Rattlin' valves

[jamman18]

Just wondering....I was reading in my Clymer manual about valve tappet clearances and was wondering if while under load going up a hill how I can hear the valves rattling.  Is that what I need to adjust the tappet clearances for?

[rrgunslinger]

What grade gas you running in your bike.  Sounds like a pinging problem.  If valves rattle I would think they would all the time. Timing could be off. 

On Fri, Jun 29, 2012 at 9:55 AM, jamman18 [via Honda CB750'S] <[hidden email]> wrote:

Just wondering....I was reading in my Clymer manual about valve tappet clearances and was wondering if while under load going up a hill how I can hear the valves rattling.  Is that what I need to adjust the tappet clearances for?

Phil. 4:13 " I can do all things through Him who strengthens me"

---

If you reply to this email, your message will be added to the discussion below:

http://honda-cb750-s.456789.n3.nabble.com/Rattlin-valves-tp4023831.html

To start a new topic under Honda CB750'S, email [hidden email]
To unsubscribe from Honda CB750'S, click here.
NAML

[robs750]

If the engine is making a rattle sound under load,sounds like it could be pinging.

The timing could be off or carbs are dirty or jetted lean.

Still a good ideal to check the valve clearance and cam chain adjustment.

[jamman18]

I run 87 octane gas and this happens only on steep hills; maybe 35- 40 degrees?

[TOOLS1]

Sounds like pinging to me also.
TOOLS

[rrgunslinger]

put 93 in it and try again.

On Fri, Jun 29, 2012 at 11:01 AM, jamman18 [via Honda CB750'S] <[hidden email]> wrote:

I run 87 octane gas and this happens only on steep hills; maybe 35- 40 degrees?

Phil. 4:13 " I can do all things through Him who strengthens me"

---

If you reply to this email, your message will be added to the discussion below:

http://honda-cb750-s.456789.n3.nabble.com/Rattlin-valves-tp4023831p4023841.html

To start a new topic under Honda CB750'S, email [hidden email]
To unsubscribe from Honda CB750'S, click here.
NAML

[jamman18]

so pinging i often fixed by higher octane?

[robs750]

Yes,using higher octane could stop pinging.

Excessive carbon buildup and or timing could be part of the pinging problem.

[rrgunslinger]

Just remember lower octain = faster burn, higher octain =  slower burn.  When new, your bike may have been happy with lower octain but as time goes on you get carbon build up and often times that will get so hot it glows and cause the lower octain fule to burn before it should.  If the higher octain fule does not stop the ping then you may have other issues that I believe were mentioned earler. (timing, lean condition, ect...)

http://en.wikipedia.org/wiki/Engine_knocking

 

On Fri, Jun 29, 2012 at 12:56 PM, Robs750 [via Honda CB750'S] <[hidden email]> wrote:

Yes,using higher octane could stop pinging.

---

If you reply to this email, your message will be added to the discussion below:

http://honda-cb750-s.456789.n3.nabble.com/Rattlin-valves-tp4023831p4023851.html

To start a new topic under Honda CB750'S, email [hidden email]
To unsubscribe from Honda CB750'S, click here.
NAML

[jamman18]

Great!  One of my cycle guru friends at work also agreed and said to go higher octane and retard the timing just a tad and it would probably take care of it.

[shinyribs]

Try higher octane before you retard the timing. These guys are right in that is most likely your issue. No need to retard your timing and possibly lose power doing so,if octane is all you need.

Also,if your bike is idling high for no apparent reason,you could have a vacuum leak causing it to run lean and there fore a little hotter. That could cause pinging,too.Did it ever ping before you rebuilt the carbs?

[rrgunslinger]

Also don't bog the motor under heavy load.  Keep the rpm's up.

On Fri, Jun 29, 2012 at 2:22 PM, jamman18 [via Honda CB750'S] <[hidden email]> wrote:

Great!  One of my cycle guru friends at work also agreed and said to go higher octane and retard the timing just a tad and it would probably take care of it.

Phil. 4:13 " I can do all things through Him who strengthens me"

---

If you reply to this email, your message will be added to the discussion below:

http://honda-cb750-s.456789.n3.nabble.com/Rattlin-valves-tp4023831p4023855.html

To start a new topic under Honda CB750'S, email [hidden email]
To unsubscribe from Honda CB750'S, click here.
NAML

[jamman18]

ok guys....I'll repond to a few things to catch up.......never rebuilt the carbs, will try just the higher octane, and what would be a good rpm to keep it at when climbing?

[jamman18]

oh, and the idle is fine.

[shinyribs]

jamman18 wrote

oh, and the idle is fine.

Sorry.I got confused with something else when i said all that.My bad. As far as climbing rpms,these bikes like to rev. Mine hardly ever drops below 4ooo rpm.Up hill or flat.

[jamman18]

actually been running 85 octane....I'll switch to 91 which is the highest in our small town

[TOOLS1]

I run 91 octain, and still have to run octain booster.
TOOLS