Oil leak and stripped bolt

If it's broken or just needs tweaked

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Gforce5
Posts: 14
Joined: Thu May 06, 2010 10:22 pm

Oil leak and stripped bolt

Postby Gforce5 » Sun May 30, 2010 6:46 pm

My 1980 cb650 has an oil leak!! I'm pretty worried that this could be a big problem and i'm going to take it in to a shop i think. It's leaking oil out of a bolt going down into the top of the engine. When i tighten the bolt it feels like it's stripped. When i took the bolt out it's not stripped, so i guess where it's going in to is stripped. I bought a longer bolt to see if it would bite further down or something and it didn't help. Anyone know how much this should cost if i were to take it to a shop or anything i can do to fix it myself or something? Thanks a lot in advance for any help.
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iamtheric
Posts: 13
Joined: Fri Jul 10, 2009 10:35 pm

Re: Oil leak and stripped bolt

Postby iamtheric » Sun May 30, 2010 7:46 pm

how much oil does it leak exactly?

Gforce5
Posts: 14
Joined: Thu May 06, 2010 10:22 pm

Re: Oil leak and stripped bolt

Postby Gforce5 » Sun May 30, 2010 10:44 pm

Well it doesn't leak when it's not running but after running it for as little as 10 minutes there's quite a lot of oil leaking from it.

Rocky
Posts: 155
Joined: Sun Jul 13, 2008 4:53 pm
Location: Portland, OR

Re: Oil leak and stripped bolt

Postby Rocky » Sun May 30, 2010 11:31 pm

I had the same problem last year when I had dropped a nut in the head area and had to take the head off. I had mixed up the bolts. But mine leaked oil or I should say gushed oil as soon as I started the engine. The blot was shorter, it should have been longer but I am intrigued to learn that has not fixed your problem. Maybe instead of the bolt the head area has been stripped. You could try helicoiling it.

I would rather do this myself with some help from somebody else who has used heli coils before and fix the problem. Don't worry it is not such a big deal. You can fix this.

What about those copper washers? Did you replace those?

EDIT: looking at the picture your posted. The bolt that you are pointing to looks WILDLY different from other head bolts. Is this the new longer head bolt?

Did you take off the head and somehow mixed up the bolts (like me) or this is how you bought the bike? PO maybe to blame for this?

Gforce5
Posts: 14
Joined: Thu May 06, 2010 10:22 pm

Re: Oil leak and stripped bolt

Postby Gforce5 » Mon May 31, 2010 12:06 am

Yeah I put some more washers and a longer bolt just to see if it would work but it didn't at all. It definitely seams like the head area is stripped, not the bolt. If I tighten the bolt it doesn't ever seam to get a lot tighter, and when I took the bolt out it's threads were fine. What's helicoiling?

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Volker_P
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Location: southern Germany

Re: Oil leak and stripped bolt

Postby Volker_P » Mon May 31, 2010 6:54 am

The problem with this bolt is that behind it there is the full oil pressure of the camshaft bearings. This makes it a difficult and decisive bolt.
Heli coil is used to repair stripped threads, you may have a look here:
http://en.wikipedia.org/wiki/Threaded_insert.
Some motorcycle parts shops sell this. I agree that someone with experience is helpful here, but it is no big deal if you are used to drill straight holes and cut threads.
In general the head cover and head threads are very susceptible and you need to follow the stepwise pattern of the book in both directions using a small enough torque wrench. I've seen few head covers with still all threads intact.
Use a copper washer and don't overtighten trying to get it tight. Instead, try annealing the copper washer to soften it or use a new one.
BTW, I am quite sue the two unlabeled bolts at the top of the drawing do not make any sense, do they?
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

If you really like this site and you would not like to see it vanish soon, have a look there: Urgent: Future of HondaCB650.com Forum

Gforce5
Posts: 14
Joined: Thu May 06, 2010 10:22 pm

Re: Oil leak and stripped bolt

Postby Gforce5 » Tue Jun 01, 2010 4:51 pm

Hey thanks a lot for the info. I guess i'll need to take the engine apart, right?

