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YZF750R no exup valve


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Hello all, I have an original 1993 YZF750R that had a seized exup valve. I removed this and servo, made up a small circuit board of resistors and diodes and plugged into ECU. Problem is, the bike now boggs down until 3,500 RPM, after this she flys all the way through to red line, but in this mode, likely to lose my licence very quickly. Any tips or ideas on how to get over the issue, and make it a user friendly bike across all RPM ? 

Thanks DeanoYZF

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Have you got a full exhaust? Or have you just removed the valve and connected the two halves?

If you're still using your original exhaust, it's designed to work with the valve. You're gonna have to get an aftermarket exhaust and probably a can too.

Modern exhaust systems are designed to give a good response over the entire rev range, the exup was apparently a fix for lesser technology...

I've been drooling over this for my Thunderace:
YZF1000 R Thunderace 1996-2003 Exhaust Downpipes Headers (blackwidowexhausts.co.uk)

I'm sure if you gave them a ring they could do something for the 750.

And these cans look good too:


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Thanks for coming back guys, I have the original downpipes (headers) but the end section is an ART carbon end can, and pipe, down to the underbelly original section. 

I was hoping many overtime have removed their seized EXUP valve, for either YZF750R or similar engine in other YAMAHA. I don't want to experiment with various jets, and float heights and keep putting back together to test, only to find again not running right. 

I am really looking for a done before this way or that, and have a final solution. It has been a long hard slog getting to this stage (a year) and while it is fun above 3,500 RPM. I would love it to be a little more user friendly. 


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There's no out-of-the-box solution for such things. Best to get it on a dyno and have it tuned that way

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I've got an ART can on the 'Ace currently! 😀

The answer is definitely the pipes. And getting rid of those original headers will only help your power to weight...
Just make sure that you have the same clearance to your fairings. Paying out for a good quality pipe will make all the difference.

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