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62benly
08-18-2010, 09:11 AM
Hi there,

I finally got my benly put back together, I cant wait to wake this baby up.

The motor would not start and I checked the timing situation and was sure I had it wrong the first time so I fixed it as I saw others had on this forum. What the one guy did with the laser was pretty nifty and I thought I'd just eyeball it instead sorta.

I found this mark to the left of the seam up top. Is that what I am to align the little cam gear 'O' mark to? Then I imagined a line like the laser and set the drive shaft gear 'O' mark to line up on the low side of the shaft.


I drew a screwball picture and took some pictures.


P.S. When the T mark on the magneto is lined up with the timing mark, the cam shafts 'O' mark is straight up aligned with the seam. If its like that the timing is good, right?

Spokes
08-18-2010, 08:07 PM
The only way to tell for sure is to remove the points and advance mechanism. The keyway on the crankshaft/flywheel should be at 12 oclock.

So if the cam sprocket is at 12 and the keyway is at 12, you should be ok.

Assuming you have spark and fuel, I would guess that you need to check the valve adjustment. If the valve lash is not correct the motor will not start and if you keep cranking the engine, you should get a nice shotgun blast out of the exaust.

62benly
08-19-2010, 09:43 AM
Thanks Spokes.

So I tore it down a little and took some pictures of the key and the cam sproket.

Looks like when the key is at 12 the sproket is at 11:55 or so. Looks like I need to adjust it just a tad.

Do I have the right idea here?

Spokes
08-19-2010, 01:04 PM
The cam sprocket "12 oclock" mark is as shown. Move the mark to said position and check your keyway.
http://www.fourwheelforum.com/picture.php?albumid=11&pictureid=268

Or,since you have the engine disassembled to this point and to make sure the timing is set, or needs to be set, remove the remaining housing to expose the timing mark on the crankshaft.

62benly
08-19-2010, 01:22 PM
Hello,

Here are some pictures of the cam sproket 'O' and the drive shaft 'O'.

Your picture of the 12 0 clock mark is great help.

Spokes
08-19-2010, 02:31 PM
It looks like the timing is OK. Check the pic
http://www.fourwheelforum.com/picture.php?albumid=11&pictureid=269

The next thing to check is the rocker clearance to the valve stem (valve lash) They should be at .003 each.

62benly
08-19-2010, 02:51 PM
I measured them a loose .004, and made sure they wiggled just a tad. The spacer fits in there very easily. should it be difficult to push the spacer inbetween the tappet and the end of the valve? I took some pictures of one of the tappets.

Spokes
08-19-2010, 03:55 PM
Well I have to say that .004 is OK and the spacer should glide in and out without play. But, being that your at an angle when you try to measure, it may seem tight. So again if .004 is accurate then you shold be good.

So the timing is good and the valve lash is good (from my perspective)

Sam Green
08-19-2010, 11:13 PM
All you need to do now is put the split link the right way round on your cam chain or it will come of and smash all your hard work.

Sam.:)

62benly
08-20-2010, 07:07 PM
Your right sam. Thanks for the pointer. I will fix it right away. Thats the last thing I need is something terrible happening like my motor getting smashed.

Still no start. Not sure why. Got spark, gas. A little smoke comes out the wrong way out the carburetor. It kinda sputters out of it quick like.

Im sure Ill figure this out soon enouph.

Spokes
08-20-2010, 07:32 PM
Check the tappet clearance on the intake valves. You may still have one (or more) that may not be fully closed. The "smoke" the wrong way through the carb can only occur when an intake valve is not fully seated.
Just for fun, check out the 4 cycle engine animation for a quick refresher.

http://www.animatedengines.com/otto.shtml

62benly
08-21-2010, 11:33 AM
I adjusted the tappets three times, from loose, to snug, to tight againts the .004 spacer. I was getting some sputs of flame out the carb on my last try, so im thinking this is still a timing problem. :cool::eek::o

I really appreciate your feedback. Im excited to get this dog barking.

Spokes
08-21-2010, 12:44 PM
My pleasure to help. I checked my manual to double check the timing marks. You appear spot on. I hope Sam Green chimes in. I have to revert back to student now that all of my input has failed to get you going.

Sam Green
08-22-2010, 12:15 PM
If the valve timing and tappet clearances are OK, you have spark and fuel but still won't start, chances are the ignition timing is miles out.
Put a small 6v test lamp between the points and earth. If the points are clean and gapped properly, with the ignition on, turn the crank slowly anti clock wise with the spark plugs out untill the f line on the rotor lines up with the ignition timing mark through the hole at 2 oclock just off the timing back plate. You have this hole in one of your pictures that you posted.
As the two line up, the light should come on. If it don't, move the points back plate left or right to correct it.
If there is not enough adjustment in the elongated slots, chances are, the complete cover that the points back plate is fastened to is not in the correct position. You might not think this cover can go on wrong but it can.
You may have to loosen the cover that the clutch cable goes through while you do this as it buts up to the cover that you are trying to adjust and restricts movement of the timing houseing cover.
Good luck.

Sam.:)

62benly
08-24-2010, 08:24 AM
Look at these two pictures (Smithers Pic is just a link here http://www.fourwheelforum.com/showthread.php?t=111&highlight=points+adjustment). When smithers F mark is lined up the high side of the rotor is just beginning to push up on the point arm.

