Its simple if it damaged the engine the manufactuers or dealers would not fit it as thay would get the bill for the repairs.      Its the same as the old story about running your diesel car on gas oil (red). Storys were that it damaged your engine, No never did any damage to any engine as it is just a cemical dye that makes it easy to trace in the system                                                                                                                                                                             

restrictors do not alter AFR, therefore wil not lean out or richen mixture, so no engine damage can occur.
as for acceleration/top speed.
150 kg with 33rwhp pushing it versus 150kg with 66rwhp. nuff said
                                                                                                                                                                             

so Yamahama you did ask and well urmmmm yes it does fair shift now!                                                                                                                                                                             

As a mom I would be saying I don't give a monkeys what you think it will or won't do to your bike, you have just passed and the law says you ride restricted! Set foot on it before that restriction is done and I will call the police, both my kids know I would do it too.

I have seen too many crashes where the uninsured person has walked away and the innocent party has been hospitalised or worse killed!

I myself have a kidney that is not as good as it should be and was in hospital with a damaged spleen because of an uninsured driver, he hit the car I was in and he walked away with nothing at all wrong with him

Fitted quite a few restrictor kits, never had to-do anything more than alter the tickover/slow running mixture, in general the kit manufacturers have factored in all the variables.

Techniques I've seen used are header-pipe/inlet tract restrictors or "slide stops". (As most bikes use CV carbs, that doesn't affect the twist grip movement.)

To make the most of the bike, optimise the gearing to the new power-curve. 
                                                                                                                                                                             

You go careful with that newly acquired speed JJ.                                                                                                                                                                             

steady as she goes jj this could be a vunerable time but enjoy                                                                                                                                                                              

its still slower than the car!!!                                                                                                                                                                             

what's the car starship enterprise?

are you twisting the thingy enough
                                                                                                                                                                             

car ship enterprise(lovin that!) is a fiat idea......yes i know, i`d never heard of it either but think the stampy floor thing is more effective than the twisty thing but havn`t had chance for a full twisty twist yet!                                                                                                                                                                             

best keep off the romulan ale then ! and clean them clingons off the starbord  lol                                                                                                                                                                             

Ok, got my sons 600 bandit restricted, and tbh when i first rode it back through town traffic and congested roads, it didn't feel any different at all, acceleration wise.

I was beginning to think the restrictors had been fitted wrongly, once I got it on the A50 I was able to give it some ....... flies up to 90mph, eases off and then creeps to 95, I managed to get it to show 100mph on the clocks, just.

But it sits at 80 no problems and there still a decent bit of acceleration left for overtakes                                                                                                                                                                             

Having fitted & removed a few restrictor kits myself i feel i am in a position to comment here ...... First off ..... the way each bike is restricted & which bike it is will affect the ''feel'' of the bike !, there are 3 basic forms of restriction.....    .....throttle stops restrict the lift of the carb slides & wont allow the throttle to be fully opened, the acceleration & torque low down in the revs is not affected by this in the slightest     .....Flow restrictors in either the carbs or exhaust (basic washers or webbed inlet stubs). these will affect the torque & power throughout the rev range & commonly need a carb rejet to make the bike run correctly, this is the main cause of all the its restricted so runs crap comments, eg many bike shops only do half the job & charge you all the money     For the newer fuel injected bikes a cdi change or re-map will effectively restrict the bike & it will run perfectly but still be on or under the 33bhp limit & its simple to get full power back as & when needed     scoobs                                                                                                                                                                              

Well, I fitted them at the garage with the mechanic, who I know well, that's why he didn't charge me any labour, dunno how they could do half a job, they're either in or not. I suppose they could piss about and not re fit the rubbers properly? which would make it run crap, but then again if it wasn't restricted and they failed on that one it would still run crap.

They were fitted to the carb inlets, FI international state that they don't need any carb re jetting as they have been tested, blah blah blah. £180 for 4 washers with holes in, so I guess that's to pay for all the testing etc.

They do state that for the bandit it will restrict top speed to 95mph, so with speedo error, they seem to be spot on. As I said in my post, it accelerates fine low down, just choked at the top end.

Now, as its the only restricted bike I have ever ridden, both before and after I can only comment about this one and I'm pleasantly surprised.                                                                                                                                                                             

Hey shadow i think you need to re-read my post mate ! i thought i was being clear by saying any exhaust or carb inlet restrictors will affect the running of the bike ! this opinion isnt based on seat of the pants testing but on extensive dyno testing, you can on occasions get away with ajusting the air mixture screws but if you want it running as well as it can you will need to re-jet !   FI is more forgiving but again i like my bikes to run correctly so will happily stand by my previous comments   scoobs