Welcome to the WRR/X Forum

A place to share your passion for the WR250R/X!
 
HomeHome  CalendarCalendar  FAQFAQ  SearchSearch  MemberlistMemberlist  UsergroupsUsergroups  RegisterRegister  Log inLog in  
WR250R/X Forum

Share | 
 

 Advice needed on wr250r low compression + hard to start

View previous topic View next topic Go down 
Go to page : 1, 2  Next
AuthorMessage
Edmonton




PostSubject: Advice needed on wr250r low compression + hard to start    Sun May 14, 2017 9:47 am

Hey Everyone,

New to the world of wr250r. Just changed over from a 640 adventure as I found the bike just too highly strung maintenance wise  Rolling Eyes

2008, 17k miles, fuel pump primes as expected, new spark, air filter all good, stator recall complete
coolant temp sensor replaced 5 months ago

New timing chain 2k miles ago.

Lithium battery installed by previous owner - reads 13.4V?! I've no experience with Lithium batteries, is this ok?

All stock.

-----

The Mystery:

On cold start, bike takes many cranks to fire up.
If I hold the throttle wide open, it will fire up in about 5 or 6 cranks.

Check engine light comes on when cold, this persists for about 15mins of running, at which point it turns off. It will remain off if the bike is then cut, and restarted...mysterious!

When warm, fires up on the button.

BUT! No error codes!!

Engine sounds sweet, throttles up as I would expect. Such a fun bike.

----

Took the bike for a compression test, came in around 40-50 PSI, however they did not do the teaspoon of oil as stated in the manual - I assume this is worth doing again with this addition?

----

I've been hunting though the forums for all clues.

By the looks of things could be:

Valves
Timing (slip of a gear)
ECU
Piston nightmare.

Any advice would be appreciated. I've not found any step by step guides to checking the valves online aside from the workshop manual.
I've never attempted adjusting timing - anyone come across a guide for this?

Thanks everyone in advance!!!
Back to top Go down
johnkol




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Sun May 14, 2017 5:12 pm

Edmonton wrote:
Took the bike for a compression test, came in around 40-50 PSI, however they did not do the teaspoon of oil as stated in the manual - I assume this is worth doing again with this addition?

Nominal pressure is 120 PSI, minimum is 105 PSI, so yours is way off. I don't think a spoon of oil would make that much of a difference, and if it does, it still means that you have to open up the motor and see what's going on.

I find it strange that the timing chain had already been changed by 17k given that the first valve check is at 26k; it appears that there was something wrong with the engine, and you may be seeing more manifestations of the same underlying problem.
Back to top Go down
Edmonton




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Mon May 15, 2017 4:01 am

I feel that wheeling it into my kitchen and opening things up is on the cards.

I've read elsewhere on this forum of someone with very similar symptoms, attributing the compression test failure to misunderstanding of the decompression system, however no details where given.

Do you think a leak down test would be a smart move at the point before I commit to popping the top?

Timing chain change is a bit of a mystery I agree.

Cheers.

Back to top Go down
johnkol




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Mon May 15, 2017 7:29 pm

Edmonton wrote:
I've read elsewhere on this forum of someone with very similar symptoms, attributing the compression test failure to misunderstanding of the decompression system, however no details where given.

The service manual makes no mention of the decompression system and how it might affect measurement; it simply instructs to keep on cranking until the pressure reading stabilises.
Back to top Go down
Edmonton




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Tue May 16, 2017 4:21 am

johnkol wrote:
Edmonton wrote:
I've read elsewhere on this forum of someone with very similar symptoms, attributing the compression test failure to misunderstanding of the decompression system, however no details where given.

The service manual makes no mention of the decompression system and how it might affect measurement; it simply instructs to keep on cranking until the pressure reading stabilises.

I came to the same conclusion.

Seems fairly simple to check over timings / valve clearances, so I'll dive into that as soon as time allows.

