crf450, please help

[250girl]

I am looking at a bike for sale. 2003 CRF450, tons of mods, $2500. But here's the catch. The owner says he hasn't ridden it in a year, and he has decided to sell it. he went to start it and clean it up... and it would not start no matter what he did. Changed the gas, checked the valves, cleaned the carb, it all looks fine but the bike will not start. He rode it into the garage a year ago, running fine. And now it won't run. In the 2 years he owned it he's ridden it 5 times. This bike seems like a really good deal, 1st owner MX guy who took great care of it, 2nd owner rode 5 times and parked it due to injury. 2nd owner now very angry that it won't start and he has to sell it for a lot less than its worth. So what would cause a bike to do this? He says that once in a while it will "pop" like it wants to start, but has yet to actually start.

Any advice would be greatly appreciated. Thanks again,
250girl

 

[IndyMX]

First do a compression test..

There are so many different reasons that will cause a 4 stroke to not start, but the most obvious is a lack of compression. Could be that the valves are shot.

 

[whenfoxforks-ruled]

What is the temperature at where you are trying to start it? Did you leave the freezer door open again? Its 2f and dropping here, thank you. I knew a guy once, he hauled his 450 in the back of a pick up truck, in 10 degree f temps. It would not start for quite a while after it warmed up. And the jetting thing.

 

[250girl]

The bike is and has been kept in a garage. I am guessing its heated, or at least not that cold. The owner said he checked the valves, suspecting that was the problem and he reports that they are just fine. Cleaned the carb, and put in new gas. Still won't start.

 

[IndyMX]

The bike is and has been kept in a garage. I am guessing its heated, or at least not that cold. The owner said he checked the valves, suspecting that was the problem and he reports that they are just fine. Cleaned the carb, and put in new gas. Still won't start.

Must do a compression test.. Could also be bad or stuck rings.

How hard is it to kick?

Mine was fairly easy to kick, until I put a new piston & rings in, and adjusted the valves.

It's now quite a PITA to kick.

 

[Matt90GT]

3 basics to make a bike start:

SPARK
GAS
COMPRESSION

-Check the spark, easily done with the tank off.
-Compression, easily done with the tank off and compression gauge. You should get like 100lbs in 5 kicks with the autocomp set.

If you have both that, then it is a carb issue. I dont care what people say about cleaning carbs cause many people dont know how to do it properly. I have seen a ton come into my place that said they just cleaned the carb and it is still green inside. So take that statement with a grain of salt. But you have to clean the pilot and main jets. Also the main and pilot orifices. Remove the fuel screw, blow air through that. clean the leak jet and 1 way valves in the bowl. Then remove the choke and hotstart. Lube both plungers. adjust to make sure there is freeplay in the hotstart - common issue with the 4 stroke carbs : hot start plunger stuck open and the bike will not start. People dont do the maintenance needed.

 

[Ol'89r]

I dont care what people say about cleaning carbs cause many people dont know how to do it properly. I have seen a ton come into my place that said they just cleaned the carb and it is still green inside. So take that statement with a grain of salt. But you have to clean the pilot and main jets. Also the main and pilot orifices. Remove the fuel screw, blow air through that. clean the leak jet and 1 way valves in the bowl. Then remove the choke and hotstart. Lube both plungers. adjust to make sure there is freeplay in the hotstart - common issue with the 4 stroke carbs : hot start plunger stuck open and the bike will not start. People dont do the maintenance needed.

I agree. If he didn't remove the float bowl and do all of the things Matt suggested, he really didn't clean out the carb.

Anytime a bike has been sitting for a long period of time, nine times out of ten the jets will be clogged.

Twofittygirl. You may want to think twice about buying this one. There is a lot more involved with keeping this bike running than your RM. Plus, if you don't keep up on the maintainance, it will be very expensive to repair.

If you want a four-stroke for play riding, I would look into the XR line. The XR's are low maintainance, easy to ride and can be found at a reasonable price. They sit much lower to the ground too compared to a CRF.

 

[whenfoxforks-ruled]

Have you seen the price tag on replacing that fcr carb? Just a little preventative maintenance, sea foam IS priceless, for the easy way out?