-
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.
22's 1980 xs650 build thread
- Thread starter Twenty2
- Start date
Okay just getting back to this after a busy Thanksgiving weekend. My apologies for the confusion, I'm pretty good mechanically but definitely mess up terminology at times, either way I think I have it figured out but just to summarize:
Bike off: 12.65v at battery
Bike (key) on: 12.2v at battery, 11.9v at ignition switch (this is where I reference the .3v drop)
Engine at idle: 13.2v at battery, 13.2v at ignition switch
Engine at 3,500 rpm: 14.5v at battery, 14.5v at ignition switch
At this point it I'm going to assume there is nothing wrong with the charging and hopefully cleaning my ignition switch will fix the .3v difference between battery and ignition switch when the key is on, but not started.
As always, thanks for the help and here's to a few more weeks of riding before the weather turns. Luckily I have a pretty healthy winter to-do list to keep me busy..
Bike off: 12.65v at battery
Bike (key) on: 12.2v at battery, 11.9v at ignition switch (this is where I reference the .3v drop)
Engine at idle: 13.2v at battery, 13.2v at ignition switch
Engine at 3,500 rpm: 14.5v at battery, 14.5v at ignition switch
At this point it I'm going to assume there is nothing wrong with the charging and hopefully cleaning my ignition switch will fix the .3v difference between battery and ignition switch when the key is on, but not started.
As always, thanks for the help and here's to a few more weeks of riding before the weather turns. Luckily I have a pretty healthy winter to-do list to keep me busy..
The bikes been great, I've ridden it only a handful of times, about 300kms but it's been great. Today
I took it out and pushed it more then I have in the past. I'm not sure if I had even gone WOT in 5th yet so today I did to give it a good test. At WOT around 4000rpm or just under there seems to be a stumble or two, I'm not sure if stumble is the correct word but it was almost like it lost fuel for half a second. It was pretty minor and I can say for sure that it even happened every time but I noticed it in 4th and 5th gear WOT around 4000rpm. Stock jetting aside from a 135 main jet (not genuine mikuni). Stock air filter with commando mufflers. Any thoughts as to what my first steps should be?
I took it out and pushed it more then I have in the past. I'm not sure if I had even gone WOT in 5th yet so today I did to give it a good test. At WOT around 4000rpm or just under there seems to be a stumble or two, I'm not sure if stumble is the correct word but it was almost like it lost fuel for half a second. It was pretty minor and I can say for sure that it even happened every time but I noticed it in 4th and 5th gear WOT around 4000rpm. Stock jetting aside from a 135 main jet (not genuine mikuni). Stock air filter with commando mufflers. Any thoughts as to what my first steps should be?
132.5 is stock for the BS34. It's written here that it was too lean even for a stock bike.
My 80SG is running the commando's and pod filters. It's at 137.5 (2 up) on the main and 45 (1 up) on the pilot. I'm thinkin' that would be a good starting point for your bike.
Fwiw... I stick to genuine Mikuni. I don't trust the Chinese repops.
No, the mix screw only plays into idle and slightly above.
When you're at WOT, your on the mains. Running it as is shouldn't hurt as long as you don't run for extended periods in your trouble zone.
I'm hoping to finish my exhaust upgrade over the winter, for now I've been using the stock headers and the 1.5" commando mufflers but the connection uses two exhaust adapters and the line between header and muffler isn't exactly straight. I would have liked to buy the 1.5" headers from mikesxs (07-0757) that it seems like a lot of other people use but the exchange rate and shipping to Canada isn't ideal and unfortunately 650direct in Canada doesn't carry those headers for some reason but they do carry a different 1.5" header - 07-14612. Does anyone have any experience with these headers? I've attached a photo for reference.
Attachments
Hey guys, beauty day out today and went to take advantage of it and the bike ran horribly. The bike has been mint since I got it running but all of a sudden today it was all over the map. The bike quit on me less then a mile from home, I realized I forgot to turn the choke off and thought that was all it was cause the bike seemed to start fine and idled fine while warming. But as soon as I turned the choke off and got riding again something was clearly wrong, if I gave it to much gas it wouldn't respond and it wouldn't hold an idle. In neutral the idle would all of a sudden rise to 4000rpm and just hold there, sometimes it would come down sometime I'd kill the bike or turn the choke on which would lower the rpms and eventually kill the bike... I'm assuming this is an air leak somewhere? I haven't sprayed anything yet to see if the idle increases but thought I'd ask if this sounds like an air leak to you all. The carb boots are new Tourmax/ARS brand and like I said everything was great last time I rode it. My other thought is maybe the gas cap seal? It's pretty cracked and I read it could mess things up? Also the bike was backfiring a lot which typically it hasn't done.
Any direction would be great.
Any direction would be great.
leaky gas cap isn't the problem.
How do the plugs look?
How do the plugs look?
Bruno_c
XS650 Enthusiast
I would first try to understand which cylinder is faulty or both. Remove the plug caps alternatively and see what happens.
