chasing gremlins - engine/carb/??? issues

Ok couple days later still running rich at 1 1/2 turns. Fewer turns started to stutter but still showing rich. I was only one size up on pilots, so I decided to go back down one size. I figured my newly freed pilot screws will give me more adjustment.

So far so good at 4 turns. Seems like a lot. So question: how many turns is too many? Where do you start to run the risk of the screw coming loose? I'll run it tomorrow and see how she does. .. thx
 
Glad to see your getting it fixed.
but if you want to set you pilot adjustment in some you can take the stock jets and with some patience you can adjust the size. with a small metal twist drill bit, find one that is just a bit bigger than the stock jet and drill "STRAIGHT". using an air drill is what i have always found easier to use. if your not confident use and extra set of jets, or if a jet is to large it can be resized by soldering the hole closed and then drilling to the correct size.
may not really apply to your situation.
P.S. Sheet metal twist drills are best suited for this as they have a larger cuting angle and tend not to walk as much, not at all with practice.
 
I may need to do something like slightly larger pilot than stock, but smaller than next size up...

I checked plugs last night, they look like they are a bit lean, not as bad as before though.

So here are some things I have noticed as I have been working on it these past few days:

* With the 145 pilot it ran rich, even at 1 turn out
* With the 142.5 pilot it is running lean, but not too bad at 4 turns. Sounds like 4 1/2 turns might be bad. For my education why is that? What could happen aside from the screw coming out?
* I checked spark, which is tough to do when you only have a kick start and no one to help; there is spark but it looks weak. Again, with no one to help not sure if I'm getting the best ground either with one hand and 2 spark plugs to deal with...

If the spark is weak, and I have suspected that off and on for a while, then that would explain why it's running rich at 1 turn it on 145's. But obviously the spark is strong enough to burn gas with the 142.5's.

I also still have the larger mains in there (2 sizes up from what I had at 142.5)... could this have something not do with it? Feels like no, but at this point I don’t know...

The bike is running great - best ever. I am tempted to run it for a while and keep checking the plugs. Maybe it just runs a bit lean... :shrug:

Love some feedback on this. Like I said running great otherwise...

Thanks
 
This is how the plugs should be. The only good way to check engine temps is with a IR temp gun. If the bike starts easy and can run up to the red line with no stumbles you should be good. Turning the mix screw past 4 turns the needle tip is out of it's metering hole and will not function proper.
 

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Thanks xschris - I currently don't have a tach unfortunately, so no real way to check that, but it doesn't stumble as high as I have rev'd it. Also, no IR gun. What temp is considered acceptable, when is it too high?

Bike starts easy, idles great... first time ever :)

Not sure if you were attaching a picture of a plug or not, but no attachment. either way I know light brown I believe s the goal. there's a pic in the manual and several on the forum. Let me know if your pic shows otherwise.

And thanks as always for the help...
 
Sorry :doh: the pic. On my stock 79 xs400 at the head on the exhaust side of the plug I get 270-285*f and the plug look like the one in the pic.
 

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What size are you "pilots?"
they should be small about 40-50 right.
142.5-145 are mains aren't they.

I may need to do something like slightly larger pilot than stock, but smaller than next size up...

I checked plugs last night, they look like they are a bit lean, not as bad as before though.

So here are some things I have noticed as I have been working on it these past few days:

* With the 145 pilot it ran rich, even at 1 turn out
* With the 142.5 pilot it is running lean, but not too bad at 4 turns. Sounds like 4 1/2 turns might be bad. For my education why is that? What could happen aside from the screw coming out?
* I checked spark, which is tough to do when you only have a kick start and no one to help; there is spark but it looks weak. Again, with no one to help not sure if I'm getting the best ground either with one hand and 2 spark plugs to deal with...

If the spark is weak, and I have suspected that off and on for a while, then that would explain why it's running rich at 1 turn it on 145's. But obviously the spark is strong enough to burn gas with the 142.5's.

I also still have the larger mains in there (2 sizes up from what I had at 142.5)... could this have something not do with it? Feels like no, but at this point I don’t know...

The bike is running great - best ever. I am tempted to run it for a while and keep checking the plugs. Maybe it just runs a bit lean... :shrug:

Love some feedback on this. Like I said running great otherwise...

Thanks
 
your are stating it is rich at idle? or in to the throttle?
idle right..
next question are the pilots pressed in or screw? not sure what you have. honda has a pressed pilot in a few years.
are you sure the complete idle circuit is free and clear. seems you may have an issue.
have you seen a pilot jet between 42.5-45?
also did you remove the butterflies? did you set them back correctly. not binding.

are the plugs black when its rich.

Side thought: did you set the vavle hot or cold? does your manual specify??

ps. if it rich on throttle did you shim your needle? change? if changed is it the same length as the stocker.
 
