First time rehab of a 1976ish basket case

Should I cut down front fender or leave it?

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Just another confirmation on the frame.
The bottom motor mount passes above the bottom frame rail, indicating a 74-on frame.
GreasyFrame.jpg

70-73 frame bottom mounts passed thru the bottom frame rails, the engine sets lower.
Frame-XS2.jpg

Frame pics of 74-on Standards and Specials.
Frame-Standard.jpg Frame-Special.jpg

It's possible that a crash repair may have required a new (unstamped) frame, but the serial number sounds like something cooked-up, somewhere...
 
TwoManyXS1Bs said:
Just another confirmation on the frame.
The bottom motor mount passes above the bottom frame rail, indicating a 74-on frame.
View attachment 127211

70-73 frame bottom mounts passed thru the bottom frame rails, the engine sets lower.
View attachment 127212

Frame pics of 74-on Standards and Specials.
View attachment 127213 View attachment 127214

It's possible that a crash repair may have required a new (unstamped) frame, but the serial number sounds like something cooked-up, somewhere...
Click to expand...
Good morning all, twomany thanks for the frame images. Between the downtubes, frame mounts, and side stand mount (post mount) it's definitely a 77-on, and the engine is from a 79 standard as per the cereal number (it's breakfast time) that should be enough to run with for now. This afternoon carbs come off and images aplenty will follow
 
Yes, I.D.ing the year of the carb set is important. These carbs are jetted or re-jetted for mods based on the year of the carb set, not the year of the motor or bike. All we can tell from the pics you've posted so far is that you have a later set ('76-'79) because they are bolted together as a "bank" and use a single throttle cable. Narrowing it down further will require a closer inspection. Here's a chart listing the stock jetting and settings for the various carb sets used. As you can see, there were many changes over the years .....

7wbHkpb.jpg
 
5twins said:
Yes, I.D.ing the year of the carb set is important. These carbs are jetted or re-jetted for mods based on the year of the carb set, not the year of the motor or bike. All we can tell from the pics you've posted so far is that you have a later set ('76-'79) because they are bolted together as a "bank" and use a single throttle cable. Narrowing it down further will require a closer inspection. Here's a chart listing the stock jetting and settings for the various carb sets used. As you can see, there were many changes over the years .....

7wbHkpb.jpg
Click to expand...
Thanks 5t, I dont believe they'll have stock jetting, seeing as they are being run with cone filters and straight pipes and the bike still seems to be running rich, but I'll post a pile of photographs and try to do some legwork on my own in terms of ID'ing based on what I unearth! Stay tuned, my work day ends in 30 minutes.. morning shifts aren't all bad
 
Oh and a quick heads up to anyone following along, I posted a clip of the first kick over fresh off of the trailer, and a few low rpm throttle blips in my album
 
That doesn't sound like it's running too bad. When you get the carbs apart, write down all the jet sizes you find for future reference. You should also check needle jet size and needle number, along with the needle clip setting. Changing the needle clip position is usually required when you start increasing the main jet size on these carbs. It has it's main effect in the upper midrange, say in the 4K range, which your video didn't get into.
 
5twins said:
That doesn't sound like it's running too bad. When you get the carbs apart, write down all the jet sizes you find for future reference. You should also check needle jet size and needle number, along with the needle clip setting. Changing the needle clip position is usually required when you start increasing the main jet size on these carbs. It has it's main effect in the upper midrange, say in the 4K range, which your video didn't get into.
Click to expand...
it felt very sluggish in the low to mid rom range, and then pushed me into the backseat at the snap of a finger (or twist of the wrist) in the higher rpm range, pretty squirly with clapped out suspension on these twisty baxkroads, so I'll be attempting to remedy that via proper jetting. One thing at a time though.. lizard brain is currently smoking thru ears
 
LiveSlowDieWhenever said:
it felt very sluggish in the low to mid rom range, and then pushed me into the backseat at the snap of a finger (or twist of the wrist) in the higher rpm range, pretty squirly with clapped out suspension on these twisty baxkroads, so I'll be attempting to remedy that via proper jetting. One thing at a time though.. lizard brain is currently smoking thru ears
Click to expand...

