Why is it so "expensive" to build a Yamaha XS500??
- Thread starter SDmtnbkr
- Start date
Altekautomotive
New Member
So here are some issues I have run into trying to remake a 75 XS500. I had a 73 TX500 When they first came out and I worked in a Yamaha shop in High School. It had a head gasket leak shortly after I started using it. Turns out, the early engines have a 2 piece head where the Cam shafts have their own holder separate from the actual cylinder head. This resulted in severe head gasket and cam holder to head oil leaks. And because of high running temps ( air cooled high output twin) and insufficient aluminum support in the head, they tended to crack heads at the valve seats. Most were scrapped when the head was removed and a crack was found as it was just not worth fixing.
One really nice feature of the bike was smooth operation made possible by the omni phase balancer. Unfortunately, this required a chain on the left side to operate and it needed to be tightened every 2,000 miles. And there was a starter chain next to it.
So, you have 3 internal chains. The cam chain is the most reliable of the 3 as it is a duplex chain that is way over designed for the application.
They are also sensitive to ignition timing and it is easy to get the timing way off if you are not careful to follow the exact procedure when adjusting the points and ignition timing. Mine was bought at a low price because the right hand cylinder had a hole in it so no compression on the right side. That required a complete engine disassembly to clean out the aluminum chards from the hole in the piston crown.
New parts with the exception of pistons, rings ( I found a 2nd oversized set and bored the cylinder), and gaskets, are almost impossible to find and expensive leaving you to surf the internet world wide to find NOS rod and main bearings and new chains. You also need a special Cam chain cutter and riveting tool and a bolt for pulling the rotor. Other than that, no other special tools are needed.
And worst of all, it is highly likely that the head may be cracked. My 75 head was the 2 piece version and was cracked. I found a used 1 piece head on the internet and it was also cracked. Shuuman Motor works out of Milwaukee Oregon who rebuilds heads and makes valves, sold me a reconditioned 1 piece head from a '78 model ( more aluminum and greater structural integrity) but it has round vs oval exhaust ports meaning I will also need to find a set of different header pipes.
Having worked for several Yamaha shops and for Yamaha Motor Co US as a service Tech, I thought it would be no big deal to adapt the 78 head on my bike. But aside from needing new header pipes, the cam chain stopper between the cams is different, The right hand cylinder studs for the cam chain tunnel are different lengths. There are no less than 3 different head gaskets offered and good luck trying to figure out which one to use to eliminate oil leaks. In the end, I used a composition gasket with the 2 oil seals on the left side and used Copper Gasket Spray to seal it up along with the 2qty semi o-ring strips between the base gasket and cases and careful use of some high temp gasket maker to glue all of that in place as you wiggle the cylinder over the pistons and into position. . It's a complex engine to assemble having timing gears on the right side with a points cam, 2 cams to index with the crank, and then on the left side, the balancer that needs to be indexed to the crank. And to make it even more exciting, unlike the XS60 where the pistons go up and down together, this is a 270 degree set up so you have to have the crank in the proper position ( can't just wind it around 360 degrees) to line up the point cam gears along with the cam sprockets.
I have mine assembled but not started as I am painting the frame.
Had I known the hassles I would face, I would have passed and sourced an XS650 which vibrates more but is bullet proof and aftermarket support is almost as strong as with the SR500 which I also own. Stay away from the XJ series for lack of parts support I had on an XJ900 Seca that I just completely rebuilt. Other tempting but difficult bikes I think I would pass on would be the XZ550 Vision. I think that the SRX600 would be a solid pick but you may not like starting a big 4 stroke single and of course, if you want high fun, easy to work on, bullet proof reliability and don't mind a kick start only bike, look at the 78 to 81 Yamaha SR500. You can do a simple 535 piston, super trap exhaust and stock air box with a K&N and up the power dramatically. Go 1 tooth larger on the countershaft and you have a fun easy to ride bike with outstanding brakes, lean angle, gobs of low end torque and unparalleled fun factor! Parts support for this is unmatched as it was made from 78 to just a few years ago and there is a huge cult following and support. Check with Vintage Spoke and Mikes XS for parts on this low cost entry.
So there you go for the good, bad and ugly on the older Yamahas.
John
One really nice feature of the bike was smooth operation made possible by the omni phase balancer. Unfortunately, this required a chain on the left side to operate and it needed to be tightened every 2,000 miles. And there was a starter chain next to it.
So, you have 3 internal chains. The cam chain is the most reliable of the 3 as it is a duplex chain that is way over designed for the application.
They are also sensitive to ignition timing and it is easy to get the timing way off if you are not careful to follow the exact procedure when adjusting the points and ignition timing. Mine was bought at a low price because the right hand cylinder had a hole in it so no compression on the right side. That required a complete engine disassembly to clean out the aluminum chards from the hole in the piston crown.