When my F mark is lined up the low side of the rotor is begining.

So the points are suppose begin to open when the F mark comes around but mine begin close, no matter what adjustment I make by rotating the mechanism within its bounds or trying to manuver the whole engine case cover.

Could it be that something else is out of whack. Yeah, yeah, it could be me and thats why I really appreaciate the benly masters who frequent this forum.

Spokes
08-24-2010, 09:15 AM
I don't profess to be a Benly Master.....But, when I rebuilt my first CA95 engine, it too would not start. After much agonizing I found that I still did not have my valves adjusted right. I know, I know, that may seem irritating. According to the manual, I will quote just what applies.

Remove the contact breaker cover and align the pointer on the generator with the black "T" on the rotor.

Remove the four caps and loosen the lock nuts on the tappets.

Adjust the tappets for intake and exaust on one side (cylinder) then rotate the crankshaft one revolution and adjust the other side.

For kicks and grins, I would do a compression check before the adjustment and after the adjustment. If the tappet (valve) adjustment causes an increase in compression (because the valves are fully seated) then you may have success.

You certainly don't have to the compression check, to check your work.

I went through the same agony on my newly rebuild motor, that's how I got the laser pic. I had to make sure I got the timing right.

Now here is the kicker. IF FOR SURE=Valves are correct IF FOR SURE=Timing is correct (the pics say yes) Then you have to do a compression check. If the compression is under more or less 110lbs (good is 120, my engine ran at 115lbs Then you don't have enough compression to start the motor. (Bad valves or worn cylinder) Let's hope not.....although not the end of the world.

Sam Green
08-24-2010, 01:54 PM
:D:D:D:D:D:D I've been called some things in my time, but Benly Master :rolleyes:
OK, joke over, just call me Sir Sam:o
I really am pleased that you have this problem because you made me think if there was anything that could be done to make this process more simple.
It took me all of 10 seconds to come up with an idea for a gadget that will help in the setting up of the ignition. I can't explain it now as it will involve some presision machining to make the gadget. I'll see if it works before I unleash it on the WWW.:)
Don't for one minute think you are the only one with this problem, I have it every time I put a motor back together, it really dose involve getting the main generator cover on in the right place and there is no way of knowing if it's right or wrong untill you find that you can't get the ignition timing correct.
In your case 62, you need to make sure that, when you fitted the points cam/advance assembly onto the rotor, did the peg on the back of it locate into the slotted keyway. If it didn't, then the ignition will be all over the place.
Another thing to check, as Ryan (smithers) said in his link, make sure the advance and retard unit is free and not sticking open, it needs to be closed to set up the timing. Do this and check back.

Sam.:) the Benly Master:D:D:D:D:D:D:D

Spokes
08-24-2010, 02:08 PM
I will be very, extemely, beyond pleased, when the final answer is found. I will print out the answer and tape into my manual!

Sam Green
08-24-2010, 02:29 PM
I think 62 is doing somthing wrong Chip Benly Master, but the outer cover really can be a pain in the butt. You wouldn't beleive how many times the same problem crops up on the CB750 and it's all down to sloppy fitting, thanks Honda:mad:

Sam.:)

62benly
08-24-2010, 02:52 PM
Ok so I checked the spark advancer peg and made sure it was on there correctly, and it was. I took some pictures.

I could rotate the ovalish rotor (Cam) 180 Degrees. Im thinking I'll try this. I took some pictures so you know what Im talking about.

Also, I have a concern about the rotor bolt Im using. Its a little bit bent. Im hoping it would straighten out when screwed in all the way, or even better, its no problem at all. I took a picture of that too.


UPDATE!!!!

Ok, so she fired up and reved like crazy. My hearts racin, the battery cable came undone and it only reved up for like 3 or 4 seconds and stopped thank heaven.

I am sure rotating the cam 180 Degrees did the trick. Now I just have to get the poor old guy to start up peacefully. Whew!!! This is exciting.

Sam Green
08-24-2010, 03:03 PM
See how easy it is, as soon as you talk to the Benly Masters, you start to figure it out for yourself. That is our magic rubbing off onto you.:D:D:D:D:D:D:D

Sam, Benly Master retired:p

Spokes
08-24-2010, 06:57 PM
Congrats and a very interesting and brilliant move! I will print this thread out and paste it into my manual. I would of never guessed that the "cam" could be installed incorrectly.

Now the fast throttle...here is the same kind of issue. In the throttle "slot" in the handlebars (assuming you have the internal throttle assembly) is a small "stay". The throttle cable end fits inside the "stay". Looking at it you will see how it fits. You can acually install it backwards! The throttle will feel as if it works! But your bike will scream the rev's! Been there done that too!

So for blasting fast rev's, check that "stay"!

Also you have an adjustment for the throttle just outside the frame at the front of the tank.

62benly
08-25-2010, 03:11 PM
I fixed the throttle problem and she purrs. Like music to my ears.

Thanks Sam and Spokes for your masterful help.


I posted a video for your pleasure. http://www.youtube.com/watch?v=Ei2MmotbfvY

Sam Green
08-26-2010, 06:17 AM
Well done 62, a nice example of the early Benly.:cool:

Sam.:)