slabby motor vs b12 motor

[boilerdude]

Is there anything that stands out about one or the other to make it better for a build? If you had them both in very similar condition a very clean slabby motor. For big bore or turbo application. What reasons might I use one engine or the other? Do either of the heads really flow better than the other? is either of the bottom ends stronger than the other? Trannies? What are some key differences between the two.

 

 

 

 

[Rene EFE]

In stock form there is a 100+cc capacity difference. This will be noticable when set up the same (carbs and exhaust)

Bandit has helical primary, whereas the Slabby will be straight-cut; less loss/more noise.

There's also the agedifference; a Slabby will be a good few years older than most Bandit engines.

There's quite a few more but someone more knowlegable than me will come along shortly and fill you in.

[Tony Nitrous]

Coil spring clutch v Diaphragm spring clutch ? 

[Duckndive]

In stock form there is a 100+cc capacity difference. This will be noticable when set up the same (carbs and exhaust)

Bandit has helical primary, whereas the Slabby will be straight-cut; less loss/more noise.

There's also the agedifference; a Slabby will be a good few years older than most Bandit engines.

There's quite a few more but someone more knowlegable than me will come along shortly and fill you in.

Bandit has straight cuts its the 1100F power-screen motor that has helical

[Rene EFE]

I did not know that

[Captain Chaos]

every day is a skool day on OSS

[Guest YoshiJohnny]

Bandits are shit

Slabbies are cool

diaphragm clutch can be converted

YJ

[Oilyspanner]

Bandits have extra output shaft bearing and are set-up for wider rear rim. The 2nd gear is stronger too, I don't know if it's all years of Bandit though.

[Swiss Toni]

If you want to keep it 'Old Skool', use the Slab motor.

If you're going to screw the arse off it...use the B12. Not saying Slabbie motors aren't fast (before I get flamed), just Bandit motors are a lot younger, and being so...less fatigued!

Only bugbear is the clutch and, as YJ says, easily converted! Your choice!

[boilerdude]

And doesn't the slabby have better carbs for turbo? 

I think I heard one of the big buffs somewhere say they're actually pretty decent carbs after you have them bored or something like that...

I recently bought a half decent slabby btw.

[boilerdude]

so the diaphragm clutch is a bad thing I take it?

[Tony Nitrous]

For me, only in stock form if you up the performance. I've had less issues with the "normal" system before its needed upgrading. 

it can be swapped out for a traditional one, or you can mod it, anything from heavy duty springs to a lock-up system. Some folk prefer the traditional style. 

I think the diaphragm style has less surface area on the plates ? 

 

[Tony Nitrous]

http://oldskoolsuzuki.info/archives/218

[boilerdude]

o i c

[boilerdude]

So I'm swapping the cct out of my parts bandit to see if that fixes the slap my slabby has at idle. Havent quite gotten the bandit one in there yet but I noticed a couple differences between the tensioners. The slabby one has an extra spring on the end of the plunger for a sort of double spring action. While the bandit just has a plunger which is noticeably more "stout" and a primary spring which is shorter but also much beefier. and no extra spring on the end...

I'm not so sure the 86 one was bad but fingers crossed the slap goes away. or else something else is wrong and maybe I got smoked on this deal a bit... we shall see.  The bike has a really rough lumpy idle accompanied by a horrible slapping noise at the lowest of idle... but then once it gets 3 or 4,000 rpms, it all smooths out. Guy told me it was the cct and i took his word for it but now im having doubts... We'll find out here anyway. Thing has 14,xxx miles on the clock and everything looks reasonably well kept on it. I figure it was almost impossible for anything horribly catastrophic to be wrong with the motor... 

[kokolis]

Carb balancing makes idle smoother

[Swiss Toni]

Carb balancing makes idle smoother

He's right! Had a H*nda 750, and the clutch used to rattle like a bastard until the carbs were balanced.

[boilerdude]

i can hear the chain slapping moar than it should. Ive owned 2 b12s now. I know what a rough idle sounds like. I'm saying this is more than just the rough idle. It's chain slap. and perhaps so much slack that the timing doesn't smooth out till it gets rolling.

 

strangely the old old that came out was only extended a few clicks. I wonder if the tensioner assembly stuff on the inside is stuck? 

[Captain Chaos]

my old man's Yamahahaha FJR started to idle very roughly over the last 20.000 km (he bought the bike new 140.000 km ago). Adjusting/balancing/whatever didn't help, so I suggested a new camchain and tensioner. First he tried only a new tensioner and it didn't really improve. With a new camchain it's like new again.

Long story short with a f*cked camchain it will never idle smoothly.

[boilerdude]

right on. I was hoping with only 15,000 miles that mine would be ok but maybe it's fucked from sitting so long with spring tension only on that one spot while it sat for years.... You're damned if you do and you're damned if you dont.

[Gpz1100_Convert]

slabby engines are far more fun when they come on cam.

bandits are more torquey or feel it anyways but they have a very flat power curve which takes away some of the fun.

 

Once turbo'd I'd use the bandit as if using stock displacement the internals are more likely to have done less miles/ less wear. Bandit cams are better for turbo due to duraction as far as I am aware (fruitloop said so). Bandit clutch is fine once lockup is installed. It is only when you start really going busa pistons etc that the clutch could become a weak point.

Mark

Edited November 24, 2015 by Gpz1100_Convert