I'm still wondering what is causing the check engine light, as it is illuminated before cracking begins. Does this suggest an issue with an injector or another sensor? Just bizarre that there isn't a code displayed with the light.

Thanks!
Ed
Back to top Go down
johnkol




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Tue May 16, 2017 4:46 am

Edmonton wrote:
Does this suggest an issue with an injector or another sensor?

If you want to troubleshoot the injector, Yamaha has a very helpful video about that:

Back to top Go down
Edmonton




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Tue May 16, 2017 5:52 am

Really useful, thank you.

Any other ideas welcomed.
Back to top Go down
Edmonton




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Tue May 16, 2017 3:06 pm

A few updates whilst waiting on various parts / tools to arrive.

A few mornings in a row, fires up on the first crank but with the throttle wide open only. (check valves as planned)

Gone through all the diagnostic tests, there are a few anomalies:

06: Coolant temperature negative30 (reads -30) Maybe this is the cause of the check engine light that clears after warmup.
09: Battery voltage reading 0.00?????

Thoughts?

Thanks!!

Ed
Back to top Go down
Guest
Guest



PostSubject: Re: Advice needed on wr250r low compression + hard to start    Tue May 16, 2017 7:06 pm

If you have a low coolant temp reading all the time, the fuel injection will have a hard time giving it the correct starting mixture. Check the battery with a load tester OFF THE BIKE. If it's failing, you won't get a solid signal to the injector, or any of the sensors. Valve clearance can cause low compression at cold cranking, that when the bike warms up opens up the valve clearance enough to run well. I've seen it on other bikes, and it's just time to check it with no money involved unless you can't do it yourself.

I'd check all of that stuff before tearing the engine apart. The rings don't just suddenly unseat unless debris went through the motor or it was seriously overheated.


Back to top Go down
Edmonton




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Wed May 17, 2017 3:54 am

I'll add that onto the troubleshooting list - including checking the spec of the coolant temperature sensor.
Really hoping its just this and valves.
Planning on redoing the compression test with oil to get an idea if its piston rings at fault.

Fingers crossed!

Thanks

Ed
Back to top Go down
johnkol




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Wed May 17, 2017 4:30 am

Edmonton wrote:
06: Coolant temperature negative30 (reads -30) Maybe this is the cause of the check engine light that clears after warmup.
09: Battery voltage reading 0.00?????

Do you have a service manual? Coolant temperature sensor troubleshooting is covered in section 8-78 there.

You previously said that the battery measured 13.6V? Did something change, or different measuring scheme?
Back to top Go down
Edmonton




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Wed May 17, 2017 5:15 am

johnkol wrote:
Edmonton wrote:
06: Coolant temperature negative30 (reads -30) Maybe this is the cause of the check engine light that clears after warmup.
09: Battery voltage reading 0.00?????

Do you have a service manual? Coolant temperature sensor troubleshooting is covered in section 8-78 there.

You previously said that the battery measured 13.6V? Did something change, or different measuring scheme?

Hey, to be clear the 13.6v was taken at the battery with a multimeter, and the 0.00v is on the DIAG on the bike.

I've a copy of the manual.

Weirdly going over the service history, the coolant sensor was changed last year..... I think someone's tried to troubleshoot this before.

Back to top Go down
johnkol




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Thu May 18, 2017 5:12 am

Edmonton wrote:
Hey, to be clear the 13.6v was taken at the battery with a multimeter, and the 0.00v is on the DIAG on the bike.

I've a copy of the manual.

Weirdly going over the service history, the coolant sensor was changed last year..... I think someone's tried to troubleshoot this before.

Have you measured the coolant temperature sensor as described in the manual?

If it measures within spec, then the only explanation I can think of is a malfunctioning ECU.
Back to top Go down
Edmonton




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Thu May 18, 2017 5:20 am

Its on the list for the weekend to check it.
If it is a malfunctioning ECU, I'm not sure what my choices are, they cost an absolute fortune to replace....
Back to top Go down
Edmonton




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Thu May 18, 2017 3:07 pm

Hey guys.

