Author Topic: Sticky valve (Read 5116 times)

weltzing · « **on:** August 17, 2012, 08:32:14 AM »

What is the easiest and best way to lube up a sticky valve?

lucky · « **Reply #1 on:** August 17, 2012, 09:51:08 AM »

Quote from: weltzing on August 17, 2012, 08:32:14 AM

What is the easiest and best way to lube up a sticky valve?

"sticky valve" who told you that?
How would you know?

Did you see it stick?

Crazy.

Lets see... you made a video then put it in slow motion...??

Exhaust ,intake? No oil in the engine?

Someone was standing there by the bike and said."sounds like a sticky valve."

Then you said "which one?" Then they showed you??

tlbranth · « **Reply #2 on:** August 17, 2012, 10:10:08 AM »

I'm with Lucky. How do you know you have a sticky valve?

weltzing · « **Reply #3 on:** August 17, 2012, 02:49:05 PM »

Hey lucky, if I wanted a smarta** answer I would have asked for one. Obviously I am not a mechanic, but someone did say to me that the valves could b sticking aas it pops once in awhile.

ekpent · « **Reply #4 on:** August 17, 2012, 05:39:39 PM »

Popping could be due to a carb issue like maybe a lean condition or an air leak in the exhaust or intake etc. Maybe even a spark plg on the verge of fouling.Make sure the valves are adjusted correctly and not to tight.

scottly · « **Reply #5 on:** August 17, 2012, 07:36:59 PM »

Three things that can cause valves to stick open:
1) Tight valve-stem to valve guide clearance, due to brand new parts.
2) Valve stems seized in the guides, due to corrosion, after sitting for years.
3) Bent valve stems, such as what happens when a 500/550 cam-cover is improperly installed.
Disclaimer: I only have first hand experience with items 1 and 2.

dave500 · « **Reply #6 on:** August 17, 2012, 09:17:14 PM »

go over your ignition fully,i doubt you have a sticky valve,is it a random pop when idleing?or on decell like down a long grade?

lucky · « **Reply #7 on:** August 18, 2012, 04:21:52 PM »

If you have done everything and the valve still pops it can be a bent valve.

A bent valve only needs to be bent a few thousandths of an inch.
But if the valve really did stick it would break a tappet or rocker arm.

You can look at the tappets and see if any of them look hammered and mushroomed.

ALSO : If the timing chain slips a tooth it could cause that kind of problem.
If you check the timing and things do not line up correctly that can be causing it.

dave500 · « **Reply #8 on:** August 18, 2012, 08:18:31 PM »

if the chain jumped a tooth itll be about 20 degrees wrong!the bike will run like crap if the valves dont collide with the piston,youd have to have a rattly top end noise for the chain to jump.

trueblue · « **Reply #9 on:** August 18, 2012, 09:16:43 PM »

Weltzing, I assume this is on your 650. Are you still using the early model carbs on the late model head. If you are the angle on the carb boots will cause air leaks which will cause popping.

weltzing · « **Reply #10 on:** August 19, 2012, 07:13:22 PM »

This is my 650, but I am still not sure if you are 100% correct on what year my head is and carbs...I have the carbs on pretty good right now and while running I sprayed around the boots with ether and listened for revving...It ran the same which leads me to believe they are sealed pretty good. The popping happens all the time...while idling it pops, on acceleration it pops, and also on decel.. I also took out my air filter and the bike runs 100% better than what it was.

trueblue · « **Reply #11 on:** August 19, 2012, 07:40:36 PM »

Where's the issue, look at the picture you supplied in your other thread, look at the spacing of the carbs to the head.

Now look at the picture I supplied of a set of CV carb bodies lined up next to a PD carb head.

The offset is the same, you have the wrong carbs for your head. Someone has replaced the engine in that bike and used the origional carbs off the bike. A lot of people don't know there is a difference in the heads. I also supplied measurements for the spacing of the ports on both the CV carb head and PD carb head.

