Haha, that story reminds me of the movie "Space Cowboys".
Hope you got more than a beer for that...
Hope you got more than a beer for that...
-
Enjoy XS650.com? Consider making a donation to help support the site.
XS650.com receives a small share of sales from some links on this page, but direct donations have a much greater impact on keeping this site going.
Well, sort of, lol. He let's me have free run of his bike boneyard out back and doesn't charge me much, if anything, for any little "goodies" I may find. Last trip out back netted me a couple XS500/400/360 clutch worms and bi-metal pushrods. The diameter of the pushrods is a bit too big but my buddy has got them at work now turning them down to 8mm for me. The other problem is they're about 10 or 12mm too short. I think I've got a solution for that though too - a new longer pressure plate pusher piece made from an old exhaust valve.
Bushes; turns out that 10k miles 79 had slop in the bushes, found she would wobble quite impressively after a bar shake at 75MPH replaced with an all balls needle kit and new tires. JP then rode that bike "briskly" for 500 miles at the Ozarks run, was fine as could be.
Talk to me before ordering an all balls needle kit, there are a couple of gotchas.
Talk to me before ordering an all balls needle kit, there are a couple of gotchas.
Great. Get, em while you can.
Interesting, exhaust valve 'pusher'. There's numerous 8mm stem auto valves with a flat backside profile...
Joe, what usually pops the carbies out of the boots is worn out advance unit weights. Wear on the tips of the weights makes the advance curve wider, idle timing gets set back to prevent timing from going into the piston-holing range at full advance, and the result is hard starting and backfire through the intake port. There are plenty of threads on repair methods, run a few searches and you'll find them.
All in all. I am having a blast fooling around with it. I've attached a photo so you can see the new Handlebars.
Beer and multimeter; perfect spring/summer combo.
View attachment 63339
Joe24
XS650 Enthusiast
Gentlemen!
I'm back. Work has been crazy busy, and I have not had much time for the bike besides riding it
Carb has stayed put since tightening the gear clamps. I've been riding a lot, and the bike has been performing well until recently.
Few problems:
1) newest quirk: flat spots. Usually only while accelerating in 1st and 2nd gear. The bikes engine power is lost for a second, noticeably, only to recover and continue as normal. This problem just popped up. I noticed a cut in the vacuum lines, fixed it, problem happening less now.
2) The vacuum lines have been poppong off at idle and when starting up. These are crappy plastic type, so ive bought some heat resistent vinyl type to replace them with. Ill also give the petcocks an insepction while i tske them apart. This may also help with problem 1
3) there has always been a minor problem of the the bike dying at idle, but as of the last week, it's gotten worse. If I keep the revs up, I can usually avoid it, but this too has become worse.
The idle continually drops, and the exhaust popping intensifies, until it pops the engine right off.
4) wrong type of spark plugs? Just took mine out and they are B8ES type, while my manual and xs650direct both state I should have BP7ES.
I also think im going to order the manual petcocks for this bike, which skip the vscuum stuff entirely. Thoughts?
Currently I have headers that have been cut short, with clamp on mufflers. I'm looking into new Stainless Headers and some mufflers that I can weld on to it, hopefully lowering backfire and popping.
Ugh, so much to learn. I'm thinking of taking a few days offf work and really getting into it. Maybe when i order up the new items.
Let me know what y'all think.
Gunna fire her up today and see if the flat spot problem has gone away with these new vacuum lines.
I'm back. Work has been crazy busy, and I have not had much time for the bike besides riding it
Carb has stayed put since tightening the gear clamps. I've been riding a lot, and the bike has been performing well until recently.
Few problems:
1) newest quirk: flat spots. Usually only while accelerating in 1st and 2nd gear. The bikes engine power is lost for a second, noticeably, only to recover and continue as normal. This problem just popped up. I noticed a cut in the vacuum lines, fixed it, problem happening less now.
2) The vacuum lines have been poppong off at idle and when starting up. These are crappy plastic type, so ive bought some heat resistent vinyl type to replace them with. Ill also give the petcocks an insepction while i tske them apart. This may also help with problem 1
3) there has always been a minor problem of the the bike dying at idle, but as of the last week, it's gotten worse. If I keep the revs up, I can usually avoid it, but this too has become worse.
The idle continually drops, and the exhaust popping intensifies, until it pops the engine right off.
4) wrong type of spark plugs? Just took mine out and they are B8ES type, while my manual and xs650direct both state I should have BP7ES.
