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hey everyone! this is my first post so bare with me if this question seems basic. i just bought a '71 honda cb450k with hopes to make a nice little cafe out of it. when i bought the bike it didn't come with the stock airbox which seemed a bit odd. the bike was running ok and i figured that id just through some k&n's on it and bob's your uncle. no such luck. it's not running too well at all. since then i've been talking to a few different guys and the diagnosis is always the same. they say "thats a great little bike but a pain in the ass to tune right" or "whatever you do, don't remove the stock airbox or mufflers!!!" crap. i don't have either. i've been told that the stock CV carbs are a real piece of work and won't allow any mods... so, its swap the carbs or track down the stock airbox and mufflers. and if so which carbs are the best replacements? any help would be much appreciated. Any suggestions???
 

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They're ok carbs - they're very finicky about clean, though.

1 - take the carbs the whole way apart and clean the shit out of them, making sure the very fine jet passages are clean.

2 - the cv slides can stick. if the bike is running, rev the motor and watch the slides - do they move up and down smootly? if not, clean the crap out of them and shoot a little wd40 onto the slides.

3 - Make sure the float levels are set correctly. Do you have the factory manual? If not, you should go here:
CB450 Manual

4 - if you've swapped out the exhaust and intake, you may need to change jetting a bit.
 

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Truly, I've never had a problem running pods or open exhaust on 450s, and I've run several different years in a variety of configurations (including both a 500T bottom/450 top and the inverse). Here's my take: they naturally run rich, so you've got a bit of room to maneuver if you want to open up the respiration some - just check your plugs after your first few rides to see that you're in range.

However, it's not even worth TRYING to get it there until you've done a few things. Check (and adjust) your timing and point gap, charge your battery, change your plugs if they're carbon fouled - then, with all other things nicely aligned, you'll have an easier time isolating your issues. Probably you're ahead of me on this, but just in case.

If you're thinking of swapping carbs, 500T's are a somewhat updated drop-in replacement. They're also cheaper on ebay, probably because most people don't know they're compatible.
 

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What Xander said. Get the other stuff right before you start messing with carbs.
Xander, Where are you now? I am back in WI are you?
Ken
 

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I am near Eau Claire. Are you going to go to the AHRMA races at Road America in June? I will be round various parts of the state, maybe we can hook up for a beer or a ride.
Ken
 

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Going to try to make it - a free weekend day is a tough thing to get these days, but we'll see. If you're going to be in the area, shoot me a note and we'll scoot around some farm roads.
 

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Going to try to make it - a free weekend day is a tough thing to get these days, but we'll see. If you're going to be in the area, shoot me a note and we'll scoot around some farm roads.
 
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