Stuck/damaged piston rings or Valve seals. 6th gen.

I bought a 2004 VFR800 with 2376 miles from the 2nd owner. He had bought it from a dealer in 2012 and it had sat on that dealer lot for an unknown amount of time he claims the bike had only 1200 miles when he bought it so obviously the bike has been deprived the road it deserved and as a result there is an issue.

I replaced all plugs and found piston #4 had been oil fouled and when I replaced it with a good plug the motor started burning oil. I can rev the motor all day without smoke but as soon as I give it full throttle that is when it spews it out, there is NO smoke on cold start or idle as far as I can tell. Also, while I am no expert, there does appear to be an excessive amount of blowby and a fair amount of oil in the airbox, video of blowby included at bottom.

I used Marvel Mystery Oil in an attempt to free any stuck rings but I suspect I cannot do that properly as the cylinder was not level and so it just drained down the side closest to the ground. I am going to lift the front of the bike and attempt to do it right but if that fails am I looking at damaged/really stuck piston rings or valve seals? With such low miles on the bike I just don't see why I am burning oil.

I almost think there is something wrong with my vtec system as it only happens at 8k plus RPMs it seems.

Blowby? - YouTube
puff - YouTube

 

Hmm

Given that bike has done such a tiny mileage - one article I bookmarked ages back immediately sprang to mind -

Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power

Read way down towards the bottom and sure enough you will find that piston rings failing to seal properly can be a direct outcome of the first owner being way too gentle in the first hour of running the bike.

Your further observation that the oil burning only happening at 8k plus might imply you need to focus on the extra pair of valves which open up in #4 cylinder when vtec is engaged.

Whilst the first video of the stationery bike does show it quite smokey - I think on a cold day mine (with 80,000km) is like that just for the first 30 + seconds until it warms up and any moisture clears, however if its still that smokey after the bike has warmed up and the FI system has switched to normal fuelling then you do appear to have something wrong.

On the second video there is a brief puff of smoke as you first move onto that road and change gears, what I could not see was whether it was doing the same when changing down - as that would point to valve oil seals. I can't be sure but the smoke seemed to appear when the bike was revving well below the vtec range.

Whilst it sounds like you are now planning to tear into the bike to try and find the problem, this could get very expensive quickly, so before doing that, I would ring around first and arrange for a motorcycle engine specialist to give it a quick check over, as they may save you a lot of time and bucks.

Good luck and let us know how you get on


SkiMad

 

Have you tested compression?

 

The blowby video was taken after an hour ride so it was warmed completely. Have not had a compression test done yet, no tool for it and don't want to pay someone else to do it..

 

New info, if the bike isn't above 150f there is very little smoke, if any, and certainly no more than I would consider normal, but if it is above that temp then there is a bunch which points even more to the vtec system since it won't engage below 150f as far as I know.

Also the video of me going onto the road I was not changing gears, I was running it out in first at the time and I cannot be sure but the puff smoke happens later in the RPMs after VTEC engaged. I did change gears down the road but I could not see any smoke on the change.

 

Decided to upload a video of a full ride just so people can see what my bike is acting like under normal and hard running. Most of the time I keep it below vtec range and as far as I can remember every time there is smoke is when I brought the bike above the 7k mark. Video is currently still processing and is about 45 minutes long.

[video=youtube;caWtdyIeAAA]http://www.youtube.com/watch?v=caWtdyIeAAA[/video]

 

Fixed the dead video.

 

One last video before I go meet with the honda dealer. Cold start, no smoke appeared until about 125f on the gauge so probably not vtec related. On the ride I did yesterday it got worse so who knows maybe my valve stem seals just hardened and are now failing under regular use...

[video=youtube_share;HU2fHmatFJE]http://youtu.be/HU2fHmatFJE[/video]

 

less than 60psi in piston #4, all other pistons were above 180. It's fucked. Time to source a low mileage motor and swap it out.

Oh forgot to mention I added oil through the spark plug well and tested again, the psi read at 120 after oil.

 

Swapping the whole engine is a bit drastic, especially if the rest of the motor is fine. A rebuild for the offending cylinder block will sort it out (rebore / rings / maybe new piston and sleeve). It's pretty routine mech work and not that expensive. I'd prefer to do this rather than get another used engine of unknown condition, pay for all the labour required for a swap, and muck around with registration paperwork.

 

I would very much prefer to keep the motor but it is not economically sound. A motor swap is $400 in labor max(which I could do myself)+900 for a low mileage motor. Rebuilding the motor is 800 labor(which I cannot do myself) plus parts, which back of the napkin is probably around 400 and would probably end up costing way more than that after the machine shop takes a cut. Oh don't forget time, rebuild will take a month probably and a swap can be done in a a weekend.

 

Sounds like you have reasoned it out.



SkiMad

 

Simple advice when trying to work this out is this.

Valve seal oil leaks always show when engine transitions from load to no load when throttle is closed, this increases the vacuum in the inlet track, thus sucking oil past worn/damaged seals.

Piston rings, always show when getting on the power especially at low speed under heavy acceleration, as the piston speeds are low at lower revs & the cylinder pressure is at its highest for longest under these conditions !

Burnt Oil smoke has a blue tinge to it, burning coolant in white.

Engines with worn parts normally exhibit their smoke all the time, more so when cold with piston rings. Yours appear to show when the engine warms, which would lead me to look at the head gasket !

Everyone has a compression tester, either your finger or a stick with a piece of rubber on it. Just remove the plug leads & a plug & put a little pressure on your stick. When cranked the cylinder being tested should pop your finger/stick off with a healthy phut noise !

 

VFR bore work requires a total engine strip, no separate cylinders, you see !

 

Big Bore donor engine then !!!!

 

Funny story, I was just reading a thread on VFRdiscussion started by someone named mohawk with a suspiciously blue vfr in their avatar. He was talking about using a 929 or 954 piston. Do you happen to know the man?! http://www.vfrdiscussion.com/forum/index.php/topic/75247-vfr848rr-anyone/
And yes I fully intend to take this motor and put 929 pistons in, not a huge upgrade but it is something to do in my spare time for not a whole lot of money on what would otherwise be 300lbs of dead weight. Probably even port and polish if that is at all useful on these motors. Given current disposable income I should be able to do it by next summer(conservative estimate).

 

Ahh I forgot about that... Good point! *facepalm*

I've been reading too many DR650 tech instructions lately

 

Would it be wise for me to disconnect the spark plug and injector for the damaged cylinder since I need to keep riding it?

 

Hmm the answer really depends on your finances, and what if anything you plan to do with the old engine after the engine swap. If you need to ride the bike then I would leave as is and just go easy and closely monitor the oil and coolant for level and contamination.

Think of it this way - you currently have an engine which is of close to zero value, and will need you to throw a heap of cash at it to repair. Add in labour rates and the repair cost is probably way more than the cost of getting a decent running example from a breakers yard. If the rings in the engine are dead then they will stay dead, if they have scored the bore, then using it may mean they get more scored. If the block is cracked, then it will still be cracked - if the gasket has failed then it will remain failed....

However the more you use it, the greater the risk of further damage - just a few bits of metal in the oil and it can be catastrophic. :kaboom:


On the assumption the engine is already headed for the skip, and you really need to use it - then do so cautiously - as you really don't want an engine seize at speed! Certainly if it was me, I would park the VFR and ride the Street Triple!

Take care


SkiMad