I also think im going to order the manual petcocks for this bike, which skip the vscuum stuff entirely. Thoughts?
Currently I have headers that have been cut short, with clamp on mufflers. I'm looking into new Stainless Headers and some mufflers that I can weld on to it, hopefully lowering backfire and popping.
Ugh, so much to learn. I'm thinking of taking a few days offf work and really getting into it. Maybe when i order up the new items.
Let me know what y'all think.
Gunna fire her up today and see if the flat spot problem has gone away with these new vacuum lines.
Last edited:
Your petcocks are vacuum operated. Stop or reduce (because of a cut line) the vacuum flow to them and they stop flowing fuel. All your problems could be related to this. You may be intermittently running low on gas, or out of gas. The vacuum lines should have little spring clips on them to help hold them in place. The dropping idle and increasing popping could be a sign of running out of fuel. Popping is usually caused by running too lean, and running out of gas is about as lean as it gets, lol. Also, make sure your hot idle speed is set to 1100-1200 RPMs. If you set it too low, these bikes can just up and stall for no apparent reason at idle.
Yes, the B8ES plugs are the wrong ones. They were the spec when the bike came out for the first couple years but that was revised to the BP7ES. With the abundance of Jap cars around now, you should be able to get these NGK plugs right at an auto parts store. The same plug at a motorcycle shop will cost you near twice as much. Be sure to gap them. They come gapped too big, at like .035" to .040" for car use. Your bike ignition won't fire plug gaps that big. Gap them at .028". At the auto parts store, you may need to ask for them by their stock number (#1034), not as a BP7ES .....
Yes, the B8ES plugs are the wrong ones. They were the spec when the bike came out for the first couple years but that was revised to the BP7ES. With the abundance of Jap cars around now, you should be able to get these NGK plugs right at an auto parts store. The same plug at a motorcycle shop will cost you near twice as much. Be sure to gap them. They come gapped too big, at like .035" to .040" for car use. Your bike ignition won't fire plug gaps that big. Gap them at .028". At the auto parts store, you may need to ask for them by their stock number (#1034), not as a BP7ES .....
Joe24
XS650 Enthusiast
Right on! Thank you.
I'll check my hot idle, change these vacuum lines out, pickup some plugs, and report back!
I'll check my hot idle, change these vacuum lines out, pickup some plugs, and report back!
Joe24
XS650 Enthusiast
New vacuum lines held on, but the bikes idle problem is still very apparent.
The RPM while warm is around 1300. I'm constantly throttling it to keep things going.
I've noticed a clear correlation between the pop sound of the exhaust and an RPM drop while idling. Popping increase and rpm decrease together until bike usually dies out.
Sometimes with a large bang. Today that bang happened when I pulled over. The vacuum lines stayed put, bit the backfire was louder and shot the left carb off its mount.
Had to loosen and rettach the carb to the the gear clamp.
Only left side. So carb needs some tune up or synchronization. I've also noticed a discolouration becoming apparent on the left side header, while the right side has stayed fresh chrome.
Spark Plugs wernt on hand, so I'll have to look around or order from xs650direct.
The RPM while warm is around 1300. I'm constantly throttling it to keep things going.
I've noticed a clear correlation between the pop sound of the exhaust and an RPM drop while idling. Popping increase and rpm decrease together until bike usually dies out.
Sometimes with a large bang. Today that bang happened when I pulled over. The vacuum lines stayed put, bit the backfire was louder and shot the left carb off its mount.
Had to loosen and rettach the carb to the the gear clamp.
Only left side. So carb needs some tune up or synchronization. I've also noticed a discolouration becoming apparent on the left side header, while the right side has stayed fresh chrome.
Spark Plugs wernt on hand, so I'll have to look around or order from xs650direct.
Last edited:
You're running lean on that left cylinder, very lean from the sound of things. The original head pipes are double wall. They were constructed that way specifically so they wouldn't turn colors. You have to be pretty lean to make that happen. Your left carb could have some plugged passageways or jets, maybe the float setting is too low, something's starving it for fuel. I would also check the timing and points gap, valve settings, anything pertaining to that left cylinder.
Joe24
XS650 Enthusiast
Roger that!
I'll run through that list this week, and then I'll report back.
Got my trusty Ckymers Manual at hand.
Thank you.
I'll run through that list this week, and then I'll report back.
Got my trusty Ckymers Manual at hand.
Thank you.
Joe24
XS650 Enthusiast
Well, with my Clymers Manual and your PDf carb guide, I took the carb apart. Then I realized just how much I was in above my head! But, this is why I got the bike; to learn how to work on it myself.
