82 cb750 - new head

[jsancle]

I bought a 82 cb750 not too long ago because I thought it would be a good investment. Owner told me it needed a new carb kit so I did that and the bike ran really tough. Note, this is the first bike I have ever owned and ever worked on. I did not check compression when buying it and after troubleshooting for days I decided to take it to a shop. They told me compression was low on all cylinders especially #4. They told me it was the valves and quoted me 1800-2500. At the same time I found a head on eBay for $60. The bike they pulled it from had 10k miles and it seemed like the smarter decision. I've been looking for for the gaskets for it but can't seem to find any for a good price. Also, is the process of removing and installing a new head difficult in any way. Like I said I've never worked on bikes before, but if there's a write up, I can do it

[TOOLS1]

$60.00 for a head sounds like a good deal. You can do a quick check of the valves and seats by pouring some rubbing alcohol down the intake and exhaust ports and checking for it to leak out between the valves and seats. A valve job on that head should be around $200.00 to $250.00. A little more if it needs shaved. Unfortunately that is not the easiest head to change, but can be done. The Factory Service Manual has a really good step by step instructions on how to do it. You can download the Factory Manual from the manuals thread at the top of the home page here. You will need a tool to hold the valve shim buckets while changing the valve shims, and a torque wrench to do the job. The valve shim tool can be bought off ebay or from a Honda dealer for around $20.00. As for gaskets, there are sets on ebay. I recommend a seller named cruzinimage.
TOOLS  
P.S. I just came across this top end set. http://www.ebay.com/itm/New-Vesrah-Top-Gasket-Set-Honda-CB750-NOS-/262071297058?hash=item3d04aaa422:g:yOEAAOSwJqpXoQD3&vxp=mtr

[jsancle]

Thanks for all the input, tools. The head arrives next week so I might have a couple questions when I start to replace everything, cheers! 

On Feb 1, 2017, at 4:27 PM, TOOLS1 [via Vintage and Classic Honda's] <[hidden email]> wrote:

$60.00 for a head sounds like a good deal. You can do a quick check of the valves and seats by pouring some rubbing alcohol down the intake and exhaust ports and checking for it to leak out between the valves and seats. A valve job on that head should be around $200.00 to $250.00. A little more if it needs shaved. Unfortunately that is not the easiest head to change, but can be done. The Factory Service Manual has a really good step by step instructions on how to do it. You can download the Factory Manual from the manuals thread at the top of the home page here. You will need a tool to hold the valve shim buckets while changing the valve shims, and a torque wrench to do the job. The valve shim tool can be bought off ebay or from a Honda dealer for around $20.00. As for gaskets, there are sets on ebay. I recommend a seller named cruzinimage.
TOOLS  

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NAML

[rich]

Have you  checked  the valve clearances  yet? Over time the clearances  get tighter and the valves won't  close all  the way. Check them before you change the head. It's  covered in the manual and one of our members even has a video on here showing how to do it.

[jsancle]

Will definitely do that, thank you!

[jsancle]

Good morning, Tools. I am almost done with replacing the head I bought online. I also purchased piston rings and replaced those while I was down there. I do have a problem though. I can't get the cam chain on. I have read a lot of threads in which other people have come to the same problem. I loosened the cam chain tensioner and pulled it all the way up and tightened it down and it is still not enough slack. Is there a trick to it? I had someone help me for three hours last night with no result

[TOOLS1]

You loop the cam chain over the sprocket, and then slide the sprocket into place on the cam. It should go easy. If it does not, you need to double check that you have pulled up on the adjuster all the way. I have seen where people were trying to pull it up by grabbing the wrong part of it. You must be pulling up on the spring loaded part, not the whole tensioner itself.
TOOLS

[jsancle]

The adjuster spring is all the way up. I tried setting the chain on the sprocket and then sliding the cam in like the manual said to do, but it does not give enough space for the cam to go through.

On Feb 28, 2017, at 12:50 PM, TOOLS1 [via Vintage and Classic Honda's] <[hidden email]> wrote:

You loop the cam chain over the sprocket, and then slide the sprocket into place on the cam. It should go easy. If it does not, you need to double check that you have pulled up on the adjuster all the way. I have seen where people were trying to pull it up by grabbing the wrong part of it. You must be pulling up on the spring loaded part, not the whole tensioner itself.
TOOLS

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[TOOLS1]

You thread the cam through the sprocket and loose chain (off the sprocket) as you put the cam into the head. Then put the chain on the sprocket and slide the sprocket up into place on the cam. It will go, trust me.
TOOLS

[jsancle]

Wgat is it that I'm doing wrong?

[jsancle]

This is where I am right now

[TOOLS1]

Why do you have vise grips in there? Those do not belong there, and would just get in your way. You are supposed to pull the tensioner up, and then tighten the locking nut/bolt on the adjuster to hold it in place. Then after the engine is all together, loosen the lock nut/bolt on the adjuster, and then re-tighten it. Also, I told you to thread the cam through with the sprocket loose, and the chain off the sprocket.  
TOOLS

[jsancle]

I used the lock nut to lock the chain in place just like you said and was able to insert the cam, but I also found out that it had bent. I ordered one online for $36 and I arrives here this weekend, so i'll be able to work on it after Sunday. Thank you again, tools!

[TOOLS1]

YOU BENT THE CAM!!!!! How did you bend the cam? I have seen broken cams, but never a bent cam. If you bent it while trying to install it, you have damaged other parts as well. The cam chain for sure, who knows what else.
TOOLS

[shinyribs]

Engine parts have delicate, machined surfaces.

Engine parts fit the engine they are designed to fit.

No engine requires muscling the parts in to position.

If you are installing any part in to any engine and find yourself using brute force to install- stop!

Never force any part , ever. Ever, ever, ever. These things fit together perfectly, there's no need for force.

[jsancle]

When installed, it didn't sit right on the head. there was a gap. About 3mm on the side of the number 1 cylinder on 1-4 tdc. When on 2-3 tdc, the space was on the number 4 cylinder side 

On Mar 1, 2017, at 9:15 AM, TOOLS1 [via Vintage and Classic Honda's] <[hidden email]> wrote:

YOU BENT THE CAM!!!!! How did you bend the cam? I have seen broken cams, but never a bent cam. If you bent it while trying to install it, you have damaged other parts as well. The cam chain for sure, who knows what else.
TOOLS

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[TOOLS1]

The cam sits that way until you tighten the caps down. The valve springs on some of the valves need to be compressed by the cam lobes (opening the valves) on some of the cylinders. To check the cam to see if it is bent, you really need V blocks and a dial indicator.
TOOLS
 

[jsancle]

Oh okay well I guess I just have an extra cam now.... 

On Mar 1, 2017, at 1:08 PM, TOOLS1 [via Vintage and Classic Honda's] <[hidden email]> wrote:

The cam sits that way until you tighten the caps down. The valve springs on some of the valves need to be compressed by the cam lobes (opening the valves) on some of the cylinders. To check the cam to see if it is bent, you really need V blocks and a dial indicator.
TOOLS
 

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[TOOLS1]

I have a friend that takes old cams and welds short pieces of pipe to them to make handles. Then he has a great club to use on Zombies when the apocalypses happens.  
TOOLS

[jsancle]

This is where I am now ( I haven't been able to work on it at all because of class). Before I bolt everything down, I wanna make sure I have correct timing. Does this look right?