Exup lag

[Swin]

My brother in law owns a Thunderace and was telling me that he has a slight delay before his bike accelerates when under throttle. Kind of like turbo lag in a car.

I thought the EXUP system was constantly engaged so could this be a problem developing or do "they all do that sir"?

Cheers for any experiences you may like to share

I have a YZF750 Exup. I only have experience with the Exup on this model. It is a well known 'fault' that they do not like to pull away in the lower rev range. Mine bogs down if I don't give it a healthy twist of the wrist. The Exup valves can also seize. He needs to check his is actually working correctly. It could also be a simple case of fuelling issue. Mixture, plugs, air filter, carb balance. All sorts really.

Ballance the carbs? Could be as simple as that. Good luck on finding the answers!!

[Swin]

Ok, cool - thanks for that, his bike tends to spend a lot of time in the garage waiting for the sunshine

So it could just be a maintenance issue - I just wanted to check if it was a sign of imminent demise!

Thanks again guys

Originally Posted by Swin

Ok, cool - thanks for that, his bike tends to spend a lot of time in the garage waiting for the sunshine

So it could just be a maintenance issue - I just wanted to check if it was a sign of imminent demise!

Thanks again guys

Oh now you mention that... It is quite probably blocked jets in the carbs. Had a similar issue with my old 250. He'll probably not have drained off the carbs before he put it to bed, the petrol will have jellyfied. He will probalby have to strip them to clean out the jets.

Unlucky because its wuite a job on a littl V twin, IL4 will be a right git!