1998 800 Bogs down @ mid-full throttle

I don't know what the problem is. I have cleaned both carbs. I have checked the resistance on the coils and the spark generator. I have replaced and checked the spark plugs and the gaps. I have checked the tank, the filters, and just about everything without taking the engine apart. No matter the gear, the bike bogs down @ mid-full throttle. PLEASE HELP!

fuel cap breather blocked?

The fuel drains from the petcock perfectly without slowing. I drained some of the gas earlier to be sure.

is the bike "stock" or modified? ie. aftermarket air filter or pipes?

Have the Carbs been balanced?? What revs?? And as Sim says, what filters/exhaust? When did it start doing it?

The bike is stock. I have not checked the carb synch. The bike sat 4 years in a friend's garage out of the weather. The filters look clean but have not been replaced. Honestly, I never removed the front air filter to see it from the outside.

When you say that you've cleaned the carbs, how have you cleaned them?  Did it sit with fuel in the carbs for four years?

If the carbs had fuel in them for 4 years, the residue from the evaporated petrol would have clogged everything up, they need stripping and dipping (do NOT get them ultrasonically cleaned as it may cause more trouble as the loosened little bits clog even more holes).

v-twin wrote:

If the carbs had fuel in them for 4 years, the residue from the evaporated petrol would have clogged everything up, they need stripping and dipping (do NOT get them ultrasonically cleaned as it may cause more trouble as the loosened little bits clog even more holes).

Interesting - I thought ultrasonic was the way to go, Andrew ?

Someone I know and trust (he builds and tunes motorcycle race engines for a living) has a dyno and he gets a lot of bikes through his workshop. Quite a number of people take bikes to him to be set up as they are not running right after they have had there carbs ultrasonically cleaned, some never work again properly and the carbs have to be scrapped/replaced. He recons that the crap that gets dis-lodged just ends up being re-deposited in an even more inaccessible place within the carb etc, I trust his judgement and will not be letting any of my carbs go near a Ultrasonic cleaner anytime soon.
I dare say some people will swear by doing it, but I'm not convinced. That just my opinion though

Could be the fuel pump isn't delivering enough petrol to the carbs. Fuel pump repair kits are  £22.34 from Wemoto check out the how to video on the page.

Could I ask if these carbs have a float chamber ?
Its just that the problem reminds me of a car I had with wrong float chamber level.

Yes there is - this link will put you to a page where you can you download an exploded view of the carbs