Hi greasy,
Gawd! I go away for Canadian Thanksgiving Day and you post four pages?
The XS650 carbs crud up for a pastime and the lower range cruds up the worst.
I'd suggest you thoroughly clean those carbs, especially their enrichening circuits and slow running needles
and road test again before swapping jets around.
Check your swingarm pivot bearing as well as your shocks for that dodgy back end.
And if the traffic Nazis ask, it's exactly the bike that's defined in the documentation.
Like our family's axe is the same one we've had for the last century even if we did replace the head twice and the handle five times.
 
fredintoon said:
Hi greasy,
Gawd! I go away for Canadian Thanksgiving Day and you post four pages?
The XS650 carbs crud up for a pastime and the lower range cruds up the worst.
I'd suggest you thoroughly clean those carbs, especially their enrichening circuits and slow running needles
and road test again before swapping jets around.
Check your swingarm pivot bearing as well as your shocks for that dodgy back end.
And if the traffic Nazis ask, it's exactly the bike that's defined in the documentation.
Like our family's axe is the same one we've had for the last century even if we did replace the head twice and the handle five times.
Click to expand...
The mystery machine has generated a lot of interest! Haha thanks for dropping in. Swing arm feels solid, with all of the crazy stuff this bikes been thru I'm not surprised the bushings been replaced, but the p/o ran it for 7 years and 5kish miles while only ever changing oil so carbs are gonna be a sludgy mess of lacquered passageways I'm sure! Just heading home now pics soon to come
 
IMG_3455.JPG
Ignorant to a process? Start with a clean workspace!!
IMG_3458.JPG
Gunk levels aren't as high as anticipated, but still plenty of work to be done. Brass floats are beautiful!
IMG_3459.JPG
IMG_3457.JPG
Left side float gasket appears to have been punctured/crushed through as apposed to a clean hole..
 
I think it was put on upside down. The hole on the right side should be fitting over that overflow pipe. You have a '76-'77 carb set there. The "tells" are the 2 round holes along the sides of the intake bells ('78-'79 carb set has 4) and that overflow pipe in the bowl, along with a drain nipple for it on the bottom of the bowl.
 
IMG_3460.JPG
Main nozzles are missing their o-rings
IMG_3463.JPG
pilot jet reads 25
IMG_3465.JPG
main jet reads 122.5

Needle reads 4m1 with clip in 3rd position.
All jets are stamped with mikuni logo. If this is factory jetting it's conclusive with a set of carbs for a '76/77
 
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5twins said:
I think it was put on upside down. The hole on the right side should be fitting over that overflow pipe. You have a '76-'77 carb set there. The "tells" are the 2 round holes along the sides of the intake bells ('78-'79 carb set has 4) and that overflow pipe in the bowl, along with a drain nipple for it on the bottom of the bowl.
Click to expand...
You guys both responded at the same time with the answer I was writing while I was writing it.. something, something, great minds
gggGary said:
Gasket put on backwards?" they have a left and right side.
Later carbs don't have those overflow tubes.
Click to expand...
That's what it's looking light. Might explain leakage from left side. Gaskets will be gettin replaced and full unit deep cleaned since there's no rush to get them back on. You guys think it makes sense to replace jets while I'm at it? They don't look to be in bad shape but I understand looks can be deceiving with jets
 
Any recommendations on a good compound to soak components in? I'm gonna hit them hard with carb cleaner but figure if I've got time why not really make sure the passages are flowing wide open?
 
JimD54 said:
I used this stuff. Worked pretty good. Any auto part place should carry it.

View attachment 127253

You can see how they turned out here.
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Man that's an intensive write up with some fantastic results. I'll be making a pit stop tomorrow after work for some of that gunk, might try pine sol too as I've seen some promising results with it
 
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