03 Warrior is splitting Intake Manifolds

[sebringwarrior]

I rebuilt my 2003 Warrior 350. It ran perfectly for about 20 hours and then started back firing just a bit but causes the Intake Manifold to split at where the rubber meets the aluminum. I rebuilt the carb. I readjusted the air fuel mixture screw. I rechecked the valve lash. I even tried a high flow open air box. The spark plug looks healthy and proper. This is the third intake I have gone through in as many weeks! A mechanic mentioned that it could be the Pulsar acting up? Can the Pulsar cause that? Has anyone heard of a warrior splitting intakes like that? Other than that, the ATV runs like a beast! Any help would be grealty appreciated!!!

Edited September 10, 2010 by sebringwarrior
mistake

[DirtDemon]

Did you do have the head serviced when you did the rebuild, vavle grind, new vavles, or anything? If the intake valve isn't sealing well or not closing all the way, then you could get combustion or just compression blowing back through the carb. If that happened when the carb slide was closed, I could see it rupturing the intake boot. This is a pretty strange occurence. I guess if the pulsar was acting up, it could cause the CDI to fire the coil during the intake stroke, that may cause enough of an explosion to blow back through the intake valve and rupture the boot. In order for this to happen, the intake valve has to be open, there must be some kind of combustion or compression building while it is open, and I would think that the carb slide would have to be closed or partially closed for the pressure to rupture the boot, those are usually pretty tough. This is one problem I have definately never heard of before, good luck to you.

Edited September 11, 2010 by DirtDemon

[sebringwarrior]

I did, infact, have the head serviced when I had the motor rebuilt. i was hoping that that wsn't the problem, but I have to concur with your analysis. thank you very much.

[DirtDemon]

You are most welcome, lets just hope that the pulsar coil is actually the issue, at least that would not require taking your motor back apart. Also, if the capacitor in the CDI box is discharging prematurely, it could cause the same problems as a bad pulsar coil. Or maybe somthing (ie. metal chip) floating around under the stator cover could be falsely triggering the pulsar coil. Just a couple of random thoughts there, woud be easier to check things like that instead of removing your cylinder head. Good luck.

Edited September 14, 2010 by DirtDemon