1982 XJ650J Cylinder Head

What cylinder heads are compatible with the 1982 xj650j ?

Could I use one from a 1982 turbo Seca 650 ?

Thanks

 

I'm not sure on the turbo motors. I believe they are different compression so something would be different.

I have an 82 650 parts bike if you're interested. I do not know the condition of the motor.

 

http://www.yamaha-motor.com/partviewer/ ... _-_1983%29

The Model Number differs.
Part Numbers match.

 

Rick I think you were looking at the 1983 maxim

The 83 Seka turbo is the 1983 XJ650LK and the part numbers does not seem to match.

 

The first 3 numbers are different. That is for model designation.

The middle 5 numbers are the same. This is the actual part number.


From Chacal's catalog:


1982 XJ650 MODELS:

COUNTRY: USA

MODEL NAME: XJ650J
STREET NAME: 1982 XJ650 Maxim
MODEL ID CODE: 5N8
FRAME ID: 5N8
SERIAL NUMBER STARTS AT: 000101
USA MSRP PRICE: $ 2,498.00
(cylinder part # 5N8-11310-10-00)

MODEL NAME: XJ650LJ
STREET NAME: 1982 XJ650 Seca Turbo
MODEL ID CODE: 16G
FRAME ID: 16G
SERIAL NUMBER STARTS AT: 000101
USA MSRP PRICE: $ 4,399.00
(cylinder part # 16G-11310-01-00)

5N8-11310-10-00
16G-11310-01-00

These are actually the same part number, but have different model designation #s.

HOWEVER, I don't know a thing about Turbos, nor have I ever seen one to be able to tell you if there are any outward differences in the cylinders.

I do know that Yamaha used the same 3 digit part prefix for other models if the part was the exact same.

Example: my 650 seca, a 5V2, is adorned with parts that have the 650UK model designation, 4K0,because it was on that bike first.

Which leads me to believe that there are subtle differences in the two cylinders.

There is also the fact that the 750 and 550 have the same part #s, but different 3 digit model designation #s

I'm not saying it wouldn't work (or that it would), just that the parts are not exactly the same.

 

The "11310" matching is key.

But the 10 vs 01 or 00 does mean there are differences.
Painted ~ Non-painted
Lettered ~ Plain
3-weeks ~ Never

 

And that is why Rick is Rick, thanks for the details.

*opening drawer on mental filing cabinet labeled XJ*

 

Except it's not quite true. The model number prefix matters BIG TIME; a lot of parts are NOT the same even though the "middle" number matches. (Side cover emblems come to mind.)

What Rick pointed out is true SOME OF THE TIME; but NOT true a lot more of the time. The suffixes (-00-00, -30-00, etc.,) are the paint or finish differences. A lot of similar-use parts have the same middle numbers; they're not at all the same. In this case, "11310" means it's the cylinder head; the three digit PREFIXes are the distinguishing numbers in this case and in most cases.

 

I just noticed that I gave the wrong part numbers. Those are the cylinder numbers.

The numbers for the cylinder head are:

5G2-11101-00-00 (Maxim head)
16G-11101-00-00 (Turbo head)

Sorry guys, my bad.

Misslaneous, Just out of curiosity, what's wrong with the Maxim cylinder head?

 

Rick, Tskaz & Others,
What is the final verdict. Will this be a straight swap. Just the Cylinder head from a Us model seca turbo into the 1982 XJ650J ( Maxim US model) ?

 

NO it will not be a "straight swap."

4U8-11101-00-00 (550 Seca head) Same "11101-00-" number, different prefix.

Now, we KNOW the 550s are completely different. So in this case, 11101-00-** just means it's a cylinder head; the model designator (5G2, 16G, 4U8) is the critical portion of this part number.

 

+1

If you were to swap out the entire top end, maybe.

But just a head swap, you're asking for trouble.

 

As for your original question of what will interchange:

Part # 5G2-11101-00-00

Was only used on the 1982 XJ650J and 1983 XJ650K Maxim.

Good news for you is that there were a LOT of them.

Why are you looking to swap heads?

 

Hi Tskaz

I have3 broken studs and it looks like someone tried to tap out one of the holes and messed it up a bit. Basically someone tapped a new hole a little away from the original stud so the exhaust flange is not lining up properly. If I have to fix it, I think I will have to fill the hole some have and try to re tap the original hole. Since it is aluminum and the holes being close to each other, I am worried about cracks developing later...

Also if I had to do anything properly, I will have to pull out the head o work on it so I was thinking if I got a good head I will do a swap.

Any suggestions.. ?

 

I keep wondering that too; and you've asked like three times now and we're not getting an answer.

WHY do you need to swap or replace your head?

The reason we're asking is very simple; the head is one of the most easily repaired/rebuilt "big ticket" items on the motor; and it's important that any replacement head come with its original cams and cam caps. Quite often some professional machine work can be had (a REAL "valve job") and the valve stem seals replaced for about what you'll pay for another one. And your replacement will likely need the same rebuild.

