FourWheelForum  

Go Back   FourWheelForum > Motorcycles & Streetbikes! > Honda Dream CA160

Honda Dream CA160 The old black horse

Reply
Thread Tools
  #1  
Unread 07-05-2013, 10:54 AM
grubsie grubsie is offline
Senior Member
 
Join Date: Aug 2011
Location: Danville, NH
Posts: 112
Default CA160 Valve Timing

Decided to tear down my '66 CA160 while waiting for my correct seat cover to arrive for my CA95 to complete it. Everything on the 160 is down to a bare frame. The previous owner couldn't ever get it running and spray painted it with white and black paint without masking or removing anything along with all kinds of wrong parts and butchered many other things.

I have plenty of work to do on this thing without even worrying about the engine yet, but I want to start tearing down the top end to see what is causing the smoking because it is bugging me. Before I took the bike all apart, I tried running it for a while after using mystery oil in the cylinders ( a few squirts overnight for several nights) along with seafoam in the oil to free up possible stuck rings all to no avail. It was real fun trying to ride it up and down the street without the use of a clutch. (All the internals under the cover on the countershaft side are missing.

I can't seem to find anything on the web for help on the valve timing. Hopefully someone here can point me in the right direction. I do not want to tear the top end down before know what timing marks to look for.
Reply With Quote
  #2  
Unread 07-05-2013, 12:19 PM
Larzfromarz's Avatar
Larzfromarz Larzfromarz is offline
Senior Member
 
Join Date: Dec 2011
Posts: 620
Default

Quote:
Originally Posted by grubsie View Post
It was real fun trying to ride it up and down the street without the use of a clutch. (All the internals under the cover on the countershaft side are missing.
Ok, but that I'll assume you mean the clutch actuator and not the dynamo/flywheel and stator found underneath the left side engine cover.
That being said the clutch is a different issue than valve timing.
Your specific question;

Quote:
I can't seem to find anything on the web for help on the valve timing. Hopefully someone here can point me in the right direction. I do not want to tear the top end down before know what timing marks to look for.
I'd first answer by asking if you have a manual- Being old school I look at the manual before the interweb. Now folks look to the interweb for the manual.

Anyway, the timing marks, in this case the T = TDC and the F= Fire or breaker points opening, on the flywheel should line up with the pointer when the pistons are at the top of the stroke. Normally the points are set to open just briefly prior to TDC. If the cylinder head cover is off, and you are at or near TDC (T on the flywheel) for the left cylinder, the timing mark on the cam gear should be at the 12 O'clock position. It's often lightly stamped and may be difficult to spot but is a large "0". If the points breaker plate and advance mechanism are removed the drive pin for the advance mechanism should be pointed at the 6 O'clock position (contrary to some manuals).
Valve adjustments should be made only when the engine is cold, with cam chain adjusted and I usually tend to set them a bit loose. I think the book calls for .002" for both intake and exhaust and I am ok at .003.-005", especially for new engines.


Speaking of... I have found that when some of these engines get revived often times they smoke and sometimes continually. I believe that as time goes along folks "turn over the engine" or force stuck and stiff engines. As fragile as rings are they are easily broken as I found on my red CA.
The best test is a leakdown compression test, then/or a regular compression test. It should tell you if you have ring or valve problem. In either case you'll be pulling the top end down if you have a problem.
Attached Images
File Type: jpg timing.jpg (152.0 KB, 8 views)
File Type: jpg DSCF1918 (3).jpg (178.4 KB, 6 views)
Reply With Quote
  #3  
Unread 07-05-2013, 01:20 PM
grubsie grubsie is offline
Senior Member
 
Join Date: Aug 2011
Location: Danville, NH
Posts: 112
Default

Thanks Larzfrommarz,

I wish I had a manual, but unfortunately I do not. Being that I am impatient, I tend to dive into things and just take a lot of notes as I go. Works for me most of the time.

I should have looked at the timing before I posted. I figured it out basically like you described only as little different. At some point after several revolutions, the "T" mark lined up with the mark on the stator cover, the drive pin for the spark advance was at 12:00, the "0" on the cam shaft at 6:00 and the master link for the cam chain was sitting at 12:00 for easy removal. Can't believe it was that easy.

