aprilla 125cc derestrictred problem

[steve0sha]

hi there my bike wouldnt start so changed the spark plug and worked but now its been restricted dont think fiddled with any other cables apart from put the temp cable back on. would of putting spark plug on it restricted it? and how do you deristict the bike anyway please?

[MaybeGuy]

hi. i dont think its possible to get restricted sparkplugs

restrictions are normally in the exhaust, airbox, carbeuretter and sometimes in the throttle mechanism.
its impossible that a new sparkplug could magically restrict all those things again.

are you sure it was restricted in the first place?
chances are theres more wrong with it than just the spark.

de restricted RS125's have a top end of about 110mph, are you sure its de-restricted?
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[Kickstart]

Hi

Suspect either the power valve has stuck (happens quite easily) or you have caught the wires to the solonoid and disconnected them.

First means taking the power valve out and cleaning it up (do it soon, longer you leave it the more stuck it gets).

Second just means reconnecting the wires (from memory one black,one white in a connector).

All the best

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

[steve0sha]

wow 2 replys within 5 mins of posting, up late i c anyway first bike so dont no much bout them had moped 125 before powervalve is it also a cdi box which is under seat in storage area u mean cables come out of there? if you can explain step by step as no idear what every part is thxs. yer my flat mate has a aprilla to and test drive it when first got it did a 100 on it. thxs 4 help. steve

[Kickstart]

Hi

The CDI unit controls the ignition timing mainly. On the later RS these are designed to cause a massive flat spot between 5000 and 6000rpm but retarding the ignition(ie, sparks later), but this "restriction" has no effect outside that rev range. The cdi unit can be modified to remove the problem (early RS125s with the Rotax 123 engine have a totally different ignition system with no seperate CDI unit).

Also under the seat is an electronic control unit for the power valve. This just receives a signal when the ignition system is generating a spark and from that knows the revs, so operates the power valve at the required revs.

Bolted to the frame rail there is a solonoid that is controlled by the above control unit. Basically when it operates it just pulls a cable.

The cable goes to the actual power valve that is above the exhaust port on the engine. All this is is a blade which is lifted up at higher revs. Effectively it opens the exhaust port earlier (crude 2 stroke equivalent of variable valve timing), which gives more top end power, while opening it later at low revs (as the later exhaust port timing gives more low down power).

If the bike has suddenly lost a load of power over 8000rpm then it is probably the power valve. The actual blade can stick easily (happens if you are running round town a lot). Or the 2 wires to the solonoid (from the control unit) have become disconnected.

All the best

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

[MaybeGuy]

fucking hell kickstart! captain knowledge rating for you!
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[steve0sha]

ok will try haveing a go at fixing problem on tues day of, its weird cos at 8000 the bike does starting pulling like a turbo but when rode today just at 60 and then no more speed