squizzymchaggis
Active Member
Maritime and Josh, thanks for the advice. I really appreciate it. And yeah, I think you're right about things based on the rocker cover.
Newbie about to start my first build - '82 Honda CB450 Nighthawk
- Thread starter squizzymchaggis
- Start date
squizzymchaggis
Active Member
I finally got enough free time to get out in the garage and get the carbs pulled. They are sitting on the bench now and I'll start going through them tomorrow night. 
squizzymchaggis
Active Member
LOL, thanks for the advice. I'm hoping to get started on them tonight. Is something like brushing the parts down with carb cleaner a good way to approach it or is it better to let the jets etc soak in it? I've heard of people doing both.
Maritime
Over 10,000 Posts
Really depends on condition they are in, if the bike is running I generally take the jets out and spray them good and look through them then spray cleaner through the bodies and all the passages, sometimes they need to soak or be boiled in lemon juice etc. but a good blast with cleaner and compressed air is sometimes enough. With you issues I would check the diaphrams for holes and clean slides as if one is sticky at all it can cause your sympton of not revving well.
squizzymchaggis
Active Member
Sounds like a good plan. Thanks for the info and advice!
squizzymchaggis
Active Member
When I pulled the float bowls off, the carbs looked like they were filled with jelly, lol. And some of the jets were completely clogged. I'm amazed the bike would even start and run. I got them all cleaned up and put back together and then went to put them on the bike. How the hell do you get them back on and keep a seal between the carbs and the exhaust boots that connect to the air box?? If I get them into position to be able to bolt them to the engine there are gaps between the carbs and exhaust boots. Or between the exhaust boots and the air box. Or both. WTF? Am I missing a step someplace? If anyone has a hint or tip they would like to share, it would be greatly appreciated. In the meantime I think I'll have a beer and start searching on here to see if I can find out how somebody else handled this.
Maritime
Over 10,000 Posts
There is some play in there to allow to remove. you need to get the clamps on either the intake boots or airbox boots then wiggle and pull them onto the other set and clamp it helps to unbolt the airbox if I remember correctly and then fasten it back on after carbs are attached. I bet the bike will fire right up and rev properly after the cleaning. ;D
PLAZACYCLEJOSH
Honda make Josh, happy Josh
I had to go out to my bike, I have been pulling the carbs a bunch lately to re-jet for my new mufflers. I put the carbs into the front boot and land them all the way. Then I stick the rear boots through the air box, it is easier to get them around the back of the carbs and get the air box to seal in the groove of the rear boot. Here are pics of my 82 cb450sc just to make sure we are looking at the same thing.
Attachments
squizzymchaggis
Active Member
Thanks for the help guys! And Josh, yes that's it exactly. I'll give it another try shortly. I think part of the problem may have been that I was trying late at night so I was tired and my patience was wearing a little thin. I really appreciate the help.
squizzymchaggis
Active Member
I got the carbs back on and she fired right up. I let it idle for a bit to warm up and then gave it some gas... And yep, it revved over 3500 for the first time. Now it's time to put it completely back together and then if it ever stops raining I'll take it out and see how it does down the street and around the block.
I did see some smoke coming out from under the exhaust. It looked like it was coming from the H pipe, but hard to tell for sure. I'm hoping it was just burning off oil and gas that had leaked onto the pipes but I need to check it out under there and see what I can see.
I did see some smoke coming out from under the exhaust. It looked like it was coming from the H pipe, but hard to tell for sure. I'm hoping it was just burning off oil and gas that had leaked onto the pipes but I need to check it out under there and see what I can see.
Maritime
Over 10,000 Posts
Huzzah clean carbs FTW! the H pipe is the low point in the exaust so any unburnt fuel would collect there as well the airbox drains go there and I think the carb overflow lines all go there too so all those things can cause smoke and burn off as well as condensation in the exhaust collects there and will steam out.
Cheers
Cheers
squizzymchaggis
Active Member
My thoughts exactly on the clean carbs, lol. And thanks for the info on the exhaust, Maritime. The carb overflow lines are missing and I haven't replaced them yet so I know thats not it, but the very well could be the rest of it. Now, if it will just stop raining and dry up some I can go ride it. I want to put some miles on it and make sure I don't need to do anything else to the engine before I move forward.
PLAZACYCLEJOSH
Honda make Josh, happy Josh
While you had the carbs apart did you check the needles? I would check and see if they are the 61A or the 61C, It really makes a difference in the handling of the bike. When I changed out mine the response was right there immediately, the bike didn't even have to warm up for it to be snappy and right there. Even the guys at the shop noticed that my bike sounded better.
Honda doesn't sell them any more but many of the dealerships across the US have them on their shelves, your local dealership would probably be able to get you the number for one of them, or pm me and I can look it up for you. Here is the thread info if you need it
1982 CB/CM 450 Drivability Performance Improvement (all manual transmission models: CB450SC, CB450T, CM450C and CM450E
“ Under part throttle operation, some owners of these motorcycles may experience poor drivability performance. This condition can be improved by fitting replacement jet needles”
First step is to replace the needles #61A with new needles #61C. Second step is to replace the mixture screws.
