85 VF700F Engine Noise

Discussion in '1st & 2nd Generation 1983-1989' started by sgtmillhouse648, Sep 18, 2019.

  1. sgtmillhouse648

    sgtmillhouse648 New Member

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    Need some help from the consortium after pulling my hair (all 3 that are left) out for a bit on this issue.

    Bike background:

    Bought the bike earlier this year with ~14k miles on it for $400 to fix up for a 'cheap bike challenge' some friends and I were running (put together a bike for <$1k to ride down 300 miles, spend 3 days riding off road, and ride back). Bike didn't run when I got it...had a temp tag from '08, with tires from '98, so realistically it ran last about 20 years ago.

    Rebuilt the bike, fired up and ran just fine, but had a ticking noise present from that first startup. Checked valves, and found a few out of spec on the high side, but did not seem to cure the issue.

    Went on the trip, bike did fine, noise is still present, hasn't gotten any better or worse.

    Bike starts, revs, rides fine, just has the nasty tick. Reviewing the valve lash procedure, I realized that these are quite a bit finickier than most engines, and realized I didn't have the cams pulled up into the upper half of the journals while setting them. So I opened it up last night, and reset lash to 0.005in / 0.12mm per the factory manual. No change in the noise.

    Shot this video quick last night to try and capture it. Frequency of the noise is 1/2 crank speed which really would scream overhead still to me. There's no bearing material in the oil, cam lobes and journals all look good with no pitting or galling.

    Stethoscope says it's coming from the back right cylinder, but can't really narrow it down to overhead or base engine.

    No difference in whether or not I squeeze the clutch in or not. Is there anything that anyone could think of that I should check? It's bad enough I'm half spooked to ride the damn thing, but can't figure it out! Had an earlier '83 750 when I was younger, and it was silky smooth in comparison to this knock.

     
  2. jeremyr62

    jeremyr62 New Member

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    Probably a dished rocker. You will probably need to remove the camshaft to see it.
     
  3. squirrelman

    squirrelman Member

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    maybe too much clearance/bearing wear between cam and bearing, try plastigauge.

    when cam lobe goes down cam is forced in upward direction so any excess clearance can cause a click.
     
  4. VF1000Fe

    VF1000Fe New Member

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    "Takes a Licking, Keeps on Ticking??,,.."

    If your Cam Followers are like the rest, they are Chrome Coated.
    Once the Chrome wears through, the follower wears Real Fast, ticking gets loud quickly.
    Adjust it out, and it wears back/ticks again, will happen in less than a gas tank.

    Note the follower wear on the right side;
    [​IMG]

    You can't see it unless you remove the Cam.
     
    Last edited: Sep 19, 2019
  5. squirrelman

    squirrelman Member

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    one reason the cam bearing might be toast is that i believe it's the last place oil is pumped to, so many dry start-ups.
     
  6. sgtmillhouse648

    sgtmillhouse648 New Member

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    Interesting, thanks for the info guys, I'll pop the valve cover back off and see what I can find.

    Cam journals looked fine, very light debris scoring, but that was about it. The dished rocker theory has me intrigued. I assume you're referring to dished/worn on the pad where the lobe contacts the rocker and not the lash adjusters?

    Thanks,
    Mlahon
     
  7. jeremyr62

    jeremyr62 New Member

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    Exactly like in the picture. The right rocker/follower pad display extreme wear. It's very difficult to see it without removing the camshaft.
     
  8. VF1000Fe

    VF1000Fe New Member

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    Cheap Is, as Cheap Does,,..

    This era/series of motors had multiple issues.
    The Cams were too soft and had "inclusions"/defects, it wore down way too fast.
    The Followers were also too soft, so they were Chrome Coated,,.. work'd long enough to get by Warranty (almost, there was a recall to replace some Cams).
    Note the Left Follower has 2 score lines in it, its not long of this world.
    Keeping your Oil very clean helps a lot, but its inevitable.

    I sent all 4 cams and all 8 Followers to Mega Cycle in California for a Grind Down, build up with Stellite, and regrind to a more aggressive curve.
    Took advantage of the tear down to do some Intake/Out & Head Porting, ground away lots of aluminum, more smooth, efficient.
    It really snarls now, but burns oil, didn't replace the Exhaust Valve Guides (but did do Guide Seals).
    Replacing Rings woulda been a much bigger job, I can live with adding oil, but can't take it on Tour anymore.
    I ran a tube from the Vent Bottle down to the chain, hot oil vapor now lubes the chain.
     
    Last edited: Sep 20, 2019
  9. jeremyr62

    jeremyr62 New Member

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    Like a total loss lubrication system then. Smart....
     
