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Discussion Starter · #1 ·
My 1985 Nighthawk 450 was running well after an oil change and tune up. Last ride though it was definitely losing a cylinder. I don't have access to a motorcycle shop locally so I used plug caps from a 1980 XS850 because mine were broken up and in far worse shape. They aren't ideal for the 450 because they have a right angle bend. I'm thinking it's possible because of this one came off partially, but IDK, and that complicates things. Hard to be scientific with variables I was unaware of. Anyway I worried it was petcock gunk, but after removing that, I found it quite clean.

I had put an inline filter because at one point I had a float needle stick and some gas leak. I seemed to run fine for a while and there is no visible gunk in there. Still after checking everything (right down to removing the rocker cover to make sure I hadn't forgotten a lock nut on an adjuster, and I hadn't), I removed the fuel filter and it seems to go right up to redline with ease again. I really had hoped to avoid pulling the carbs till spring time. I do ride year round, weather just isn't bad enough to prevent it.

I've ran inline filters on these before with no problems, but coould that really be it?
 

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Some inline filters can restrict flow, especially when the fuel level in the tank gets low. If the inlet screens on your petcock are in good shape and you keep your tank clean, inline filters shouldn't be necessary,
 

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Agreed, but any corrosion in the tank will eventually end up in the carbs as a fine rust mud. A magnetic "trap" in the fuel line can help, even a different fuel tap with a sediment trap, with a small magnet in there can help, even an easy removable magnet in the tank.

Condensation and modern fuels and bike storage, but he uses the bike all year round....even in the wet?

Petcock gunk......filters remove debris, and just like a vacuum cleaner, they need to be cleaned ( replace a partially blocked filter, its dune its job, right ) from time to time.

Do a flow test with and without a filer, say a gallon from a full tank takes 40 seconds with a filter and 35 without one ?? figures plucked from the air......as an example.

Remember when cleaning a tank start at the tank filler cap.
 

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Discussion Starter · #4 ·
IDK I used one of those cone ones with the gold inner filter and it looked clean. I ran one of those on my total gas hog XS1100 without issue (literally 25MPG), I'm really starting to think one of my plug wires just came off a bit, was firing sometimes and grounding on the head at others. I still haven't put the filter back on, but I think it may have been spark. That's why it sucks when you notice two problems at once, it's easy to guess wrong.
 

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I've never had problems and have run inline fuel filters for years. But to put in a filter because of a sticking float needle doesn't make sense -- the filter isn't going to stop the fuel flow.
 

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Discussion Starter · #6 ·
I've never had problems and have run inline fuel filters for years. But to put in a filter because of a sticking float needle doesn't make sense -- the filter isn't going to stop the fuel flow.
It was not a sticking float, just a piece of debris keeping it open.
 

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Discussion Starter · #7 ·
Was just watching bike videos, Lots of guys need some carb syncing! What is it with all those guys idling at 2k without choke?!? My bike, warmed up purrs along at800-1k.
 

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Was just watching bike videos, Lots of guys need some carb syncing! What is it with all those guys idling at 2k without choke?!? My bike, warmed up purrs along at800-1k.
...and running on one cylinder at idle too... they haven't yet (and may not ever, it isn't in everyone) developed an "ear" for that
 

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Discussion Starter · #9 ·
You can get a twin bench synced and running pretty good, but plug it in and it's always off a bit, no matter how good your eye is.
 

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Discussion Starter · #11 ·
If I were to guess mine should be about synced. The bike did sit, but PO was a good friend of the local Honda shop owner before he closed up. He had it gone over there regularly. It will almost idle without choke after just about 45 seconds of choke in 40 degree weather. Warmed up you could probably get it to idle at 500rpm without dying. Like I said somewhere, I hope not to mess with carbs before next spring or summer. I'm actually hoping to add something bigger to the stable. I love my little 450 but I'm a big fan of mid sized all purpose bikes. A Nighthawk 550, 650, or 90s 750 would probably be ideal for me.
 

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Correct idle speed is 1200 +/-100 rpm. If you're relying on the factory tach that may explain the 800 rpm idle.
I haven't used or found a need to run an extra fuel filter. The petcock screen should be cleaned periodically but it's so fine a mesh that it will catch almost anything that will mess up the carbs. Yeah, you can get some fine sediment in the bowls which is cured by periodically draining the bowls. I do that when changing oil.
 

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I went with a T mod and filter on my cl350 and its never starved for fuel.
 
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