Pre-buy WR450 Problems. Need help.

I had a look at an 04 WR last night. It's very tidy and hasn't had a lot of use. The guy is the second owner.

However the first owner has removed the spark arrester from the exhaust and has changed the main and pilot jets I'm assuming as it comes with a pilot jet and 165 and 155 main jets.

When warm it idles for a bit then stalls. Also when taking it for a quick ride it doesn't run very smooth. It's pretty responsive, no bog.

I know they run hot but noticed after a minute or two the header was glowing red hot so am guessing she's a bit lean.

I pulled a little choke and it responded with out throttle and idled well with just the smallest amount.

I don't think it should be a major to sort out, maybe needs pilot jet adjusted?

The other issue was that apparently it keeps blowing bulbs. The battery was flat so couldn't test any other electrics. (It has all the road gear on it). Is there an adjustable voltage regulator or is it most likely something that needs replaced?

Any opinions or advice would be much appreciated.

This is the machine (NZ trading website similar to Ebay).

Sounds like the jetting is off. A competent bike shop can resolve it for an hours labor.

Glowing header is normal. The bike is not meant to just sit and idle. It is meant to go!

Blowing bulbs is usually a bad ground connection but it cvan be hard to resolve unless the person doing the work is very electrical savy.

The ad is gone

Took the carb off for a look. Adjusted pilot screw. Put back together and set pilot screw in until it stalled then backed out a couple of turns at the most. Idles nicely now and doesn't die. Think it's lean still so maybe a bigger main jet. Not sure what's in it at the moment.

Are there gaskets that have to be replaced everytime you pull the carb apart to change jets? Wasn't sure today so left alone for the mean time.

Also put a multimetre across the tail light with bulb out. When giving it a few revs it goes up to 22V. I'm sure it would've gone higher too with more revs so am assuming the regulator is buggered.

So you bought it then?

Gaskets need to be replaces when they are bad. You can have a 20 year old bike and the gaskets might be good, or a 2 and they are bad. But you should be able to take a peek without an issue.

And you are showing the classic signs of a bad reg/rect. It's either not hooked up right or bad check it over to make sure it's not dangling or something easy like that.


the carb has a gasket at the top but you dont need to take that part of the carb off to do the work your looking at doing, the float bowl which youll be taking off has an o-ring seal so youll be fine, just make sure that is still round and rubbery and not flat and falling apart. and yeah sounds like the regulator t me. just take a look at the wiring first to make sure its all hooked up right before replacing it. -Wes

I have an 04 WR and it has just started blowing bulbs regularly the last few weeks. It did it once last year and then was OK until this season.

I have purchased a new reg/rect but have not yet installed it since where I ride the cops are few and far between and really don't seem to care about trivial stuff like working lights during the day. When I have a break in my time to ride (about 3 weeks) I intend to install the new reg/rect (among other things) and will let you know if it helped.

If you do yours first would love to hear if it solved your problem...Please post.


And where is your fuelscrew turned out to?

Just need time to tinker on the bike as it's at work, which I haven't been to for the last week. Can't find any regulators in NZ either. I queried someone on eBay but no reply.

Fuel screw is set about a turn and a half out. Might adjust the needle when I next do a few things on it. Have to change tyres from road to dirt and take the road gear off as well as gear it down a bit.

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