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Discussion Starter · #1 ·
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Hey Guys,

I just got this bike (my first) in July. Been taking it slow and steady, getting some experience on the bike and making some fixes as I go. I'm searching for new tires now (dry rot and worn tread as is).
I have a few questions...
Am I correct in translating the manual specs for the Tires from (Front) 3.60S19-4R = 90/90/18, (Rear) 4.10S18-4PR = 100/90/18?
At the moment the bike runs nicely up to 3-4000 rpms in lower gears, but bucks/drags about 2-3000 in higher gears.
I've replaced the front boots (cant find back ones), put in a new carb screw set and new fuel mixture screws (they were busted). I bought the new jet needles (to replace recall) but havent installed them yet because I wanted to ride it again.

Its a really great little bike! I'm almost glad it I cant get the rpm's up because I'm a new rider. I am REALLY looking forward to feeling it move though so any advice y'all can offer is GREATLY APPRECIATED!

Thanks!! Jess
 

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I have a 1980 cb400t, the tire specs in the manual are the same as what you have, 90/90/19 is right for the front, 100 or 110 apparently both work on the rear, I got 110/90/18 and they are working fine.

As for the running issues, you're probably better off with the original brass parts. The rubber parts are much more important to replace to prevent leaks, have the mixture screws function properly, have the accelerator pump function, the air cut valves etc. The intake boots are a good first step, the airbox boots aren't that important to replace, but if there are any gaping holes you will need to patch them with whatever works.

Check out the rebuilding VB carbs sticky if you haven't already. I don't know much about the needle issues but on my bike it kinda coughs and sputters when cold at partial throttle but then catches after you get to 1/2 and up. When it gets nice and hot it runs a lot smoother.
 

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Discussion Starter · #3 ·
Thanks 80cb400t! Now I can shop for tires. Good to know the airbox boots aren't a factor - they's hard to find. My buddy suggested using silicone on them while installed, but the airbox is a bitch to get out and I gave up (for now).
What exactly did you mean by "sticky"? I'll try to pay more attention to the changes in the sputter as the bike warms up.
G'night!
 

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They don't seem to degrade quite like the intake boots do, probably from less heat/gas exposure. Just get them fit properly into the airbox side and get the carb side clamped on firmly, don't worry about the silicon unless you're sealing obvious holes.


Stickys are important threads that get kept at the top of a message board, the one I'm talking about is at the link below. To get there or anywhere next time you click index near the top of the page and scroll to the SOHC 400/450 section and find the part of the bike you're interested in.
https://www.hondatwins.net/forums/63-fuel-supply-carburation
 

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Welcome aboard. You'll find lots of information in the SOHC section that will help you and when in doubt ask questions. You've got the tire sizing down so look for decent ones, lots of cheap stuff available but they wear quickly and the ride/handling won't make you happy.
Yes, those air box boots are a major PITA to install with the air box in place. Honda's version of is to remove the rear tire, inner fender, etc to pull it backwards in the frame. Most of us just wiggle, curse, wiggle, curse, repeat until they're in place. Getting them real warm helps, think hair drier or setting in the sun.
 

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Nice bike!
 
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Discussion Starter · #7 ·
Almost 6 months into my CB450T 1982 HAWK. Had a great ride in Montauk today - 50 degree weather and dry roads. Now planning winter projects. Just got a free 1983 Honda nighthawk and will swap the 83 handlebars, shorter exhaust and the cast comstar wheels to the 82 Hawk.
Im still having a hell of a time with the Carbs on my bike. As I mentioned in the first post, I've replaced the boots, put in a new carb screw set and new fuel mixture screws and replaced the jet needles per Honda's service bulletin.
One of my spark plugs shows the bike is running rich no matter what the needle adjustment is.
The most OBVIOUS issue with the carb mechanics is that one of the brass needle seats is pressed in and the other, larger one, is loose.
Does anyone know if this is normal? Are they meant to be different? If so should one really be loose?
We're going to pull the carbs from the 83 nighthawk and check them out. If they look good, I'll use them on the 82 Hawk and hopefully that will resolve my partial throttle issue.
Any thoughts?
 

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IDK what you mean by bucks and drags at 3k in higher gears? The engine running well has no real power in 4th through 6th under 4K on the RPMs Mine really like 5500 or so to cruise. These little things were made to rev.
 

