1972 Honda n600 bad timing? White smoke?

honda
timing-belts

#1

So I had oil leaking out of my starter so I ended up pulling it and replacing a gasket behind the flywheel… Now the car didn’t run because the timing was off by a lot so I jumped a few teeth on the timing chain. Now I have a bunch of white smoke and the car lacks power. It will stall going reverse out of my driveway unless I rev it high. The engine itself has less then 5k miles on it as it’s rebuild so I don’t think it’s a head gasket if it was running fine before I pulled the flywheel off. The idle sounds fine and feels smooth but puffs white smoke. I used a timing gun and adjusted it, and seems on point but now I’m stumped. What could it be?


#2

If the timing chain jumped some teeth, how did you correct the problem?


#3

By jumping it back to where I had marked it. When I first timed it I was with a co-worker he marked the cam and the chain. So we jumped it back.


#4

Oil smoke is often thought of as being blue in color but it can also appear as white. Any chance the jumped chain caused a valve to tap a piston and cracked it or screwed up an intake valve guide or seal…


#5

If it did, how can I check it?


#6

WHOA…Whoa…Whoa… Timing was off by a lot so my chain jumped? I think you have that sentence backwards. If this engine does not have the cam phasing proper…do not even attempt to run it.

Far as I understand this…this is an Air Cooled 600cc Honda Twin…right? Of course it is…Anywho… Please do not run this engine…and I mean…at all…till the timing chain is sorted out…the tensioner is correct and the cams are phased properly. Nothing but Badness will come from running this engine out of phase and you may find you need to rebuild the cylinder head if it was run far enough out of phase.

Your task right now…is not to start or attempt to run this engine…at all. You MUST phase everything correctly and ensure it is able to turn over correctly…and ensure the timing does not skip or jump at all…at all at all… I cannot overstate this.

After you get the cam and crank phased correctly…and the t chain adjuster adjusted…you need to hand rotate the engine several revolutions… then prior to starting it up…do a compression test and after a positive report of compression results only then can you start it. Then you can run it…and tune it. Till then…do nothing but phase this engine properly

@ok4450 spelled out in basically one sentence, what my diatribe above was worrying over… When you run any engine out of phase…the Pistons Kiss the Valves…and I promise you dont want that…in any way.

Blackbird


#7

For folks that are curious, here’s the engine:


#8

@“Honda Blackbird” @ok4450
After I was jumping the chain I hand rotated the engine and some parts did get stuck. If it did get stuck I chain jumped one more and hand cranked it again then it was freed. Then we checked to see if the spark was off or not. I’ll look at how to phase an engine, thank you all.


#9

One bad step and then engine’s toast, you understand, right?


#10

Yes I do, understand. Might wait until I go into work Wednesday to ask my boss what he thinks I need to do.


#11

Here’s a good article on cam chain stretch in your engine:

http://honda600coupe.com/tech_pages/cam_chain/index.html

In it is a link to a shop manual, too.


#12

I worked on a few of these things and drove them back in the 80s at the Honda dealership when a straggler would show up.
Honestly, I don’t remember much about them other than their being a motorcycle with 4 wheels with the later ones being water cooled if I remember correctly.

These things are collectible now; a notion that no one back in the day would have ever believed.


#13

Collectable, and I imagine parts are not at the dealer. Guy at school had one, ‘friends’ turned it sideways in the parking spot (by hand), trapped him in.


#14

Putting a mark on the cam and the chain to check cam timing later is useless. The chain and the cam gear will not retain a consistent relationship. What counts is the relationship between the cam gear and the crankshaft gear. There are preexisting arks on each along with alignment marks on the block and the head. This is what you use to check cam timing with.

There are some cams gears that are timed by having a mark on each gear and you mark the chain links that are x number of links between them. Then you put one marked link on the marked sprocket of the crank gear and the other marked link on the marked cam gear sprocket. As the engine is rotated, the marked links will not land on the marked sprockets very often.


#15

Driving a Deuce & Half on the Tomei Expressway many years ago those little Hondas and a small Subaru were so under powered that I passed them like bicycles. And when driving a Jeep next to them they sounded like an egg beater stirring a bowl full of rocks. Of course the Japanese usually junked cars when they reached 100,000kms so there was no need to build cars that would last any longer.


#16

As I mentioned previously, I remember practically nothing about these cars and have no literature at all on them.

Since this car has what essentially is a motorcycle engine is it possible this problem is caused by something like a crankcase breather or breather gear out of whack?

My old Harleys and Triumphs have and had breathers and if they’re out of time all kinds of grief can happen including excess smoke.
If the OP has a manual on this thing, maybe perusing it for info on a breather would help.


#17

After you’ve confirmed the valve timing is spot on, you might try a compression check. That will probably tell you whether or not you’ve suffered serious internal engine damage due to the valve timing being out of whack prior.


#18

@ok4450 I did have oil leaks that I was getting upset then after looking at the shop manual I noticed that the previous owner plugged the breather on the crankcase. So I unplugged it and added a tube so it can vent. However this is after the white smoke so I have not ran it. It is also a manual transmission if that’s what you were wondering.

@texases I’m not that strong of a guy and I can lift the back and drag it, so if I park bad it’s not a big deal just a quick drag can fix it.

@keith Is there a ratio from where the cam and my marked link will meet and I can keep jumping it and hand turning to see if it’s free and see how the timing is?
Just looked at blocks that they are selling online and don’t see any alignment marks on them.


#19

Something tells me the “White” would be classified as “Grey or Blue” to a trained eye. You dont really have the provisions to produce proper “white” smoke.

I know this may sound confusing…but we Gear Heads can almost tell you what you had for Breakfast by the type of smoke coming out of your tailpipe… LOL… A little joke obviously but the color of the exhaust does tell certain tales…that I promise you.

Get your timing proper…follow procedure to the letter…be sure you set the cam chain adjuster properly…and rotate by hand…then do a comp test…this is important…

I hope your valves are OK…

Blackbird


#20

@"Honda Blackbird"
Okay, I’ll get a compression test kit. You’re probably correct. Last time I was at work I said a car was blowing white smoke and it was gray to our service writer.