i have a problem with a 1998 thundercat.

it wont start in the morning but it will fire straight up when bunked and run fine for about 10mins, then it will start bogging down and wont want to rev and it starts sputtering ect, if you mess around with the throttle (keep opening and closeing it) it will eventually pick up.

any ideas???

its had new plugs and carbs drained ect ect.

I had a similar prob years back wi cbr 600, turned out to be a blocked tank breather. Prob a long shot but worth a look, you could try opening the petrol cap to release the pressure and see if it helps. Another reason could be out of balance carbs or float levels wrong.

Dunno if this helps but good luck with it.

Johnny

Dodgy Tesco fuel?

Does it only happen in cold weather, don't know if cats suffer from carb icing?

What's it like when it's warm? - if it runs perfectly OK when warm then get the valve clearances checked.

Not sure about the 600s but the 1000s have very long valve clearance checks & get left, I had a FZR1000 where the clearances closed up, this gave poor starting (no compression as a couple were slightly open), as the bike got warm, everything expanded & it ran sweet, I tried everything before checking the valve clearances, once sorted it started perfectly.

Could well be carb icing as stated above. Try some silkolene Pro FST in the petrol tank and see if it still does it.

Carb icing only really happens with the throttle held in one position for a while (like on the motorway) so varying the revs keeps it all going and clears the ice crystals.

5t.

it wont start on electric starter, has to bunked, then runs ok after its been bunked, then after 10mins it starts bogging down like its choking up, after opening and closing the throttle for a while it eventually clears.