Hydro Motor Valvetrain Inspection-Set it and Forget It is asking for trouble.

[Orange Guzzi]

I pullled my 26, 000 mile hydro motor apart to inspect and replace some parts.  I found 3 of the 4 hydraulic tappets stuck fully extended.  I used a pin to release the pressure, but the tappet would not compress.  It took several attempts and lots of pressure to break the tappet loose and compress.  A good rinse of all 4 with carb cleaner had them all compressing and returning to the same overall length.  The 3 stuck/solid lifter locations had valve stem damage and rocker arm wear.  The 4th, exhaust, right side, looked good. 

After repairing, replacing and reassembly, there appears to be very little oil flow out of the rocker arm pins.  This is the lubrication source for the valve end and rocker contact point.  I am going to check the oil pressure in the motor.  I suspect 2 issues.  Low oil pressure or the stuck over extended tappet did not release valve spring pressure enough to allow the valve to rotate in service.  Causing the valve stem and rocker damage.

I placed the tappets in oil and pumped them up until solid, reinstalled, adjusted the lash 1 full turn of the adjusting screw after the adjusting screw contacted the push rod.  1.5 mm is the suggest preload.  1 full turn is 1 mm preload.  The tappets have spring loaded freeplay now.  When I started the engine, it sounded great, very quite.  I rechecked the clearance after starting and stopping the engine several times. 

How did the bike run on the road?  Well if you put V11 Sport pistons in a Hydro motor, hold on.  The motor was not put together for the long haul.  It is coming apart to replace the clutch, transmission seals & bearings, cam chain tensioner, deep sump-outside filter, balance.  While on the bench, the engine will be inspected and repaired as needed.  And a little more head work.  I am not happy with the squish band.  Getting some random knocking on 87 oct. pump gas.  Compression?  Over 200 psi. 

I never ask for permission or ask if it could be done, I did it and it worked.  V11 and or Sport 1100 pistons will fit with a little head work.  The combustion chamber needs to be opened about 7 mm around the squish area and 30 degree angle.  A few minutes on the rotary table and flapper sanding wheel made short work on opening it up.  I dry fitted and inspected clearance without the head gasket installed.  I did not want to crash the piston into the head.  I used the 1.2 head gasket. 

The most obvious change is the side to side rocking at idle and throttle opening.  The engine runs much better, quiter and smoother.  I would contribute this to the freshened top end and the valves sealing much better.   

I would suggest that if you have a hydro motor, inspect the tappet and rocker arm assembly.  They can be adjusted. The hydro adjusting screw is different than a solid lifter screw. The spherical end is smaller and there is not a tab to hold while tightening the lock nut. The hydro push rods are concave on each end.  The end on the tappet appeared to wear to match the tappet hole.  If you take them out and do not replace, put the down end down.    Set it and forget it is not a good idea based on what I have seen inside my engine.  They are most likely over tightened and the tappets are not working.  Causing valve and rocker arm damage.  Comparing the tappets in my engine to the drawing specifications, the installed tappets are longer than the drawing by several mm.  If the Shop the did the recall used the "gage" with the shorter over all length per the drawing specification, compared to the longer ones installed in My engine, the valves were installed over tight.  Is it too late for a second recall on the first recall?  Another reason I suspect this, I have read where people have had to force the valve spring down to get the rocker pin into the engine.  There should not be any preload on a fully retracted rocker screw.  The rocker pin should push right thru and then the preload added with the adjusting screw. 

Since there is very little information on the WWW about the hydro motor, I am sharing what I know.  Your mileage     may very. 

[Chuck in Indiana]

John.. is this a hydro that had a previous failure? The reason I'm asking is my Lario engine had some stuff go through it by a previous owner, and it wasn't properly cleaned out. The Pressure Relief Valve blew off at 20 psi because of this. Maybe one of your issues?

[Orange Guzzi]

John.. is this a hydro that had a previous failure? The reason I'm asking is my Lario engine had some stuff go through it by a previous owner, and it wasn't properly cleaned out. The Pressure Relief Valve blew off at 20 psi because of this. Maybe one of your issues?

I am the second owner.  Scootopia, Louisville, KY did the recall.  The previous owner said it was done prior to any failure. 

I have not seen any indication of metal going thru the engine. 

Are you saying that debris in the PRV could keep it cracked open and the pressure through the engine low?  Sounds reasonable.  As I posted, the rocker assemblies do not appear to be getting good oil flow. 

[Chuck in Indiana]

I am the second owner.  Scootopia, Louisville, KY did the recall.  The previous owner said it was done prior to any failure. 

I have not seen any indication of metal going thru the engine. 

Are you saying that debris in the PRV could keep it cracked open and the pressure through the engine low?  Sounds reasonable.  As I posted, the rocker assemblies do not appear to be getting good oil flow.

Yeah. I wiped a cam lobe on the Lario, but had bad lash caps, too. Which came first, the chicken or egg?  Possibly it was the PRV all along.

[guzzisteve]

There are special tool kit for Hydro's, and a solid slug tappet to set clearance, when you install pumped up tappets you use a few tools and the pins go right in. They are under very slight preload, just enough to use special tools.
I do know where you can get new stuff. 

[Tom H]

I have both manuals for the recalls. There is a special tool to hold the rockers down to remove the pins. And it also explains how to hold up the lifters on the cam to remove the cam.

Tom

[Orange Guzzi]

I have both manuals for the recalls. There is a special tool to hold the rockers down to remove the pins. And it also explains how to hold up the lifters on the cam to remove the cam.

Tom

I found an image of the tool and the dimensions of the hydraulic tappet.  When I checked the tappets in my engine to the drawing dimensions, the installed tappets were .65mm longer than the dimension listed as the fully extended length. 

Can you post up an image of the tool and any dimensions you may have of the tool and a tappet. And or the installation procedures.

 If the tool is shorter than the fully extended tappet (base on dimensions on the drawing I have)  by .65 mm and 1.5 mm of preload are added, that totals 2.14 mm.  The working range of the tappet is 3.23 mm.  The tappet has 1.09 of actual working range or 33% of the maximum compression range if the tool is used to set.  Quality control, wrong drawing or wrong dimensions on drawing? 

I installed mine with 1 full turn of preload after the  screw head was seated in the push rod and the push rod would rotate with some resistance.  Turning the engine over by hand, the only leak down I could hear was past the rings. The engine sounded great.  My friend said it sounded much better than before in the valve covers. 

[Tom H]

I'll see what I can do tonight or tomorrow.

Tom

[Orange Guzzi]

I read the entire procedure for the final recall; did not find a dimension for the tappet-slug (gauge) anywhere in the procedure. 

I found this in the maintenance manual:

Tappet Extended:  33.85 +or- 0.45
Tappet Working Position:  32.15
Tappet Bottomed:  30.62 +or- 0.27
Min Travel:  2.5





Perhaps someone who has the tool kit could measure the tappet-slug and post the measurement here?

I put the top end back together, went for a test ride, got a bad "pinging".  Drained 87 pump gas, added 93 and went for another short ride.  Same ping.  Pulled the heads again.  (I intended on doing this anyway, I was just doing a fit up with new pistons).  Exhaust valve on left side was hitting the piston and intake was slightly touching, making the "pinging".



I pulled the valve springs off, put the rockers and push rods back in with out the valve springs, put piston on top dead center.  With the adjusting screws turned all the way in/maximum clearance, then adding the 1.5 preload, the exhaust valve comes in contact with the piston. 



Inspecting the hydraulic tappet length again, I measured 34.68 mm.  Which is longer than the 33.85.  This adds .83 mm of preload to the working length before the 1.5-1.7 is added as specified.  Causing the valves to hit the piston as it passes tdc.  I have not done any valve work or sunk the valves into the head. 

Let me add this, I installed V11sport pistons in the motor.  They are higher domed, smaller land between the edge of the piston and the where the dome starts than the stock piston.  Stock piston has a smaller diameter and lower dome.  I suspected the "pinging" was from the higher compression, squish band being to tight.  I had checked the fit up with out the head gasket installed and solder, no valves installed.  The gasket raised the head another .042" which is more than enough squish clearance.  I also cleaned up the head by opening up the squish band and rounding the edges. 

It looks like the best solution is to take some metal off the bottom of the threaded hole side of the rocker arm so the adjusting screw will turn in further and allow for more clearance on the tappet. Or add a thicker base gasket, raising everything up.  Kinda defeating the purpose of the high compression pistons.  Base gasket sound like the easiest and 200 psi is high. 

How did the bike run in the two test rides? More horsepower at lower rpm's. Smooth, the torque from cracking the throttle in neutral is greater, bike falls right hard.   The clutch cannot handle the input, it slipped as the h.p. went up.  It was slipping prior to new piston on occasions though.  It has been pulled and will be updated.  The clutch friction disc have 12,000 miles and are withing specification on thickness.  The intermediate plate was not changed when I replaced the oem riveted clutch.  It is worn. 

A quick check of compression was 200 psi.  High.  The V 11 has a higher duration and higher lift cam, larger head opening, larger valves and the valves are sunk further into the head with shorter valve steams.  Allowing for the rocker assembly to interchange between the various 1100cc engines.

The higher domed pistons do have clearance for the bigger valves, but I suspect the out of specification hydraulic tappets and the preload add to the clearance issue. When I reassemble, I am going to set the tappet clearance with out the valve springs in stalled.  This way I can raise and lower the valve by hand to feel when the valve stem is making contact with the adjusting screws.  The push rods will still rotate by finger with preload.  I can turn the adjusting screw with my finger, add preload and still turn the push rod.  Giving a false setting. 



   

[Orange Guzzi]

Greg Bender pulls thru.  Thanks Greg.

    Hydraulic tappet refitting instructions
    Credit: Thanks to John Matthews for making this document available to me.
    File size: 51.6 MB
    Pages: 25