  10. sgtmillhouse648

    sgtmillhouse648 New Member

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    Makes sense...they're definitely flawed bikes...happens with anything that was as radical as these were at the time. They've got a lot of character though which is what I really enjoy about them...used to have a little A mod autocross car that I repowered with an old VF750F engine that was an absolute riot. Picked this bike up for a cheap bike challenge (adventure/offroad riding for about 1000 miles or so) with some friends for $400...put a few hundred more into it, and it did great...looking at fixing it up a bit more nowadays for kicks and giggles as it's a nice smooth commuter with quite a bit of character.

    [​IMG]
    [​IMG]

    I did come across this thread Here which linked to this youtube video:



    Sounds identical to mine, so the valve covers will come off this upcoming week to pull cams and check the rockers.

    Really appreciate everyone's help!
     
    Last edited: Sep 23, 2019
  11. squirrelman

    squirrelman Member

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    adding a few paint marks b4 cam removal will help with proper timing upon re-assembly.
     
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  12. sgtmillhouse648

    sgtmillhouse648 New Member

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    So I got the beast torn down yesterday. Originally attempted to pull the exhaust rocker out without realizing 1. The cam needs to come out to get the clearance needed to pull the rocker out, and the cam cap bolt also is a failsafe interlocking with a shoulder on the rocker shaft preventing it from backing out...That unfortunately ended in a broken rocker shaft.

    So I pulled the engine out, and started tearing down the top end. Didn't find what I thought I would however.

    Key observations:
    1. The wear on the rockers and cams is visible, but is still within the chromed layer of the rockers. There was no dishing or anything like that that I could find.
    2. I did find some spots of pitting on the exhaust rockers and cam lobes. The pitting in the rockers was below the chromed layer. I can't think that this would have caused any noise though.
    3. All journals were in great shape with no signs of debris or oil starvation.

    Photos of everything can be found on my google drive Here.

    So at the moment I'm at a bit of a loss as to where the noise is coming from. Planning to plastigauge the cams tonight to see if I can see anything. Other than that, everyone's guess is as good as mine. If the plastigauge doesn't show anything, I may pull the rear head to inspect the cylinders, or even drop the pan to get to the rods, but i'd like to avoid that if possible
     
  13. jeremyr62

    jeremyr62 New Member

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    As far as VF top ends go, that isn't too bad.
    You might as well check for this.

    I had a VF500 that failed like this.
     
  14. sgtmillhouse648

    sgtmillhouse648 New Member

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    I really hope it's not a toast bearing, but i'll add that to the list of things to check. Would have thought if it was a cooked bearing that it would have come apart in the last 1500 miles or I would atleast see bearing material in the oil.

    Plastigauged the exhaust cam on the rear cylinders over lunch. Everything came back in at 0.040-0.060mm which is within spec.

    If I'm not able to find anything, any ideas from anyone as to next steps? Put it back together with non-pitted rockers/cams and make sure my ear plugs are in tight?

    Is setting the lash via the single gauge under the cam lobe the preferred way to do it vs 2 gauges at each valve?

    Thanks,
    Malhon
     
  15. Captain 80s

    Captain 80s Member

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    Did the noise happen to get louder on revving deceleration? If so, tensioners could be the problem.
     
  16. sgtmillhouse648

    sgtmillhouse648 New Member

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    Nope, noise is loudest at idle and part throttle up until about 3500-4000rpm...after that it appears to go away...whether that's because it's actually getting quieter, or it's overshadowed by the exhaust, I'm not sure.
     
  17. Captain 80s

    Captain 80s Member

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    Replace what you can, re-assemble paying close attention to your valve lash procedure, re-up your AAA membership, put your ear plugs in and ride the piss out of it. Meanwhile keep an eye out for a good donor motor/bike.
     
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  18. sgtmillhouse648

    sgtmillhouse648 New Member

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    That's the plan. Will do a bit more tinkering on it this week, and have replacement cams/rockers on the way to replace the pitted parts. Will do a leakdown just for kicks before it goes back together, but other than that, my AMA's current...glad years of KTM ownership prepped me well for old bike ownership :Rofl:
     
  19. VF1000Fe

    VF1000Fe New Member

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    A Big End problem is more of a Knocking than a Ticking.
    I've used the Cam Clamp thingy, but it seem'd to be more a hassle than useful.
    I just rotate the Cam so the Follower is somewhere on the Base Circle, 180' away from the Lobe, and ALWAYS use 2 feelers of correct size, one under each Adjuster Screw.
    Doing it without the clamp means you might have the gap a little Wide, better than too Tight.
    Note: If the Gap is too tight you could have a Valve Not Seating @TDC and then have Detonation Slam the Valve Shut (Tick!).
    Also had a Loose Exhaust Pipe Clamp at the Cylinder, makes a Ticking sound.
    With my hearing the way it is, might still be Ticking,,..
     
    Last edited: Sep 23, 2019
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  20. VF1000Fe

    VF1000Fe New Member

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    Owning one of these Bikes is also a Total Loss of Money, but gotta spend it somehow,,..
     
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