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Discussion Starter · #1 ·
I have a 1974 Honda CT70. I'm the original owner. it has 1172 miles, This is a summer driven, around the neighborhood type bike. When it has a freshh plug and fresh fuel it's a one kick starter after it's warmed up. If I start it every day it is fine, but if it sits a few days it fights me to get it running. It seems to want to flood, even though I do not choke it. When I do get it running,at WOT, it picks up speed and runs great with about 25% of choke engagement.. Everything is factory stock as bought. I'm thinking a hotter plug ( I don't know the number) and maybe a main jet change. Any thoughts? Thanks
 

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A complete disassembly and thorough carb cleaning, using carb or contact cleaner and compressed air, might be the solution. If it runs smoother with the choke partially closed, that's usually a sign of dirty carb passageways.
 

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I have a 1974 Honda CT70. I'm the original owner. it has 1172 miles, This is a summer driven, around the neighborhood type bike. When it has a freshh plug and fresh fuel it's a one kick starter after it's warmed up. If I start it every day it is fine, but if it sits a few days it fights me to get it running. It seems to want to flood, even though I do not choke it. When I do get it running,at WOT, it picks up speed and runs great with about 25% of choke engagement.. Everything is factory stock as bought. I'm thinking a hotter plug ( I don't know the number) and maybe a main jet change. Any thoughts? Thanks
A complete disassembly and thorough carb cleaning, using carb or contact cleaner and compressed air, might be the solution. If it runs smoother with the choke partially closed, that's usually a sign of dirty carb passageways.
Agree with dirtbkr188, your carb needs cleaned or rebuilt. If you are cleaning it, pay attention to the float needle and seat, and especially the pilot jet, which is most likely clogged. Hondanuts .com has a keister rebuild kit with all the parts for a rebuild. If it looks fairly clean inside the bowl, you could probably just run a guitar string that is .010 or smaller gauge through the pilot jet, and get rid of most of your problem. Also worthwhile to address the points, if you have not done them in a while. They will corrode over time and need to be cleaned or replaced.
 

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1200 miles, and 48 years..? If you are willing, it's probably a good time for some regular maintenance.
Clean the oil spinner and adjust the clutch. Clean and adjust the points. Definitely adjust the valves. Check the air filter for sure...they turn to dust in about...47 years :).
Adjust the cam chain tensioner too.
Any and all of those things are due, unless you know that they've already been done.
 

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Discussion Starter · #5 ·
A complete disassembly and thorough carb cleaning, using carb or contact cleaner and compressed air, might be the solution. If it runs smoother with the choke partially closed, that's usually a sign of dirty carb passageways.
Thanks for the reply. I have gone through the carb twice.
 

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You're asking for advice, and you're GETTING good advice. I'm with those 2^. If you're running partial choke...plus hard starts, you need to clean the carb...3 or 4 times if that's what it takes. Pull the jets and emulsion tubes and poke out EVERY hole with a wire before the compressed air and cleaner. Visually see thru EVERY hole. (There are 10 or 20 holes there)
Also check/set the float height...that could cause your flooding. Look to see the numbers on the jets while you're in there...see if they're correct.
Check the air filter element.
 

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You're asking for advice, and you're GETTING good advice. I'm with those 2^. If you're running partial choke...plus hard starts, you need to clean the carb...3 or 4 times if that's what it takes. Pull the jets and emulsion tubes and poke out EVERY hole with a wire before the compressed air and cleaner. Visually see thru EVERY hole. (There are 10 or 20 holes there)
Also check/set the float height...that could cause your flooding. Look to see the numbers on the jets while you're in there...see if they're correct.
Check the air filter element.
Listen to Kirrby. If the main jet emulsion tube was not tapped out and cleaned, that could cause the top end problem. Another area that is sometimes overlooked is the needle just under the slide, where a ring of varnish will form and cause uneven running.
 

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Discussion Starter · #8 ·
Listen to Kirrby. If the main jet emulsion tube was not tapped out and cleaned, that could cause the top end problem. Another area that is sometimes overlooked is the needle just under the slide, where a ring of varnish will form and cause uneven running.
ok. ill put it in the jewelry cleaner one more time and see what happens. Any thoughts on a good main jet size and is the reccomended second groove setting what everyone uses?
 
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