Ian's TX/CBR500A Yamahonda whatever

grcamna5 said:
Fell off the bench?

Haha, not quite. I just set the upper case on the ground because I ran out of bench space. The cardboard box is just where I kept all the covers and electronics while I was disassembling.
 
The head itself is in ok shape. Needs some serious cleaning, lots of carbon and surface corrosion from sitting. Valve cutters are WAY too much, so I'll be making some angled grinding tools at work on the lathe. I need to source a later model cam chain tensioner (adjustable) and I'll have to scrounge an exhaust valve from my 2 piece head to replace the one I broke when taking the 1 piece head apart (same part). Other than that, it takes an updated head gasket and I'll need to use the valve cover from the spare engine as well. Everything else is the same. It's a fairly common swap due to the cracking issue on the 2 piece, so the parts are somewhat readily available.
 
I had a blue 74' TX500A w/ the 2-piece head and did a full top end job on it back in 1991' and made sure to slowly torque the head to spec and did a couple re-torques after that and didn't have any issues over the 12,000 touring miles I put on it.I did run out of adjustment on my(lower) cam chain adjuster sprockets though.I sold the bike but really should have installed a fresh chain and sprockets before I sold it.They sure have plenty of mid-range power !
 
I haven't torn into the original engine yet, only the spare. It has the older style cam chain adjusters (either all in or all out, no in-between), and both the starter and counter-balance chains have a healthy amount of stretch (again, fixed tensioners for both chains, and both had more than comfortable amounts of play). I'll be looking for the later adjusters that were supposedly externally adjustable for those 2 chains, they're just a bit more rare than everything else.

On paper, these bikes put down a whopping 38-41 WHP and weighed in at 540 wet... I'm hoping to gain performance through judicious use of a cut-off wheel and aluminum, and (if budget allows) updating the CV carbs to a set of VM Mikunis and building a fully custom exhaust. Haven't had any forward progress on finding the later model hi-comp pistons though.
 
Not as bad as a 69 CB750... But still very hard to find. Most stuff has to be swapped out or upgraded to newer versions, or built from scratch.
 
So I got some time in the garage last night and today. Started tearing into the "good" engine. Got down to getting the pistons out and oil pump, cylinders and up are also off. I'll let the pics speak, I'm tired,

Also, one of the main reasons for tearing this apart was the belief that pretty much all of the early model engines, with 2 piece heads, have cracks in them from overheating... Mine didn't... It was actually cleaner than the 1 piece I'm putting in it's place :/

P.S. I found after pulling the valve cover that someone had done some "repairs" at some point, and replaced one of the valve spring adjustment screw with a machine screw... yes, you read that right; a machine screw... Ugh.
 

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as far as I can see from the pics it looks good except for the 'valve adj. machine screw'. You won't have to worry about the valve stem wearing on that one ::)
 
Honestly the inside is in great shape, other than it's a 2 piece head, and the intake cam lobe being trash. The crankshaft is getting swapped out to the heavier one (designed to reduce vibration even more than the balancer). The cam adjuster from the original engine is going into the 1 piece head, and the starter and balancer chain tensioners are being swapped in from the spare, as they have much more life left in them, and they're non-adjustable, so I'll take what I can get there. Now I'm just waiting on a clutch holding/removal tool and then I can finish cracking her open. Still waiting on Copper Gaskets to get back with me about a new set of case and head gaskets too.
 
The inner hub free spins with the nut that holds it on the shaft. You have to lock the inner spool in place and pop the nut loose. I could probably bust it loose the same way I did the spare's, but I'd worry I wouldn't get lucky twice and not break anything.
 
The (my Craftsman 19.2 vt.) impact w/ a fresh charge and holding it tight w/ a few thick rags from the top could work.
 
I can get a clutch holding tool for $17. I might have to wait a couple days for it to get here, but I'll have it whenever I need to work on the clutch in the future. Also, an electric impact is a lot more expensive than a clutch holding tool, lol.
 
Jewbacca said:
I can get a clutch holding tool for $17. I might have to wait a couple days for it to get here, but I'll have it whenever I need to work on the clutch in the future. Also, an electric impact is a lot more expensive than a clutch holding tool, lol.

You NEED and impact for so many other reasons, shit I have all three cordless impacts and use them all and then a corded electric that I use for car/truck lugs :eek:

This: has been the bad dawg in the box lately... powerful tool for decent money, I already had the charger from a kit on sale for the 1/4" and 3/8" impact for $149 and this was $119 to add on. so now 1/4 3/8 and 1/2 rigid stuff... bust loose or bust off anything.

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you can also use a breaker bar put gearbox in top gear(dont use low ) and make a holding tool with a flatbar welded to and old cs sprocket
 
Jewbacca said:
I can get a clutch holding tool for $17. I might have to wait a couple days for it to get here, but I'll have it whenever I need to work on the clutch in the future. Also, an electric impact is a lot more expensive than a clutch holding tool, lol.

That's a good deal for a clutch holder.
 
I've got air impacts, like 4 of them, but my compressor is in about as many pieces as my bike, and they usually stay at work. My clutch holder is slated to get here by next Monday. but if I get impatient and want to get it done this weekend, I'll probably make something at work to use for now, and when the tool gets here, well then, I'll have an actual tool for later use.
 
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