SOS - 2009 CRF450R Starting issues


Recommended Posts

Hey everyone, been a long time since ive owned a dirtbike and been on here! But I got my self a sweet little side project a few months back (I use the tern sweet very very loosly ūüėā).

 

Anyway it was a blown up beat to crap 2009 CRF450r, not a bike I would normally buy or want, but sometimes things fall into your lap, I must have done something bad in a previous life ūüėā.

 

So last week get the engine and bike back together all buttoned up. Wouldn't start. Cracked the shits and left it to last Friday when I had more time.

 

Tested everything cleaned some plugs and gave the fuel pump external 12v along with the bike circuits. She fired up a treat. Hooked everything back up, started again went for a little ride, left it on a happy note and went home.

 

Come in Saturday same story, kick it till the cows come home, no go, jam 12v up it and fires straight up.

 

Tested the stator, condensor, reg/rectifier with all the manual tests, all seem to pass. Checked wiring from stator to reg, wiring from ecu to various places, checked kill switch etc. All good.

 

Once it was running, I rode it around for a good half hour, let it sit for 20 minutes cleaning tools up and it started first kick. 

 

Its meant to be going for rec reg Friday but that ain't looking good.

 

Once you get it running, runs like a top. The bike had been sitting for 5-6 years blown up, going to test fuel pump current draw see if something funny is going on there.

 

I have already destroyed the budget so would prefer not to spend money but it is what it is and a bike that starts is much preferred ūüėā.

 

If the brains trust out there have any ideas it would be much appreciated.

 

Also its good to be back and I havent even ridden it bush yet!

IMG_20210529_163246101.jpg

  • Like 2
Link to post
Share on other sites

I just checked current draw of fuel pump and injector, about 1.4amps for fuel pump and right around 1 for injector. So don't see them being an issue.

 

Possibly stator or condensor/capacitor?

Link to post
Share on other sites

I started with the same bike - the first of the fuel injected Honda's.  It was always a pain to start. - Heaps of power with small throttle input and flamed out like a candle flame in a wind tunnel.

I can't really add too much, but If the Capacitor is off, then you wont have sufficient charge to run the injector or pump.

There is a starting procedure when cold that worked most of the time. 5 slow kicks to prime the injector then one reasonable kick after a slight pause.

A couple of items that I used to tinker with to deal with starting issues:

  • I mucked around with the throttle position sensor (TPS) as well as if it is out by¬†a bit the it will be hard to start. It has to have the output Voltage set to a specific value (Sorry I¬†can't recall the value) with¬†very small tolerance either way.
  • I assume the valve clearances are in check and the stop button LED isn't flashing a code
  • This model also had an issue with the auto decomp timing.¬† There is a mod to the spring tension on the auto decomp cam. I think they changed the whole mechanism in the following models.
  • Also if it has a headlight/ break light¬† running off the¬† the fuel pump hot lead - disconnect it - it might be killing the power to the pump.

I hope this helps.

 

  • Like 1
Link to post
Share on other sites

Haha yeh I know they had their problems.

 

It has a heavy flywheel so hopefully that will help with flame out see how we go.

 

Valve clearances are good and lights arent wired up yet. I really feel it is a voltage issue, as soon as I supply 12v through capacitor plug fires up easily. Will keep doing some digging. Appreciate the response.

  • Like 2
Link to post
Share on other sites

Well haven't even ridden the bike and about ready to part it out.

 

Checked tps voltage, fine. Swapped out stator/reg/condensor. No change. Had to leave before I set fire to it.

  • Haha 1
  • Sad 1
Link to post
Share on other sites

One thing to springs to mind given that you mentioned a straight 12V in the Capacitor makes it fire up straight away is " does it have a good earth."

Run a quick ohms test from the earth to the earth side of the capacitor.

image.thumb.png.f560ae4a6f94d4f90ebf701c96e96d26.png

Link to post
Share on other sites

https://thumpertalk.com/forums/topic/733201-hard-to-start-cold-2009-crf450r/page/2/#comments

In this thread they discuss the capacitor not holding charge and it is a 10,000uf 50V cap....never confirmed if that fixed it but you could rig up a cheap capacitor from Jaycar and see if it works, before you fork out $ for a Honda one.

