Valve clearance success! Thank you!!!

I just want to say thank you to this site. I got my new valve shims installed thanks to all the handy information on this site and the kind people who contribute to it.

I picked up a couple issues. Being inexperienced, I used a torque wrench on my head cover bolts, and stripped 3 of them. Yep that't right 3 of them. I didn't get it right with one so had to try another, and another. Oh well, hellicoils here I come. I read on here that the pinky method is best for torquing those babies.

Now that the valve clearance is good, my hesitation issue is resolved, though I have not gone for a long ride until I get my bolt treads fixed. I did notice that she is really noisy when I get up to highway speeds. From 4.5 to 5.3 rpms is where the problem lies. I am hoping a serious carb clean and sync will resolve that.

Also a lot more popping now. Right from initial startup.

Thanks again for any input.

 

The key when using a torque wrench for small fasteners is to use a small torque wrench; one that only goes up to about 200 inch-pounds.


What noises are you hearing, and did they pop up since the valve cover problem? You might just be hearing the valve cover rattling.

 

The popping sound has been there since I had a sync and clean by a pro. It never did it before. It happens mostly on deceleration. Now that the valves are set properly, it is doing it a whole lot more.

It is hard to explain the noise at highway speed. I just know it is different. Like the usual engine sound only noisier. It sounds like she is straining.

 

You are likely too lean on one or more cylinders. Pros make mistakes too. Re-colortune, or pull the plugs nd see which ones look rich, then turn the idle screw(s) out 1/4 turn to see if the popping diminishes. If it does, keep going a little richer until it goes away.

 

All my plugs are black and sooty before valve clearance. Which, I understand, means too rich. I have only ridden it once, gonna check for adjustment screws and turn them slightly the same amount to see if it makes a difference to the popping sound. How much run time does it need before I know the black soot is not a problem anymore?

 

Just a few miles at the correct mixture (an the engine at operating temperature) and the plugs will not be black anymore.

 

If your plugs are black you are probably not lean. While the popping on deceleration indicates a lean condition it might be lean because of a leak in the exhaust somewhere. You might want to check the exhaust system for tightness and possibly holes which would allow air to be drawn in.

 

Maybe. maybe not:

Why are my plugs carbon-fouled (dry, sooty black deposits)?:

- Carbon fouling is the result of incomplete combustion----for any reason. It is most often associated with an overly rich fuel mixture (whatever the cause), but can also be caused by an overly lean fuel mixture (or poor spark, etc.) In a lean-mixture condition, most of the un-burnt mixture gets pumped out the tailpipe, but some fuel droplets remain in the cylinder and add themselves to the next intake charge. That's not a very precise way of metering the mixture, so when it's finally rich enough for a spark to ignite, that particular charge may be too rich, resulting in incomplete combustion and plug fouling. So carbon-fouled plugs can be due to rich or lean conditions.......your Colortune spark plug will tell you for sure. If you have a light blue or white-ish flame, intermittent flame, and/or intermittent flashes of yellow within an otherwise white-ish flame, then your fuel mixture is too lean.

And by the way.........if the spark that happens to ignite this overly-rich mixture is the "wasted spark" (which occurs in each cylinder at the top of the exhaust stroke, it will occur JUST AS THE INTAKE VALVE IS OPENING ---- so the backfire pressure wave may be directed back up the intake tract!

 

Chacal is spot on, that popping and farting is also called "lean misfire!
And if bike is too rich we called it "raw farts" extra fuel that ignites in exhaust pipes.
You see that on race cars and bikes as a flame shooting out the exhaust on deceleration.

 

...Now that the valve clearance is good, my hesitation issue is resolved, though I have not gone for a long ride until I get my bolt treads fixed. I did notice that she is really noisy when I get up to highway speeds. From 4.5 to 5.3 rpms is where the problem lies. I am hoping a serious carb clean and sync will resolve that...

Both of my XJ7650's have/had a "resonant frequency". My maxim makes an unholy racket from about 4200-4900 rpm. I don't remember where the SECA's noisy zone was exactly but it was similar. Years ago someone here, probably K-Moe or Chacal told me it was normal and that the rubber inserts in the cooling fins were supposed to dampen the effect but They harden up or fall out over time.

 

^ that might be contributing to the noise, but the description is of a lean misfire on deceleration. The resonant "buzz" would be present at a steady speed.

 

I read the OP as two different noises. The popping on deceleration and the resonant buzz.

 

Whoops, bad post.......!

 

So did I, and I attribute the buzz being mainly due to the broken valve cover bolts.

 

sorry, but.........................

K-Moe or Chacal told me it was normal and that the rubber inserts in the cooling fins were supposed to dampen the effect but They harden up or fall out over time.

so that's what those little rubber blocks are for..... damn..... would have never thunk of it..... god, I love this forum!!

Trainer6

I am hoping a serious carb clean and sync will resolve that.

The popping sound has been there since I had a sync and clean by a pro. It never did it before. It happens mostly on deceleration. Now that the valves are set properly, it is doing it a whole lot more.

Do I understand this correctly, I think I'm lost here... you had a shop do what? Sorry I'm slow..........................
I'm with K-moe, I would re-sync and re-colortune myself and go from there....

 

Ok I was away for a couple days. Missed some posts here. Ok so the popping sound is quite separate from the Noise at 45 to 50 RPM. We already discussed the idea that the Pros did not do that great a job, in another post. Which is why I am beginning to do my own work. Clearance valves are now good.

So just to clear things up here.

There are 3 head cover bolts stripped. All on one side. Could it contribute to the noise at the higher RPMs as K-moe suggests?

The black sooty spark plugs suggest rich mixture, while the popping sound suggests lean mixture. Checked exhaust, not seeing an issue with them.

I am looking out for colortune plugs in Canada, auto parts stores in my home town said they have not heard of them. Lol.

 

Next step is to sync the carbs again. I either take it back to the pros and have them do it or get my own gauge rack. I heard of people making their own home made jobbies. Has anyone had any experience with that?

 

Morgan Color Tune

They also make one of the best carburetor synchronizers on the market.

Both can be found on ebay or ordered directly from Morgan in the UK.

 

The black sooty plugs suggest plugs that are not reaching their self-cleaning temperature. That can be caused by either a rich mixture or a lean mixture (though it's more commonly caused by being rich).

And that'd be a Gunson Colortune. Morgan does not make that particular tool.

 

You are correct sir! I ordered mine through Morgan when I ordered the Carb Tune. Just a slip of the old memory!

 

What was your experience when ordering from the UK? Everything is in GBPs... not US Dollars. Does the shopping cart do the currency conversion? Just curious...