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I need some big help.  I removed and replaced my rear cam chain tensioner plunger a few months ago.  Pretty straight forward work.  I followed the shop manual and guidance from a member on this site.  Pretty straight forward (or so I thought).  When I tried to start the bike after reinstallation the motor would not start.  I exhausted all trouble shooting I could think of and some members on this site suggested.  I finally broke down and took it into the Honda dealer shop yesterday.  They called me and said the timing was off upon reassembly and that I had now damaged the valves and the motor was going to require a complete valve replacement on the rear two cylinders!!!!  Total estimate was upwards of $2800!!!!

 

I can not imagine how the timing would become changed when replacing the plunger.  The mechanic on the phone said something about the motor not being at the proper position during plunger removal and this would allow the motor to "roll back" and thus timing gets off.  The shop manual does not say that the motor needs to be turned or timed to any specific setting (i.e. #1 tdc) before removal and installation.  The only proof he really offered of this is that compression was low on the cylinders.  I asked again how timing can become that off as it is a chain on teethed gears and it would have to jump completely to move like that.  He didn't seem to have a solid answer for me.  I am truly in disbelief this could or would happen.  I am also wondering how he could say I have valve damage when he only had the bie for a few hours so I can't imagine he was able to visually inspect the valves?

 

I really need help here.  I want my bike running again but I also don't want to spend a lot of money on work I truly can't imagine is necessary.  I don't think they are trying to take me but I am wondering if they are just looking at the work I did and the low compression and jumping to a solution (a very expensive one!).

 

Any help/guidance/information would be greatly appreciated.

 

Thanks,

Matt

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He's right about having the motor in the correct position I'm afraid. With no tension on the chain the timing can alter as the cam sprocket jumps back if there is pressure on the cam lobes from the springs. That's why it's essential to have the lobes in the right position when you unload the tension. Easy mistake but costly.

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Slotting in a 2nd hand engine I reckon to be cheaper....

 

 

PS: I assume American English differs from English English, seeing you call yourself knobber..... 

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The chain guide above the cams should stop the chain jumping the sprocket but you should always set rear bank TDC BEFORE removing the tensioner.  It is unlikely to have jumped teeth, but you may have allowed the cams to rotate forward creating slack in the pull side of the chain. The CCT does NOT have enough tension to reset the cams to their original position.  When you then turned the engine over, the slack would get taken up first without moving the cams, then the cams get dragged around a number of degree LATE which could cause piston to valve interaction which is bad.

 

The shop manual definitely says set to TDC for 3T on page 8-14 last picture , before releasing the CCT tension for camshaft removal.

 

The rear bank has the cam pulse sensor which is used to determine which cylinder in coming to TDC on a firing cycle that may explain the no start. If it was in the correct place, then the front 2 cylinders would fire regardless of what the rear pair were doing.

 

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10 hours ago, Knobber said:

I am also wondering how he could say I have valve damage when he only had the bie for a few hours so I can't imagine he was able to visually inspect the valves?

By using a borescope it only takes a few minutes to inspect the valves and seats. He only needs to remove the spark plugs.

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I truly appreciate the responses.  It would appear I have made a "rookie" mistake that is going to cost me.  I plan on stopping over at the shop tomorrow to talk face-to-face to see what can be done and determine the extent of the damage.  I am going to have to go back through my manual as I do not remember ever reading setting the engine prior but that could easily have been serious oversight on my part.  Again, thanks.  This forum has been great, even if it bears bad news for me!

 

PS  Knobber means the same in both the President's English and the Queen's!  (call sign given to me, not chosen.)

 

Ciao'

Matt

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+1 on buying a used motor and swap it for the damaged one. You can always rebuild the damaged one for fun.:goofy:  

Sorry for your troubles.

 

BTW. Seriously. Thanks for posting the information for those of us who have not done this. I do prefer to learn from others mistakes rather than my own.