See inline below

your are stating it is rich at idle? or in to the throttle?
idle right.. Don’t know – I am checking the plugs and they are black with soot with the 45 pilots. How do you check if it is rich on idle or throttle?

next question are the pilots pressed in or screw? Screw in

not sure what you have. honda has a pressed pilot in a few years.
are you sure the complete idle circuit is free and clear. seems you may have an issue. Bike idles fine, carbs have been thoroughly cleaned, everything good

have you seen a pilot jet between 42.5-45? No

also did you remove the butterflies? did you set them back correctly. not binding. Did not remove butterflies. Carbs have been sync’d with the bike hot

are the plugs black when its rich. Yup

Side thought: did you set the vavle hot or cold? Valves set cold, that is what I was told to do does your manual specify?? Cold I believe, not looking at it right now

ps. if it rich on throttle did you shim your needle? change? if changed is it the same length as the stocker my needle is not adjustable…

Thanks
 
sync the carbs as best as possible first. Then if you have to go four turns out on the pilot screws the the adjustable needles need to be raised one step then go back to the 1 and 1/2 turn starting point on the pilots. The pilot jets should go up one size when the needle clip position cant be raised anymore. Then you can start from the middle position again, and raise or lower to taste depending if you have to go over 4 turns out or less than 1&1/4 turns in. As far as I know needles that do not have the 5 adjustable clip positions can still be shimmed and raised to compensate for the slight variation between the pilot screw adjustment and actual pilot jet size. Your carb may not have them on there but my jet kit came with some shims incase my needle clip position was not the adjustable type. ... :shrug: technically they are all adjustable
 
Thanks - I may try this on the weekend if I am still stuck.

I still think I have coil issues - this morning it just decided to run on one cylinder, basically for the whole way to work, about 5 miles. There is gas getting in there for sure, but my right cylinder just didn’t pop one time. I saw weak spark on both when I checked last weekend...

I've tried many different combos of jetting from a bit lean to a bit rich, and I've had it running great several times. It only starts to run bad randomly, and it's always the same story whether rich or lean: one cylinder either fires weak or not at all. I think I know the jetting that would be ideal, as I said I’ve had it running great for 3 days in a row no problems, then crud and fouled plugs and no love out of the blue…

If the spark is weak and getting weaker, wouldn’t it run well then eventually show rich and foul the plugs? Stands to reason… but I don’t know…

I don’t know if it is all spark, but a portion of this problem has to be spark. And except for today it's never just not run at all on one cylinder, just pops here and there with moments of one cylinder. It always came back which made me think it was mixture every time. My guess is weak and failing coil(s) are contributing... I have the electronic ignition on mine and it’s never been adjusted from factory (sealed screws, I opened and looked but didn’t adjust). Not sure if the ignition itself is failing… ideas there?

So, troubleshooting continues… love some feedback on the latest… thanks
 
Sorry TimmyT, I have to disagree. My input in red:

sync the carbs as best as possible first. Make sure to sync with the engine at operating temp. Take it for a brisk 20 min ride before syncing. But, don't waste your time getting the sync perfect just yet. Fine tuning comes last.

Then if you have to go four turns out on the pilot screws the the adjustable needles need to be raised one step then go back to the 1 and 1/2 turn starting point on the pilots. This is incorrect. If the Pilot screws require 4 or more turns out to get a good idle, then the Pilot Jets need to be increased. The Needles are not doing anything at idle.

The pilot jets should go up one size when the needle clip position cant be raised anymore. Then you can start from the middle position again, and raise or lower to taste depending if you have to go over 4 turns out or less than 1&1/4 turns in. Incorrect. Raising the clip on the needle DECREASES fuel by lowering the needle. The opposite is also true.

As far as I know needles that do not have the 5 adjustable clip positions can still be shimmed and raised to compensate for the slight variation between the pilot screw adjustment and actual pilot jet size. Your carb may not have them on there but my jet kit came with some shims incase my needle clip position was not the adjustable type. ... :shrug: Be careful when choosing washers to shim the needles. They may be of slightly different thickness' and cause frustration. Measure them and make sure they are very close in thickness.

technically they are all adjustable Everything is adjustable, though the size of hammer varies... :)

For best tuning results, get the bike running, then the main jets dialed-in at full throttle and high RPM. Then work your way through the needle adjustment to the Pilot jets, float height and idle mixture. Any other method will result in having to make multiple changes of the same jets/settings. The jets all overlap in function during operation, with the Main jets being the most critical. Read this page on CV carb tuning for detailed information.
 
All good points. Thx

I am currently checking my electrical to be sure I don't have another problem. The running on one cylinder has me scratching my head. I tested the coils as outlined in the manual, but someone check me: test primary by putting pos. lead on the red/white, neg. on the orange. I got 3.5 ohms which seems close if not low. Bike was warm.

To test secondary pos. lead on the tip inside the coil body, neg to ground out on frame. Right? Don't know if I'm doing that step right. I think I am. At any rate I get no response on either coil.

Love some input on this.

Assuming it's not the coils, it may be the TCI. I've seen this come up several times on a few forums I've searched. I know there's no way to test this, but want to check; is it located under the battery box, right? Just want to follow through with a thorough exam of electrical and look for bad wires etc... gotta fix this before Monday morning. .. thx
 
Coil testing. Primary should be 3 ohms +/-10% at 68* so yours are high.
 

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Hi XSChris - I have this same book. Didn’t look in the back where there are model specific specs. Thanks...

I did test the way it is illustrated, and I still don’t get a reading on my secondary coils. No movement on multimeter. Primary shows 3.5, so yes it is high...

Could the bike even run (albeit very poorly) on the primary alone? Doesn’t seem possible...
 
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