Modified Exciter fouling issue

[ex570]

I have a modified 87 ex570 which runs twin psi pipes, bored 38mm round slides, .020 shaved head, yxr clutch upgrade, v-max 4 front struts, 5.5"wide kit, 91 rear suspension etc, etc etc. I use to run Wisecos in it and was having longevity problems, also ran roundslides with powerjet setup, In posting previous problems many members offered suggestions and reasons not to run Wisecos and powerjets with fuel frothing issues and harmonics. I now have a new set of OEM pistons at .010 over (ceramic coated) with a new to me used crank ( old one had bearing chatter at PTO side and excessive clearance on the lower rods, power jets are blocked off and mains are 330 mag/ 340 pto, needle clip is in position 3 with both washers under, airjet is at 1.5 perhaps a bit lean will likely end up at 1 turn out. Sled runs well when warm and jetting appears to be safe in the mid and above for running at 300meter elevation. Here is the question, when cold the pto plug almost always fouls on starting, sometimes having to switch in a fresh plug, sometimes I need to baby it till it clears and starts to fire. Once warm it is fine all day, no problems when hot. My timing is retarded about 2 deg. I had retarded it 3 deg wondering if detonation was a issue with the Wisecos upon the OEM rebuild I expected higher compression and so tried 3 deg with the twin pipes and am aiming for 8100 rpm which it appears to pull. I had 135 psi mag/ 127 psi pto upon assembly after 240 km I now have 145 psi mag / 137 psi pto so I would say rings are now seated. I am running standard NGK BR9ES plugs. Does anyone have any ideas as to the cause of the cold start fouling on only one side? I am thinking it is carb related perhaps a worn float neddle, leaking float any suggestions. I supose could flip carbs and see if problem follow the carb. Thanks in advance.

 

[ex570]

Fouled pto plug

Common no wild speculation from anyone, guesses? anything.

Surely some one has run into a similar situation at some time regarding consistant fouling of one plug during start up when cold.

Ex570

 

[kaw550]

I had a similar problem due to poorly adjusted choke cables.