Load tested the battery - passed with flying colours.

Next stop multimeter fun at the weekend, ill let you know how that goes.

Ed
Back to top Go down
Edmonton




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Sat May 20, 2017 4:12 am

Right chaps!

Just retested compression, warm engine.

Without oil 0PSI!!!!! I checked this 3 times.

With oil 105PSI!!!! Balls.

Guess I'm checking out that piston.

Also when warm, internal diagnostics reading the coolant temp at 66 and battery still reading 0.00v.

Any wisdoms?

Cheers.

Ed
Back to top Go down
Edmonton




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Sat May 20, 2017 4:31 pm

Updates!

Got to the valves.

As you would hope they are all in spec, on the tight side mind - but still in spec.

Timing is also bang on.

Onwards to the piston next.

Ed
Back to top Go down
johnkol




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Sun May 21, 2017 1:41 am

Edmonton wrote:
Just retested compression, warm engine.

Without oil 0PSI!!!!! I checked this 3 times.

Didn't a shop test compression just a week ago and found it to be 40 PSI? These measurements seem to be all over the place.

Opening up the engine looks unavoidable; good luck!
Back to top Go down
Edmonton




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Sun May 21, 2017 3:22 pm

Hey everyone, managed to get a bit of time this weekend to get into things!!!

So a few issues when removing the cylinder, was quite a battle to get it to lift up. Here is why:

Quite a corroded dowel pin, I suspect gasket failure here.

I have to say, tip of the hat to the team that designed the engine layout. Really easy to work on.

BUT THEN:


YEP we have some light markings on the wall here. Can feel the ridges with a finger :(

So here what I'm thinking.
Coolant sensor failure leading to failure of the rings? Would explain the replacement of the coolant sensor that was done.

So a few questions guys,

I will be replacing the main cylinder and piston rings. I assume the piston doesn't need to be replaced, I can see any signs that it contacted the cylinder wall.

New damage in my learning curve, so any comments would be ace.

Cheers guys.

Ed
Back to top Go down
johnkol




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Sun May 21, 2017 11:37 pm

Edmonton wrote:
YEP we have some light markings on the wall here. Can feel the ridges with a finger :(

So here what I'm thinking.
Coolant sensor failure leading to failure of the rings? Would explain the replacement of the coolant sensor that was done.

First of all, light markings cannot possibly account for a compression of zero PSI. How do the rings look like?

Secondly, if the coolant sensor failed and was replaced (as indicated by the maintenance records), then why is the new one failing too? And how any of this explains the ECU diagnostic showing battery voltage as zero?

I would be very hesitant replacing anything before I had answers to these questions and was confident I had found the root cause of the failure.
Back to top Go down
Edmonton




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Mon May 22, 2017 4:25 am

johnkol wrote:

First of all, light markings cannot possibly account for a compression of zero PSI. How do the rings look like?

Secondly, if the coolant sensor failed and was replaced (as indicated by the maintenance records), then why is the new one failing too? And how any of this explains the ECU diagnostic showing battery voltage as zero?

I would be very hesitant replacing anything before I had answers to these questions and was confident I had found the root cause of the failure.

Cheers Johnkol.

I'll get the rings out and check the gaps when I have a moment, visually there is nothing off.

The piston itself has some light vertical scoring in line with the cylinder walls. Incidentally, no materials were found in the engine oil, or on the magnetic plug.

Checked the coolant sensor, all within electrical spec there. The strange thing is once the engine is started, if you turn it off and recheck the coolant temp, it is reading out.
Also the fan was spinning up as expected....

Have to say the battery voltage at 0.00v is a complete mystery to me. Google cannot help!

I've pulled the ECU and cleaned the contacts, so lets see if that helps when everything goes back together.....