So, yeah, took it all apart, check both jets, and everything seemed in good working order. I had no idea how to check float level,but they both seemed to be at the same level.
The only difference between the two was the idle mixture screw. The left, problematic carb, was 1 full turn more lean, so I matched it up. I read this is preset on 79 carbs, but after adjustment, cold idle seemed more stable.
I have attached some photos of the carburetor. To my amateur eyes, it seems in good working order.
Is there an agent I can spray inside to make sure it's clean? Do you have a recommendation?
So, it looks like I will have to learn about timing, point gaps, and valve settings.
Also, the only NGK type spark plugs I could find had an added R in the model name. Which stands for resistor. Recommended? People selling said it made a better, bigger spark. But I thought it better to just have the normal, spec'd spark plug.
Thanks again for all your help. I'm having a fun learning, though sometimes I would just like to be in the road! And, wishing I had more mechanical knowledge... In time I guess.
PS: the jets were 137.5, 30. Looked like new.
Also, are there fuel Strainers/filters? It seems the petcocks go straight to the carb. I'll do some more research on that subject today.
So, yeah, took it all apart, check both jets, and everything seemed in good working order. I had no idea how to check float level,but they both seemed to be at the same level.
The only difference between the two was the idle mixture screw. The left, problematic carb, was 1 full turn more lean, so I matched it up. I read this is preset on 79 carbs, but after adjustment, cold idle seemed more stable.
I have attached some photos of the carburetor. To my amateur eyes, it seems in good working order.
Is there an agent I can spray inside to make sure it's clean? Do you have a recommendation?
So, it looks like I will have to learn about timing, point gaps, and valve settings.
Also, the only NGK type spark plugs I could find had an added R in the model name. Which stands for resistor. Recommended? People selling said it made a better, bigger spark. But I thought it better to just have the normal, spec'd spark plug.
Thanks again for all your help. I'm having a fun learning, though sometimes I would just like to be in the road! And, wishing I had more mechanical knowledge... In time I guess.
PS: the jets were 137.5, 30. Looked like new.
Also, are there fuel Strainers/filters? It seems the petcocks go straight to the carb. I'll do some more research on that subject today.
Attachments
Joe24
XS650 Enthusiast
Hi Joe,
a pressurised can of Canadian Tire carb cleaner works good, put the stinger tube down every hole and push the button to see the cleaner squirt out the other end.
Consensus is that you should have resistor plugs OR resistor plug caps.
There is a combination reserve fuel level tube & filter atop your petcocks inside the fuel tank.
Mine fell out one time and lay on the bottom of the tank.
This is asymptomatic until you switch to reserve and find it has already been used so zero your odometer every fill-up and fill up again when the mileage number tells you.
a pressurised can of Canadian Tire carb cleaner works good, put the stinger tube down every hole and push the button to see the cleaner squirt out the other end.
Consensus is that you should have resistor plugs OR resistor plug caps.
There is a combination reserve fuel level tube & filter atop your petcocks inside the fuel tank.
Mine fell out one time and lay on the bottom of the tank.
This is asymptomatic until you switch to reserve and find it has already been used so zero your odometer every fill-up and fill up again when the mileage number tells you.
The jets you found are both one size larger than stock. That's good because with your mods, you will need bigger jets. I see from your latest pics you also have the UNI pods. The pilots are probably OK but eventually, you might want to try another size up on the mains (140). The mix screws setting for your carb set is 2 1/4 turns out. Start with that setting and fine tune from there. The '78-'79 carb set sometimes likes a bit more, like 2 1/2 to 2 5/8 turns out.
Many of us just use a 6" steel rule calibrated in MM on one side to measure our floats. The BS38s make this method pretty easy because the jets aren't mounted in between the two float "bulbs" like on most other carbs, obstructing the view. You measure off the gasket surface on the carb body, not the gasket. Place the rule on the far side and sight directly across the tops of both "bulbs". You must look straight across the tops, not from too low or high of an angle, or your reading will be off. Measure each float twice, once from each side. Many times the floats are twisted or tweaked on their mounting bracket and one side sits higher or lower than the other. Measuring from both sides is the only way you'll catch this.
The spec for your floats is 24mm +/- 1mm. The pic above is of an earlier set with a spec of 25mm.
