gsxr11 vs b12 for track

[ziggy]

Planning to build a n/a for some track fun. Plan is hi comp pistons, cams, head work, carbs etc. Which one would be better choice - 11 or 12? Cheers 

[colinworth79]

there is not a lot in it if your going to change the pistons and cams . Bandit has a weak clutch that will want swapping for a gsxr unit . Gsxr 11 M has shims and there is not much choice of cams .

[ziggy]

Cheers for that Colin, will use 11 for now then

[ziggy]

Btw, what's the real difference between locknuts and shims?

[Gixer1460]

7 hours ago, ziggy said:

Btw, what's the real difference between locknuts and shims?

Over-rev a bike with shims and you'll find out! Buzz the motor = valve float = shims pop out / jam = piston and valve party!

[Oilyspanner]

The 1100 M/N engines have small shims that sit in the top of the retainers, it's possible with enough valve float for them to jump ship, this is just before the valve says 'hello' to Mr Piston though !  If the valve springs aren't saggy, clearances correctly set you are very unlikely to have problems, you need a good 4mm of float - the shim head 750 M revved to 13,000 - the 1100 only revs to a true 10,800 revs before the rev limiter cuts in (about 11,500 on the original clock). I use my 1100N pretty enthusiastically and it's been fine - the fact that there's still a lot of shim head engines out there after years of abuse tells you the head is fine with std cams.

I wouldn't put higher lift cams in mine though, that's the main difference between shim heads and screw and locknut heads. The 1100 M/N has an extra output shaft bearing , like the B12, that allows for the slightly longer shaft for the 180 tyres, earlier models only had up to 160 width as standard.  With a big bore 1186/1216, good porting (attention to detail, not loads of material off), good ex. system and carb set-up, you can get into the mid 150 hp bracket with standard cams /valves - this gives a really nice spread of power too and over 90 lb/ft of torque. If you're going for BIG power, screw and locknut is the way to go - for big valves/big cams / big block etc

If anyone has a neglected shim head engine lying about , I'll have it !!

[ziggy]

So would it be better to use blandit engine then? I have not opened the 11 up yet but pretty sure it's the late one with shims

[Oilyspanner]

Bandits are a good basis for serious work, if you do as the guys have said with the clutch. You might gather that I'm fond of the 'shim head' engines, which have the best 1100 ports as standard and the inlets to inlet rubbers are shaped for the big 40mm carbs, so are very good for mild/moderate tuning.  If you've got a shim head, the inlet rubbers will have 41c on them, the code of the last oil cooled 1100s with the 40mm cv carbs.

If you want to shift the torque curve further to the top end with big cams don't use the shim head, well you could swap all the valve gear from a screw and locknut head . . a bit much work though.

Just my thoughts -  some of the chaps on here have done s-ite loads of work to their oilers over the years (eg. G1460), how wild do you want to go will decide which route to take engine wise.