  • Like 3
Link to post
Share on other sites

Does the fuel pump  run and there's fuel pressure  when your having the problem? If so I wouldn't think it's the capacitor. If not capacitor is a good tip as per Cujo or maybe the pump is dodgy; the sustained voltage / bigger current zap when you feed it the 12 volts directly is acting like a heart starter.

 

Link to post
Share on other sites

Well I went back for a little fiddle tonight.

Pressure checked pump at 12v - 50-55psi. Pressure checked pump while kicking over, pressure built up.

Pulled injector out, injector is spraying when you kick it.

Checked resistance of coil, all good. Checked resistance of coolant temp sensor all good. Going to check IAT sensor at some point. Rechecked timing yet again and did a leak down test while I was in there and its all good.

Currently have a second hand capacitor in it and made no difference, not saying that ones not a dud haha.

Wondering if maybe it is flooding, or has a weak spark. Will recheck valve clearance while I have the cover off but they were fine when I built it.

Will keep doodling away at it.

  • Like 1
Link to post
Share on other sites

Weird. Spark and petrol plus it runs once it gets going indicates its not a cam timing or compression issue. If it was OK cold and a problem hot I'd say valves not sealing.

Weak spark sounds a reasonable theory. Bit of a long shot. Are the sensor coils resistance in the alternator in spec: both before and after you get it running. These can start to get weak on the way out but they may heat up with a bit of current and then run (until they totally fry). ECU can also get dry solder joins that may warm up with a bit of current and then work (pretty rare though).

The MAP sensor could be coated if the filter gets overoiled.

 

Link to post
Share on other sites

Need to narrow down fault, throw a bit of extra fuel down intake and see if it starts. If it does you know its on the fuel side or visa versa. If its on the fuel side check the ECT sensor at the ECM end of wiring harness.

Link to post
Share on other sites
  • 2 weeks later...
On 6/6/2021 at 5:14 PM, dazzrmx said:

Maybe its tired.

I know if a permanent magnet is not stored correctly in its keeper ( in this case the  flywheel rotor and it's stator) for an extended period of time it can loose some of its magnetic strength to the point of failure.  Perhaps this is the case in this instance if the bike was in bits for years and the rotor was  not kept sitting on the stator . 

My suggestion would be to put a voltmeter and amp meter on the output of the stator when its not working ( kicking and looking at voltage peak- you will need a analog meter )  ,  juicing it up  , resting the bike again for a very short period  then doing it again  comparing the voltages   Sounds like your exciting the magnetic into working but then after a good rest it's lost most of magnetism again.    Another way would be to measure the magnetic field strength  with a Steel ruler ( at what distance does it get sucked in )  when bad and when good.   Food for thought anyway :) 

Link to post
Share on other sites
1 hour ago, PeteV said:

I know if a permanent magnet is not stored correctly in its keeper ( in this case the  flywheel rotor and it's stator) for an extended period of time it can loose some of its magnetic strength to the point of failure.  Perhaps this is the case in this instance if the bike was in bits for years and the rotor was  not kept sitting on the stator . 

My suggestion would be to put a voltmeter and amp meter on the output of the stator when its not working ( kicking and looking at voltage peak- you will need a analog meter )  ,  juicing it up  , resting the bike again for a very short period  then doing it again  comparing the voltages   Sounds like your exciting the magnetic into working but then after a good rest it's lost most of magnetism again.    Another way would be to measure the magnetic field strength  with a Steel ruler ( at what distance does it get sucked in )  when bad and when good.   Food for thought anyway :) 

Yeh I have been reading about loss of strength but I compared it to the standard flywheel using a 1/4" extension and they bolt felt about as strong as eachother but im not ruling it out, easy enough to swap a flywheel.

It was blown up for about 5-6 years but still together, but was also reading about heat effecting magnet strength, and the bottom end bearing failed until it seized so anything is possible!

I havent gone back to it yet but will in the next week or so!

Thanks everyone for their thoughts.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.