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Rechecked the manual and under the section for tensioner plunger removal/replacement, nowhere does it say the engine needs to be at a specific setting (i.e. TDC).  That doesn't mean it shouldn't, but you would expect the Honda service manual to mention important details such as this.  I am still completely mystified that this could happen.  Even if the valves have pressure on them, to make the cam roll over without moving anything else seems awfully crazy.  Again, for this not to be mentioned in the manual is killing me!  Oh well, hopefully everyone else learns from this (I know I have!)

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Rechecked the manual and under the section for tensioner plunger removal/replacement, nowhere does it say the engine needs to be at a specific setting (i.e. TDC).  That doesn't mean it shouldn't, but you would expect the Honda service manual to mention important details such as this.  I am still completely mystified that this could happen.  Even if the valves have pressure on them, to make the cam roll over without moving anything else seems awfully crazy.  Again, for this not to be mentioned in the manual is killing me!  Oh well, hopefully everyone else learns from this (I know I have!)

Hi sorry to hear about your woes I must just have bin very lucky. Just taken both my ccts out n re-tensioned them after taking it to local garages n getting quotes of 4n5 hundred pounds.
I was told by one garage something about engine position but I'm a spanner noob of the highest n didn't think twice about it. Just pulled em out re-tensioned n back in. Looked on utube never found any vfr cct removal vids, n this n other vfr forums had how to do it but nothing about positioning of engine.
I Will think seriously next time I have to do them. Good luck on resolving this


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Well, to follow-up.  They ran a bore scope down the motor (spark plug holes) and showed me pictures.  I couldn't make much out of it but they said there was a lack of carbon build on the intake valves (?) and this indicates damage?  They also reset the timing and did a leak down test and found 10-15% loss across the back cylinders (I am probably paraphrasing and missing some wording here).  They said this indicates damage as well.  They insist the cylinders should be TDC on compression to avoid a load on the valves when removing any tension on the cam chain.  I rechecked the service manual and nowhere does it say to do this.  Doesn't mean it shouldn't but you would think they would.  I asked about resting the timing and starting the bike and see what happens and they did not like this idea.  Said it could cause further damage to cylinders and what not.  Unfortunately, short of taking the bike back from them and working on it myself and I stuck going forward with the work to the tune of $2500! 

 

Just wanted to pass this along for anyone else that might commit to this work to watch what you do and don't make the mistake I made.

 

Ciao'

Matt

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You could probably buy another 06 VFR for not much more than $2500.

I would suggest buying a replacement engine and either installing it yourself or having an independent shop install it for you.  This will cost under $1000 with indy shop labor.

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Knobber -so sorry to hear about the clashing of parts inside your engine. If it helps, I have a very clean 7400 mile 2007 VFR800 6 gen engine that is available for $500. It measures 200psi compression on all four cylinders, + or - a couple psi. I'm in San Diego, so not too far from you. Let me know.

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I'd give it some thought but started down the road of ordering pieces!  I plan on staying on top of them - probably won't do anything but will make me feel better.  Hate to say I could get taken but I also hate to pay for work that isn't necessary!  Thanks for all the input.

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Knobber,

I hate to see you go down the wrong, read more expensive, road.

Before you get too far into fixing your motor, just remember that it's not so much the parts, as it is the labor that will get you.  Especially dealer labor.

And there is a lot of labor in fixing a broken interference VTECH motor that jumped timing.

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16 hours ago, Knobber said:

they said there was a lack of carbon build on the intake valves (?) and this indicates damage? 

Not in this case as your engine has not run since you worked on it. A compression loss can indicate valve damage and it should be visible on the pics that a valve is not properly seated flush against the valve seat when closed. Also you should be able to see, on both the valve and piston, where they have made contact.

 

As you said, nowhere in the manual does it say to put the piston in TDC. Also the question is which one as when you have one at TDC the adjacent piston is at BDC. Looking at the pics in the service manual  I too wonder how the chain can jump a tooth with the chain guides still in place.

 

 

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On 2/21/2017 at 4:30 PM, sfdownhill said:

Knobber -so sorry to hear about the clashing of parts inside your engine. If it helps, I have a very clean 7400 mile 2007 VFR800 6 gen engine that is available for $500. It measures 200psi compression on all four cylinders, + or - a couple psi. I'm in San Diego, so not too far from you. Let me know.

