unirocket
New Member
Out for a ride with a buddy today, and his CT keeps cutting out under load. Checked the carb and adjusted it - doesn't seem to help. Attached is a video.... https://vimeo.com/121948856Anyone know where to start?
Sputtering ct 70
- Thread starter unirocket
- Start date
unirocket
New Member
Ok - back from the ride... Had to load his in the truck to get it home... More information - checked the float and cleaned the carb last night, and it ran for a bit, then he rode it today over to my house for about 4 miles, and it started sputtering again. The fuel tank is plastic. He's missing the fuel screen (and will likely order one). Haven't gotten a look at points as condensor, but would that be the culprit?
andrewdell19
Active Member
You'd probably get more hits in the tech area
Did you check the jets? And make sure all those little holes are clear?
What is the needle placement at on the C clip?
Is the air filter clear? ie if you unscrew the chrome sides does it fix the issue?
Could possibly be a venting issue from gas cap. Is it positioned to the ON position? If so, what happens if you unscrew the gas cap a little? That would give a quick fix to a venting issue.
Points could absolutely be the problem. Bad points can cause a variety of issues.
Did you check the jets? And make sure all those little holes are clear?
What is the needle placement at on the C clip?
Is the air filter clear? ie if you unscrew the chrome sides does it fix the issue?
Could possibly be a venting issue from gas cap. Is it positioned to the ON position? If so, what happens if you unscrew the gas cap a little? That would give a quick fix to a venting issue.
Points could absolutely be the problem. Bad points can cause a variety of issues.
Enginedoctor
Well-Known Member
i'm leaning carb. i ususally do.
andrewdell19
Active Member
its the most likely culprit with it getting clogged etc... I wonder why they invented direct inject/fuel injectors...
cjpayne
Well-Known Member
So, its sputtering once it's up to full temp, consistantly? Does it do it randomly? Does it sputter once it's fired up and then driven(without warming up at all)?
What mods have been done, if any?
Is it running ethanol gas? If so, for how long? I ask this because you may be getting pieces of fuel line stuck in your jets from prolonged exposure to ethanol that eats the lines up.
Have you changed the plug?
Have you checked the points gap? What is it?
unirocket
New Member
Thoroughly cleaned the carb last night - everything was fine. Air filter is clear. Removed gas cap while running - same issue.
Seems to happen consistently when engine is warm, but has happened on cold starts as well.
The theory of ethanol is decent, but the lines are new, and premium fuel without ethanol...
Will keep you all updated. Thanks for the tips.
Hey guys, thanks for the replies. It's my CT that's acting up.
It sputtered when cold yesterday, cleaned the jets and float valve, managed to tweak the float height and needed to readjust that, afterwards it ran great and I called for an after work celebratory ride
. I drove 4-5 miles across town to meet up, we drove another couple miles and all of a sudden the sputtering hit all at once. I'll check tomorrow if it acts the same cold but I believe it will. Another point is that it idles great but any bit of throttle and it sputters.No real mods. The carb is not original but is one of the better, reproduction style ones.
New points and condenser last summer. Haven't changed the plug recently but it doesn't have many hours on it, think I have a few spares, will throw one in. Haven't rechecked the points gap but will do that.
To me, it really seems like a carb issue and specifically some kind of blockage. I bought some inline fuel filters tonight. I'll get those in place and clean the carb again. The other thing in the back of my mind is the coil acting up once it gets warmed up.
Let us know if you have any ideas or confirmation of any these theories.