New parts with the exception of pistons, rings ( I found a 2nd oversized set and bored the cylinder), and gaskets, are almost impossible to find and expensive leaving you to surf the internet world wide to find NOS rod and main bearings and new chains. You also need a special Cam chain cutter and riveting tool and a bolt for pulling the rotor. Other than that, no other special tools are needed.
And worst of all, it is highly likely that the head may be cracked. My 75 head was the 2 piece version and was cracked. I found a used 1 piece head on the internet and it was also cracked. Shuuman Motor works out of Milwaukee Oregon who rebuilds heads and makes valves, sold me a reconditioned 1 piece head from a '78 model ( more aluminum and greater structural integrity) but it has round vs oval exhaust ports meaning I will also need to find a set of different header pipes.
Having worked for several Yamaha shops and for Yamaha Motor Co US as a service Tech, I thought it would be no big deal to adapt the 78 head on my bike. But aside from needing new header pipes, the cam chain stopper between the cams is different, The right hand cylinder studs for the cam chain tunnel are different lengths. There are no less than 3 different head gaskets offered and good luck trying to figure out which one to use to eliminate oil leaks. In the end, I used a composition gasket with the 2 oil seals on the left side and used Copper Gasket Spray to seal it up along with the 2qty semi o-ring strips between the base gasket and cases and careful use of some high temp gasket maker to glue all of that in place as you wiggle the cylinder over the pistons and into position. . It's a complex engine to assemble having timing gears on the right side with a points cam, 2 cams to index with the crank, and then on the left side, the balancer that needs to be indexed to the crank. And to make it even more exciting, unlike the XS60 where the pistons go up and down together, this is a 270 degree set up so you have to have the crank in the proper position ( can't just wind it around 360 degrees) to line up the point cam gears along with the cam sprockets.
I have mine assembled but not started as I am painting the frame.
Had I known the hassles I would face, I would have passed and sourced an XS650 which vibrates more but is bullet proof and aftermarket support is almost as strong as with the SR500 which I also own. Stay away from the XJ series for lack of parts support I had on an XJ900 Seca that I just completely rebuilt. Other tempting but difficult bikes I think I would pass on would be the XZ550 Vision. I think that the SRX600 would be a solid pick but you may not like starting a big 4 stroke single and of course, if you want high fun, easy to work on, bullet proof reliability and don't mind a kick start only bike, look at the 78 to 81 Yamaha SR500. You can do a simple 535 piston, super trap exhaust and stock air box with a K&N and up the power dramatically. Go 1 tooth larger on the countershaft and you have a fun easy to ride bike with outstanding brakes, lean angle, gobs of low end torque and unparalleled fun factor! Parts support for this is unmatched as it was made from 78 to just a few years ago and there is a huge cult following and support. Check with Vintage Spoke and Mikes XS for parts on this low cost entry.
So there you go for the good, bad and ugly on the older Yamahas.
John
Untame
Been Around the Block
Thanks for the great and thorough write-up!
I'm leaning toward a XS750 triple for a cafe build. What is your take on that platform?
Altekautomotive
New Member
I like the xs750 triple although it is not immune from initial design issues. Plannn be on changing the primary drive chain and you need a 32mm deep socket to remove the clutch. I used to bore them to fit the XS1100 pistons but you could use CS850 pistons, rings and head gaskets. They respond well to a 3 into 1 exhaust if you can even find one today. I used to chick the valves in a drill press and polish them then do a hand lap to the seats. second gear wear was a problem but once you fixed that, they were pretty good running and dependable bikes. The later years had TCI vs points so that was a plus. Not sure of availability of main and rod bearing inserts but valve shins are the same as a Z1 Kawasaki. I would endorse one of these with an 850 overbore!
Untame
Been Around the Block
Thanks!
wfo speedracer
Been Around the Block
When I worked there Yamaha had more recalls on the XS500 and 750 between 73 and 78 than all other recalls they ever had combined , that was between 82 and 88 .
crazypj
Split personality, I fake being smart
The XS500 was over engineered with too much going on for the era.
It made it quite unreliable, my cousins husband had 5, one to ride and 4 for spare parts.
Even most basic parts are hard to find, oil filters haven't been made by Yamaha since the 80's
It's a motor full of innovation and very interesting but needed more development than it got.
Personally, the last time I had one in pieces was around 2004, got stuck looking for a cam chain rivet link which I believe are available now much easier than they were 20 years ago.
Second year XS750 triple was a good bike, don't get one with Hitachi carbs though or be prepared to swap them for Mikuni set
Edited, should have looked at date of OP, 2016, bit late with reply
It made it quite unreliable, my cousins husband had 5, one to ride and 4 for spare parts.
Even most basic parts are hard to find, oil filters haven't been made by Yamaha since the 80's
It's a motor full of innovation and very interesting but needed more development than it got.
Personally, the last time I had one in pieces was around 2004, got stuck looking for a cam chain rivet link which I believe are available now much easier than they were 20 years ago.
Second year XS750 triple was a good bike, don't get one with Hitachi carbs though or be prepared to swap them for Mikuni set
Edited, should have looked at date of OP, 2016, bit late with reply
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