Many of us just use a 6" steel rule calibrated in MM on one side to measure our floats. The BS38s make this method pretty easy because the jets aren't mounted in between the two float "bulbs" like on most other carbs, obstructing the view. You measure off the gasket surface on the carb body, not the gasket. Place the rule on the far side and sight directly across the tops of both "bulbs". You must look straight across the tops, not from too low or high of an angle, or your reading will be off. Measure each float twice, once from each side. Many times the floats are twisted or tweaked on their mounting bracket and one side sits higher or lower than the other. Measuring from both sides is the only way you'll catch this.
The spec for your floats is 24mm +/- 1mm. The pic above is of an earlier set with a spec of 25mm.
Joe24
XS650 Enthusiast
Who wants an update! Heh.
The bikes been out of commission, but thanks to the unwavering support of 5twins, progress was made. I thought I'd share the most recent event on here to spare him my constant PMs.
So far: Full clean and adjustment of carbs. Valves adjusted. Still to do: timing, points, carb sync.
The new problem arose after what was the best ride on the ol gal thus far. She finally idled with consistentcy. After the 40 minute ride I took a quick stop to grab something at the grocer, and upon start, a new sound and shakeyness arose.
Here's a video. Notice the backfires and loud pops of the left side of the engine.
https://goo.gl/photos/nKiUJ354QikmnX3s6
Essentially, the left side is not running well. It wants to cut out, and pops very aggressively, especially down gearing and idle.
Only obvious problems besides the above stated ToDo list are: idle mixture screws are missing their springs, but i checked and they were still at normal settings. Also, the left petcock was covered in grime, and looked wet as if leaking. I've attached a photo of the petcock.
I'm going remove the fuel lines and open the petcock to Prime and see if it's flowing. I purchased manual petcocks so I might have them installed and see if that circumvents this problem.
1 step forward 2 steps back since I started tinkering.
I'm thinking I should have waited for a 650 to pop up that hadn't been botched and was more well taken care of.
Flames and clamp on exhaust should have deterred me. This bike has not seen much love.
The bikes been out of commission, but thanks to the unwavering support of 5twins, progress was made. I thought I'd share the most recent event on here to spare him my constant PMs.
So far: Full clean and adjustment of carbs. Valves adjusted. Still to do: timing, points, carb sync.
The new problem arose after what was the best ride on the ol gal thus far. She finally idled with consistentcy. After the 40 minute ride I took a quick stop to grab something at the grocer, and upon start, a new sound and shakeyness arose.
Here's a video. Notice the backfires and loud pops of the left side of the engine.
https://goo.gl/photos/nKiUJ354QikmnX3s6
Essentially, the left side is not running well. It wants to cut out, and pops very aggressively, especially down gearing and idle.
Only obvious problems besides the above stated ToDo list are: idle mixture screws are missing their springs, but i checked and they were still at normal settings. Also, the left petcock was covered in grime, and looked wet as if leaking. I've attached a photo of the petcock.
I'm going remove the fuel lines and open the petcock to Prime and see if it's flowing. I purchased manual petcocks so I might have them installed and see if that circumvents this problem.
1 step forward 2 steps back since I started tinkering.
I'm thinking I should have waited for a 650 to pop up that hadn't been botched and was more well taken care of.
Flames and clamp on exhaust should have deterred me. This bike has not seen much love.
Attachments
Last edited:
Joe24
XS650 Enthusiast
Ugh, I am such an idiot. Well, that problem is solved and bikes back. Vacuum line popped off.
I'm installing manual petcocks this weekend so won't have that happen again.
Then, timing, points, new throttle and clutch cables, and a fresh oil change.
After that our problems should be limited to electrical:. Charging and lights.
Also, I was thinking of installing new fuel filters. I'll look today for some 90 degree angled ones. Any advice/recommendations on this topic?
Thanks again,5twins!
I'm installing manual petcocks this weekend so won't have that happen again.
Then, timing, points, new throttle and clutch cables, and a fresh oil change.
After that our problems should be limited to electrical:. Charging and lights.
Also, I was thinking of installing new fuel filters. I'll look today for some 90 degree angled ones. Any advice/recommendations on this topic?
Thanks again,5twins!
Don't forget to cap off those vacuum ports on your manifolds once you install the manual petcocks and remove the vacuum lines or you'll have two massive air leaks, lol.
These 7/32" (5.55mm) ones are the perfect size. Put some sort of spring clip on them to help hold them on or they can blow off if the bike backfires.
These 7/32" (5.55mm) ones are the perfect size. Put some sort of spring clip on them to help hold them on or they can blow off if the bike backfires.
