1340 Options (1127 vs. 1157)

[nightrider]

So I'm going 1340cc.

I Have two options in my shed to work with,  b12 motor or my 1052 block with a gsx1100F Helical 1127 crank and clutch.

I know the Teapot Coil Spring clutch is stronger then the b12 Diaphragm Clutch but are there any other advantages one offers over the other?

Which has the better head?

etc, etc.

Decisions, decisions.

[zedhead]

I might've imagined this, but I think I heard stories of the helical gear on the clutch winding itself apart in high power applications... and the B12 clutch issues can be overcome, you can get lock-up conversions for them, and you'd probably want to do that on any clutch if you're going 1340...

[Oilyspanner]

Bandit will be better, reasons as above, plus the Bandit had an extra output shaft bearing for the longer shaft required for the 180 tyre - heads are pretty similar, although with such a big motor, with a big block, you'll need to port it anyway/fit larger valves etc to get the best out of it.

[nightrider]

Hmm, ya I was wondering about the helical. Had to be a reason why they only used it for two years out of the whole SACS history.

 

This engine will be a speed trials engine, not a drag bike engine.

Figured I wouldn't really need a lockup as gearing will all be pointed to top end. No sudden explosive low / mid range power outputs.

Am I wrong?

If I need one I'm not apposed to getting one.

Thoughts?

 

[1260pete]

You may get away with an extra diaphram spring but lock up would be better, its torque thats the problem.

[Gixer1460]

Plus its always higher gears where clutch slip usually manifests itself - you pulling higher gears won't help the situation. ie to go fast you need power and pulling taller gears from lower in the range is where the torque will induce the slip. It can be done using clutchless shifting but just needs a bit of wheel slip or a bump that jars the suspension / drivetrain and it could trigger slip. Although simple devices they are fit and more or less forget!

[clivegto]

I have a 1340 motor and would not run it without a lock up clutch.

[Fastbyme]

One piece crank in power screen motors ... Shame the pressed crank gsx tales of woe followed it 

they are good motors even with helicoil cut gears ...good smooth power 

[nightrider]

Ok, sounds like a lockup then.

Anyone have recommendations for a lockup supplier States side?

[nightrider]

Think I'll be saving the Heli crank for the street engine.

it's NOS complete with rods, just gotta use it on something

[mcguire1205]

MTC Engineering, for the lockup.

[McLean Racing]

WarpSpeed Racing in the UK do the lockup units