Newbie about to start my first build - '82 Honda CB450 Nighthawk

My plan for the day was to adjust the valves, put the ignition coil and tank back on the bike, and then check the timing. Best laid plans, right?

Well, I noticed that there were two different bolts holding the valve cover on but thought that a PO must have lost one and replaced it. I got the valves adjusted and then noticed that the place where the right hand valve cover bolt screws into the head was broken. The threads are all broken off and there isn't anything left for the bolt to screw into. I don't know how it wasn't blowing oil out from under the cover every time it ran. I tried tapping the place to create some new threads for the bolt to go into but the hole it too shallow to get enough threads. In glancing at the manual it looks like the bolt actually screws into the rocker arm assembly so its time to do some more research as to exactly what part I will need.
 
The manual is confusing. I looked at the wiring diagram and it appears to have a CDI - but with much lower coil resistance/impedance so it's important to test with a multimeter that can read really low resistance. I want to say it is something like 0.5 Ohm but check that. If it's really open circuit at the coil, then it cannot generate any sparks at all. Were you getting sparks as you kicked it over with BOTH plugs grounded?

Some auto parts stores have plug testers 0 they are just a variable gap and can be hooked onto the motor at one end and plugged into the plug cap at the other. they are usually pretty cheap and much easier to see a spark than on a plug resting on top of the motor.
 
Teazer, I tested it with one plug grounded at a time and was getting a spark, but did not test it with both plugs grounded. Is it supposed to be done with both grounded at the same time?

Oh, and I found rocker arm assemblies for my bike on ebay and you can see where the bolt for the cover should attach.
 
Also, when I tested the coil at the primary contacts the reading bounced between .1 and .3 Ohm but the manual calls for .5 Ohms.
 
If you are getting a spark on each side when the other side is grounded, I'd call that good and move on.

FYI the two sets of numbers are 0.10 -0.30 Ohm,s on some models and .55 -.65 ohms on the other according to Clymer.
 
I ordered the valve rocker arm assemblies that I found on ebay. Once I get those I will switch out the assembly on the right so that I can bolt down the valve cover on that side. Once I have the valve cover bolted down so that I don't blow oil everywhere when I start the bike I will put the ignition coil back on, remount the tank and then check the timing and also make sure I'm getting a spark on each side while the other side is grounded.

Teazer, so do I ground both plugs on the engine block and just check both of them? The first time I checked it I left one plug and pulled the other and grounded it on the engine, then did the same for the other side. Both sides gave a spark when I did it that way.

I know the carbs need work, I'm just trying to make sure that I'm getting a good spark and that my ignition system is good before I jump into the carbs. I'm trying to rule out one variable at a time.
 
You can ground both plugs against the head/cylinder and check for sparks on both sides at once.
 
Yeah.. Sounds like Carbs to me. But then I always like to start simple.
 
I have read in several threads that the best way to clean carbs is with a sonic cleaner. I was thinking about getting one from Harbor Freight tools thought I'd see if there is anyone that has experience with these cleaners and which one they would recommend.

Also, any carb parts that should be put into one for some reason?
 
are they actually guumed up with old gas ? and or lots of white fluffy stuf? if not some careful thorough hand cleaning will do the trick just fine
 
xb33bsa said:
are they actually guumed up with old gas ? and or lots of white fluffy stuf? if not some careful thorough hand cleaning will do the trick just fine
Click to expand...

Eeew white fluffy stuff...whats the best way to get rid of that? I pulled a old Tillitson off a '84 Moto-ski the other day, it is gummed, rusted and white fluffed! Soak it in something? Gas? Can you buy a vat of carb cleaner?
 
yeah you can get the dip can of the carb cleaner at auto parts stores, i hate that shit though stinks too nasty :mad:
 
I got in the rocker arm assembly that I bought off eBay. Time to get that switched out, then check the timing and clean the carbs.
 
Got the rocker arm assembly switched out and the valves adjusted, now its time to reassemble everything and check the compression and timing then on to the carbs.
 
Just checked the timing and the timing mark didn't budge a bit so its not advancing as the engine revs. I guess its time to look for a new CDI.
 
Hopefully I will get the carbs pulled off the bike and can start cleaning them in the next few days. Anybody have any tips or tricks they would like to share?
 
If you can leave them on the rack so you don't mess with the mechanism that opens the butterflies etc. You can get all the parts off you need to leaving them together.
 
The CDIs on these guys are pretty bullet proof, but the carbs can be pretty funky if they are not tuned in right, and if there are problems like your rocker cover then I'm sure the carbs have had similar treatment. I did a lot of searching on the ignition and there isn't very much you can do and the parts aren't readily available.

The stock carbs have a dead spot between idle and mid range rpm, the new needle takes care of that. The link Teazer gave you is legit. This one is also a good one http://www.hondatwins.net/forums/63-fuel-supply-carburation/21654-carb-information-years-jetting-more.html

When I went through mine I found that the POs had lost o-rings on the pilot screws and other simple fixes that really made it run like a top. Look specifically for miss-matched jets, the stock main is 115, the secondary is 72, and the pilot is 38. Also these ones are supposed to have the little black rubber plugs on the pilot jets. The pilot screw should be out 2 1/2 turns at sea level, 2 at higher elevation.
 
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