Big TX500 project, any help appreciated!

Most of the problems were from overheating IIRC. I don’t know if that was because of riding them hard but I suspect it may have something to do with it.
 
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Most of the problems were from overheating IIRC. I don’t know if that was because of riding them hard but I suspect it may have something to do with it.
Sure you're not thinking about the TX750? They had a funky exhaust "balance tube" thingy across the exhaust ports, which no doubt caused hotter running. And the balancers on the 750 whipped the oil into a froth, which didn' t help either.
There was a couple of maybe -78 XS500 in town, and I never heard about any major problems.
 
Here’s my game plan:
Going to do a dry fit… will assemble carbs( carbs have already been rebuilt- will see)
New battery of course
Check points
Connect auxiliary gas
Fire her up
Hopefully no issues… then teardown and begin restoration
I have some vacation days coming up so …..
 
There's a link on this site somewhere to an ADV Rider thread where a bunch of young guys set out on a cross country trip on a bunch of dirt cheap old UJMs, one of which is a Yammie 500. As far as I recall, the cylinder head cracks do not pose any operational issues.
 
There's a link on this site somewhere to an ADV Rider thread where a bunch of young guys set out on a cross country trip on a bunch of dirt cheap old UJMs, one of which is a Yammie 500. As far as I recall, the cylinder head cracks do not pose any operational issues.
I remember reading that! It was a great story. The engine on the 500 top end was torn down and reassembled on the road.
 
My shop is full of bikes now. No room. Just lowered one of my goldwing builds to a ridiculously low number. Should get some nibbles on it now :)
 
Here we go:

https://www.advrider.com/f/threads/cross-country-on-a-50-bike-ny-sf-and-back.366117/

Post #75. Bike loses compression. Cracked head is found. Culprit is actually coked valve that won't shut properly. Crest toothpaste for an on the road valve lap. Back to touring..

Lifetime memories made on that trip, no doubt. A 76 XS500 and 73 TX500 in that group.

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Getting awful nostalgic for these old 70s bikes as I get older. I was in damn elementary school when this was built.
 
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I really want to keep this bike as original as possible but I’ve been down the road ( not literally :) ) with stock carbs and might not want to fight that again!
Here is a plan D if carbs don’t work out. Done this many times with Goldwings…. Will see.
 

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The Mikuni CV carbs fitted to the '76 and later 500s are actually quite good, basically the same carb that was fitted to the '76-'77 650s .....

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In fact, I adapted the above set for 650 use and they work well .....

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Currently building single carb manifold. Have no idea if it will work, therefore just using pvc for now. Pics later.
Had my first encounter with a very rude buyer yesterday for one of my goldwings. Nitpicked every inch of the 40 yr old bike … anyway…. I sent him on his way :)
 
Currently building single carb manifold. Have no idea if it will work, therefore just using pvc for now. Pics later.
Had my first encounter with a very rude buyer yesterday for one of my goldwings. Nitpicked every inch of the 40 yr old bike … anyway…. I sent him on his way :)
A single carb on a 180 degre crankshaft twin may cause issues with uneven carburation, due to the 180/ 540 degree spacing of intake events. I read that Norton struggled with this on their P86 Cosworth Challenge prototype racer development into a street bike in the 70s.
 
A single carb on a 180 degre crankshaft twin may cause issues with uneven carburation, due to the 180/ 540 degree spacing of intake events. I read that Norton struggled with this on their P86 Cosworth Challenge prototype racer development into a street bike in the 70s.
Noted…. I will probably end up buying the carb kit( $400) after jumping through all the hoops.
 
What’s wrong with the set you have IIRC those were 32mm? Step one is evaluation of what you have and what you will need. Don’t go down a rabbit hole before you even know if what you have will run.
I hear you. I just installed a new battery and starter switch. Good news …. Starter works.
The stock carbs we’re supposedly rebuilt by the po but I’m not sure I’m trusting that. The quick single carb route is cheap and easy and should be able to hopefully assess the health of the engine off of that. Will go from there.
 
The stock carbs we’re supposedly rebuilt by the po but I’m not sure I’m trusting that.
If the PO says they're rebuilt, why not give 'em a shot? Nothing to lose 'cept a small gas puddle on the ground. Seems to me that would be the quickest route. Pour some gas in 'em and hit the starter.
 
Hallelujah!!! Bike is running! I have lots of tuning to do but she’s alive!! Tons of rust came out of exhaust!! Had to leave throttle partly open for her to stay running but engine sounds really strong. No leaks from stock carbs. Will still need to check the points but at least she’s running. Great feeling!!
 

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