valve job at 70,000?

[kwb210]

Is there a typical mileage level/range that valves need attention?

I have a 1977 R100/7, runs excellent in all respects, it is new to me. I've ridden it a couple of thousand miles, total mileage is 70,000. Prior owner took VERY good care of bike. There is a small bit of oil leaking from the push rods so I plan on pulling the cylinders and replacing the oil seals and of course new head gaskets etc. I'm wondering if I should also do some level of a valve job, complete if needed or just lap the valves, don't know til I get into it. A valve job would take a couple of days, days that I want to be riding, a cylinder removal/re-seal is an evening. I hate to do the cylinders and then do the valves later this winter because I hate to waste a head gasket let alone pay the price for two sets.
Appreciate your comments!
Kurt

[sumran]

I would wait until winter to replace the PR seals. You will be able to fully evaluate the valves once you pull the heads. It doesn't sound like the seals are leaking much and it keeps your options open.

[Bill Burke]

Take it to a bike shop and have 'em perform a leakdown test on your compression. That'll tell you how efficient your engine is at the moment. My bike has 77K on it now and is down to 45% of peak on one side and 62% on the other. Time for a top end job, including valves.

[108625]

You can get an idea what shape your valves are in without pulling more than the spark plugs. Put the bike on the centerstand and in gear, then rotate the rear wheel to turn the engine over and open each valve. Shine a penlight in there and look at the edges of the open valves to see if they're O.K. If they're razor sharp, or tuliping over, they definitely need replaced. If not, they ought to be fine to at least wait until you have the heads off later.

[mmmalmberg]

Yeah I wouldn't spend money on a valve job if compression's good and the valves look more or less OK. You can replace the p.r. seals without pulling the head off the cylinder so you won't waste a head gasket.

[carockwell]

Keep in mind that the motorcycle shops typically have a long backlog of work in the summer. You probably want to wait until winter to do the valves.

[jamesdunn]

Keep in mind that the motorcycle shops typically have a long backlog of work in the summer. You probably want to wait until winter to do the valves.
+ one. Around 70 -80, 000 is about valve job territory. Check as stated here by others though. Maybe previous owner did the valves.

[beemerPhil]

Airheads typically 'need' valve work around 80-90k, provided it's not one of the early 80s bikes that had valve "issues". Obviously, yours isn't.

Does it idle well? Valve problems will show up first at idle; if it responds well to tuning and idles strong and smooth at the right speed, you don't need a valve job.


The pushrod seals on a '77 are adjustable. If they're not cracked/split, any competent airhead tech can do this- it takes a "special" drift from BMW, or a piece of appropriate pipe cut off at an angle. Later (nikasil) bikes are NOT adjustable- if you try this on one of them, you'll break stuff.

+1 on waiting til winter for this sort of thing- esp valve work, if you decide to do it. You're unlikely to live near someone who can do a really good job- there aren't that many good airhead shops around. Plan on shipping time to and from someone who can get it right.

[AnnapolisAirhead]

You can pull the cylinders back far enough to replace the pushrod seals without detaching the head from the cylinder, leave the nuts at 12 and 6 o'clock in, remove four nuts on the studs, pull the rocker assembly and pushrods. I keep them in order. You may have to nudge the cylinder wall with a rubber mallet and it'll wriggle free.

I'm not sure of a 1977 has a shim between the cylinder and the block or not--my '83 R100T does not, so I put a very thin layer of Permatex Gray before re-assembling. Be careful not to smear it around the base of the top two engine studs...oil travels along there all the way to the rocker assembly.

One trick with the seals is that there is a raised rubber line than needs to go at 6:00 when they are in, but you may have to turn them each 1/4 turn as you slide the cylinder back on in order to clear the frame tube, then put them at 6:00. They'll fully seat as you torque the heads (25 ft. lbs.).

It's about a 1-2 hour job depending on your comfort level.

Things to be careful about:
Don't put too much sealant on the engine/cylinder mating surfaces
Don't clog up the base of the top two engine studs or it'll block oil deivery to the valve train
Don't pull the cylinder all the way out...you DO NOT want the piston rings to be exposed (I think TDC 'ing the engine will give you the most travel, where the pistons are closest to the valve, do each side separately). This will give you more room to work on the pushrod seal, not much is needed, just clear the frame and keep the piston rings inside the cylinder.
Don't over torque the heads, no more than 25 ft.lbs...remember, its an aluminum bloc and easy to strip


I didn't know there is any adjustment to the pushrod seals, since they rubber. Learn something new every day.

For what its worth, you'll be removing the exhaust and carbs anyway to pull the cylinder back, so before you remove the nuts on the engine studs, turn the engine by hand and look into the intake and exhaust port to watch the valves, look for razor sharp edges, etc. Might help to shine a flashlight into the spark plug holes as you look into the intake and exhaust ports.

Good luck. I'm helping a friend do his seal this Friday. If you get stuck drop me a PM.

[RandyB]

Get Oak's top end manual. Great reference. I've pulled and worked on the top end without it and with it and I'll never be without a copy again.

[beemerPhil]

[QUOTE=
I didn't know there is any adjustment to the pushrod seals, since they rubber. Learn something new every day.
.[/QUOTE]

:type

The metal collar on the pushrod tube that presses the seal against the block is a tight slip fit on the tube. Using a suitable tool, it can be tapped down the tube so as to squeeze the rubber seal a bit tighter. Later models have the collar welded to the tube; these are not adjustable, and using the tool on these bikes will pull the pushrod tube out of the cylinder!

:doh

+1 on Oak's manual- or get your experienced airhead friend to let you watch him do his bike!

[wecm31]

I have also been pondering the need for a top end rebuild. My 85 R80 has 80K miles and top end is untouched. I will take the advice next time I pull the plugs to peek inside and inspect the valves for wear, the clearance has not changed a bit in the last 20K miles, always found within spec so I don't think I am receding. Compression is ~ 115 psi, have not done a leak down check, beyond my tool kit!! What other symptoms apart from rough idle would tell me I should pull the heads for rework? Hard starting? Oil consumption? No issues currently, but I much prefer to spend time and money in January as opposed to July and want to stay on top of potential problems.

[20774]

Rough idle, as long as it's not a carb issue, might be caused by valves closing up. Checking the valve clearances are regular intervals will give you some warning if you see the clearance close up within 500-1000 miles. First time you see this happen, you might chalk it up to not paying attention the last time you set them. Do it again and recheck. If they've closed up again, then it's not you...it's the bike.

[PHMarvin]

Hi, KWB210,
Remember, your '77 R100/7 was designed for LEADED premium fuel. If (when) you do a top end job, don't forget to have the valve seats replaced with unleaded-compatible seats. Since you're on the west coast, I would have Ted Porter do the work. It won't be cheap, but if you just grind and lap the valves / seats, you will probably shortly have experience with valve recession caused by lack of lead in an engine designed for it. Good Luck!

[kwb210]

Wow, great comments! I did a compression test yesterday. Bike was hot, ran the carbs out of fuel, removed carbs, pulled plugs and installed hose/gauge. Ran starter until gauge did not increase, stopped at 148-almost 150 on the left. Did same to the right and was expecting a little differnece, but exact same, 148-almost 150. Did the test again and exact same results.
The idle is a bit rough, bike wants to idle at 500 unitl it is 100% to temps, usually seems like awhile before i don't have to hold it at 1000/1200 to keep it running. Once hot it idles okay, not perfect. At least I know the numbers, while I'd like to seal up the tiny little leaks at the base of the cylinders, I would like to do valves since its all apart, but not now as was commented. Its still sunny! Thanks for all the commments. Keep em coming!
I'll keep you all posted.
Kurt
77 R100/7
turned 70,000 Sunday afternoon while on vintage ride at the end of the Mt Baker Hwy at Artist Point, as far as you can go.

[20774]

Pulled plugs....AND grounded them to the engine, right? That must be done to prevent any inadvertent shocks to the coils and/or electronic engine.

[kwb210]

Yes, I forgot to mention that. I installed the plugs into the spark plug wires after removing them from cylinder heads, then grounded both plugs to the cylinders while cranking. That sound better! hehe. And here I thought I had been so complete in my description, should have proof read it!
thanks!
Kurt

[kwb210]

ready for the measurement. Got the compression gauge installed, spark plug grounded to cylinder. Did two readings both just shy of 150.

[kwb210]

plugs were milky chocolate color, dry. they are Bosch wd6c. Notice my ebay purchased Hazet spark plug wrench!:thumb

[kwb210]

valve cover off, nice and clean other than drips of oil

[kwb210]

Right side valve cover off, again nice and clean, notice my new Northwoods Airhead exhaust wrench, a must have to safely remove exhasut nuts.

[kwb210]

got the header pipes pulled off. high quality fastners make for pleasant work.

[kwb210]

left side head removed & cylinder barrel loosened from the engine block

[kwb210]

left side piston resting on red rag for protection, some carbon deposits that will need to be removed.

[kwb210]

push rod seals are stiff, dired and brittle - they are headed for retirement!

[kwb210]

the right side head off, good old duct tape on the carb opening, don't need to risk debris getting inside and starting an additional project!

[kwb210]

right side piston removed, rod resting safely on red rag. Considering removing rods and having them balanced. Getting time frame and of course pricing. Would like to see if perfectly balanced rods will reduce some buzzing at higher rpm.

[kwb210]

filled the gunk tank, put the parts in the tank. right side parts on the, yup, the right side and left on the left. Parts will be spending the night in the tank!

[kwb210]

After work today I scrubbed the cylinders and then cleaned the solvent off w/ brake cleaner. Being thoughtful to keep the right one on the right and the left on the left. they cleaned up okay, good enough for a bike that will be riden.

[kwb210]

the oil that squeezed its way out of the leaking cylinder heads was somewhat baked onto the block, took some extra effort to clean it up, all while avoiding damage to the connecting rods and keeping junk out of the block, I used brake cleaner, nearly a whole can for both sides. Cleaned all the threads and its ready for the re-install.

[kwb210]

I tossed all the oily rags and cleaned up the floor area and my yellow cookie tray that I use to set parts in. Got the cookie trays from a bakery that was tossing them out. They work well for keeping small parts from wandering away! Plus they are nice and bright, great place to put cleaned and ready to install parts. I won't start the re-assembly until at least one more day while the pistons and heads get more soak time n the gunk tank. that carbon is stubborn!

[RandyB]

right side piston removed, rod resting safely on red rag. Considering removing rods and having them balanced. Getting time frame and of course pricing. Would like to see if perfectly balanced rods will reduce some buzzing at higher rpm.

Balancing is well worth the trouble. While you're at the machine shop, take the dedicated sockets you use for swing arm, steering, etc. and have them mill them off flat so they work on those thin nuts.

I just reringed and did PRT seals on my GS. This thread is giving me nightmares but it runs like a scalded dog now.

[kwb210]

pistons soaked for 2 days in gunk tank, here they are sitting on top of the heads, cleaning solvent really loosened the carbon. I used a wire brush on the end of a drill motor.

[kwb210]

cleaned pistons are all dry after shooting w/ brake cleaner.

[kwb210]

heads sat in the solvent tank for 2 days, they took more time to clean, used a few different wire brushes to reach into the middle.

[kwb210]

both heads cleaned up fairly well.

[kwb210]

to really get all the deposits I may remove the valves. But what an improvement!

[kwb210]

got the parts all lined up and basically ready to assemble. Still have not decided if I will remove valves.

[mmmalmberg]

Don't forget to pull those tappets out and make sure they don't have any pits etc.

[kwb210]

pushrod tubes lubed up and installed on the pushrod tubes

[kwb210]

piston installed on the rod, brand new circlip!

[kwb210]

cylinder jug pushed over the rings and installed

[kwb210]

installed the valve train, made the mistake and removed the rod so that all the needle bearings could escape (!) A little lesson in reading ahead on the direction sheet. Lots of greasey fingers and those tiny little needles, getting the right number into each side, and making them stay on their own side, whew!

[kwb210]

I cleaned the exhaust nut with a brass wire brush on the end of the drill motor, made it nice and shiny! And yes, applied anti-seize to the threads.

[kwb210]

Opened the fule petcocks and started her up. Always like the smell of hot lubricants burning away, for a few minutes anyway. Turned her off and there was a leak from the valve cover gaskets. A dribble, but a leak nonetheless. And during this process we of course adjusted the valves. Over the weekend i rode a couple of hundred miles, mileage was better probably due to the correct valve adjustment and maybe from de-carbonizing (?). Now gotta address the valve cover leak.

[44006]

What did you use for solvent that worked so well on the carbon?