Author Topic: DE RESTRICTING 4HX  (Read 308 times)

Biker81

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DE RESTRICTING 4HX
« on: November 05, 2019, 07:21:24 PM »
Hi All ,

I posted before about de-restricting my 4HX Swiss import.

The washer in the exhaust has already been removed and my power valve is now working but I'm guessing not opening as much as it can do due to restriction !??? When the bike is powered off there is a guide hole on the power valve assemble that moves this guide hole lines up with a hole behind it on the body fitted to the cylinder . The size of the hole is about the size of a small allen key .

I'm guessing this needs adjusting and I read before about some restriction with the rev limiting in some way electronically ?
If there's anything else kindly let me know.

Thanks,

Ian.

41juergen

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  • Location: Hanau, Germany
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Re: DE RESTRICTING 4HX
« Reply #1 on: November 06, 2019, 10:20:21 AM »
Regarding the washer, I had 2 in my exhaust, so both need to be extracted. The PV pulley can be mounted in 2 different positions on the PV shaft. I recon to take of the exhaust and than fit the pulley onto the PV shaft making sure the PV is fully open. Electrical wise you only need to make shure that there is no additional little box mounted (as in Germany sometimes) which reduces the max speed to 80km/h... Or you invest in a little Zeeltronic CDI to get the best out of it.

Biker81

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Re: DE RESTRICTING 4HX
« Reply #2 on: November 06, 2019, 08:05:06 PM »
Thanks for the info Juergen. I had a good look into the expansion chamber with a fibre torch and I couldn't see any more washers. OK so regarding the power valve fully open , is that when the ignition is off ? I guess the best way to do it alright is when exhaust is off . I've had the bike up to approx 120kmh so I guess there is no electronic restriction then. The power just seems to stay around 9000rpm. I had an older model TZR125 when I was a teenager and it was much faster !! I have a Gilera GFR125 and I am used to the power of that so I need it to go quicker  :D (-P)

41juergen

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Re: DE RESTRICTING 4HX
« Reply #3 on: November 07, 2019, 08:18:53 AM »
Yes that sounds like the PV is still restricted. Here is a link with pics showing how to modify that (sorry in German, but may be Google translater will do the job)...

http://www.yamco.de/tzr125offen.html

Biker81

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Re: DE RESTRICTING 4HX
« Reply #4 on: November 10, 2019, 05:24:11 PM »
Thank you Jeurgen !