Bike lacks power

[Ryan F]

@declan they are a few ebay but they are quite pricey, was going to see if any shops near me would de-restrict it for me

[declan]

@Ryan-F well you have your issue then it’s the powervalve yeah an engine porter should be able to do it no problem, the powervalve should whine as you turn the key if it doesn’t then there’s an issue the valve should be aligned through the exhaust port so that it’s a smooth transition as you look through the exhaust port there should be no step or ridge

[Calum]

@declan The issue being on the new models the powervalve retards after 8K RPM. Starving the engine of the power.

Getting an older CDI unit, or an aftermarket one, would rectify this.

[declan]

@Calum but it’s alreday revving freely so surely the cdi isn’t the issue I though if the cdi were restricted it would only rev to 9k like mine

[Calum]

The later CDIs control the powervalve servo. On crossers, the powervalve is controlled by the gearbox, or by exhaust pressure. On the DT it's controlled via the YPVS CDI. Early models this was separate from the CDI. Later models it was an all in one.

[Ryan F]

@Calum Is there a year roughly I would need to buy? and would I need a new loom or would it just be a case of wire it up and it's ready to go?

[Ryan F]

@declan Yeah the power valve works and wines as I turn the ignition I will have to look into what callum said about an old or aftermarket CDI, I was just scratching my head a little as it all seemed ok

[Calum]

@declan said in Bike lacks power:

m

It's like a 3RM model CDI. But to be honest, just get a Zeeltronic for it. It'll be better in the long run since it will be new, rather than buying something old and potentially faulty.

https://www.thetuningworks.co.uk/store/product_info.php?products_id=1268

£165

[Ryan F]

@Calum Ok thank you, do they come with like a base map at least?

was looking at getting another top end and getting it ported also.

[Calum]

@Ryan-F Zeeltronic provide an array of maps that you can base yours on. They are more aggressive than the OEM maps. I've just left it as the one they provided. I altered the powervalve timings but that's about it IIRC. Best get the handheld programmer too. I found mine came with some crazy map that was totally inappropriate.

[Ryan F]

@Calum Ah ok thank you for the help, I was looking at the older CDI's but like you said alot of them look crusty and I know what you mean about the zeeltronic that is going to be my next buy 100% I don't want to make the bike crazy or nothing and i don't want mega horsepower I just like the torque and acceleration.

[Oisin]

Would a pinned powervalve create a loss in power and acceleration? Just wondering thanks

[Calum]

Depends where you pin it.

So it's not a clear cut answer.

On an unrestricted CDI a pinned powervalve would be detrimental to performance.

On a DTRE/X Ignition, a pinned valve will allow you to rev past 9K.
On a CDI where the ignition is severely retarded past 8K then it will be a loss of power all round.

If the CDI allows power up the higher revs, but, like the RE/X ignition, retards the powervalve, pinning it open will allow you to get that upper power, sacrificing low end.

It's not clear cut. For optimum performance, set it up properly and leave it alone.

[Darty]

Just on ride ability, I feel it’s slower over all with turning the PV off essentially,

That’s where a good expansion pipe really helps,

[Oisin]

@Calum yea I ok and how do u tell if the cdi is restricted? I have a DT 125r 2005

[Calum]

Well if the bike lacks power, that's usually a good indication that the bikes restricted.

[Oisin]

@Calum haha I get yea. And how would one unrestricted it

[Calum]

@Oisin You tried searching?

https://dt125r.co.uk/topic/578/derestricting-guide