I'm thinking you may have just badly fouled the plugs from running with the choke on until it died. First thing I'd do is clean them or better yet, replace them, for now. If that clears things up, you could probably save those old plugs with a thorough cleaning and then a good run to really finish the cleaning process. But, how many miles are on them? If 3K or more, I'd just replace them. I like to replace mine every 3 to 4K miles. By then, they're usually starting to show some wear and the bike always runs better after I swap them out. I find this old engine design to be pretty tough on plugs, wearing them out pretty quickly. It's only like $5 to replace them so I consider it cheap insurance to keep the bike running it's best.
Time to start the winter to-do list but being in Canada makes it harder to find parts, has any Canadians used Partzilla or Part Shark? I'd like to purchase new idle mix screws, I can get them from the dealer but they are the same price as Partzilla and with Partzilla they show up to my front door but this is assuming there are not any extra duties or taxes charged when they cross the border. So I'm wondering if the part + shipping will be my only fee when ordering from these sites or will I get dinged with other fees along the way?
Thanks.
Thanks.
If you're going to do it, I'd go with Part Shark. Every part I've price compared has been cheaper from them, sometimes by quite a bit. For instance, I just got new BS34 plastic floats from them. They were about $27 each from Partzilla, only around $20 from Part Shark. I saved like $14 and that more than covered shipping.
Look fluffy, not oily, feel oily? Clean with a torch, run it again, see what they look like. Nice to have a spare set or do a plug chop out on the road see what they look like there.
Yeah, I noticed that too, will definitely use Part Shark over Partzilla.
I put in some new plugs and all is well, I fouled them by leaving the choke on to long, this riding season I might consider a plug chop but i'll need to decide whether I want to put my Uni pods on or not first, either way a spare set of plugs will now accompany me wherever I go, once I find a suitable fork bag.
My next project is to either rebuild the forks (new seals and oil) or just new oil. There doesn't appear to be any oil leaking from the seals when I push down on the bars but that could also be because the fork oil is from 1980 and not there anymore haha. Should I go ahead and replace the fork seals because they are likely 40+ yrs old even if they could be sealing just fine? The reason I hesitate with this is because I don't have quick access to welder to build the tool I would need to take the forks apart to replace the seal. Without having that tool and reading about some of the horror stories about removing the seal the full fork rebuild is intimidating me a bit...
I don't replace a seal unless it's leaking. On my '78, I replaced one years ago when I renovated the bike. To this day, I'm still running with one original and one new replacement. Sometimes minor leaks are simply dirt in the seal. Clean it out and many times that will fix it. That being said, it's a good idea to take the forks apart just to thoroughly clean them. Forks don't get hot in operation like a motor so the sludge build-up in the bottom doesn't get broken free, mixed with the oil, and drained out. You literally have to scrub the insides clean, swab them out to get all the gunk out.
You can buy a nice little Allen socket for disassembling the forks. It's a 17mm Allen socket made for VW drain bolts. Jetmechmarty recently talked about this. He bought a Snap-On but there are cheaper ones available .....
https://www.amazon.com/dp/B003LIX22G?psc=1&ref=ppx_yo2_dt_b_product_details
The key to this working is it's small diameter, small enough to fit down inside the fork tube. I have a rather large 1/2" drive 17mm Allen socket that doesn't work. It's O.D. is too big to fit into the fork.
You can buy a nice little Allen socket for disassembling the forks. It's a 17mm Allen socket made for VW drain bolts. Jetmechmarty recently talked about this. He bought a Snap-On but there are cheaper ones available .....
https://www.amazon.com/dp/B003LIX22G?psc=1&ref=ppx_yo2_dt_b_product_details
The key to this working is it's small diameter, small enough to fit down inside the fork tube. I have a rather large 1/2" drive 17mm Allen socket that doesn't work. It's O.D. is too big to fit into the fork.
This and a 20 inch extension. And....
I believe this covers 1977 and up forks.
I just serviced mine and discovered the springs were sacked, so they got new springs, copper washers, seals and oil. The oil should be replaced often, like every third engine oil change.
Another thing is the Factory Service Manual says 44.5 ft lbs on the damper rod bolt. I believe that should be 14.5 ft lbs.I don't replace a seal unless it's leaking. On my '78, I replaced one years ago when I renovated the bike. To this day, I'm still running with one original and one new replacement. Sometimes minor leaks are simply dirt in the seal. Clean it out and many times that will fix it. That being said, it's a good idea to take the forks apart just to thoroughly clean them. Forks don't get hot in operation like a motor so the sludge build-up in the bottom doesn't get broken free, mixed with the oil, and drained out. You literally have to scrub the insides clean, swab them out to get all the gunk out.
You can buy a nice little Allen socket for disassembling the forks. It's a 17mm Allen socket made for VW drain bolts. Jetmechmarty recently talked about this. He bought a Snap-On but there are cheaper ones available .....
https://www.amazon.com/dp/B003LIX22G?psc=1&ref=ppx_yo2_dt_b_product_details
The key to this working is it's small diameter, small enough to fit down inside the fork tube. I have a rather large 1/2" drive 17mm Allen socket that doesn't work. It's O.D. is too big to fit into the fork.
