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nicksta43

Cam chain tensioner or something worse?

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That is strange... Kind of makes me think fueling or timing (spark plug timing) issue. Does anybody know where the crankshaft position sensor is? Has that been looked at? Have you taken the stator cover off and had a look in there?

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It sounds like AFR issues maybe. Have you tried to sync the throttle bodies? You can do that again after you do the valves. Maybe the O2 sensor issues. Sounds alright when you run it up a bit. Try these (easy) before pulling the head. Fingers crossed for ya.

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19 hours ago, nicksta43 said:

 

I'm not sure what to do. 

Maybe the best thing would be to just suck it up and open up a credit card, take it to a shop and tell them to make it right. I really don't want to do that but I think I'm not up to fixing this. 

I admit to being electronically illiterate, so if a "bad running" engine doesn't have carburetors, points & coil ignition (or magneto) then my first response is to blame the f'n computer.  I don't know if it makes sense to take the ECU to a dealer or even to one of the vendors here who re-map computers,  for testing and diagnosis, but that might be a possibility.  Even better, if there is a forum member living near Nicksta43 in Texas willing to lend him an ECU  to swap in for a test, that could be helpful.  Or a longer distance good Samaritan,  with a bike apart for some other purpose, or snowed in for the next month...  

Current asking prices for used ECU's on eBay are between $160-250.  Actual selling price for a stock one (from eBay completed auctions) was $92 in Nov.2018.  Obviously these are NOT high demand items, so a best offer might work out.  It might not be worth the gamble to buy one outright...but maybe a seller would be willing to "sell" one and charge a re-stocking fee ($25 to $50?)  if that isn't the problem and his ECU is returned in same condition as sent.     

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2 hours ago, justplainbill said:

I admit to being electronically illiterate... 

I bet I am more electronically illiterater than you, jpb!

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1 hour ago, wordsmith said:

I bet I am more electronically illiterater than you, jpb!

Anything is possible, but I didn't even know what a jpb is (looked it up), so I may hold  both the Electronically Illiterate and  Online Chatting Lingo Ignoramus championship belts. 😀

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Posted (edited)

I would do a "hard reset" of the ECU...might have some bad lingering values floating around... So the ECU might be using values prior to the repair/service or mod that was done... 

It would be another good idea to check your current sensor values against the service manual since some got unplugged and moved around

Check hoses for proper placement-might have one or two switched up...it's possible debris is fuel rail/injectors since it was "loosened up?" And resulted in a split o-ring... Has a TB synch been done? 

Edited by norcal616

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1 hour ago, justplainbill said:

Anything is possible, but I didn't even know what a jpb is (looked it up), so I may hold  both the Electronically Illiterate and  Online Chatting Lingo Ignoramus championship belts. 😀

I think Worsmith mean jpb as in JustPlainBill :)

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4 hours ago, justplainbill said:

Anything is possible, but I didn't even know what a jpb is (looked it up), so I may hold  both the Electronically Illiterate and  Online Chatting Lingo Ignoramus championship belts. 😀

jpb is my lazy way of referring to justplainbill.   Sorry if I offend!   You must now hand back the Online Chatting Lingo Ignoramus (OCLI) championship belt, and I have a firm grip on the Electronically Illiterate (EI) one...

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3 hours ago, koth442 said:

I think Worsmith mean jpb as in JustPlainBill :)

Good call.  Didn't even cross my mind... jpb was defined in an Urban Dictionary as "just playing bitch"  -- meaning  the preceding remark was made in a playful way.  And that's how I took it. 

So now someone has to explain to me what a hard reset of the ECU entails?

 

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I'm going to go ahead and get the valve clearances back in spec then sync the TBs and see where we stand after that. 

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Hard reset of the ECU will put the ECU back to the original values...no long/short term values it learned over time are being reused such as fuel/ign trims...

It's also possible the AIS system is faulty, broken ign coils, faulty spark plugs, clogged air filter, faulty crank sensor, faulty o2 sensor...wrong sized or material used for replacement o-ring??? 

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There's lots of possibilities here...

Nic - sorry to hear that not much has changed with the running condition. Let's rewind for a second:

When you checked compression this latest time, how did the spark plugs look? Black?

What changes/mods have you performed to the bike since new? Specifically have the TPS/APS settings been adjusted? Have you installed anything to "trick" the ECM into being in closed loop mode, ie O2 optimizer or another add-on that interrupts the O2 sensor wiring? (Just so you don't take this the wrong way, I'm looking for information... not finger pointing).

Have you checked codes again? Is the FI light illuminated?

RE: "Hard reset" of the ECM, our bikes don't have a sophisticated enough computer similar to automotive ECM's... I think the only thing the ECM compensates for (historically speaking) is a "learned idle" value. This IS NOT accessible via the DIAG menu if I remember correctly (IIRC), and can only be checked/reset with dealer software. Generally this value increases (from 0 standard to either 1 or 2) because of a carbon build-up in the Throttle Bodies. There's a service bulletin (not warranty) available from Yamaha about this symptom and it may not pertain in your situation, Nic.

Only other thing I can think of is are you POSITIVE that the cam timing is correct? it's easy to slip out of time on this engine when re-assembling, and it will cause the EXACT symptoms that you are experiencing, right down to lower compression numbers due to TOO MUCH fuel being injected at the wrong time and it not being combusted completely and/or properly. This causes the rings to not seal as well until the crap gets burned out of there, meaning a lower compression reading. 

I believe another forum member had a timing issue some time ago.

"Arm chair" DX is hard, but if you keep us posted, we can keep throwing ideas at you before you bite the bullet and take it in.

 

-Skip

 

Edited by skipperT
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