HRC kit installed, problems followed

[kssandduner]

I got my HRC kit installed last thursday. Everything went fairly easy, no problems that I could see. The only thing I did a little different was I installed my K&N air filter off my 400ex, and I decided to not run an air box lid at all. I took it for a spin down the dirt road and it ran awesome, I was really impressed. So then I slapped my paddle tires on and loaded it on the trailer. Friday morning we left for the little sahara in Oklahoma. I rode it fairly hard all day friday without a problem. Then on saturday afternoon we met up with some guys that had a 450R and a Pred. We raced through the bowls and through the trails hard. That was the hardest I had ridden it since I bought it. I was riding it hard, but didn't feel like I was abusing it. Then torwards the end of the afternoon it stopped running right, it started missing out really bad, wouldn't rev out at all, and developed a strange ticking noise in the top end just a few rpms above idle. I babied it back to camp, and loaded it up on the trailer. When I got back on sunday I pulled off the cover on the head not knowing what to expect, but found nothing out of the ordinary. Everything looks fine. I had first thought that maybe the decompressor adjustment had backed off and was causing it to run lean, but it checked out fine too. I'm really confused at what happened, you would think that if I did something wrong on the installation it wouldn't have ran fine for so long?? Anybody have any ideas?? It's most likely going back to the dealership this week.

Joe

[Bretmd94]

After riding it that much the valves might be needing the clearance checked.

Also riding it that hard might have not been the greatest idea. Cams and any other internal parts should be broken in properly just like a new piston.

One thing I knowticed that you didnt mention was the jetting.. You did rejet after all the mods right? I think the kit comes with a new jet. You might have been running lean. If the kit was made to run with its stock filter and the HRC lid, and then you decide on getting rid of the lid completely and run a really high flowing filter compared to stock, you should have to beef up the jet size. Im running 185, 190 (dunes) and all i have is exhaust and filter with no lid.

Check the piston for any damage that looks like it was running lean, check the clearance on the valves, Make sure nothing became unseated (i had a valve do that on my raptor).

If you dont find anything and it all looks good, take it to a dealer or someone that knows a ton.

[lukester720]

Sounds like you need to take the carb and engine apart and see how much sand you have in them. Do you have sand in the intake? I wouldn't run a k+n if I were you definately not without a prefilter or airbox lid, almost forgot in the sand. Even if it wasn't the problem this time its something to think about because next time it might be. I think a good dual stage foam filter is the way to go.

[kssandduner]

I've never had a problem with my K&N's letting in sand. I had the same filter on my 400ex and never had a problem. I've run K&N's on every bike i've ever owned. I haven't actually had the filter off yet, but i had the carb apart, and there was no sand in there, so i doubt i'll find much sand in the motor if i'm not finding any in the carb.

[lukester720]

Just figured I'd check. I know that when I ran my k+n on my 400ex the inside of the intake boot would get all dusty, didn't happen once I switched to foam. Good luck figuring it out.