Enginedoctor
Well-Known Member
andematt i almost thought it was a thread-jack :caked:, i had to read the op.
okay, here's a carb cleaning write up. if you have the original, i personally would consider cleaning it and shelfing it, but it's really up to you. a good repro can work fine.
make sure you have a constant supply of GOOD, clean fuel. i've seen this fool many a people. no joke. bad gas is more than just the reason i'm single :nitro: make sure the fuel lines aren't coming apart and leaving teeny tiny bits of rubber in the fuel supply. i've seen that cause issues too (usually flooding, but sometimes clogging of needle/seat).
okay, so if everything fuel delivery is in order, the next symptom you're showing is 'overheating' or too close a valve adjustment. no, they're not the same, but one can cause the other in these engines. pull the 17mm (i think) aluminum caps on top of the head. oil might drip out of the bottom one. keep in mind you're (generally) on top of it when removing it, so it might almost be a 'righty loosie' thing from an upright perspective, if you know what i mean…. there should be .002" or .003" of clearance on the tappet adjustments, WHEN THE VALVE IS CLOSED. i usually run just a bit more on the exhaust. they're a 9mm nut and then a teeny square you can probably just fingernail.
try those two things. when you said 4 or 5 miles, that's usually, in my experience, more of a valve adjustment thing. the bike could also be too lean, making it hot, also a carb thing…. try moving the needle in the throttle piston, if you believe that to be the case.
let us know how it works out.
okay, here's a carb cleaning write up. if you have the original, i personally would consider cleaning it and shelfing it, but it's really up to you. a good repro can work fine.
make sure you have a constant supply of GOOD, clean fuel. i've seen this fool many a people. no joke. bad gas is more than just the reason i'm single :nitro: make sure the fuel lines aren't coming apart and leaving teeny tiny bits of rubber in the fuel supply. i've seen that cause issues too (usually flooding, but sometimes clogging of needle/seat).
okay, so if everything fuel delivery is in order, the next symptom you're showing is 'overheating' or too close a valve adjustment. no, they're not the same, but one can cause the other in these engines. pull the 17mm (i think) aluminum caps on top of the head. oil might drip out of the bottom one. keep in mind you're (generally) on top of it when removing it, so it might almost be a 'righty loosie' thing from an upright perspective, if you know what i mean…. there should be .002" or .003" of clearance on the tappet adjustments, WHEN THE VALVE IS CLOSED. i usually run just a bit more on the exhaust. they're a 9mm nut and then a teeny square you can probably just fingernail.
try those two things. when you said 4 or 5 miles, that's usually, in my experience, more of a valve adjustment thing. the bike could also be too lean, making it hot, also a carb thing…. try moving the needle in the throttle piston, if you believe that to be the case.
let us know how it works out.
cjpayne
Well-Known Member
I've had heat kill the primary's before, due to an overheating issue and/or age(originals). That was my first thought about yours. You can also hook up a cheap (needle type) ohm/volt meter to measure and watch the behavior of the volts coming from the primary. When my primary was failing(causing sputtering) or intermittent failure, the meter reading would read steady and then all of a sudden go wild(needle would bounce back and forth) when the sputtering started. I also recently had an aircleaner problem that was blocking the air inlet to the carb when the rpm's increased. The screen inside the aircleaner had broke and let the round blocker fall forward and obstruct the air inlet. You could actually have two problems that are aggravating each other, so be on the look out for that too. Been there, done that.lol
unirocket
New Member
Hey all - we believe the issue was a bad condenser. I had another in my spare parts. After popping that in, seems to have fixed the sputtering issues. Like we said - it only seemed to happen after the bike would heat up. Odd part is that the condenser that was in the bike was basically new as well - must have just been a bad one. Anyone else had bad luck with the Daichi condensers?
Enginedoctor
Well-Known Member
the condensers on these bikes compared to the condensers on say, an old tecumseh flathead 5hp, are, for whatever reason, very much prone to failure. a good one, in certain cases, might even be better than a new one… if you get what i'm saying.
sometimes when people solder the connection on top of the condenser, they ground out the edge. i doubt it was your issue, but it can, and does happen. generally, in those cases, there is no spark, not intermittent spark
and yes, i've seen heat kill a condenser.
sometimes when people solder the connection on top of the condenser, they ground out the edge. i doubt it was your issue, but it can, and does happen. generally, in those cases, there is no spark, not intermittent spark
and yes, i've seen heat kill a condenser.