rg125f derestriction

[1992rg125]

i have a 1992 rg125 f and it only dose 80mph up or down a hill sat up or prone

i need to know where the restrictions are and how to remove them

eny help will be great
thanks for you time
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ns125r1992
rg125f1992
next who knows

[Kickstart]

Hi

Exactly which model of RG is it? Old RG had a missing power valve setup but mainly the restriction was in the exhaust.

Newer shape one had just an electronic restriction stopping the power valve opening. From memory you had cut the black and white wire from the cdi to get the power valve to work.

All the best

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

[Barry_M2]

[1992rg125]

its the newer one and all i can find on the internet is that id have to cut the pipe in half to remove a small washer from middle and remove some fiberglass and mesh from the chamber

but wear is the cdi so i can check if it has alredy bean done
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ns125r1992
rg125f1992
next who knows

[1992rg125]

dose cutting the two wires make the pv work or dose it fix it open
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ns125r1992
rg125f1992
next who knows

[Barry_M2]

[1992rg125]

thanks

will i have to re jet it after

and do you know where i can get a manual for it

once again thanks to all
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ns125r1992
rg125f1992
next who knows

[Kickstart]

[1992rg125]

just checked the wire has already bean cut

so dose eny body know what size jet i would need for the standerd de-restricted pipe

and the jet size for a jolly moto pipe

thanks for the help
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ns125r1992
rg125f1992
next who knows

[Kickstart]

Hi

Not sure they needed any change in jet when derestricted, and there was nothing in the exhaust to derestrict.

Check you power valve is working properly (they were renowned for failing with the valve dropping down to the piston causing serious damage, same as the RGV250) and also do a compression check on it.

All the best

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

[1992rg125]

i found this on the internet
https://membres.multimania.fr/rg125f/debridage_eng.html
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ns125r1992
rg125f1992
next who knows

[1992rg125]

and i found this gide to derestrict the pipe

https://www.125ccsportsbikes.com/forums/index.php?showtopic=62988
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ns125r1992
rg125f1992
next who knows

[bryvw1973]

hi

i think you can unplug the black and white wire from under the seat i know thats how the tsr was restricted i think its the same for the rg

bry

[1992rg125]

its alredy done
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ns125r1992
rg125f1992
next who knows

[MarJay]

First things first.

Have you checked that the engine is in a good condition, and has had the correct maintenance done on it? If it has worn rings for example the compression will be down and you'll be losing power.

Has the engine had a rebuild recently?
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[1992rg125]

i dont know its done 14000 mils and i dont know if its been rebilt or if its on its first set of rings
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ns125r1992
rg125f1992
next who knows

[Kickstart]

Hi

With just the cdi wiring mod done it should do a hell of a lot more than 80. If the power valve is working correctly (and they do fail expensively) then something else is wrong. As mentioned earlier do a compression check first.

All the best

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

[1992rg125]

how can i check if the power valve is working corectly

and how do i do a compretion test

thanks for the help
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ns125r1992
rg125f1992
next who knows

[Kickstart]

Hi

For compression, get a compression tester, take out the spark plug and screw in the tester then crank the engine over with the throttle wide open until the reading on the tester stop going up.

As to the power valve, I presume that on the RG it operates when you turn on the igntion. If so check it actually does operate. You will probably need a manual to find out how you are meant to set it up and check it is right. Beyond that you probably need to strip it down and check it. The barrel is the same as the RGV250 I think and they are infamous for eating the power valves (and it will wreck the top end if this happens), and from memory about a 10k life wasn't unusual. Hopefully one of the former RGV250 owners can give more details.

All the best

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

[1992rg125]

took it to work this morning and i have heard a little rattle and it has not much

so i have decided to get it all sorted by doing a top end rebuild with a prox piton kit and possibly a prox con rod kit
and possible a upgrade pv kit from tuning works

will a ts125r kit fit as the engins look identical

also i am going for a piper cross filter and a jolly moto pipe
i will also re-jet and have the pv set up right

any thourts on this plan anything you would change enything i have forgotten

o can anybody tell my what sort of speed it should reach if all of this is done

thanks for eny views and advice
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ns125r1992
rg125f1992
next who knows

[Kickstart]

Hi

Don't bother with the pipe and filter yet. Get it sorted first otherwise you are just adding something else to confuse problem solving.

Don't know about the TS con rod kit, but possibly not even if they are basically the same engine (con rod length is one of the things played with when deriving one engine from another for a slightly different purpose). Also fitting a new con rod is not a home job, certainly not something to be done by someone inexperienced.

Realistic top speed will be just short of 100mph true top speed. Indicated probably a bit higher.

All the best

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

[1992rg125]

i will not be the one rebuilding it
my dad raced karts and did his own engins 1986 rd125lc with
tzr crank
34 mm macoony
yz piston and rod
2 mm of the top of the barrel and packed up the bottom 2mm to raze the porting

got a real 110 mph but that engine would be completely unridable in a bike no power below 11000rpm and revs to 14000rpm
(but id have a very good go of it )

so hes doing the rebuild

he says the prox piston would be a good ider

so will the tsr piston kit fit
and what about the pv kit
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ns125r1992
rg125f1992
next who knows

[Kickstart]

Hi

Not certain on the con rod kit.

Think the power valve kit will fit (and from memory RG125 barrels seem to land up often getting used to replace those destroyed on RGV250s as they are the same). However the supplier should be able to confirm this for you.

All the best

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

[1992rg125]

thanks to all of you

theres more snow coming so i will take it of the road when it comes

report the results when i have ran it in after xmas

then when its all sorted put the filter and pipe on it

my dads mate had an rgv250 and siad that to make the pv more relabel take of the cover and keep it well lubed wd40 once evey 3 month

once again thanks to all of you for the help

best of luck with all of your endeavors
and have a merry xmas
and a happy new year
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ns125r1992
rg125f1992
next who knows

[Kickstart]