Over on ADVrider someone also had some vertical scoring on their cylinder at 7000miles and had the whole thing re-lined and a new piston and rings. But they weren't having weird ECU issues.

I've just had a look through the ECU troubleshooting in the manual, there is a fault code for Vehicle system power supply (Monitor voltage), which is error code 46.

Which is odd as I'm not getting that error stored....

scratch
Back to top Go down
johnkol




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Tue May 23, 2017 12:57 am

Edmonton wrote:
I'll get the rings out and check the gaps when I have a moment, visually there is nothing off.

The piston itself has some light vertical scoring in line with the cylinder walls. Incidentally, no materials were found in the engine oil, or on the magnetic plug.

Checked the coolant sensor, all within electrical spec there. The strange thing is once the engine is started, if you turn it off and recheck the coolant temp, it is reading out.
Also the fan was spinning up as expected....

I have opened motors before where compression was zero, and I found compression rings broken in two; how it would be possible for the rings to be intact and still get a compression of zero is beyond my comprehension.

So turning the bike on (not starting it) you get an indication of very low coolant temperature. What happens when you turn it off and back on again (without starting it in between)? Still low coolant temperature? It's only after you start it that the coolant temperature starts reading correctly? How long does the motor have to be working before you get reasonable readings?

When you say the fan was spinning, you mean that you left the motor running long enough for the coolant to reach high enough temperature to activate the fan?
Back to top Go down
Edmonton




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Tue May 23, 2017 5:39 am

Johnkol,

Wise words, I've just pulled the piston out. Have a look at this baby.


I totally agree that there is definitely something up with the electrical system.
Interestingly, if you disconnect the coolant sensor its reads...guess what... - 30 degrees.

I traced back the leads, good connection back to the ECU.

BUT THEN

Some complete clown had spliced in the heated grips into the head fuse, at the fusebox end. WTF. I noticed some very un-yamaha cabling hidden in the loom.

The check engine light is illuminated whilst everything is unplugged as before, I can only assume this means an issue with the ECU.

So here is what I'm thinking.

ECU got damaged
Caused overheating to occur in cylinder.
Balls up. GAHHHH

As for the compression reading zero, I'm not sure what to say here. :hmmm:

Thoughts?

Back to top Go down
Jens Eskildsen




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Tue May 23, 2017 1:45 pm

How's the valves?

What does the engine do, based on coolant temp, other than start the fan?

The cylinder seems very glazed, it almost has a mirror-ish finish on it, were it should be looking very dull, in lack of other words.
Back to top Go down
johnkol




PostSubject: Re: Advice needed on wr250r low compression + hard to start    Tue May 23, 2017 10:21 pm

The bottom of the piston looks fine, but then again I wouldn't have expected to see any damage there. If the rings look good too, then I cannot explain how one can get a compression reading of zero.

Edmonton wrote:
Interestingly, if you disconnect the coolant sensor its reads...guess what... - 30 degrees.

So basically upon starting the engine the ECU behaves as if there is no connection to the coolant sensor, but as the engine heats up the ECU suddenly establishes contact with the sensor and starts displaying the correct information? Have you been able to determine at what point this connection gets established, and whether it is consistent?

Agree, a malfunctioning ECU would explain the electrical gremlins that you are seeing.
Back to top Go down
Sponsored content




PostSubject: Re: Advice needed on wr250r low compression + hard to start    

Back to top Go down
 
Advice needed on wr250r low compression + hard to start
View previous topic View next topic Back to top 
Page 1 of 2Go to page : 1, 2  Next
 Similar topics
-
» Small sand blaster.....advice needed!
» Buying a new wr250r from a dealer, advice needed.
» 2008 WR250R won't start
» Storage of WR250R - advice needed
» Falcon 87 - Advice needed for electrical issue

Permissions in this forum:You cannot reply to topics in this forum
Welcome to the WRR/X Forum :: Technical :: General Maintenance Discussion-
Jump to: