XR70 ran out of oil.......

[jaction125]

Ok so I ran an xr70 out of oil. It's a borrowed bike and I need to fix it. It didn't sieze, just started burning oil and making some light tapping noise.

The noise I can deal with but me thinks it's still getting a new piston, pin, rings, clips.

I realize that nobody can really tell without seeing it, but do you fellas think that'll do it?


How tricky is it to time this engine when all is said and done, is there a secret in disassembly to keep it in time?

I saw in the parts fiche that there are a few little dowels and such, should those be replaced?

Thank you in advance!

 

[Ol'89r]

Ok so I ran an xr70 out of oil. It's a borrowed bike and I need to fix it. It didn't sieze, just started burning oil and making some light tapping noise.

The noise I can deal with but me thinks it's still getting a new piston, pin, rings, clips.

I realize that nobody can really tell without seeing it, but do you fellas think that'll do it?


How tricky is it to time this engine when all is said and done, is there a secret in disassembly to keep it in time?

I saw in the parts fiche that there are a few little dowels and such, should those be replaced?

QUOTE]

jaction.

Those are pretty easy engines to work on, no real tricks involved.

BEFORE you take the engine apart, check the valve adjustment for excessive clearance.

The main thing to look at is the camshaft and followers. Usually that is the first area to experience damage from the loss of oil. Check the cam lobes for signs of heat, (blueing, discoloring, scratches, galling.) Check the mating surfaces of the cam rocker arms for the same things. This could be where the 'ticking' sound may be coming from.

Don't worry about the little pins and dowels, those can be reused.

When you get it apart and inspect everything, we can do a better estimate on what you may need. :cool:

 

[Patman]

Out of curiousity... how did a borrowed bike run out of oil? Was it borrowed for an extended period of time or was it already burning a lot of oil and it just wasn't checked?

 

[jaction125]

You got it Patman. I borrowed the thing from a pretty good friend, who loans it out pretty regularly. It was his kid's bike and the kid lost interest, so it kind of became a community pit bike. Well I happened to be the lucky guy riding it when it finally didn't have enough lubrication. I'm not upset about it at all, just wish I woulda checked it. As far as I can tell it wasn't burning any, but it probably didn't have any left to burn once I got it.

On a side note, I borrowed it to do a little oval racing on it with some buddies, and I was really wringin it's neck. Think pavement oval and knee dragging...

Heard the obvious noise and shut her down. The next day I dropped the oil and here comes every bit of two teaspoons worth. I had prolly put about 2-3 easy hours on it while tooling around with my nephew on his 50 and it ran like a champ.

I guess my point is that you can run these suckers with no oil for a long time before you end up in trouble. I have no clue how long this thing ran without oil before I got my hands on it.

89'er--- Thanks for the info, I'll wait to order parts until I get it apart. You rock!!

And I'm sure I'll be back in here ask what the hell I did wrong while trying to repair it!

 

[Vic]

Have you tried adding a quart of 20w50?

 

[Patman]

OUCH! I guess the up side is that they are pretty cheap to repair. Maybe it's time for a little performance enhancing modifications? Oh and a little pink ribbon or something as a reminder to check the oil prior to lift off ;)

 

[jaction125]

Yeah when I busted it the first thing that came to mind was a 110 kit from bbr, but the guy wants a grand for it, so it's gettin whatever is the cheapest.

Note to self, do not borrow bikes anymore....

Vic- that's not a bad idea, maybe worth a shot.....

 

[Patman]

Check out www.powroll.com for some inexpensive alternatives.

 

[Ol'89r]

Have you tried adding a quart of 20w50?

Too late! :yikes:

jactson.

Check the valve clearance first. If it is in spec you may be able to get away with that. If there is excessive clearance and the cam is already damaged, then even 90w/150w won't help.

 

[Vic]

IMHO, fixing this beater is not the responsibility of jaction125. This guy lends it out to every T,D and H, so he obviously doesn't care much about it. If it runs, I say throw in a quart and give it back.

 

[Patman]

Sometimes it's cheaper to do the right thing than deal with the bad karma down the line.

 

[jaction125]

I don't feel particularly responsible, just going after the classy thing to do.

 

[jaction125]

Too late! :yikes:

jactson.

Check the valve clearance first. If it is in spec you may be able to get away with that. If there is excessive clearance and the cam is already damaged, then even 90w/150w won't help.

Any idea what the clearance should be? Actually does anyone know where I can find the specs? I wish I had a service manual for this thing, but I'm not gonna go out and buy one for a relatively simple repair job, not to mention I'll never see this bike again....unless I have to.

89'er- You are a big help, thanks again! I am going to pick the bike up this weekend some time and get into it, I'll be sure to let you guys know how it goes.

 

[Vic]

Sometimes it's cheaper to do the right thing than deal with the bad karma down the line.

It's always right to do the right thing, regardless of the consequenses.

In this case, I don't think it's wrong to not fix what you didn't break, but if jaction125 wants to step up, there's certainly nothing wrong with that either.

 

[Ol'89r]

Any idea what the clearance should be?

jaction.

I don't have the recommended clearances but, .001 to .002 on the intake and .002 to .003 on the exhaust would be in the ballpark.

 

[jaction125]

I took a look at it last night and it appears that the cam, lifters, valves arer ok. No bluing or anything like that so I ordered top end parts from Service Honda and we'll get a better idea once I take it apart. I took the intake off so I could see in the cylinder, piston looks like crap so me thinks it has a blown ring.

 

[tnrider]

looking at the 97-03 shop manual for the xr70 says:

inspection:
-------------
remove the valve adjuster hole caps

remove the left crankcase cover

turn the crankshaft counterclockwise, aligh the T mark on the flywheel with the index notch on the left crankcase.

make sure the piston is at TDC (top dead center) on the compression stroke.

check the valve clearance by inserting a feeler gauge between the valve adjusting scre and valve stem.
intake/exhaust valve clearance 0.05 +- 0.02mm (0.002 +- 0.001 in)


adjustment:
------------
adjust by loosing the lock nut and turningh the adjusting screw until ther eis a slight drag on a feeler gauge.

hold the adjusting screw and tighten the lock nut.
torque: 9 N.m (0.9 kgf.m, 6.5 lbf.ft)

recheck the valve clearance

check the valve adjuster hole cap o-ring is in good condition, replace if necessary.
coat the o-rings with clean engine oil and install them on the valve adjuster hole caps.

apply clean engine oil to the threads, install and tighten the valve adjuster hole caps to the specified torque.
torque: 12 N.m (1.2 kgf.m, 9 lbf.ft)

install the left crankcase cover.

 

[jaction125]

For those that helped, thanks alot! I did the job this weekend, wasn't too bad. I bit the bullet and bought the Honda service manual. It ended up with a broken oil ring (smoke) and the wristpin was siezed to the piston (knock). The cylinder was fine, so after $125 worth of parts and 3 hours of my own labor, it's overwith.

I am actually glad now that this happened. Several years ago I attempted to do a top end job on my rm125 and didn't fare well, snagged a ring on a port during reassembly. It really scared me off of doing my own motor work. But now I have some much needed confidence, and will be doing my own internal engine work now.

Thanks again 89'er,tnrider and the rest!

 

[tnrider]

Thanks again 89'er,tnrider and the rest!

glad i could assist.

but... you first posted back in october and just now did the repair - and i thought i procrastinated in doing bike service - i feel much better about myself now

 

[jaction125]

Hey man! My garage is cold! :)

 

[tnrider]

Hey man! My garage is cold! :)

i can respect that.

one solution is to really warm up the bike first - then when the hot oil spills on your hands... :yikes: