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Valve lapping????

  • Thread starter Thread starter turkeyroll60
  • Start date Start date
T

turkeyroll60

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So here I am suffering from my usual case of friday night insomnia. The only thing to do is to surf the net in an attempt to learn as much as I can about my bike and all the technical aspects of maintenance and repair. I have come across a tool called a valve lapping tool and a video demo showed it at work. Is it really that easy??? The reason I ask is that I am anticipating there being a exhaust valve that may not be properly seating in my bike and this looks like a good solution.
 
Yup,,,,the lapping tool, the lapping compound, and it will create itself a new seat,,,,don't overdue it
 
Very important to use good quality lapping compound of the correct grit. I tried the Permatex that they sell at the chain stores and it almost ruined the parts. It took me an hour to lap the resulting deep scratches out of the head with proper compound, which I found at Goodson.
 
I lapped mine after getting the valves faced and the head wet blasted and it was easy as pie. As stated earlier just make sure you get good compound and you should be right. The compound I used was fine and mixed with water from memory, just had to squish it around in the tube before using it.

However, Tkent's question is probably the most pertinent to start with... are you sure valve clearances are good?
 
Jumping way ahead. Adjust the valves and get the bike sorted before you pass judgement. You can NOT troubleshoot a bike that has neglected maintenance.

Perform a hot compression test with the throttle open before you judge the valves.

Regarding valve lapping, it is NOT intended to reseat worn valves/seats. It's only for cleaning and verifying the valve to seat contact area. If there is significant wear the proper way to fix that is by cutting the valves and seats - performing a "valve job". Lapping is the last step in a valve job, and frankly, if the parts are machined properly lapping is not necessary.
 
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Ed, sometimes they just like to take schit apart to see what's inside.
Parts bikes for the rest of us.
 
No......no adjustment yet....I am waiting on the feeler gauges and tappet depressor to show up in the mail. Then I will perform the adjustments if necessary and then check the compression before moving on. I am just looking ahead and anticipating what may need to be done. There is a tapping noise coming from the left side exhaust valve and this has got me thinking. I have seen the inside of engines before so my curiosity has been satisfied. I am learning and figured it would be a good question to ask as they say the only stupid question is the one that is never asked. Thanks for all the advice.

Here comes one more for you all........What do you mean when you say the parts have to be machined properly? I.E. If I were to order new valves and seats why cant they just go in? What is the specific part of the machining process that has to be done to make these things seat properly? O.K. bring it on, keep it clean but let's make it fun........NO ONE WILL HAVE MY BIKE FOR PARTS!!!! NO ONE!!!! LOL:eek:
 
Replacing the valves is fine, otherwise they can be cut to reclaim a flat surface (which is much cheaper than replacing them). Valve seats can also be replaced but it's much simpler and cheaper to just clean up the seats with a cutting tool. The valve guides are a wear item so it's always good to check them using the wobble test as defined in the service manual. Any time the valve guides or seats are removed, a proper valve job must be performed since they will not index correctly back exactly concentric.

All this work is expensive. It's much cheaper to just search ebay for a low mileage cylinder head as necessary.
 
There is only 8500 miles on the engine as indicated on the title so I'm guessing, other than oil changes, there was no other maintenance done on the bike. I will not know what really needs to be done until I open it up. I was reading about exhaust valves and the fact that they are subject to way more heat than the intake valves and that these valves take such a beating if not regularly adjusted that they just keep receding into the head where they cause some really nasty valve and cam problems. WE SHALL SEE..... Thanks Nessism.
 
8,500 miles?
Not 85,000? not 850,000???
Damn, that's a brand new engine.

Like I said, some people just like to take schit apart to see what's inside.
Take a lawn mower engine apart for kicks, leave the bike alone.
They're almost the same inside anyway.

Parts for the rest of us.
 
8500 miles in just broken in. Adjust the valves and you should be good to go.
 
I've never yet done a valve job on my 850L. Check out the mileage on my sig. It does need new seals on the guides though, maybe even new guides, as it sucks oil out through them. As long as I keep the rpm down under 7500 it doesn't go through oil too fast though.:D
 
I read somewhere a long time ago, to test if your valves are seated nicely you can turn the head upside down and cover the valves with acetone. If it leaks, you'll easily see it in the intake or exhaust ports; if it holds, you're good.
Of the handful heads I've tested actually, most will hold the acetone back; but I have seen some worn out heads leak. I stopped the leaking on my cl175 by lapping the valves on my kitchen table.
 
The fact that it had low miles and it ran was a big reason why I bought the bike. I just keep looking at her in the garage and picturing her cleaned up and restored. So earlier today I was excited to see that my order from powersportsuperstore.com arrived. I ordered feeler gauges and a tappet depressor in preparation for a valve job. I got Steve's spreadsheet for valve clearances ready to go as well. When I opened the bag they sent me the wrong part. I got the feeler gauges (32 gauges ranging from .03 to 1 mm but the tappet depressor tool wasn't there, in its place was a contact point for an ignition system). So in my frustration I went out to the garage and decided to start the bike up and maybe go for a little ride just for fun. As I let the bike warm up for about 5 minutes I felt the left side exhaust flange near the engine and it was a little warm to the touch. I did the same on the right side and it was burning HOT as it should be I assume. Is it low compression that could be causing this? I will get started on the valve adjustment and wait for powersportssuperstore.com to figure out their blunder. Oh by the way, they also sent me an extra feeler gauge set although I only paid for one. I did the right thing and told them that I would send it back with the contact point I do not need. It is what it is for now....... :D
 
Once properly warmed up, if that cylinder's header is only warm, then it's not firing properly plain and simple. Which of course, could be any number of things...lack of fuel, intermittent spark, too much fuel, etc. First, as others have mentioned, check the valve clearances. Instead of waiting on the tool, just use the zip-ty method (check basscliff's site). Once those are set properly, then you can begin checking things for proper operation.
 
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