Part numbers: 16113-MC0-305 Needle Jet #61C and 16016-413-751 Pilot Screw
The needle is a the standard needle for a 1983 CM450 A and the Pilot/mixture screw changes numbers to 16016-KC2-970 and shows available still on 4-23-2013. The screw has been used on 121 different engines from 1980 to 2004.
Honda doesn't sell them any more but many of the dealerships across the US have them on their shelves, your local dealership would probably be able to get you the number for one of them, or pm me and I can look it up for you. Here is the thread info if you need it
1982 CB/CM 450 Drivability Performance Improvement (all manual transmission models: CB450SC, CB450T, CM450C and CM450E
“ Under part throttle operation, some owners of these motorcycles may experience poor drivability performance. This condition can be improved by fitting replacement jet needles”
First step is to replace the needles #61A with new needles #61C. Second step is to replace the mixture screws.
Part numbers: 16113-MC0-305 Needle Jet #61C and 16016-413-751 Pilot Screw
The needle is a the standard needle for a 1983 CM450 A and the Pilot/mixture screw changes numbers to 16016-KC2-970 and shows available still on 4-23-2013. The screw has been used on 121 different engines from 1980 to 2004.
squizzymchaggis
Active Member
Alright, here's the good and the bad. First the good... I took it for a ride around the neighborhood. Started right up and the engine ran well. No problems revving all the way up to red line. Granted I didn't get over about 40 but I was just happy to be able to ride it.
Josh, somebody (I think it may have been you) mentioned before about the needles. I had intended to check them when I had the carbs off but screwed up and forgot to do it. Thanks for the reminder, and you can be sure I will be pulling them soon to to check. Since these are not the original carbs I'm hoping that whatever PO replaced them did the needle change at that time, but we will see.
Now for the bad... Evidently I only have three gears right now. When its in neutral the shift lever won't go down into first. I'm assuming that it has the usual pattern of being one down and 4 up. So I had to pull the shift lever up to get it into gear. I assume (yes I'm assuming a lot and I know the saying, lol) that I was therefore starting off in second. I could shift up into the next gear (3rd?) and the one after (4th?) but that was it. It wouldn't shift higher, and it was hard to get it to shift at all, although downshifting was easy. If anybody has any suggestions on where to start I'm all ears. In the meantime I'm going to start reading up on transmissions here and in the service manual.
I'm sure my family thinks I'm nuts but I'm loving this
Josh, somebody (I think it may have been you) mentioned before about the needles. I had intended to check them when I had the carbs off but screwed up and forgot to do it. Thanks for the reminder, and you can be sure I will be pulling them soon to to check. Since these are not the original carbs I'm hoping that whatever PO replaced them did the needle change at that time, but we will see.
Now for the bad... Evidently I only have three gears right now. When its in neutral the shift lever won't go down into first. I'm assuming that it has the usual pattern of being one down and 4 up. So I had to pull the shift lever up to get it into gear. I assume (yes I'm assuming a lot and I know the saying, lol) that I was therefore starting off in second. I could shift up into the next gear (3rd?) and the one after (4th?) but that was it. It wouldn't shift higher, and it was hard to get it to shift at all, although downshifting was easy. If anybody has any suggestions on where to start I'm all ears. In the meantime I'm going to start reading up on transmissions here and in the service manual.
I'm sure my family thinks I'm nuts but I'm loving this
Maritime
Over 10,000 Posts
Shift pattern should be on the side cover near the shift arm. my 450T was a 6 speed. 1 down 5 up. The 400T was a 5 speed 1 down 4 up. Check the position the arm is in if it is mounted too high or low you can have issuse shifting in one of the 2 directions. 1 spline off can make difference. My motor came out of an 82 450T.
squizzymchaggis
Active Member
Maritime, thanks for the info. I had to remove the shift arm when I took the side cover off to check the timing. I just put it back on where it looked right and didn't even think about how that might have an effect on the shifting, so I may need to move it a spline or two.
If that doesn't do it, I'm hoping it's the clutch. I the box of spare parts that came with it was a set of clutch rings so I'm hoping that if it's not just the shift lever in the wrong place then maybe a PO replaced the clutch and didn't install the new rings correctly. I'll be sure to check the shift lever first just to be sure.
If that doesn't do it, I'm hoping it's the clutch. I the box of spare parts that came with it was a set of clutch rings so I'm hoping that if it's not just the shift lever in the wrong place then maybe a PO replaced the clutch and didn't install the new rings correctly. I'll be sure to check the shift lever first just to be sure.
Maritime
Over 10,000 Posts
It should shift without the clutch when not running. you sometimes have to rock it back and forth between shifts but with the engine off it should click down one, then up 4-5 depending on what transmission is in there. Try that, then you know it may be the clutch not disengaging fully when running but even then it should go into gear without the clutch, it will just jump and stall.
squizzymchaggis
Active Member
Ok cool. I will try that tonight. Thanks for the all the information! I've been so busy lately that I haven't had a chance to do much searching and reading on here yet, so I appreciate the advice.
