YDIS Carbs - How do they work?
 

Can anyone explain how the YDIS system works for me please?

I have a problem with the following http://www.horizonsunlimited.com/hub...leration-62808

It cuts out all of a sudden under full throttle and under acceleration, and once the revs drop back it cuts back in again. It's like you've hit the kill switch, let it loose speed, then hit it again to bring the engine back to life.

I'm fairly happy having done some work on the bike that it's not electrical, the bike will cruise at 90mph, so long as I take my time on part throttle getting there - no hard acceleration. I think it's fuel starvation.

Once the secondary SU carb opens - is this the only carb feeding in fuel? (hence a problem with it will cut the engine). Once the revs drop, would it switch back to the primary carb (hence the engine cutting back in)?

If I understand how this thing works, I have a better chance of figuring out what the problem is

Thanks

I think you are right in saying that it is fuel starvation, and that's where I would start looking. Pull the fuel line off the tank, check you have a good flow out of the petcock, and then take it from there. Sounds like you will need to remove the carb and dismantle - a fiddly job, but not difficult. I'm guessing there will be a blockage in there somewhere. Main jet in the RHS carb would be the obvious candidate.

If the carb checks out OK, I would run a full check on valve clearances, compression etc before going any further. Also check the carbs are synced correctly. A search on this site will bring up the details.