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Discussion Starter · #1 ·
Has anyone done this ? Will it improve performance ? Any tips or suggestions appreciated..1986 nighthawk 450
 

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Do you have the Factory Service Manual for your bike? I'm sure someone will offer one soon if you don't.
 

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There's no benefit for performance in removing it. There is the benefit of eliminating future vacuum leaks however.
You'll want the '86 specific FSM, PM sent
 

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Removing the canister will do nothing to improve performance.
Back in the old days, fuel tanks had vented caps so that fuel vapors could escape. Without being vented, on a hot day the evaporating fuel could produce enough pressure to bulge or rupture the fuel tank. The only problem with this is that those fuel vapors add significantly to smog/greenhouse gases. And as they evaporate, the remaining fuel becomes less easily ignited, and more likely to gum up your carburetors.
The fix was to get rid of ventilated gas caps, and instead route the vapors to a charcoal canister. The vapors condensed and were captured by the charcoal. Once the fuel tank cooled or the fuel level dropped, the condensed vapors were drawn back into the fuel tank. So no fuel vapors escaping to the environment, the gasoline retained its integrity as a fuel, and you got even better gas mileage.

If you simply disconnect the canister, the fuel vapors go directly to the atmosphere. Not good for you or anyone. And some emissions systems are more complex, incorporating vacuum lines into the equation- if you just disconnect everything, you introduce a vacuum leak that will mess with performance.

I'd leave it intact.
 

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Discussion Starter · #9 ·
So i just received the manual...ty sooo much, and i have a better idea of the canister function, so my question is..will removing any of the cali emissions systems improve performance ? ...the reason im seeking more performance is because my friend rides an old sx650 and in a drag we are litterally dead even, just looking for a bit of a boost to take him.
Ty all
 

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Nope, removing won't change a thing in performance. Want maximum performance? You start by having everything working at 100%. Things like ignition timing, fuel mixture, compression, etc.
 

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How old are your wheel bearings? Experimenting with tire pressure one or two pounds higher may add a tiny boost too. Then maybe go one tooth higher on your front sprocket. K&N air filter. Rotella T. Tuck your head down when speed reaches 35mph.
And experiment with different octane fuels, my CM400C was better on mid-grade fuel, I think it was 89 octane. Also make sure your accelerator pump works.
 

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Discussion Starter · #12 ·
Ty for suggestions..bearings probably original, took out airfilter, seems faster without it, ill check tire pressure, having it timed this week ...how would i know it accel pump wasnt working correctly ?
 

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By getting it timed are you aware that timing on these is more like check it to see if it's working, no adjustment possible. If it is not working (yours sounds fine but worth a check) you have to get out the multimeter to decide what to replace.

Accelerator pump not working is if you snap the throttle open and nothing (or missing etc.) happens for a second before it revs, although that's not a specific test. Either way to properly fix that symptom the carbs would come off. If you have the carbs off at some point you can open the throttle while fuel is still in the bowls and you should see a little squirt from the little brass nozzle in each carb that point towards the cylinder
 

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Discussion Starter · #14 ·
Thanks..so accel pump is working fine, im not sure i understand what you mentioned about timing ?
 

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I don't know if you have any mechanical background so sorry if this comes off as at all condescending. The timing in the 450s is all electronically controlled, it's not like an old car distributor where you turn it or an older points style where you adjust gaps etc, both with the goal of making the spark occur at a slightly different time to make the vehicle run better. The CDI (black box on the left side under the tank) controls the timing advance and pretty much is either in 100% working order or 0% working order.

The process to check it is in the manual but you basically attach the timing light, point it at the rotor (which you take the cover off of on the left side of the engine), and see what the marks are at idle, then rev it to 4000+ and see if it changes to the appropriate place. If it does, your timing is as good as it will get without complicated mods I do not actually know how to do.
 

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Discussion Starter · #16 ·
Ty..not condensending at all..i think im pretty good at mechanics, i adjusted my valves last week, rebuild 3 vintage husqvarnas...but timing, ive never really been good at...so pretty much if its running ok ..its in time ? I really appreciate you staying with me in this thread even though i have strayed a bit from original post.
 

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I get that, I am the same about turn signals and lighting and how suspension actually works. That's correct, the only way the timing seems to fail is if the bike doesn't want to go above 4500 rpm or won't do more than 65mph in top gear
 

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The CDI (black box on the left side under the tank) controls the timing advance and pretty much is either in 100% working order or 0% working order.
Not quite right. The advance timing is a voltage relationship between the stator advance pulsar and the primary pickup read by the CDI unit. As RPM increase the advancer generates a stronger signal/voltage overcoming the primary.
I have tried combinations of 3 different stators and CDI's in an attempt to get a pair that was as close to stock as possible. Just changing the CDI alone would change readings some as would just changing the stator. https://www.hondatwins.net/forums/6...timing-curves-stock-cm-cb-sohc-400-450-s.html
 
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