I have a spare head, low mileage with good cams and caps; I bought it because I have one broken fin. But it's not on the bike and won't be until the bike needs a valve job; then when I swap heads, the replacement will get that work done to it.

Why we swappin' heads anyway?

 

++1

The key word here is professional. He's not talking about taking it to Billy Bob's Country Shed and having them blown out with a torch and filling the hole with JB Weld.

Find a quality machine shop in your area and have a talk with them. They should be able to fix you up.

But if you find another 5G2 head for a reasonable price, you can never have too many spare parts.

 

No wait hold on; I must have still been typing when the answer got posted.

Replacement IS a viable option at this point, especially if yours is already that badly buggered up. There are TONS of 650 Maxim parts on eBay; you just have to be careful because of all the mis-listing BS. The key is this: most sellers part out a bike pretty much all at the same time. Find somebody parting out an '82 or '83 650 Max and ask him about the motor. The key is to find one that somebody hasn't already taken TOO FAR apart; I got my spare head complete with cams and caps; it's from a 9K miles bike.

Put a post in "Sell, Trade, Swap, Wanted" LOTS of us have "extry" stuff laying about. Find another 5G2 head, and do a quick valve lap with new seals. The repair will be ugly.

 

Thanks Tskaz, bigfitz52.... sounds like a plan!

Thanks everyone... I will keep you updated as I progress!

 

Wizard is correct about the whole Part Number's needing to be the same.

He's also right about you not abandoning your head for some other one in a swap-out.
The one you swap too might be worse.

Broken-off fasteners are NOT a huge problem anymore.
You can have ALL the fragments removed without harming the Head.
Even if you tried to remove a Stud and have a broken EZ-Out to deal with; the fragments can be removed.

Electrical Discharge Machining.
A modern miracle that removes the fragment and leaves the aluminum undamaged.

Wire EDM Machining will save your Head.

"Wire EDM machining (Electrical Discharge Machining) is an electro thermal production process in which a thin single-strand metal wire in conjunction with de-ionized water (used to conduct electricity) allows the wire to cut through metal by the use of heat from electrical sparks.

Due to the inherent properties of the process, wire EDM can easily machine complex parts and precision components out of hard conductive materials.

Wire EDM machining (also known as "Spark EDM") works by creating an electrical discharge between the wire & the workpiece.
As the spark jumps across the gap, material is removed from both the workpiece & the electrode." -- IDS Co.

The fragment is actually disintegrated.

 

EDM isn't a silver bullet, it's very expensive & after the 'treatment' the hole will still need to be drilled out & re-tapped. Treat all suspect bolts with Kroil before attempting to undo them.
Prevention is better than cure.

 

It was after seeing the OP's answer to us asking "why" that I changed my recommendation to "replace." Based on the above quote, it sounds like it's past "EDM" territory into "ugly repair" land.

Replacement is certainly a viable and probably more desirable option at this point.

 

i stopped at a machine shop today and asked about having a bolt removed by edm but the edm man was off today.
the man couldn't understand why anyone would want to use edm to take a regular steel bolt from a aluminum head, no need for it,regular machining can do the same thing, cheaper.
they use edm to cut carbide dies and mandrels to cold draw steel.
a 6mm bolt out and a insert or retapped hole would be about 200$ and if you insisted on using the edm machine, it would be more but he didn't know how much

 

Has anyone played around with HTS-2000 ?

 

After Kroil don't work.
After Reverse Drilling doesn't help.
You might even break-off an EZ-Out (as mentioned), ...
You can get pretty far up-the-creek.
But, you still have an Ace in the Hole.

An alternative that will remove the fragment and save the day.
Unless:
You act too late.

Having the option to get the fragments burned-out is an option to use before the bad situation you could find yourself in gets made a whole lot worse.

 

The bike came to him with the head pre-ruined. We're talking about a remedy here. I still vote for finding a non-ruined 5G2 head from a low mileage motor, doing a basic valve job on it and swapping out the damaged one.

The cost to properly fix the existing part in its current state far exceeds what another head would cost; and a valve lap with new stem seals would be in order either way.

We're talking about a cylinder head here. Temp's too high.

 

Agree with the cost issue.

There are a couple of heads on flebay right now that would work, for around $80 shipped. Not sure of condition though.

 

hi All,
I looked at the part number for the cylinder head 1982 XJ750 Maxim and it seems to be the same as the XJ 650. Are the cams and valves the same for both models:

The cylinder head 5G2-11101-00-00

and cam shafts:
4H7-12171-00-00
4H7-12181-00-00

seem to be the same... can I do a straight head swap from a 1982 xj750 maxim into my 1982 xj650 maxim ?

Are the valves also the same ?

 

Yes, both heads are the same.
5G2 is the YICS head, and they have the same model and part number. They would be a straight swap.

The valves, cams, shims, valve springs are the same so they will interchange, but like Fitz said, it's better to get the complete head.

 

I think Hogfiddles (Dave Fox) has a NOS head for that engine.