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Almost 6 months into my CB450T 1982 HAWK. Had a great ride in Montauk today - 50 degree weather and dry roads. Now planning winter projects. Just got a free 1983 Honda nighthawk and will swap the 83 handlebars, shorter exhaust and the cast comstar wheels to the 82 Hawk.
Im still having a hell of a time with the Carbs on my bike. As I mentioned in the first post, I've replaced the boots, put in a new carb screw set and new fuel mixture screws and replaced the jet needles per Honda's service bulletin.
One of my spark plugs shows the bike is running rich no matter what the needle adjustment is.
The most OBVIOUS issue with the carb mechanics is that one of the brass needle seats is pressed in and the other, larger one, is loose.
Does anyone know if this is normal? Are they meant to be different? If so should one really be loose?
We're going to pull the carbs from the 83 nighthawk and check them out. If they look good, I'll use them on the 82 Hawk and hopefully that will resolve my partial throttle issue.
Any thoughts?
No, that's not normal, that well could be your problem. Try the Nighthawk carbs. Another thing if you haven't or don't have a proper one, go on youtube and search home made manometer.
 

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They aren't actually pressed in, I dropped one out of my carbs and didn't realize once. I thought there was something about the 81+ carbs where there was a needle upgrade recommended, see if you can find it in the stickies of the section I linked above.
 

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Discussion Starter · #11 ·
Thanks all - now that I’ve been riding it for a few months I definitely see what you said @markjs, it likes to rev for sure. We did make a manometer for the rebuilt 83 interceptor (in the background of the new pics I’m posting) but I don’t think we ever ran it on my 450. Will try that!

@80cb400t, I did the needle swap and it helped a little, but still running rich.

Hopefully the nighthawk carbs will be the fix but I’m still wanting to ride it while weather holds, so will do once temps drop a little.

For now, here’s a pic the bars swapped, and a very messy garage. Don’t think they’ll be much left of the nighthawk when we’re done.

Have the remains of a parted out interceptor too. Any suggestions as to what to do with all the leftovers!?! ?
 

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Discussion Starter · #13 ·
CB450T carb issue finally resolved!
The needle set/ jet (NEEDLE SET, JET 16012-413-751) was placed in the carb UPSIDE DOWN.
I knew it looked odd when I opened them up the first time, but never imagined it was in wrong, just went ahead and got the new carb screw set and new fuel mixture screws and replaced the jet needles per Honda's service bulletin.
Then I finally managed to sit through a video of someone cleaning similar carb who actually removed this "set" for the needle and by punching it through the bottom after removing the main jet. When he put the carb back together I realized mine was upside down.
Replaced old chain and sprokets while that DAMN giant airbox was out too. Sadly the boots from the 83 nighthawk were too long so had to us emy old scappy boots but MY GOD IT RUNS SO MUCH BETTER.
Also replaced the fork seals, and tightened up the back suspension.
I just wish the weather was better. Im freezing my butt off riding around now!
:)
 

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Almost 6 months into my CB450T 1982 HAWK. Had a great ride in Montauk today - 50 degree weather and dry roads. Now planning winter projects. Just got a free 1983 Honda nighthawk and will swap the 83 handlebars, shorter exhaust and the cast comstar wheels to the 82 Hawk.
Im still having a hell of a time with the Carbs on my bike. As I mentioned in the first post, I've replaced the boots, put in a new carb screw set and new fuel mixture screws and replaced the jet needles per Honda's service bulletin.
One of my spark plugs shows the bike is running rich no matter what the needle adjustment is.
The most OBVIOUS issue with the carb mechanics is that one of the brass needle seats is pressed in and the other, larger one, is loose.
Does anyone know if this is normal? Are they meant to be different? If so should one really be loose?
We're going to pull the carbs from the 83 nighthawk and check them out. If they look good, I'll use them on the 82 Hawk and hopefully that will resolve my partial throttle issue.
Any thoughts?
I just got the same bike a couple weeks ago and I swapped out my handlebars for some emgo brat styles. I now have extra throttle, brake and clutch line. Did you happen to do something similar?

Sent from my Moto Z (2) using Tapatalk
 

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Discussion Starter · #15 ·
In search of 1982 450cc Honda Hawk just like the one above.
I sold it last spring and wanted the 450 back since the day it left, but the kid I sold it to crashed it.
So, licking my wounds and hoping to locate one somewhere in the NY metro area - or a comparable bike up to 650cc.
I bought a 1989 Hawk 650, and its great fun and in beautiful condition but its wrecking my wrists on longer rides.
Thanks to anyone who can advise.
Jessica
 
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