subt3rra
SUBT3RRA
looking for aftermarket coils. pretty sure mine are dead...
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chasing gremlins - engine/carb/??? issues
- Thread starter subt3rra
- Start date
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- Tags
- backfire missing fire
subt3rra
SUBT3RRA
I have been swapping plugs out to limp along until I can afford new coils. One fouled thsi morning and I did a quick change to keep going, When I kicked it over with a new lpug it was still running on one cylinder. Thought maybe I hadn't seated the plug cap, so instinctively I grabbed the plug boot - ZAP! got a good shock. So I know the coils not completely dead...
So now I am thinking, I have new plug cables, new plugs (back to stock - they work better longer, the 5k ohms ones didn't work well) still not enough spark, shocked myself on the boot.
There's not enough juice getting to the spark plug somehow, and it's finding another way to ground out. I don't think you're supposed to get shocked by touching the plug wire or boot when running (perhaps a bit isn't uncommon, but I don't think like that)...
Thoughts?
I am getting tired of riding my "XS200"... one lunger... coils soon, but wnat to be sure that's really it. I think it's part of it, but... ?
Thanks
So now I am thinking, I have new plug cables, new plugs (back to stock - they work better longer, the 5k ohms ones didn't work well) still not enough spark, shocked myself on the boot.
There's not enough juice getting to the spark plug somehow, and it's finding another way to ground out. I don't think you're supposed to get shocked by touching the plug wire or boot when running (perhaps a bit isn't uncommon, but I don't think like that)...
Thoughts?
I am getting tired of riding my "XS200"... one lunger... coils soon, but wnat to be sure that's really it. I think it's part of it, but... ?
Thanks
Okay, I am just jumping in, Is your fuel Petcock have a fresh tubing, that is not creating a air leak? I usually put a zip tie on both sides. You should be able to test for airleaks by spraying carb cleaner near the outside of your carb boots.
subt3rra
SUBT3RRA
Hey all
Update: I have been riding it for 2 months now with the same coils. I went to a salvage yard to source some, and the guy didn’t think it was the coils. Being low on funds I listened to him and gave fine tuning the jetting a try. It ran “better”, enough that I haven’t replaced them yet. Here’s what how it’s been running:
In cooler, kind of foggy morning weather it is more likely to miss and run on one cylinder, fouling a plug. I am at 1 3/8 turns out. 1 ¼ is too lean (won’t start) and 1 ½ is too rich (fouls plugs every time). On dry warm mornings it’s hit or miss, but by the time the bike warms up it runs OK (misses a bit but always on 2 cylinders once warm).
So it’s been like this for 2 months. I am hopefully getting coils today (salvage, but testing them first before buying) so I will update on any difference I find.
Cross fingers… Thanks
Update: I have been riding it for 2 months now with the same coils. I went to a salvage yard to source some, and the guy didn’t think it was the coils. Being low on funds I listened to him and gave fine tuning the jetting a try. It ran “better”, enough that I haven’t replaced them yet. Here’s what how it’s been running:
In cooler, kind of foggy morning weather it is more likely to miss and run on one cylinder, fouling a plug. I am at 1 3/8 turns out. 1 ¼ is too lean (won’t start) and 1 ½ is too rich (fouls plugs every time). On dry warm mornings it’s hit or miss, but by the time the bike warms up it runs OK (misses a bit but always on 2 cylinders once warm).
So it’s been like this for 2 months. I am hopefully getting coils today (salvage, but testing them first before buying) so I will update on any difference I find.
Cross fingers… Thanks
subt3rra
SUBT3RRA
FYI, tested compression, 160 on left, 170 on right (right is the one that is missing)... petcock is fine...
subt3rra
SUBT3RRA
OK, so I went to my local salvage yard (Bent Bike for those of you in Washington State, awesome place! ). I went there to get the coils and some baffles for my pipes (they are too loud for me, now that I have about 6 months riding with them ). I went in and asked for the coils I saw last time. Different guy and I had the same discussion I had last time I was there, and I told him I had messed with the jetting the best I could get it and I am fairly sure it’s the coils. I mentioned I need baffles too, and he asked why. I said it’s too loud, and I’m running pretty well open pipes.
Long story short, he said the back pressure may be too low, and therefore the bike can’t maintain enough pressure to burn the gas efficiently, hence the missing, running unevenly and fouled plugs. The coils should work fine even slightly out of spec. If the backpressure is too low it would not only run badly, even if the coils are perfect, but I could burn up the valves, even if the plugs are showing rich.
