.

10.5:1 assuming 1mm head gasket with 81mm gasket bore size. Sounds a lot more reasonable. Probably a small drop in power over my current 1157 stock bore + DOT head.

Well after acquiring an SV piston from that site, I did some measurements and got a compression height of 24.8mm, which is .01mm less than what I have seen quoted for a stock Busa piston. That may just be tolerances or measurement error, but even so, I calculate the extra clearance at approximately 0.5cc if correct. Now, if a DOT head has a 22cc chamber, and an SV piston has a 4 to 4.5cc dish, I am getting a CR of up to 12.7:1. That seems a bit much for street use. Here's my calculations: 8.1 x 8.1 x 5.9 x .7854 + (22 + 4) = 330cc 330cc / 26 = 12.7 If I throw in the extra half cc I get 12.47. Would either be useable in the street? Someone want to check my numbers? This is before the head gasket though. SV has bigger valves than a DOT head, so the valve pockets may not need much work, if at all. I am wondering how much heavier this complete piston is than a stock 1157 one.

Dot head is screw and locknut on forked rockers, not shims. You will need the dot head inlet rubbers to match the ports. They are different parts numbers to other boilers. I ordered mine along with the head they came off of from that auction site. I also have RS38's on my bike and need to set up the accelerator pump. Other than that, it rips! 89 slingshot cams really wake up this motor. I had to renew the o-rings on the inlet rubbers. I liberated some for our stock. I needed #130 o-rings, but managed to make #129 work. Get yourself a heat gun to soften up the inlet rubbers. You'll be swearing if you don't, then you'll swear some more when you heat them up and they pop in easy like. Now waiting to see if I have managed to procure a 1216 block. It's an addiction.

I read it as they were using Busa pistons to save weight and allow the engines to spin up quicker, then they pulled out a leaf from the muli layer gaskets to up compression at the same time. Seems like it was more lore than actually useful, as 17grams per piston hardly seemed worth it. The mod seemed to fall out of favour a few years ago. Anyhow, just looking for a cheap 1216 that doesn't waste the CR increase the dot head gave me. Some back of a napkin bore x stroke calculations got me 12.5:1 in an 1157 with a dot head but I am probably making a few too many assumptions.

Does anyone know if a stock 81mm SV650 piston would work in a 1216? I was curious if it might give more compression than a stock Hayabusa piston. Pin height seems to be different and the dish seems less pronounced.

http://www.carpenterracing.com/headporting.htm

When I went looking for hotter cams, I happened to find a ratty 89 Slingshot sitting in a breakers yard in Edmonton, Alberta, about 2500km west of me ( I was visiting family). I stood by as the cams were removed from the motor, and they were stamped B (intake) and G (exhaust), so that's about as authoritative as it gets I suppose. My K4 Bandit intake cam was stamped W. The 88 DOT head GSXR cams are both B, and reinforces the statement that the 89 had a softer exhaust cam than the 88. According to the manual I have, 91 750's are stamped A, except for Sweden which are stamped C on the intake.

Had my K4 Blandit out today for its first real run with a 1991 GSX-F DOT head, 89 slingshot cams and rs38s with pods. Well worth the effort. I was up to 240km/h and it was still pulling well, whereas the stock setup would have been falling on its face by then. I used Gurls blouse Graphite Gray Metallic paint for the head and its pretty much a perfect match for the paint color.

This tap worked for me on that Suzuki which shall not be mentioned. It still needed the handle trimmed to clear the tops of my RS38 carbs. Much cheaper than a Pingel. Use of wood screws not recommended. https://fortnine.ca/en/acerbis-replica-Gurls blouse-tank-petcock

Ok, so 500cc * 1.6 / (1157/2) = 1.38, so, 0.38* 14.7psi = 5psi on a Bandit 1200 motor. Probably not enough for a massive power gain, but I wonder if such a low figure would play nice with a higher compression ratio?

Does anyone have a general guideline as to how much displacement a supercharger should have for a given engine size? I see lots of small blowers from Japanese Kei cars on offer for little money, the Aisin AMR500. They displace 500cc per revolution and are good to 16,000rpm, so with a 1.6 overdrive and keeping it to 10k rpm or less you should be good to go. I've run the numbers through an online calculator but i get only 4psi of boost for the answer. I'm not too sure how much confidence I should have in these answers. Any ideas?

