I have a 08 yamaha xt660x and in the last few weeks ive

Removed snorkel
K&n air filter
Black widow twin cans

These mods have transformed it from an asthmatic pensioner into a proper nice solid motor

However almost immediately it has started cutting out whilst riding

Maybe 3 times an hour

Can anyone tell me what i need to do to sort this problem please?

Is your idle speed high enough? It MUST be north of 1400rpm (ideally 1450) otherwise it will cut out on a sudden closed throttle (usually when going down through the gears).

Remember that any changes you make to intake or exhaust will almost always affect the idle speed. Idle speed should be checked and adjusted after any change made. Even a fresh spark plug or new stock air filter can alter the idle by 50-100rpm, which is enough to trigger the typical XT cutting out behaviour.

You might also want to consider a fuelling device with the mods you have made. Not essential, but it will help a lot. As would an O2 controller.

__________________

Thanks

But how do i adjust idle and how do i tell what the rpm is as it does not display?

I havent got a manual

Thanks.

Ignore that - ive just searched it on here and got the info

Thanks

Do u think adjusting idle and the fuel in the diagnostics will be enough for my setup or will i need the fuel mod?

Cheers

As I mentioned earlier, you'll be fine without a fuel mod/O2 controller, but you are on the limit regarding how lean the air/fuel ratio will be. The bike will run more smoothly, pull from lower down and generally feel much perkier with these two mods fitted.

Not essential, but worth doing.

__________________