Well, since I wanted baffles anyway, and it seemed like this may kill two birds with one stone I bought the baffles and went home – put them in yesterday, and rejetted to a stock pilot and 140 main, just in case...
Runs perfect – wow.
I mean it hasn’t missed once, balanced carbs after valve tune, etc. Just perfect. I am still fine tuning it as the mixture is showing a bit lean at 1 ¾ turns out, but that’s about it. I think we are on the right track. However given my experience thus far, I will reserve final judgment once I get a few weeks down the road, but I think it was lack of back pressure the whole time.
What has me confused thought is how many people say they are running open pipes, and jetting up 1-2 sizes, and turning their carbs out 3 turns and such. Maybe it’s each bike is different, but I’m trying to learn here too. Could it be these guys are running on borrowed time? I mean my bike ran, not well but it ran. I just wonder how many of these bikes are slowly burning up because of open pipes and the wrong jetting... it took a while for my bike to show these symptoms...
Like I said, I’m learning. I hope to make this a hobby of mine, so the more info the better. I’d love to hear anyone else’s input, experience and feedback on this.
For the time begin I am glad to be close to finished with the tuning, and can now turn my attention back to the fun part –
and customizing...
Thanks
). I went there to get the coils and some baffles for my pipes (they are too loud for me, now that I have about 6 months riding with them ). I went in and asked for the coils I saw last time. Different guy and I had the same discussion I had last time I was there, and I told him I had messed with the jetting the best I could get it and I am fairly sure it’s the coils. I mentioned I need baffles too, and he asked why. I said it’s too loud, and I’m running pretty well open pipes. Long story short, he said the back pressure may be too low, and therefore the bike can’t maintain enough pressure to burn the gas efficiently, hence the missing, running unevenly and fouled plugs. The coils should work fine even slightly out of spec. If the backpressure is too low it would not only run badly, even if the coils are perfect, but I could burn up the valves, even if the plugs are showing rich.
Well, since I wanted baffles anyway, and it seemed like this may kill two birds with one stone I bought the baffles and went home – put them in yesterday, and rejetted to a stock pilot and 140 main, just in case...
Runs perfect – wow.
I mean it hasn’t missed once, balanced carbs after valve tune, etc. Just perfect. I am still fine tuning it as the mixture is showing a bit lean at 1 ¾ turns out, but that’s about it. I think we are on the right track. However given my experience thus far, I will reserve final judgment once I get a few weeks down the road, but I think it was lack of back pressure the whole time.
What has me confused thought is how many people say they are running open pipes, and jetting up 1-2 sizes, and turning their carbs out 3 turns and such. Maybe it’s each bike is different, but I’m trying to learn here too. Could it be these guys are running on borrowed time? I mean my bike ran, not well but it ran. I just wonder how many of these bikes are slowly burning up because of open pipes and the wrong jetting... it took a while for my bike to show these symptoms...
Like I said, I’m learning. I hope to make this a hobby of mine, so the more info the better. I’d love to hear anyone else’s input, experience and feedback on this.
For the time begin I am glad to be close to finished with the tuning, and can now turn my attention back to the fun part –
and customizing...Thanks
The 3 turns is a general this will get it running zone. When the Yamaha put this out on the market, the Specials anyways, they pluged the access to that screw, and had it at 1.5 turns, for smog reasons (epa or whatever) better pollution purposes. The jetting, I still haven't figured that out yet.
robbiecampbellsoup
XS400 Enthusiast
Hey - sorry for the naive question - when you're referring to "turns" in and out, are you referring to turns out of the idle mix screw, or of the actual jets? Is there individual adjustment on each jet that allows it to be 'leaned' or 'enriched' within a range around the "size"? What is the size by the way, is it an area of the hole, or a diameter or an arbitrary number? Does the next size up/down also cover a range of the previous jet via these adjustments?
I'm trying to figure out the steps I should take to get my '83 Maxim running a bit more smoothly, especially the throttle response around idle and below 2500 RPM. The power below 2500 and above 7000rpm also need to be improved.
I'm trying to figure out the steps I should take to get my '83 Maxim running a bit more smoothly, especially the throttle response around idle and below 2500 RPM. The power below 2500 and above 7000rpm also need to be improved.
Jets should be all the way in and snug. We are taking about the screws that are on the top of the carbs on the engine side facing forward. You still may have yours capped. There are threads on here on how to remove them. Turns out are for them from a lightly seated all the way in position. Put a mark on your screw driver so you know when you have made one full revolution.