Rocky
Posts: 155
Joined: Sun Jul 13, 2008 4:53 pm
Location: Portland, OR

Re: Oil leak and stripped bolt

Postby Rocky » Tue Jun 01, 2010 5:50 pm

No.

You just need to take the head cover off, which would mean that you may also have to dismantle the whole rocker arm assembly but thats about it. Once you have the head off, helicoil the suspected hole but remember to sequentially remove the bolts when removing the head cover, i would probably number them. The Clymer manual should have directions as well about that. Once the thing is helicoiled, inspect the rubber coins, apply some sealing lubricant, reassemble the rocker arm and tighten the head back on, adjust valves and you are on your way.

cb650
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Re: Oil leak and stripped bolt

Postby cb650 » Tue Jun 01, 2010 7:42 pm

You might not even have to take the head cover off on that bolt
Did you clean the tank out?!?!?!?!

Gforce5
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Joined: Thu May 06, 2010 10:22 pm

Re: Oil leak and stripped bolt

Postby Gforce5 » Wed Jun 02, 2010 1:11 am

If I'm going to be drilling and stuff won't that get debris into the engine unless i take the head cover off? I actually don't think I have enough experience to do this but I might be able to find a friend who does. Anyone know how much this might cost at a shop?

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Volker_P
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Location: southern Germany

Re: Oil leak and stripped bolt

Postby Volker_P » Wed Jun 02, 2010 2:20 am

I'd even say that with the head cover on it is less problematic about the filings etc. However they are more difficult to get out. Another point is that your drill must be long enough and also the insert tool might be too short or not turnable. But the really problematic item might be that the final depth position of the threaded insert is harder to estimate with the head cover on.
BTW, there seem to be inch bolts slightly larger than 6mm bolts, they are 6.4mm thread outer diameter or so. One can try to just turn one in (without any drilling) and hope that it fixes the problem. I did this on my dirtbike for a less important bolt. But you need a good feeling for bolts and materials to guess the torque it can stand and moreover this is the bolt with oil pressure behind.
If you can move the bike somehow to the shop in a clean way, you may disassemble the head cover yourself to save money. Just call a shop, tell your problem and ask for a price. Could imagine the thread repair alone might be around $30-50.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

If you really like this site and you would not like to see it vanish soon, have a look there: Urgent: Future of HondaCB650.com Forum

cb650 bobber
Posts: 43
Joined: Tue Jun 01, 2010 8:57 pm
Location: san antonio tx

Re: Oil leak and stripped bolt

Postby cb650 bobber » Wed Jun 02, 2010 1:27 pm

mine did the same all i did was tap it out to a std. size i think it was 1/4 " an it worked just fine

gruntfuddler
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Location: Northern Ireland

Re: Oil leak and stripped bolt

Postby gruntfuddler » Wed Jun 02, 2010 2:29 pm

I had the same problem (the oil coming out via the bolt hole on both sides). They had been heli coiled before and I got a guy to do time serts(http://www.youtube.com/watch?v=qFSyfY1VLtU) which really looked to be the job, but when they were done the curved surface in the cylinder head at the end meant that the time serts could not be seated correctly and they came out on the bolts as they were tightened down.

I struggled long and hard to find a solution which included buying replacement heads which turned out to be the wrong fit for the CV carbs. Eventually I stuck a shorter bolt in and closed up the opening with a nut on the other side which stopped the oil coming out, but it took a gasket sealant between the head cover and head to properly keep oil from sweating out at the edges.

Gforce5
Posts: 14
Joined: Thu May 06, 2010 10:22 pm

Re: Oil leak and stripped bolt

Postby Gforce5 » Thu Jun 03, 2010 2:32 pm

Thanks for all the advice but I think i'm going to just take it in to a shop. Adjusting the valve clearance looks like it's beyond my ability.

Rocky
Posts: 155
Joined: Sun Jul 13, 2008 4:53 pm
Location: Portland, OR

Re: Oil leak and stripped bolt

Postby Rocky » Thu Jun 03, 2010 4:47 pm

Really?

Adjusting valve clearances is kinda easy compared to everything else. If you don't wanna take a chance then take it to a shop.


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