Help! crf450r

[slowguy820]

Hi i have had this bike for like 6 months now. i have about two hours on it total ride time since i bought it. it blew a crank at about 30 mins. i bought it used so what can you do. went through the motor replaced all everything it needed. took it to the track and dxidnt get through a day of racing just wont run now. will start for a secound or so but then shuts off. replaxced the ecu unit ran for a about ten mins now wont start. i can smell gas when kicking. after replacing ecu had a bog off the bottom end. please post advice if you have any thank.

[toombstone]

First things first,,, do a compression check... Just off the top of my head but I think that bike wants 68lbs after about three kicks at wot.

R

[slowguy820]

its got plenty of compresion. i cant even start it without something to lean it on. my 07 starts like a dream when its off the stand. brand new top end and the valves were just adjusted. but if you think i should do a compression test i will. oh yeah i replaced the auto decompression in the head cause it is a animal to kick.

[ds66]

What model is it? And what work did you or the mechanic do after it 'blew a crank'?

[slowguy820]

I took the bike to my mechanic and he tore it down and put in a new crank, piston, rings, oil pump, valves and cam chain. When he gave it back to me it ran good but he said it had an electrical problem that he could not diagnose without a lot of testers. So it ran for like an hour and then would not start.

It's a 2009

[FORMA MOTO]

2009's had defective fuel pump. Put in an '11 pump.

[ds66]

Hm, so its not the engine. Might be worth your while to find a bike electrician. I played around with a KTM for 2 years with the jetting only to finaly finout it was the stator.....

[slowguy820]

When I kick it I smell gas. So I figure the pump is good. That's where I am at has to be coil or stator. There is no indicator light on on the kill switch.

[ds66]

I would look at easiest part first. The coil, easier to replace or swap out with someone just to check. I gut feeling is its the stator, lack of spark? Same thing happened in my KTM, had the stator rewound and the problem was instantly solved.

[slowguy820]

Thanks that's what I was thinking. I was just looking for some advice to see if I was heading in the right direction . I will let you know what I find.

[toombstone]

Respectfully.... You can bounce around and test a bunch of different things, but it works best to have a plan, and then work that plan... I know this bike, trust me...

Let's start with the compression test... I can explain my "madness " in detail later when I'm not typing with a thumb...

R

[klxchrisE]

Listent man, I just went through all this with my 450. That 09 fuel pump is so problematic it's not even funny. That's why when you look it up in a parts fische they give you the upgraded pump. I replaced my stator, coil, and condenser and it was a simple fuel pump malfunction. Just because you smell gas doesn't meen it's working properly. Those filters clog really easy too. The design of the pumps are flawed to begin with. The two wires have a tendancy to touch each other and short out the entire system. Don't forget, on these modern EFI bikes if one component on the electrical system goes out... Nothing will work. (No spark either). Also, check your oil level to see if there is gas in the oil. If so you might need a new injector also. A compression test is simple to do if you have the tool. So do that first. If you have compression i would pull that fuel pump and go from there. I have a working fuel pump I'll sell you cheap but it's not the upgraded one.

[slowguy820]

I tested my fuel pump with a 9 volt battery and it seemed to pump just fine. That's another reason I wasn't thinking fuel pump. But if you think that's what it might be I'll check again .

[FORMA MOTO]

I tested my fuel pump with a 9 volt battery and it seemed to pump just fine. That's another reason I wasn't thinking fuel pump. But if you think that's what it might be I'll check again .

Unless you can test for pump pressure, you don't know if it's working. If the pump does not create proper pressure, then the fuel does not push through the injector fast enough to atomize, and it won't create a good mixture. Just air with big drops of gas in it will not allow combustion.

[The Captain]

Easy things first, check the fuel filter in the bottom of the pump assembly. Being an '09, and if the fuel wasn't filtered before filling the bike, that sucker will be clogged.

[eaceti]

Ground the plug & kick it over, if your getting spark the electrical should be ok. You could test the wiring with a multimeter, I dont think you need multiple testers. Did you double check your timing? That is a cheap & easy fix.

[klxchrisE]

I tested my fuel pump with a 9 volt battery and it seemed to pump just fine. That's another reason I wasn't thinking fuel pump. But if you think that's what it might be I'll check again .

I did the same thing. I even went as far as filling a container with gas, placing the pump in the gas and then puting a 9v charge on it. Just because it's pumping doesn't mean it's the correct pressure. Also it's a 12v system not 9v. If you have the money, I would just replace the entire fuel pump assembly. When you look up the part in the parts fiche, it's upgraded from the factory. If you don't have the money start with a $40 filter kit for it. Remeber to place all the gaskets back EXACTLY the way you found them. When you re-install it it's going to take like 40-50 kicks to rebuild pressure in the system too. Make sure you're at TDC every time you kick it. This is one of the most finicky bikes I have ever riden. Fun, but a ton of work. Keep us posted.

[slowguy820]

Thanks guy I replaced the fuel filter already. So will check the fuel pump out

[toombstone]

Wholey Christ.... I work in these bikes every day, there is a method..... Just because it pumps fuel dies not mean it works, seals wear out, then not enough pressure to push through Injector..... You can shotgun test this thing to death guys......

Compression check or I'm out.

R

[ds66]

How do you do a compression test? Or does it need to go to a mechanic?