I was taking off the cam cover and the threads for the bolts came with them on not one or two not even three but four. When i got it back together she poured oil out can any one help with a fix. I hope a heli coil job is the last resort and if so do I need to pull the head. Please be gentil im very POed lookes like the cover was off before

I just finished replacing the gasket and bolt seals on mine today and noticed that one of mine is stripped too. So I am anxious to here a solution because I am nervous that all my work to get it to stop leaking is wasted. I am pretty sure the Previous owner stripped it because that it is the section where it was stripped that was leaking the most.

If the threads have come out with the bolts, then the only real option is heli-coils.

If it's the rubber valve cover gasket type, you'll want to get a new one and the bolt rubbers to suit (this is on the 750, I'm not familiar with the 650 top end).

If the Holes are just STRIPPED, ... you Tap the Hole with a Bottom Tap that will accommodate a Heli-Coil.

www.emhart.com/product...licoil.asp

If the Anchoring Threaded Part is FRACTURED, ... the Repair will be more complicated.

The Hole(s) that are fractures need to be closed with WELD.
Redrilled and Tapped.

durafix.com

It is possible to use JB Weld to reconstruct the Anchor Hole
Drill and Tap.

kscdirect.com/item/JBW...BTUBE%250A

The theads were on the bolts came off like a spring.What is the anchoring theaded parts and what do you meen by fractured.

yamyboy wrote:

What is the anchoring theaded parts and what do you meen by fractured.

The part of the head where the cam cover bolts screw into. They might be cracked as well as stripped out.

where are they at ? the corner ones go right into the head, heli-coil
the others might just be in replaceable parts, unless their bearing caps

there are on the ends and in the center.Thay are all weak by the feel of them

Problem is, people think you can stop an oil leak by tightening the bolts past torque, the bolts have a shoulder, this bottoms & either cracks the cam cap or strips the thread, you must fit new rubber doughnuts, these hold the valve cover down & stops leaks.
(IF YOU HAVN'T GOT RUBBER DOUGHNUTS IGNOR THIS POST)

Not sure if the 650 has the rubber doughnuts Wiz - looks like the cover is just bolted directly to the head (with a gasket, of course)



And here's the link to the site I got that pic from

www.cmsnl.com/yamaha-m...odel16707/

Helicoils are much easier and will work just as well so I'm leaning that direction for you.
You have two very good options that I have used. One is more expensive than the other and requires more work but is much stronger. The helicoil route is the least expensive and for the torques you should be applying to these cap bolt, it should be adequate. If the head has been stripped out extensively and there is no deeper thread to purchase on (great idea Rick!), the thread-locking rout is your best bet. I used the thread locking because it has a steel insert with a great deal of surface area to provide good grip. You can find both and get an idea of what they are all about by checking out this link www.mcmaster.com/#thre...ts/=5doven . Keep in mind, the thread-locking inserts start at about $180 for the kit (the installation tool is over priced IMHO). If you are clever and have access to a lath, you can whip out an installer in a few minutes with tool steel.
Good luck!

Hillsy wrote:

Not sure if the 650 has the rubber doughnuts Wiz - looks like the cover is just bolted directly to the head (with a gasket, of course) And here's the link to the site I got that pic from www.cmsnl.com/yamaha-m...odel16707/

Just that you know, the exploded view is from a 650 turbo.

That drawing is not accurate at least not for the maxim 650, It does require the rubber donut seals around the bolts. Mine is not striped bad but I can tell it does not tighten enough to stay tight. That is why I think the PO had so much trouble with getting it to stop leaking. I am going the heilcoil route becuase it looks relatively simple and looks rather permanent.

I have an extra (1982) XJ 650 Maxim head that could be had cheap...

The YICS motor has the molded rubber gasket, bolts with stop collars, and uses the rubber donuts.

The non-YICS motor simply has cap screws holding the cover against a paper gasket.

The YICS motors often get their bolts stripped by somebody who tried to "tighten them up" to stop an oil leak. One of my bikes came "pre-helicoiled."

The key to the valve cover on the YICS motor is what everybody is talking about, the rubber donuts. They push the cover down; the bolts STOP. Once the donuts get all baked hard and compressed, they won't hold even a new gasket down properly and it will leak.