GS450 Cylinder Head Replacment

[Motor Hippie]

Hello,

I am currently rebuilding my 1981 GS450T. I need a new cylinder head because the exhaust studs snapped off in the head and when I tried to drill them out and retap the holes I botched the job.

Anyway, my question is are there other years that I can easily use to replace my head? I have had little luck locating an 81 head in usable condition. Thank you all.

If you are interested I have some pictures of my build and progress (or lack of it) here. It may be a few posts back. motorhippie.blogspot.com

 

[Hornswaggle]

I can't help with your question, just wanted to say welcome to another Mn 450T

 

[Guest]

Keep an eye on eBay during the off-season.
Did you inquire in the parts wanted section?

 

[bgmart450]

You can check Alpha-Sports and look at the different years, I'd focus on 1980-83 years first, then check the rest. Shame you don't need a cylinder since I have one sitting here with pistons I'd let go dirt cheap.

 

[Nessism]

Broken exhaust bolts are avoidable (for the most part). I wish you guys would do some reading about stuff like this before hamfisting the bolts.

BTW, yes ebay. You should be able to find a head for less than $50 so it could be worse.

Edit: lots of cheap head on ebay. Unfortunately, many have broken exhaust bolts stuck in the threads.

 

[Motor Hippie]

Thanks for the advice. I have been checking ebay, but I haven't seen much within a few years of my bike. I have seen a few 86 heads that look nice which is what piqued my interest in the first place. I guess I should have been more specific.

Yes, I did hamfist those bolts. That was a few years ago, before I realized the value of shop manuals and online research. I should have stopped when the first bolt snapped, but I thought, "Well, maybe the other ones aren't as bad." Luckily, I have a CX500 I can ride while I work on the 450 (well, whenever the snow goes away.)

Thanks for the responses and the welcomes. I have found motorcycle forums to be great places full of helpful people. Cheers.

 

[Guest]

Welcome to the forums

The '80 to '82 model year 450's share the same head, although I think the '83 T still used it as well, but you'd need to confirm that.

Find the part number from Alpha Sports or some other online fiche then do a reverse parts lookup and that will tell you exactly which ones will fit

 

[XTlegend]

About 10 years ago I bought a cheap arc welder as I too sheared off an exhaust bolt. There was enough sticking out to weld a nut onto though and out it came. Since then the welder has paid for itself many times as several suzuki's I've had (and friends!) have suffered from the same problem ......

 

[Motor Hippie]

I got a cylinder head from a great guy down in S Minnesota. I've spent the last few days putting the engine back together. I've got the camshafts back on and the chain under tension, and I'm fairly certain I did it right according to manual. However, I cannot manually turn the crankshaft. It does not want to move at all and I don't want to break anything by wrenching on it too hard. Here are the questions:

How hard should it be to turn the crankshaft when everything is back on? Is it possible to overtighten the camshaft brackets to the point where the camshafts can't move? Because it is a new head, woud I need to adjust the valves before I put the camshafts back on?

Thanks, and sorry if this was covered elsewhere. I was not able to find a thread on this topic.

 

[Guest]

You should be able to turn it. Loosen the cam caps and see if you can turn the motor.
Remove the spark plugs.
Will it turn and hit a spot or not turn at all?
Are the cam caps in the proper position?
Are you sure the timing is not 180 out?

 

[Motor Hippie]

It wont turn at all.

I will try loosening the caps. I am pretty sure I have the timing right, but I will definitely double check that. I cannot remove the signal generator (slightly corroded screws that started to strip, so I stopped trying) to get a better look at the markings, so it makes it a little hard to see exactly. I do have the spark plugs out.

I did not have the lubricant recommended in the manual for the shoulders. I put motor oil on all the friction areas. Could that be part of the problem as well?

 

[Guest]

No oil is fine
Get a impact driver to get those screws out and replace them. Use anti-seize on the new ones.

 

[Motor Hippie]

Thanks. You have given me plenty of ideas to keep my hands dirty for a while.

 

[Guest]

So you got a head, which cam's did you use ?

Originals or did the head come with cam's


I have had the same problem.

2 heads, 2 sets of camshafts

one set of cams will work with both heads

the other set has a tight exhaust camshaft that stops even the crank rotating when the caps are tightened down to spec.

I think your new head is tight and the old one was loose.


Sounds like you need some plastigage to see whats going on there.


If this is the case you can remove the endplugs and have the head line bored for the cam journals to give you 0.0013" to 0.006" oil clearance.

 

[Motor Hippie]

I used the original cams, as the new head did not come with new cams. I ended up loosening the caps just a bit, and everything turns fine now. I thinm I had them torqued down a bit too tight. I rechecked the alignment and I believe everything is as it should be. I'm just waiting on the new head cover gasket to arrive and I'll be able to button her back up and put the engine back on the frame.

Thanks for the advice as always. I appreciate all the help.

 

[Guest]

You can't tighten down the cam caps too much. Well unless you strip them out. Sorry to say you will have to get the right cams or have your head and cam caps machined.

 

[Guest]

+1 chef. And If you could tighten them up that much the bolts would break or strip the head

Helps to have a defective torque wrench too Been there


If you use that cap your going to have to machine the cam or the head and cap.

However, with mine it was just the cap that was tight.


I took one off the old head, (A,B,C,D) Mine was cap B.

It seemed to rotate just fine without any play so I checked with plastigage in a few spots and it was within spec.


hope this helps.

 

[Motor Hippie]

Okay. I will try using the the caps from the old head and see if those work. Thanks.