Quote from: trueblue on August 04, 2012, 02:38:14 AM

I just went and did some quick measurements, the CV carb head from 1-2 and 3-4 is 65mm, in between 2-3 it is 92mm. The PD carb head the measurements for 1-2 and 3-4 are 76mm, and 2-3 is 81mm. These measurements are centre to centre.

From all this information it should be quite easy to figure out what carbs your head requires.
If you have the wrong carbs on your engine don't expect it to run right.

scottly · « **Reply #12 on:** August 19, 2012, 07:49:50 PM »

Quote from: weltzing on August 19, 2012, 07:13:22 PM

I also took out my air filter and the bike runs 100% better than what it was.

Sounds like a plugged air filter. I'll bet a cyber beer your spark-plugs were sooty...

weltzing · « **Reply #13 on:** August 20, 2012, 09:56:07 AM »

How much would a set of working cv carbs set me back??

weltzing · « **Reply #14 on:** August 20, 2012, 09:57:58 AM »

If I get the serial numbers off the motor tonight and post them on here, can someone match them up to the correct year of thr motor? Then we can b 100% sure

onepieceatatime · « **Reply #15 on:** August 20, 2012, 10:13:50 AM »

It could be the original motor with a newer head, so even if the serials can be matched to year it will not mean anything except the head does not match the PD carbs, and it looks like you need either a set of CV carbs of a correct year head. If you get the CV carbs, you should go for the 44C from '82 instead of the 44A from '81.

weltzing · « **Reply #16 on:** August 20, 2012, 11:38:49 AM »

And the difference between those carbs is.what? Not sure where to find a set besides finding a scrap bike with cv's on it

onepieceatatime · « **Reply #17 on:** August 20, 2012, 12:54:49 PM »

They show up on ebay, or you could post on the wanted section here, or on http://www.hondacb650.com/index.php

The difference between the VB44A and VB44C is that the C has screw in slow jets and the A has press in.

dave500 · « **Reply #18 on:** August 20, 2012, 12:57:09 PM »

yours look like cv carbs?

onepieceatatime · « **Reply #19 on:** August 20, 2012, 01:03:18 PM »

Quote from: dave500 on August 20, 2012, 12:57:09 PM

yours look like cv carbs?

all you can see in the picture he provided is the mounting rail for the carbs. The picture with the obvious CV carbs is posted by trueblue.

dave500 · « **Reply #20 on:** August 20, 2012, 01:06:07 PM »

thanks im a dummy,i shouldve scrolled a bit more?

weltzing · « **Reply #21 on:** August 20, 2012, 01:17:18 PM »

Yeah the only true way is to measure the port spacing....I
Ebay is ususly way over priced for whole racks of carbs....anyone ever heard of the minnesotas largest bike yard in shakopee mn? I might try there first.....and one other thing is what bikes are the 44c carbs on??

onepieceatatime · « **Reply #22 on:** August 20, 2012, 01:18:13 PM »

dave500, we all miss something at times, and based on your contributions to the forum, I would definitely say you are no dummy.

Weltzing, On the left in this picture is CV and on the right is PD carbs. The PDs were on '79 and '80 CB650s, and the CVs were on '81 and '82 bikes, but as stated, the '81 had the VB44A model, and the '82 had the VB44C model if you go looking for them. One advantage of the CV carbs in my opinion is that the place where the choke cable attaches is metal, whereas it is plastic and prone to breaking on the PD carbs.

weltzing · « **Reply #23 on:** August 20, 2012, 05:19:30 PM »

And another thing, how will my cables line up with the cv.carbs?

onepieceatatime · « **Reply #24 on:** August 20, 2012, 05:27:12 PM »

Quote from: weltzing on August 20, 2012, 05:19:30 PM

And another thing, how will my cables line up with the cv.carbs?

I don't think the cables will be a problem, but am not 100% on that. The only snag I can think of is the fuel line is a different diameter for the '79 and '80 bikes than the '81 and '82 bikes, but you can get an inline fuel filter at autozone that has 1/4" and 5/16" barbs on each end which should solve that problem.

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Author Topic: Sticky valve (Read 5116 times)