YZF-R125 derestriction

[bbou8284]

hi
can you derestrict a Yamaha YZF-R125 which improves the speed quite a lot, i have read a few things and its says that because of electrics and the fact its 4 stroke that you cant derestrict it.

[chris-red]

It's full power as standard. If you want to go quicker buy a 2 stroke or a bigger bike.
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Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

[Rottweiler]

no offence but for what you get with them r125 there a total rip off !! nearly 3grand for what ? ok it looks orite but thats bout it..........
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were: piaggio nrg..ybr 125
now: cg 125

[adama]

Is it your first bike?, 3k+ for what they are is a bit steep, and as far as i know..stock is full power, unless you wanna get a new exhaust system to add maybe a few bhp...all you can do i believe.
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[deanoet]

[ThoughtContro...]

[TUG]

[chris-red]

[TUG]

[Kickstart]

Hi

I would call that tuning rather than just derestricting.

A well designed cat should flow fine and not really restrict power. A well designed airbox will give you power, and dumping the airbox on most modern bikes is likely to lose you power.

The RS is restricted by replacing the power valve with a blanking plate.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[TUG]

[Kickstart]

Hi

Those are not really restriction though (no more than saying it is restricted by not being fitted with nitrous). I would call changing those tuning at which point power largely comes down to how much money you want to spend.

I would say derestricting is removing the restrictions the factory put in place to limit power / speed.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[TUG]

[Kickstart]

[TUG]

I think we can agree we look at it from different perspectives?
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Haz ER-5, innit!

[Kickstart]

[TUG]

Well in a way derestricing bikes is performance tuning then?...
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Haz ER-5, innit!

[Kickstart]

[chris-red]

I'm gonna fit a Turbo to the Speed Four to derestrict the intake...
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Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

[TUG]

[EUMP]

Could pop in a big bore, but if your riding a 125, then im assuming your early/late 17, so you cant yet

[racetec001]

Hi,after reading the posts on this subject and feeling a bit miffed,i thought i should contribute a little as i feel comments along the lines of paying a lot of money for the type of bike,get a bigger bike and the likes are to be kind,both crass and off point.
From experiance on type i would make these comments and also dispell the myths on cats cdi units and the like.
Fact; some cats perform better than others but all cats without exception impede performance in simple form,the better a cylinder head flows [intakes and exhales] the greater the performance,period,cats restrict exhaust gas removal because firstly they cause a positive exhaust gas pressure between the cat and the exhaust manifold[not good for head gas flow] and then there are a dozen other reasons i won,t bore you with unless pressed.
The cdi unit in this case,is coupled to digital fuel mapping and factory fixed set to give optimum performance whilst achieving emissions compliance,hence it is possible to gain considerable power by removing the cat and tricking this unit to perform better,i will explain the mods i have done and the power gains a little later run out of space on this post.
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forward motion,max attack

[racetec001]

FOLLOW ON FROM PREVIOUS POST.

Ok,my sons bike,09 model with 1800 miles,standard bike,power run on dyno,14.2 kw 74 mph.
Mods done,cat removed, exhaust manifold matched to cyl head,inlet intake re worked and matched to inlet port, road run for 50 miles then second dyno run 15,7 kw 83 mph.

After re think and speaking with yam technical,stock bike has ignition retarded by 4 degrees to eleviate engine knock because of high cylinder head temps from low octane fuel and heat build up from cat.

Second mods put inline electronic filter between ignition sensor and cdi to gain 5 degrees of ignition advance by delaying ignition signal [confusing the cdi],changed fuel to optimax[shell V power] and added octane booster.

Further power run on dyno 17.2 kw 91 mph with a improved 40 mph to 70 mph over stock just shy of 4 seconds quicker.

More devolpment now,i have a spare engine in bits doing a lot of technical calculations and measurements,so far i have found that the camshaft has plenty of lift but is shy on duration on both the inlet and exhaust side,so needs reprofiling plus i have,nt done anything with the electronic fueling yet,so will keep you posted as devolpments are made.
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forward motion,max attack

[0ddball]

I wouldn't take much notice of any power readings given by a dyno operator who actually thinks potential top speed and acceleration can be measured on one.

[tutton]

Also dosnt it change depending on whos dyno it is, so if your operator isnt the best your readings could be total bollocks.
But thats not even road speed so any headwind etc then say bye bye to all your hard hours of graft to gain 15mph from a 125.
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Past: '05 Peugeot XPS '99 Aprillia RS125 '94 FZR600R
Current: '02 ZX636 A1P '51 CCM R30