Author Topic: It's running, kinda.... need some help please? (Read 16575 times)

BrianAdair · « **Reply #75 on:** January 30, 2011, 09:13:50 AM »

Quote from: 754 on January 30, 2011, 08:33:39 AM

if you really used wire, rather than a drill bit or rod.. to bench synch, it may not be so close.. the straighter the better..
On a 315 cam, it is set at 12 thou, and its not really that loud.. may be a tad loud at idle, but not revved up.
Dont worry about idle tight now, and dont let it run a very low rpms if its not running smoothly..

12 thou? dang...

Well it wasn't really a wire, it was a torch tip cleaner, the one I used was around a 1/16.

BrianAdair · « **Reply #76 on:** January 30, 2011, 09:22:07 AM »

Quote from: lordmoonpie on January 30, 2011, 09:05:50 AM

Quote from: Brian77cb750 on January 29, 2011, 08:08:24 PM
Ok.... $:-\$ lol

Just seems noisy to me, its like CLACK CLACK.... lol I would think it would be smooth. but then again if I'm getting too much fuel, would that make it clatter also?

Yea the sprocket I don't know just kinda scary, but as you say probable not as bad as I'm thinking.
Hmmm, if you haven't torqued down the slotted cam sprocket it could be that moving. If it's not fully tight, as the engine comes on to compression the camchain tightens on the sprocket on the back, up stroke of the chain and will pull the sprocket around to the far end of the slot. As it goes past TDC the chain pulls harder on the down stroke of the sprocket and pulls it around to the other end of the slot and you get a very audible "CLACK" as it goes from one end of the slot to the other, the sound of the bolt hitting the end of the slot. Worst thing is unless you turn the engine over with the cam cover off you might not see it as the different tenesions on the camchain can actually pull it into a slot position that looks right compared to where you think you left it - the bolts are tight, just not tight enough! Personally I'd get the cam cover off, turn the engine over by the crank and listen for the clacking then. If it is the cam sprocket bolts being too light you don't want to run it like this as you'll be varying your timing all over the place while running and putting the camchain under sudden and very strong loads over the TDC point, increasing the possibility of a break and major engine disaster.

Don't want to be a scaremonger but for a simple check and a bit of time to remove the cam cover/engine you could save a whole world of pain later...you did dial the cam in anyway didn't you?

Had this self same problem with my slotted cam sprocket which is why I raised the possibility. Thankfully I found it while bench testing and not running the engine. The slotted sprocket required a higher torque on the bolts than standard to keep them from slipping - about another 4lb/sq in if I remember correctly...

Yea, I have considered pulling the cover just for peace of mind, I know I done it right, but then when I think and dwell on it I start second guessing myself cause it was so long ago that I put it together before the first start.
No, I didn't dial it in, I just lined the marks up, as u would with a stock cam.
So I guess it could possible be off around 3* or so.

I don't feel its the chain, I know it has to be the rocker arms, you can feel the valve cover while running and tell. Kind of like the old broom handle to the ear trick to hear a knock in the low end of a car engine.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #77 on:** January 30, 2011, 10:36:20 AM »

Brian,

That thing sounds pretty damned good to me! Sounds like a tight new engine. Can't remember the day mine sounded that good. I didn't hear anything with my less than optimal ears that I shouldn't have heard. And it fired up at the very touch of the button too. There's no way you'll get it to sound quiet like a modern engine. Degree the cam then I say get it fine tuned per instructions and sync the carbs and hold the bars tight and lean forward the first time you crank it. It will surprise you and straighten your arms out if you're not expecting it.

BrianAdair · « **Reply #78 on:** January 30, 2011, 10:47:08 AM »

Quote from: Jerry Rxman Griffin on January 30, 2011, 10:36:20 AM

Brian,

That thing sounds pretty damned good to me! Sounds like a tight new engine. Can't remember the day mine sounded that good. I didn't hear anything with my less than optimal ears that I shouldn't have heard. And it fired up at the very touch of the button too. There's no way you'll get it to sound quiet like a modern engine. Degree the cam then I say get it fine tuned per instructions and sync the carbs and hold the bars tight and lean forward the first time you crank it. It will surprise you and straighten your arms out if you're not expecting it.

I like the sound of that Jerry!

I'm down at the shed now, pulled the valve cover and everything is still good, cam sprocket still in time, with marks. Going to set lash back at 5 and 6 and then start it up again.

BrianAdair · « **Reply #79 on:** January 30, 2011, 02:08:33 PM »

Ok, here's a new video.

I pulled the valve cover, and the cam sprocket was still in place, checked over some things, and re-adjusted my valve lash to 5 & 6.