It is a pure naked head IIRC so you'll have to move valves, new stem seals, and the cam etc....and then since the head is so purdy, you'll need to refinish the rest of the engine

 

My other reply didn't make the forum for whatever reason..........I'll try again----I don't have a NOS head. I have a NOS cylinder assembly for a 650 maxim.

Dave Fox

 

I have someone offering me a head locally which he thinks is from a 1982 XJ750.

He says it has the following casting marking at the bottom of the head:

"y3 5G200" He says it has a valve cover that says "YICS" on it.

I am trying to see if this will be compatible for my 1982 XJ650J Maxim US.

Is there any other marking I need to look at on the head ?

It comes with the cams and caps too.

Thanks for all your help in advance

 

Should be the same, the 650 (yics) and the 750's have the same part number.

However, the 750 cams are different from the 650 cams, a little more lift on the intake side and probably some additional durantion and/or overlap. The 750 cams will "work" on a 650 engine, but you may have to fiddle around with carb (fuel mixture) tuning, and you run the risk of having a "over-cammed" engine which tends to make the engine perform poorly, especially at lower/mid rpm's.


NOTE: people inquire as to camshaft specifications and interchange. We have compiled the following information for your reading pleasure:

XJ650 all models except Turbo:

Intake Lift: 8.50mm
Exhaust Lift: 7.80mm

Duration:
Intake opens 34-degrees BTDC
Intake closes 58-degrees ABDC

Exhaust opens 66-degrees BBDC
Exhaust closes 26-degrees ATDC

Overlap: 60-degrees


1981-83 XJ750 models:

Intake Lift: 8.80mm
Exhaust Lift: 7.80mm

Duration: not given

Overlap: not given


SOME TANTALIZING THOUGHTS: although we have not----and do not know of anyone who has---there may be opportunities for performance gains via cam-swapping between different models. Here is what we can say with surety:

b) all XJ650 (except, perhaps, for the Turbo models), XJ700 non-X, and XJ750 model cams will interchange. Here's the lift variances between them:

Intake:

* 650 models (except Turbo): 8.50mm
* 700 non-X models: 8.80mm
* 1981-83 750 models: 8.80mm
* 1984 XJ750RL models: 8.80mm

Exhaust:

* 650 models (except Turbo): 7.80mm
* 700 non-X models: 8.30mm
* 1981-83 750 models: 7.80mm
* 1984 XJ750RL models: 8.30mm


Since the cam lift durations and overlap specifications are not available for all models, we can only (for now) guess what those differences are; however, it would be reasonable to speculate that the 700 non-X and XJ750RL cams are the "hottest" of the bunch, followed by the 1981-83 750 cams, and lowest on the totem pole would be the 650 non-Turbo cams.

Although camshaft design and swapping is a real black art, as not only are lift, durations, and overlap issues involved, there's also cam-timing considerations as well as the interaction between all those factors and cylinder size, air flow into and out of the cylinders, etc. to account for.

Please note that in order to correct (or enhance) other design parameters or issues, it is sometimes best to swap out ONLY the intake OR the exhaust cam (rather than both)......so much depends on the engine and bike in question, the intended usage, rpm power range desired, etc.

Like we said, a black art....... Remember, "hotness" in camshafts, just like beauty, is in the eye of the beholder, and it depends on whether your definition of "hot" is "low-end power", "all-around power", "high-end screamer", or some other variation of the above.

If anyone has any experience with cam swaps on these engines, please let us know what you did, and how it worked out!!

 

Well there's a difference in the piston rings so the cylinder bores must be different, would assume the pistons are different as well?

 

Cylinder/piston size is the primary displacement difference between the 650, 700 and 750 motors. We're talking head interchangeability.

 

So... Can I do this....

My cams and shims on the current head seems fine. Can I swap them into the new head ie the (750 head). Do I keep the original caps or the one that came with the new head. When I am saying new head I am referring to the 750 head. It comes complete with valves cams shims caps etc.

Since Chacal says that the 750 cams are different, will swapping my caps cams and shims into the 750 head solve the problem. If it will work is there anything else I need to watch out ?

I preferred to do a perform a complete swap but if the 750 cams can give bad performance on the 650 motor, I am guessing swapping my current cams & shims into my new head would solve the problem.... I am hoping I am on the right track. ... ?

 

IF (and it's an IF) the bearing surfaces in the heads and the caps are still in nearly perfect shape, and IF both camshafts' bearing surfaces are within spec (24.967mm~24.980mm diameter) then yes you can swap the cams. KEEP the caps with the head they came with.

What you'll need to do is carefully measure the bearing surface diameters on both camshafts, and then perform a camshaft bearing clearance check on your proposed "new combination." This is a relatively simple procedure but it requires the use of 'Plastigauge.' The process is explained very clearly in the factory book. PM me with your email address and I can scan and send you the page.

Don't count on necessarily using the same shims; once the swapped cams are in place you'll need to go back and re-check your valve clearances.