Wr45 Surge

Issues with the Blue Beast. I have a 2006 WR 450. All of the free mods and jetting was done in 2006. I was out the my boys and we were running through this knarly sand wash. I was in third and trying to stay in the power. I could feel the bike surging and lurching in the higher rev limits. I was not red lining it. I noticed the chain was very loose. Limped back to the house tightened up. So we headed back out. This time I was on a fire road in the same gear and about the same area but not as bad. Either time I could not hear anything it I could just feel it. It was like the choke or about to run out of gas feeling. The choke was off and the gas was full on. I have not messed with the jetts in three years so they are good. I took the bottom of the carb off there was just the tiniest bit of something at the bottom. I took a can of carb cleaner and used about ½ of it inside of the carb. Any other suggestions? I’m going to finish putting it back together today and try it out. Could too much spray tack on the filter cause this and if so shouldn’t I feel it in other places as well?

Is this the 1st time you did this type of riding (IE: high speed / sand wash)?

If so it could be the Famous CDI hic-up. Just throwing out ideas.

No we are always in that wash or others like it. The wash is not to fast due to all of the turns. We use it for training for out desert racing plus it is a total blast. Tell me more about the CDI hic-up.

Thanks. I am hoping to get off cheap. I think if I need to start shelling out a lot of dough then a 2010/2011 YZF-450 may be sitting in my garage intead. I am even going to change the gas just incase I got some bad stuff at the pump. Maybe add about 1/2 gal of VP102 to five gal of Chevron 97.

a 2010/2011 YZF-450 may be sitting in my garage instead.

That's the kind of thinking we like to hear!

At what throttle setting were you noticing the surge? 1/4 or 1/2 or full throttle. I would change out my pilot jet with a new one just in case these are bunged up a bit. Hard to clear so cheaper to replace with new ones keeping it the same size.

Ok I cleaned the snot out of the carb checked the fuel lines changed the plug and no joy still surged in 2nd and 3rd gear 20 to 40 MPH on speedo. So I tried to disconnect the the TPS and it still surges. The jetting is what came in the AIS removal kit and it has run fin at the 2200 foot level just fine for the past few years. Compression seems ok starts on first kick

Have you tried un-pluging the TPS? If it works might just need to adjust it.

I already tried that including checking all of the connections for the CDI. I am tring to find someone in the area with the same year so I can try to use their CDI and see if the works. I dont want to shell out 400 bucks with out knowing for sure because mama will be pissed if I do and I'm wrong.

I took the carb apart yet again pay real close attention to everything. This time I noticed that the needle is all the way to the left side of the carb. So I separated the main jet from the needle jet and I noticed that the main was worn from the needle wearing against it. I also noticed that the plastic housing for the hot start cable going into the carb was also broken. I ordered the parts and decided to test run it again. This time I noticed that it did it towards the top of second gear in everywhere in third. I also noticed that going from second to third it would feel like I’m hitting neutral. Then it would grab then skip. In fourth and fifth all seems fine. I’m starting to thing I am on the verge of losing third gear. I got to talk to the bike shop in the morning to verify it and see what it is going to cost.

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