Author Topic: Help!!!! valve lash increasing when warming up (Read 3128 times)

750caferacer · « **Reply #25 on:** April 10, 2020, 12:18:56 PM »

for the most part yeah but the other ones do loosen up not as much probably due to the heat. and whats the point in building something and not riding it! id rather have many trial and errors with making it functional then build a bike as a show piece.

bryanj · « **Reply #26 on:** April 10, 2020, 01:04:58 PM »

Thing is to learn what happened and to do that you need to inspect the oil jet(s) and discover exactly what blocked them, report back with pics if possible and we will do our best to help you ensure it doesnt happen again.

754 · « **Reply #27 on:** April 10, 2020, 01:23:03 PM »

It only takes a piece around the size of a pinhead or so of gasket or sealer...to make the oil starving happen..

seanbarney41 · « **Reply #28 on:** April 10, 2020, 06:45:07 PM »

Quote from: 754 on April 10, 2020, 01:23:03 PM

It only takes a piece around the size of a pinhead or so of gasket or sealer...to make the oil starving happen..

even leaving out the o-rings located under the outside end of the cam towers will damage the valve train...just not as quickly

PeWe · « **Reply #29 on:** April 10, 2020, 11:16:02 PM »

2x2 o-rings needed for both cam towers/holders. The outer just a stop.

Don R · « **Reply #30 on:** April 13, 2020, 09:05:52 AM »

A sohc might be different but a pushrod engine always checks different hot and cold. My big block chevy with aluminum heads checks .006 looser hot.

750caferacer · « **Reply #31 on:** April 13, 2020, 10:49:06 AM »

Is there gonna be a difference in the cam and rocker arms and boxes between the years the sohc was made?
i mean what years and motors can i pull parts from like cam and rocker boxes and stuff?

bryanj · « **Reply #32 on:** April 13, 2020, 11:37:06 AM »

All will fit but stay away from 77/78F

750caferacer · « **Reply #33 on:** April 13, 2020, 12:01:52 PM »

whats up with 77 78 f stuff?

bryanj · « **Reply #34 on:** April 13, 2020, 12:50:23 PM »

Different valves,valve angle,cam, i think rockers and they wear out valve guides quick

seanbarney41 · « **Reply #35 on:** April 13, 2020, 01:07:34 PM »

Quote from: bryanj on April 13, 2020, 12:50:23 PM

Different valves,valve angle,cam, i think rockers and they wear out valve guides quick

the only difference is longer valve stems and different keepers and the 77/78f valve guides are made from inferior material. Everything else swaps any year 750 head. In fact, 77/78f is the hottest grind available from the factory and is good for slightly more power up top. I have 77/78f cam, towers, and rockers in a 76k motor for 20,000 miles now and it works great.

750caferacer · « **Reply #36 on:** April 17, 2020, 09:28:26 AM »

i will post what i find when i have time to tear bike apart!

Jerry Rxman Griffin aka MuthaF'er · « **Reply #37 on:** April 17, 2020, 10:09:20 AM »

Did anyone mention the main difference in valves with the F2/F3 other than the issues the head presented? Larger valves for improved performance. That and a few less oil return holes that have to be plugged up to go on the other engines unless the F2/F3 jugs and pistons are used which should be done with the F2/F3 head.

750caferacer · « **Reply #38 on:** May 25, 2020, 06:41:21 AM »

Well yesterday i dove in to the cb750........

My beautiful girlfriend and myself got the motor out and up on the bench and began the tear down.
As you can see in the pictures the poor cam, cylinder 1 & 2 cam box, and rocker arms didnt make it.
I will say this though the oil filter is a champ and pervented it from spreading!!!!
Seems like the head cavities caught mostly everything and didnt let the returns take to much metal back down to the bottom end.
Gonna pull the oil pump and check it even though it has like 75psi of oil pressure im gonna check the pick up on it.
The last picture was the cause of all this, seems as if when i replaced my head studs with the hd studs aluminum from removing the factory studs was left in the oil galley and stopped up my metering valve

no silicone was present in the galley so that good!

bryanj · « **Reply #39 on:** May 25, 2020, 06:58:13 AM »

That had no oil from first start!