Starts a lot easier with straight exhaust valves... Exhaust cam was retarded just enough to burnish the piston reliefs. Couldn't see any damage by eye, but filling the chambers with gas revealed leak through to the exhaust ports. I swapped in my Bandit valves and the chambers stayed full of solvent overnight so I'm satisfied they are sealing well. Finally buttoned it up and started it, and was immediately rewarded with a cloud of smoke from a pinched valve cover gasket leak. That was after the last headpipe bolt refused to thread in and I had to disassemble it again to chase the thread. Hoping to hit around 130bhp at the wheel, which the RS38s should help with. What a cunt of a job getting them into the inlet rubbers in cold weather. Finally had to run an extension cord out the back and hit it with the heat stripper, whereupon they popped into place almost silently, which was both a relief and a pisser considering the effort expended in the previous hour with ratchet straps and cursing. Must be the most prolonged dot head swap in the history of this goddamned motor, but it's finally in and working. It better go like a streak of shit through a tin whistle!

Well, drama..... Finally fired this thing up after finding a fuel tap to fit. Started up fine, but what a racket. Are RS carbs that noisy? It sounded like detonation. I was concerned I was getting valve to piston interference with the 750K cams, but I checked and triple checked my cam timing according to the Bandit manual, and swapped out each cam sprocket one at a time to ensure I didn't mix them up. Got it to idle on choke and went to fill it up but it just ran rougher and rougher until it died. Pushed it to the gas station, put in some high test and cranked but would not fire. Also sounds like the starter motor was working hard. Pissed off good. 2km push to home. Flooding? Got the odd backfire from the pipe. Sounded like it was trying to fire but couldn't catch, kinda like starting a stored bike after the winter with old gas in it. Dumb question, does the RS carbs come with jets installed already? If not, that would explain a lot... Plugs were black but not wet. Got some smoke on start up which I put down to the new head pipes burning off oil. Idle screws were lightly snugged by finger and backed out 1/4 turn. Individual pod filters. The K&N RU2922 were far too wide to clamp down properly on the RS38 bellmouths, and they only went onto them by about 1/4". Also a loud buzzing sound. This is my first time with RS carbs so I don't know what they are supposed to sound like. Pretty poor result for the time I put into this, I was careful not to rush it. Haven't had time to sort it out, but it will come right, hopefully before the snow.

I'll let you know! My teapot DOT is going on my K4 Bandit. Incidentally, it seems even teapot cams are higher lift than what the Mk2 Bandit uses.

Thanks fellas. Hoping for as little drama as possible, as the riding season is getting short and I'd like to have a few runs on it before I have to tune up the snowblower. I got 38's as they were actually $100 cheaper to buy than the 36's on Am*z*n, even if they are a bit much for such a mild upgrade. Call it future-proofing I guess. Took forever for them to arrive, and The Man took another $200 tax bite when they showed up at the door. Came the same day as the Black Widow head pipes. They weigh a hell of a lot more than the pipes do!

Powder seems to hold onto the heat quite a bit more than paint http://www.chopcult.com/news/articles/techs-by-steve-brewdude-garn-head-coatings.html

Fitting the DOT head to an 1157. Using K&N RU-2922 duplex filters. Yoshimura RS3 can and midpipe, Black Widow headers on the way. Considering the displacement is not enlarged, and the carbs are setup generally for a pipe and filters + some headwork, does anyone have an edjumicated guess as to what the likely jetting would be required for this setup? I'll fuss with it for awhile, but there is a dyno and setup guy near enough that I'm willing to chuck some money at it if it gets too infuriating.

Jesus Dave, you lucked into another set of smoothbores I see. Good luck with the build, your other bikes turned out ace. You're on as many Suzuki sites as I am... I did a few weeks at M7 last winter. Your lovely face is still on the instruction sheet for changing out the coalescing filters on the main air line from M5. If you ever come across a pitch black 1980 1000S with an 83 motor, wheels, and 81 1100 tank on your travels out west, it used to be mine!! Too bad I didn't know you had those carbs, I might have swapped them for a set of Bandit BS36's that will become redundant next week. Would have saved me the $1200 for those RS-38s!