Hi all, because of an oil leak my mechanic has told me that i need to do the "top end". He mentioned changing the gaskets (he said there were 4 gaskets in all) and he also mentioned a valve job and new piston rings. Can anyone confirm this information and if possible provide a ball park amount this all should cost? Being new at this, I'm not much of a mechanic but I love these bikes! I appreciate any help.
Top end gaskets
- Thread starter burmdoge
- Start date
DrJ
Over 1,000 Posts
Depending on what bike you have that sounds about right. Doing the top end requires replacement of these gaskets: base, head, valve cover and depending on the engine one or two on the side where the cam mounts. Also depending on your bike is whether the mechanic needs to remove the engine from the bike or not. After all the gaskets are replaced, the valves will need to be adjusted and the ignition timed if the points are cam driven. Ballpark estimate would be anywhere from $400-$600 including parts. This is why many vintage riders learn how to do there own wrenching.
My bike is a 78 cb750k. I wish i could do the work myself but i just don't have the time. My mechanic is charging me $300 for labor not including parts. I see the top end gasket kits on ebay for about $80. Does that sound right? Also, for the piston rings I see them for about $30 on ebay. The all say sets of piston rings, can someone tell me how many I have to buy? Or perhaps provide a part number? Thanks so much, everyone is so helpful here. 
Shoot. Ok, so the CB750 engine needs to be removed from the frame to do anything to it at all beyond adjusting tappets.
$300 is CHEAP for this job if he does:
Remove the engine
Tear down top end
Replace rings
Rebuild top end with new gaskets/o-rings as needed
Put the engine back in the bike
It would take me 3+ hours probably to get the engine out! $300 at $70 hour most shops charge is only 4 hours labour so you're doing good for the money.
How does the bike run? Doing all this entails resetting the timing which should be quick for the mechanic to do. Are the carbs in good shape?
Check in at www.westernhillshonda.com for parts for the bike. Also don't shy away from calling your local Honda dealer.
$30 / set of rings is a decent price. You'll also be into honing the cylinders which will run about $20-$30 per hole.
So...
$300 labour
$80 gaskets/o-rings (easily - might be more)
$120 rings
$100 hone
$200 valve job (disassembly, cleaning, lapping valve seats, checking guides, reassembly)
If you get away with that you're doing well. I'd gladly pay a pro $300 labour vs. doing it myself, especially on the Honda 750 given the engine removal. If he's including the valve job in his $300 price, then jump! How well do you know the guy? Beware the $300 quote becoming a $900 reality when you go to pick up the bike because you and he had different understandings of what was included.
$300 is CHEAP for this job if he does:
Remove the engine
Tear down top end
Replace rings
Rebuild top end with new gaskets/o-rings as needed
Put the engine back in the bike
It would take me 3+ hours probably to get the engine out! $300 at $70 hour most shops charge is only 4 hours labour so you're doing good for the money.
How does the bike run? Doing all this entails resetting the timing which should be quick for the mechanic to do. Are the carbs in good shape?
Check in at www.westernhillshonda.com for parts for the bike. Also don't shy away from calling your local Honda dealer.
$30 / set of rings is a decent price. You'll also be into honing the cylinders which will run about $20-$30 per hole.
So...
$300 labour
$80 gaskets/o-rings (easily - might be more)
$120 rings
$100 hone
$200 valve job (disassembly, cleaning, lapping valve seats, checking guides, reassembly)
If you get away with that you're doing well. I'd gladly pay a pro $300 labour vs. doing it myself, especially on the Honda 750 given the engine removal. If he's including the valve job in his $300 price, then jump! How well do you know the guy? Beware the $300 quote becoming a $900 reality when you go to pick up the bike because you and he had different understandings of what was included.
Yea, he said $300 was for the gaskets and the piston rings. He said he would decide if a valve job was necessray upon inspection. So I'm hoping all is fine when he opens her up. Besides the oil leak the bike runs great so I'm hoping this job will do the trick. Anyhow, thanks a bunch TinTin. You've done more than answer my question, thanks again!