Anyway, cylinders looked pretty good, only some very light scratches, valves looked good. The rings were OK but the pistons definitely had brown blow by on the sides. Similar to the browning in the picture you sent, only worse.

I took off the top ring on each piston and set then in their corresponding cylinders about an 1" down from the top. If sitting on the bike, the end gap in the ring on the right side is .020" and the left is .021". I think they have reached end of life. I will have my machinist check the piston and cylinders, but I think I have to go to the next size pistons and rings.

Having never been inside a 160, I think someone else already had as I noticed at the base of the cylinder where it meets the engine, there was some green rubber type stuff around the oil dowels. I am assuming that there should be o-rings there instead.

One last thing, if standing in front of the motor (exhaust side)with the pistons still in place, I noticed markings on the intake side of the pistons as"IN" or they would read "NI" if standing at the back of the engine (intake side). Is this correct?
Reply With Quote
  #4  
Unread 07-05-2013, 03:24 PM
Larzfromarz's Avatar
Larzfromarz Larzfromarz is offline
Senior Member
 
Join Date: Dec 2011
Posts: 620
Default

Do make note of the piston orientation if retaining the pistons. On the stock pistons you might find an arrow, meant to face forward, like in the pic. You didn't report the bore size so you may have an overbore already.
On some of my rebuilds I don't mind building the engine a little loose, as I mostly never intend to use the engine hard. While a 20 thou end gap is a lot (book calls out .029 as the limit), I usually don't come as close to the 6 thou my book calls for. I think my last motor was at about .008"-.010". Remember even if you just hone or break the glaze the gap will increase so you may be looking at up sizing or just finding a suitable cylinder set.
I don't know if you could get away with the next size ring and adjust the gap allowing you to the keep the pistons.
Regarding the piston marking, it is my understanding that there is indeed a piston pin offset that necessitates the marking.
Don't get me wrong, I'm old school (enough) that I still like the feel of paper and even greasy paper, in my hands. I buy a manual for everything I have, even if don't use it. I'll be ok when the EMP goes off......
Attached Images
File Type: jpg DSCF1924 (2).jpg (167.0 KB, 4 views)
File Type: jpg DSCF2489.jpg (243.6 KB, 5 views)
Reply With Quote
  #5  
Unread 07-06-2013, 08:43 AM
grubsie grubsie is offline
Senior Member
 
Join Date: Aug 2011
Location: Danville, NH
Posts: 112
Default

Ordered a Clymer manual last night from bikebandit.

I only have an "old school" set of vernier calipers without the dial. My eye sight isn't what it used to be but the skirt of the pistons measure at 1.968" or 50mm. By a little research, it seems that 50mm is standard size. I can't get an accurate reading on the cylinders.

There aren't any markings on the pistons except for the (NI) or (IN), depending which way you are looking at them, that I am assuming is the intake side. No arrows... nothing like STD for standard or 0.25 for 1st over etc. Would be nice to know the measurements. If standard is 1.968, 1st over should be very close to 2.218?

Probably will go to 1st over as I am planning on making this my daily rider to work and back in town. Want to build this a little more custom like this blue one that one of the other members did. Can't remember his name but he did an outstanding job on it.

The white one is the 1966 CA160 I have. Does anyone know which year those handlebars came stock on? I know they didn't use them in '66.
Attached Images
File Type: jpg Blue CA160.JPG (59.5 KB, 9 views)
File Type: jpg CA160 Left Side.jpg (106.9 KB, 8 views)
File Type: jpg CA160 Right Side.jpg (106.6 KB, 10 views)
Reply With Quote
  #6  
Unread 07-06-2013, 09:40 AM
Larzfromarz's Avatar
Larzfromarz Larzfromarz is offline
Senior Member
 
Join Date: Dec 2011
Posts: 620
Default

That'll be neat bike... a little "bratty". The white bike has "clubman" bars, definitely aftermarket and, sorry but upside-down. They are meant to be a low position racing bar.
That being said they don't look horrible as is.
Honda may have used different vendors for their piston castings. With the numbers you are initially looking at I believe you might get away with a ring job and no oversize. On the other hand if it's apart and you have the means go oversize. Std size rings are harder to find anyway.
And yes you have to get used to back and forth from English to metric. In these cases I prefer the metric references.
Reply With Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -8. The time now is 04:51 PM.


Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.