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If I was closer, I would love to snap that up!

 

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I made a similar mistake when adjusting the valves on mine...missed a torque spec and the front cam gear came loose...I kept the bent valves as a reminder.  I was able to swap in a used head for minimal expense.

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Thanks Seb. I suppose putting it on a streetcorner here in CA w a sign reading "New York or Bust" might be counterproductive...

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Well, talked with the mechs today.  They said they have seen two of the valves.  One is scuffed and the other is bent.  I have told them I want them to hang on to all the parts so I can see them.  Trying to learn from my mistakes!

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  • 4 weeks later...
  • 7 months later...
On 2/20/2017 at 4:25 PM, Mohawk said:

The chain guide above the cams should stop the chain jumping the sprocket but you should always set rear bank TDC BEFORE removing the tensioner.  It is unlikely to have jumped teeth, but you may have allowed the cams to rotate forward creating slack in the pull side of the chain. The CCT does NOT have enough tension to reset the cams to their original position.  When you then turned the engine over, the slack would get taken up first without moving the cams, then the cams get dragged around a number of degree LATE which could cause piston to valve interaction which is bad.

 

The shop manual definitely says set to TDC for 3T on page 8-14 last picture , before releasing the CCT tension for camshaft removal.

 

The rear bank has the cam pulse sensor which is used to determine which cylinder in coming to TDC on a firing cycle that may explain the no start. If it was in the correct place, then the front 2 cylinders would fire regardless of what the rear pair were doing.

 

Can I get the shop manual for 6th gen? 

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2 hours ago, Cheeky800 said:

Can I get the shop manual for 6th gen? 

 

Check the Downloads section here.

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Knobber, I'm really sorry.  But can you try to remember the sequence of events during the  rear CCT installation?

 

1)  Did you put tension on the rear CCT BEFORE you pulled it out?  Or did you just pull it out without putting the CCT key and applying tension on the CCT?

2)  Did you rotate the engine somehow when the CCT was out of the engine by rolling the bike in gear?

3)  Did you move the bike when the CCT was out of the engine and bike was in gear?

 

Because nowhere in the Service Manual does it say you MUST set the engine to TDC BEFORE removing front or rear CCT!  For the rear CCT it just says, remove the heat shield, set the tension on the old CCT, unbolt, replace new CCT (with the tension set), bolt up, and go.  If setting engine to TDC was crucial per your dealership, Honda would not forget this step on the SM or they will get sued!

 

Also, if indeed your engine got damaged when you spun the starter, $2,500 is ridiculous!  SFDownhill has a newer engine than yours for a quarter of the price.  He's in your neck of the woods.  You sure you want the dealership to do the work?

 

I remember when I took my Corvette to a shop because it was running rough.  Mechanic drove it with me to note the rough running engine.  They looked into it and later told me the engine has a cracked cylinder head and needed to be replaced for $1,500!!!!  They said they "pulled the spark plugs" and they were "wet" from coolant and therefore surmised that the engine had a cracked head.  I said HELL NO!  I took the car back.  When I got her home, I checked the coolant level and it was normal.  So I pulled the spark plugs and guess what?  Half of them were old and the other half were new.  I remember  paying another dealership to replace the car's spark plugs (ALL the plugs) about 30k miles prior.  Well they only replaced 4 of the 8 plugs because the other four on the right side of the engine was much harder to remove and replace!  So those four had almost 50k miles on them (scheduled replacement was every 30k).  I replaced all the spark plugs and the engine was back to smoothness!  If I listened to those mechanics I would have been out $1500 for no good reason other than a botched diagnosis and a prior lie from a reputable dealership!

 

 

 

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  • 3 months later...

might have avoided valve damage if you had removed the clutch cover access hole and slowly turned the crank BY HAND and stopped turning if you felt resistance. 

 

not to have tried this was another mistake  :blush:

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