(21-08-12, 09:41 PM)mars696 link Wrote:Petski,i have exactly what you said. When i start the engine,the downpipe of cyl 1,run colder than the others.... The jet i'm talking about,is where is the yellow arrow i draw...(see pic pls).[size=1em]At my carbs these jets are completly blind..and i dont know if it sould be this way or not...i cant even find it at the Yam manual.[/size]
You now know where to be looking then, cyl 1. Please note that the photo shows the jets removed. I'm not 100 percent sure but I think the yellow arrow points to a plug which does not have any hole. It was two years ago since I did it so memory is not that fresh. I have a fully working set of carbs in the garage at home. I'll take the bowl off one tonight.
A blocked airfilter won't cause problems as described here, no harm fitting a K&N though!! A faulty HT lead, spark cap or plug can. The way you can rule this out is to move the sparkplugs (put 1 in 2, 2 in 3 etc) and see if the problem moves (feel the downpipes again). You can also swap the wiring on the coils. One coil fires cyl 1 and 4 and the other 2 and 3. Eg: There's no harm putting lead 2 on plug three and vise-versa. Just swap them over and again, see if the problem moves.