Spark plug chop

[BlueBlaster99]

What do you guys think of this plug chop? Sorry, I broke the electrode, but I saved just enough. The top was white. I’m have a bit of a stumble right before the power band at 3/4 to full throttle. I’ve got a 280 main in it now and needle clip one up from middle position. It was stumbling at low to mid and that got much better when I raised the clip up one from center. It’s not perfect, but much much better.

thank you for tour help once again!

 

[Awk08]

I'd go one size larger main
return the needle to the middle slot, it's what works on these bikes for most all mods except a DMC exhaust <(it likes the clip lowered 1 slot to richen the mids)
raising the clip, lowered the needle and leaned out the mids, that's a recipe for a mid throttle boom
your stumble at low to mid transition is probably an airscrew adjustment, have you tuned the airscrew for highest idle ? ....
https://www.blasterforum.com/threads/adjusting-your-airscrew-pilot-jet.51060/

 

[BlueBlaster99]

Thank you once again for helping me with this thing. One more thing I forgot to mention is that after riding for a bit, the idle hangs for 15 seconds or so. The bike did respond well to raising the needle clip up a nitch, could I be compensating for something by doing this? The bike was pressure tested, completely rebuilt, and I just had the cyl ported and polished by KOR and he also did the head mod. The thin runs amazing as long as you keep it on the power band. Also if you really wind it out it 6th gear it breaks up a little. It seems to smoke quite a bit and seems very rich at low to mid-rpm. I'm beginning to wonder if something is broken/missing in the carb somewhere??? Also, what is the acceptable operating temp of the engine? The highest I've seen it is 300F. I'm scared to damage my fresh engine. lol