I did notice the cam chain tensioner was loose, so I re-adjusted it also. It starts right up again, but still hear the tapping...

guess maybe I'm not used to the sound of an old SOHC with a cam in it.

Heres the video, let me know what you guys think.

Thanks for all of your input and help guys!

bear · « **Reply #80 on:** January 30, 2011, 02:30:58 PM »

That's not right.

Something's hitting something.

Cheers,
Brian

scunny · « **Reply #81 on:** January 30, 2011, 02:34:34 PM »

I'm with Brian on that one, sounds too metalic. best way I can describe the sound you are after is " like the rustling of autumn leaves"

bear · « **Reply #82 on:** January 30, 2011, 02:43:45 PM »

Quote from: scunny on January 30, 2011, 02:34:34 PM

I'm with Brian on that one, sounds too metalic. best way I can describe the sound you are after is " like the rustling of autumn leaves"

That's very poetic of you Larry

Sorry Brian but if you have your valve train bolted down right, then I think you may have a valve tapping on a piston

Cheers,
Brian

Jerry Rxman Griffin aka MuthaF'er · « **Reply #83 on:** January 30, 2011, 03:14:34 PM »

I'm hearing metallic. If you do have a valve tapping a piston would proper degreeing in of the cam possible eliminate that? Will adjustment of the cam chain affect valve timing?

BrianAdair · « **Reply #84 on:** January 30, 2011, 03:30:47 PM »

....

...

I was thinking that could possible be the problem, I'm getting frustrated to the point of selling it all!

Nah I can't

Well, I guess, go back to the stock cam, which I really don't want, or thicker head or base gasket?

I really don't want to tear it back down again.

Can some one explain to me at what point the pistons would make contact?
I'm a little in the dark on understanding how a 4 stroke engine works, cause when pistons are at their highest point TDC the valves are closed...?

mlinder · « **Reply #85 on:** January 30, 2011, 03:59:36 PM »

Not on the exhaust or intake stroke, they arent. Only on the compression and expansion stroke.

scottly · « **Reply #86 on:** January 30, 2011, 05:50:26 PM »

There is a period at the end of the exhaust stroke, when the piston is approaching TDC, and lasting until after TDC at the start of the intake stroke, that both the intake and exhaust valves are open. This period is called the overlap of the cam. High performance cams generally have more overlap to favor higher RPMs, at the loss of lower RPM torque.

I would reset the clearance to .012, as Frank suggested. See if the sound changes. Also, make sure you're getting oil to all the rockers.

It sure runs well!!

BrianAdair · « **Reply #87 on:** January 30, 2011, 06:02:43 PM »

Quote from: scottly on January 30, 2011, 05:50:26 PM

There is a period at the end of the exhaust stroke, when the piston is approaching TDC, and lasting until after TDC at the start of the intake stroke, that both the intake and exhaust valves are open. This period is called the overlap of the cam. High performance cams generally have more overlap to favor higher RPMs, at the loss of lower RPM torque.

I would reset the clearance to .012, as Frank suggested. See if the sound changes. Also, make sure you're getting oil to all the rockers.

It sure runs well!!

I was just doing a search on the web to try and figure out how to find the lobe centers, since I have no data on the cam. I was going to try and just dial it in the same on the centers.

I was also thinking of opening the lash up as Frank said to see if that changed it. So .012 on both? or say .011 and .012?

I checked all with this clay, before I put everything together for the final time, @ 5 & 6 and had enough clearance I thought. I even deepened the valve pockets on the pistons a bit, (not so much the depth of them but the angle that they were at). You can't feel or hear it turning it over by hand, kick starting it, only when it's running
I guess after torquing the head down the gasket compressed more than I thought it would.

scottly · « **Reply #88 on:** January 30, 2011, 06:17:48 PM »

Did you do the clay with the cam installed? If so, how much clearance do you think you had? You don't have to torque the head down, just snug, but if you have a used gasket that's already been compressed, that's better.

I would loosen both to at least .012, and see if the noise changes.

BrianAdair · « **Reply #89 on:** January 30, 2011, 06:27:44 PM »

Quote from: scottly on January 30, 2011, 06:17:48 PM

Did you do the clay with the cam installed? If so, how much clearance do you think you had? You don't have to torque the head down, just snug, but if you have a used gasket that's already been compressed, that's better.

I would loosen both to at least .012, and see if the noise changes.

I think I had around .045 to .050 on the Intake, and around .070 or .075 on exhaust. Yes with this cam installed. After this measurement I took a little out of the pistons on the angle because it was closer on the way the angle was cut in the piston that the depth.

