Cylinder Head Question

[dps650rider]

I am thinking about getting another cylinder head off ebay to recondition so I can just do a swap with minimal down time. I always see the cylinder heads sold separately from the cylinder head covers, are these align bored so that a cover needs to stay with a head or are they interchangable?

 

[BluzPlayer]

Align bored.
Head and rocker cover should have matching #s

 

[kshansen]

I have heard of people being able to use mismatched heads and covers. That said I would not consider it unless someone was giving the parts to you for free.

Same thing with crankcases, I have not checked the engines on the three xs650 engines I have but would assume they also have number or some identifying marks on them to keep the upper and lower sections matched.

 

[BluzPlayer]

Unfortunately there are vendors on ebay intentionally creating orphan heads by seperating the two parts and selling them individually.
Some are perhaps unaware. Others just don't care.
I would not use a mismatched set unless they were close enough in tolerance to be align bored again for a match.
Won't know that from buying online until you get it in your hands.
But that's just me and my devalued 2 cents.

 

[Jim]

Well technically it's called "line bored" not align bored... as in a straight line.

Having said that, yes, they are line bored as a set. Matching two of different numbers is hit and miss.... mostly miss from what I can tell. Got a few mix and match number head/rockers boxes. None of them line up good enough to use.

 

[dps650rider]

Thanks all, that is what I expected. I don't think I remember them ever being sold as a set... what a waste.

 

[Jim]

Just to expand a bit, they're joined together with guide bushings on two of the crankcase studs. You "could" leave those out. The main concern is the bores the cam bearings run in. With the bushing in place, the bores are slightly out of alignment. Remove the bushings, use the cam bearing to "align" the two and I believe you could make them work. I tried it once just sitting on a bench and it looks workable. And that's the reason I keep these gathering dust on the shelf... should the need ever arise... in a pinch, I'll give that a shot.

 

[650Skull]

I think its because sellers see something that comes apart and have no idea they have to be a set, buyer beware and all that shit. A lot of people who own X650's don't know about this and getting them re-drilled would make the holes to big and you would have to get special seals made.

made a thread once where people could post their mismatched heads in the possibility that some one would have the other to match it..........went down like a lead balloon..

 

[650Skull]

Thanks all, that is what I expected. I don't think I remember them ever being sold as a set... what a waste.

Ask the seller if they have the other rocker cover or head and explain to them they have to match. If they have one there is a good chance thay have the other to go with it and you then have a matching head............Ask the question

 

[Jim]

Ask the seller if they have the other rocker cover or head and explain to them they have to match. If they have one there is a good chance thay have the other to go with it and you then have a matching head............Ask the question

Exactly right. Often times I'll see a head on Ebay and if you click on the "See More From This Seller" button, you'll find the rocker box he's selling separately. Ask him to verify the numbers match and ask about a package deal.

 

[Jim]

Here's a perfect example... one of the first to pop up. Seller has matching head and rocker box for sale.... as two separate items.

Here: https://www.ebay.com/itm/324957247522?hash=item4ba8f61822:g:rq0AAOSwwNBajzpk

And here: https://www.ebay.com/itm/3636662930...7bbm6ryALbmO7eqhBSevP3T8aw==|tkp:BFBMvIHc7api