Ok, fIrst,I know nobody can diagnose, much less fix one over the net or the phone, but I wanted to see if anyone had any ideas or experiences so I might know what to look for before I strip the engine out for a case split.

It's had an occassionalslight knock (only when cold) for about 20,000 miles after I completely rebuilt it. (35,000 now) I read an older post of similiar noises that turned out to be one bad roller on a rod. But this won't do it under acceleration particularly after it's up to temp. Recently, it has a knock very audible at the nose cone when it's COLD. Seems like the warmer it gets, the less you can make it do it and it's quiet at high speeds under load or otherwise when up to temp, though it's vibrating a bit more than usual. I changed the cam, heads and entire valve train about 3000 miles ago and on the test run, it sounded like something grinding up in there and missed a bit - figured it was carbon broke off the piston and fouled a valve for a few seconds. Hasn't done that since. I had the nose cone off recently to replace the gasket and didn't notice anything out of whack, but wasn't looking either. No metal or anything in the bottom of the case though. And I cut the oil filter open - perfectly clean.

I have noticed before when I was into it,that turning the oil pump by hand (on the bike)feels like it has regular hard spotsand today I could hear a mild grinding at idle through the oil tank filler hole. Sorta makes me wonder, but can't imagine thattraveling that far and sounding like a knock.

Also, I've known of one case where a pinion gear was cracked and made a deep knock, so has anybody had anything else freaky happening like a cam gear or worm gear that would sound like a rod knock???????

Don't worry, I won't type and whine, just wanted some ideas from experience that might help me know what to put under the "microscope" in the cam chest before I decided whether to tear it all down.

Thanks

 

Pull your cone and check your lifter rollers. This was where my similar knock was coming from, and had I looked right off the bat I coulda caught it before it cost me big bux to fix...

bbs

 

Will do, BB Sue. Was going to do that yesterday, but wantedto listen one more time before doing anything. Startedand reved up high. It was quiet - couldn't make it rattle. And it'll turn up 4500 rpm smooth and quiet, so I'm unable to believe it's a rod bearing. Rode a few miles today and heard it now and then but not like the other day. So, I'll pull the tappet guides/lifters this afternoon and see what I got. They're Jim's lifters, maybe 8000 miles, but that doesn't mean much. New SE-1 cam (and bearing) about 5000 miles ago, sure don't want to messthat up.

Thanks for the reply, will post an upgdate asap.

 

It may be possible that you only hear it when cold because you oil is thinner when cold. 20-50w is 20w when cold and 50w when warmed. At least that is my understanding.

I really do not think that you have anything to worry about right now. You could try changing your oil to a straight 50w to see if the noise completly disapears. Or take into consideration that your motorand all gas motors are designed to run at a certain tempthat is warm or hot to the touch. My point is that you may hear things on a cold motor until it reaches the desired temp. Relax.

 

I`m thinkin` that when cold,his lifters are (or have)bled down and thus the noise.Check your tappet screen for debris before you do anything.Could be a bad lifter and won`t hold the oil.When you take the nose cone off check clearances on nose cone brass bushing,breather gear,breather gear shim and the tappet rollers themselves.The problem is most likely NOT in the block since it goes away when warm.Good Luck,Toby Before you disassemble get the cylinders to TDC and see if one of the pushrods are way looser than the others.

 

I do run straight 50W summer, 30W winter. 20-50 will not keep the oil light off at idle (1000rpm) when it's warm and I don't run it in anything I own, butI do appreciate your input, thanks

Tore it down to the rims Saturday (and split them too)All the bearings were pretty and could be re-used. The lifter rollers looked like new. The SE cam with less than 5000 miles had lost a good chunk of the hardface on the bearing end (new bearing and it was still good) so that explains some of it. Also, the rear wristpin was tighter than after I reamed it on installation(?) The piston wasn't worn on the pin andit swivled butI hadto drive it out of the rod, so I suspect that was the main culprit for the temperatire related knock and the bad (new) cam contributed to the vibration. Also, the bearing cages had chewed into the thrust washers almost through to the flywheels (both sides) yet the rods had barely made a mark on the washers. Couldn't get the side play under .028 when I assembled the flywheels (it was my first) but never thought that would let the bearings "walk" back and forth that much. (I did get it trued to .0004, if that counts for anything) I'll do better next time even if I have to get out the clover compound and lap the darned pin to the rims.

I reckon I didn't hone the rear bushing enough to hold oil and it was tryingto seize after 3000 miles. (my fault) The engine made a grinding noise just after installing that cam and new (torrington) bearing. I'd had the heads off and figured it was rear cylinder carbon breaking loose and fouling the valve cause it missed too. NowI know - it was that brand new cam loosing it's stuff right out of the box. Kinda ticked about that, but nothingto do but replace it.

Hope to have it well on the way back by next weekend's end, unless I decide to trick-up this spare set of heads I have. At any rate, I appreciate everyone's input and suggestions and will post an update when it's back on "all-fours."

 

PS

I checked the lifters (internal) by counting turns till they got loose while on base circle - they were all just like they should have been.