750caferacer · « **Reply #40 on:** May 25, 2020, 07:22:40 AM »

whats crazy it is took about 1500 miles before it locked down!

ekpent · « **Reply #41 on:** May 25, 2020, 08:11:49 AM »

Nice pics of the gruesome carnage

I have a cam in my stash from an engine that has even less metal on the end. It went on to live again as will yours.

750caferacer · « **Reply #42 on:** May 25, 2020, 01:06:36 PM »

does anyone have a good cam and cam box with rockers?

750caferacer · « **Reply #43 on:** August 10, 2020, 12:49:45 PM »

BUMP DOES ANYONE HAVE A GOOD CAM AND CAM BOXES?

PeWe · « **Reply #44 on:** August 10, 2020, 01:13:09 PM »

754 · « **Reply #45 on:** August 10, 2020, 01:31:16 PM »

Yes mine went at least 1500 miles too. Wore off about as much as yours.
Working on motor tip, put a 2x4 under the front lower motor mount , or a 2x2 , and it will sit real sweet..

BoneDigger · « **Reply #46 on:** August 10, 2020, 05:12:58 PM »

As the others say: check eBay for a used cam and left side cradle. I had a block in my left side oil feed at my engine case, preventing oil from going up the cylinders on that side. The bike locked up the same way as you described, but the damage was not as bad. The left side of the cam had some minor scoring on it, but both bearings of the cradle were toast. Shop around a bit on eBay. There are lots of cradles and cams right now. But make sure that the cradle you buy has the top clamp halves. These are matted to the cradle and both are stamped with a set of letters to make sure they are matching sets. I found a couple of eBay sellers trying sell cradles without the top clamps. When I asked the, they either never answered, or suggested I buy the top clamps From someone else. Don’t do this. They should have match letter codes. Just skip that seller and go to the next one.

HondaMan · « **Reply #47 on:** August 10, 2020, 05:56:10 PM »

Quote from: BoneDigger on August 10, 2020, 05:12:58 PM

As the others say: check eBay for a used cam and left side cradle. I had a block in my left side oil feed at my engine case, preventing oil from going up the cylinders on that side. The bike locked up the same way as you described, but the damage was not as bad. The left side of the cam had some minor scoring on it, but both bearings of the cradle were toast. Shop around a bit on eBay. There are lots of cradles and cams right now. But make sure that the cradle you buy has the top clamp halves. These are matted to the cradle and both are stamped with a set of letters to make sure they are matching sets. I found a couple of eBay sellers trying sell cradles without the top clamps. When I asked the, they either never answered, or suggested I buy the top clamps From someone else. Don’t do this. They should have match letter codes. Just skip that seller and go to the next one.

A tip about this: if you are stuck with only the lower bearings, you can use the upper ones by boring the upper caps to match the outside edges of the lowers, or bigger. The uppers are never touched by the cam. Even on my own, at 138k miles, the upper caps have never been touched by the cam. When Honda sold replacement bearings, they often did not have the 'match' stamps on the bearings, just the extra-wide top caps. I have often seen these replacement bearings in the K0/K1 engines that were repaired for one reason or another with new bearings here. And, none of those caps had wear marks on them, either!

750caferacer · « **Reply #48 on:** August 11, 2020, 07:39:41 AM »

is a r6 stamped cam a good cam?

750caferacer · « **Reply #49 on:** August 11, 2020, 08:02:30 AM »

compaired to my k cam? will i notice a difference at all? i really just want my bike back on the road but if it is going to kill the power the idk about it.

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Author Topic: Help!!!! valve lash increasing when warming up (Read 3128 times)