The head gasket came with the pistons it was a thicker gasket .056 instead of the .043
I didn't have an old one at the time, plus they would have been different thicknesses and my stock one was too small for the pistons to fit through.

scottly · « **Reply #90 on:** January 30, 2011, 06:50:52 PM »

Sounds like plenty of clearance. Whew..
Listened to the video several times, and it sounds to me like you may have some valves too loose, possibly do to procedure? If you are following a procedure that sets lash on more than one cylinder per crankshaft position, it may not work for your cam.

MRieck · « **Reply #91 on:** January 30, 2011, 06:51:49 PM »

Quote from: bear on January 30, 2011, 02:30:58 PM

That's not right.
Something's hitting something.

Cheers,
Brian

I definitely agree....and I hate to say that. Sorry.

BrianAdair · « **Reply #92 on:** January 30, 2011, 06:55:13 PM »

Quote from: scottly on January 30, 2011, 06:50:52 PM

Sounds like plenty of clearance. Whew..
Listened to the video several times, and it sounds to me like you may have some valves too loose, possibly do to procedure? If you are following a procedure that sets lash on more than one cylinder per crankshaft position, it may not work for your cam.

I do one cylinder at a time TDC 1&4 find the loose ones say #1 and adjust. rotate over to 1&4 again and do #4.

Same on 2&3

scottly · « **Reply #93 on:** January 30, 2011, 07:02:39 PM »

OK, that's one more thing off the list..?? Does it sound any different on the left side?

BrianAdair · « **Reply #94 on:** January 30, 2011, 07:08:02 PM »

Quote from: scottly on January 30, 2011, 07:02:39 PM

OK, that's one more thing off the list..?? Does it sound any different on the left side?

It's the same all the way across.. $:-\$

I'm thinking the valves are kissing the pistons.... I'm relly wanting to go out to the shed right now and adjust the lash to .012 and see what happens..

If they have been making contact, and I know that isn't good and it's possible, do you think I have cracked my pistons or bent the valves?

I guess I need to do a compression test also.

scottly · « **Reply #95 on:** January 30, 2011, 07:29:19 PM »

When I first got my bike, I found so much wrong with it I tore the whole thing apart. One of the things I found was small indentations in the 836 pistons, where the valves had been making contact. Fearing the worst, I took the head to the local Honda shop, and specifically asked that the valves be checked for bending. The shop told me the valves were OK, and I cut the valve reliefs into the pistons to match my cam.
If you had seriously bent valves, enough to crack the pistons, I doubt the motor would run so well, plus it would have made a hell of a racket when the damage was done.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #96 on:** January 30, 2011, 08:16:15 PM »

Brian,

What's the link to your cam thread? Has the cam been ID'd? Cam "TIMING" moves the valves closer/farther from the pistons during a specific cycle in piston movement. ie could open them at an incorrect "TIME" when the piston is too close.

May be time to walk away for a few days. You are close and can't let it get to you at this point. Check out some info about the 4 cycle engine valve/piston operations for a better understanding in the mean time.

BrianAdair · « **Reply #97 on:** January 30, 2011, 08:27:22 PM »

This is it Jerry http://forums.sohc4.net/index.php?topic=80296.0
No I never really found a clear ID of the cam still up in the air.

Yea, I think I do need a break, I just went down and adjusted the lash to .012 started right up as always, but still the same sound. $:-\$

I hope, and think, an older guy I know, that used to build these and turbo bikes in the late 70's is going to stop by tomorrow and listen to it, he's been a mechanic for motorcycle atv dealerships over the years.

When I say older I mean as in knowledge and wisdom...

Jerry Rxman Griffin aka MuthaF'er · « **Reply #98 on:** January 30, 2011, 11:34:36 PM »

You gotta watch them old bastards!

That cam doesn't appear to have a great lift, just great duration provided that was a stocker next to it. If the lift is close to stock I'd be real surprised it there was any interference. Of course it also depends on having the head and cylinders shaved too. Head gaskets can come in different thicknesses too if you should need a thicker one.

754 · « **Reply #99 on:** January 31, 2011, 12:13:20 AM »

I cant hear or watch the video, but my guess now is the valve may be kissing the pistons or a few of them.. If you can get a cylinder light, pull a plug and have a look.
Probably have to come apart, you get away with slight contact for a short time, but revving it out, will probably bend something. Check plug for electrode touching.., rare for that to touch but I had it happen.. wouldnt even run.. (350 slugs with too high domes + longer hi-po plugs)

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Author Topic: It's running, kinda.... need some help please? (Read 16575 times)