Yamaha DEFECT or What???????

Ok, I've been doing some searching on here and this is what I've found.

Alot of people are having problems with thier hot start plungers freezing up. While trying to fix mine, I broke the prongs that hold the cable in the carb. Some one said this is a very common occurance because of the type of lube and corrosion that gets in under that plastic cap.

Has this happened to anyone and what have they done about it? Did you take it to a dealer and have them fix the problem. This is a '03 450 with a stock plunger.

Every time i change my oil i also take the extra minute to take off the plunger, shoot a little WD-40 into the opening and put it back together....havent had a problem yet.

Yes, it happened to mine too. When I finally got it unstuck I cleaned it up and coated it in anti-seize. No more problems.


We had this problem for a while with my son's '01 YZ250F using a Dr.D hot start. The only thing that will cause the white crusties in the hot start bore (or anywhere else in a carb) is water. When the bike sat for a week after we washed it, it would stick. Dubach sent me a couple of seals for the unit for free (he was going to send me a whole free hot start kit, but I told him not to). This only partially solved the problem, but it was cool of him to do it.

First, get rid of ALL of the corrosion you can find. It grows back if you don't. Use WD-40 and a nylon 30 caliber rifle bore brush to clean the carb. If it's really bad use brass at first. Lube it with a tiny bit of waterproof or graphite grease.

To keep it from repeating, avoid spraying the carb with water more than absolutely necessary. After the wash, start the bike and run til it will stay lit without the choke. Raise the rpm a bit 2000-3000, hold it there and open the hot start. This will draw out any moisture in the airway around the hot start valve.

It's been working for me.

Cool. Sounds like this will all work.

But what do I have to do to replace the plunger? I broke the clip that hold the cable. How do I get it out? Dealer or what? This is my big delema now.

I noticed my hot start plunger starting to stick during one of my rejetting episodes. It looked to me like the seal on the plunger was causing all of the stiction. I removed it and have had no problems since. The hot start works fine too. So far, the plunger bore is staying clean without the seal. :thumbsup:

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