Think I Lost My Head!

SYMbionic Duo · Post by **SYMbionic Duo** » Mon Jul 09, 2012 5:12 pm

So i'm out riding, and there is a ticking noise.
Hmm, Mental Note: need to do a valve check before i ride again.

Ride a little more, Hmm power seems off. I should head for home.

Aw man, there is a 5-0 on the river road, the other cars are going to be driving 20mph now, the speed limit is 25. Grrr...

Wait what's that loud metal on metal rattle. Crapsnacks!

Oh it went away, good thing I'm only a couple of blocks from home.

In my driveway letting my BlackJack idle, and no ticking noise, no loud rattle, but the idle sounds high like the auto choke is engaged. odd...

Lets give the throttle a twist. RATTLE, CLUNK, THUD. Double Crapsnacks!

That's not good. Try the starter, no start just "whirr" hmm, Kick start ? no resistance.

And there I left it.

So I'm guessing that I have a valve either stuck open, or broken. If it is broken, what are the odds that my cylinder has survived? if i need a new head, should i go for the 58.8 or the 61mm BV head?

Conjecture welcome.

Wheelz · Post by **Wheelz** » Mon Jul 09, 2012 8:37 pm

Did you pull your cvt cover? I would bet that it is your front variatior plate that has come off. From the way you describe it.
Was there a god awful noise when you went to start it in your driveway?
Then it would not engage when turning over?
If I'm correct in understanding your description.

easy fix if this is it.
But still "CrapSnacks!!!!!

"

SYMbionic Duo · Post by **SYMbionic Duo** » Mon Jul 09, 2012 8:43 pm

This happened late last night, so i haven't looked at it yet.

There was a loud noise and the engine died, when i went to rev it.

If the variator plate came off, the engine would still start.

Will update tonight, probably.

gr8dog · Post by **gr8dog** » Mon Jul 09, 2012 9:59 pm

Check your oil level. My Buddy ate all its oil at around 1900 miles. Yes, I had been changing oil as scheduled. The noise you described matched my experience. The result, every part that the oil touches needed to be replaced. No Buddy for me for an entire month. Genuine covered it under warranty. That was August 2008. Now with over 10,000 miles I have not had any more problems. Good luck.

lovemysan · Post by **lovemysan** » Wed Jul 11, 2012 2:56 am

Sounds like the con rod let go. Pull the spark plug insert a pencil. Rotate the kick start slowly to see if the piston comes up or down.

agrogod · Post by **agrogod** » Wed Jul 11, 2012 9:12 am

lovemysan wrote:Sounds like the con rod let go. Pull the spark plug insert a pencil. Rotate the kick start slowly to see if the piston comes up or down.

Now that is a solid garage mechanic tip! Added to my repertoire of knowledge.

SYMbionic Duo · Post by **SYMbionic Duo** » Thu Jul 12, 2012 4:51 pm

Tuesday Night.
So taking lovemysan's advice, i pulled the plug... hmm that came out way too easy. Nope, piston still moving.

why the hell can't i get the plug to screw back in, what am i doing wrong?

Take the valve cover off, hmm dark brown marks around the exhaust valve.

Wednesday.
So I drop the engine, so I can get the shroud off, and get a better look at the plug hole.
Deep-fried Crapsnacks on a Stick! (it's a Minnesota thing dontcha know)
The threads are stripped on the head, and there are metal shavings around the opening. Fearing what i might find, i rotate the flywheel and sure enough there are shavings on the piston.

So now I have questions.
1. Should I take the jug off to make sure that there aren't any shavings between piston and jug?
2. Is it possible that the plug was blown-out? or is it more likely that the plug was cross-threaded 6mo ago, when i put it back in.
2b. If the exhaust valve wasn't adjusted properly, is it possible that this was the cause of the problem?
3.Sounds like an opportunity for performance parts. If I get a big valve head, should i go for a 58.8mm (stock size) or 61mm?
3b. If i go with a bv head, do i upjet and/or open the air box?

-duo

Robbie · Post by **Robbie** » Thu Jul 12, 2012 9:34 pm

1. I suspect the plug blew out from previous crossthreading.....therefore, the shavings you see are likely from you trying to re-install the plug at this time.
2. My thoughts are above in #1
2.b------no

3. and 3b......your call and wallet.

The dark oil around the exaust port wall is normal....this is the hottest point of the cyl head.

I would use a 150 psi compressor of adequete cfm and using a air gun I would blow out the cylinder from the plug hole......Then I would flood the cylinder with brake clean and blow it out till dry a second time.

I would buy a threadsert kit with the tap.
Coat the tap with grease to catch any aluminum debris......The kit comes with a twist drill to resize the hole for the tap.....coat the drill with grease as well for the same reason.
Use a slow speed drill to re-size the hole, then, using the grease coated tap, thread the hole for the insert. Brakeclean and compressed air again after threading but before insert install.
Intall the threadsert or time-sert, whichever you choose per directions.
Clean and blow out the cylinder one more time.

Or, remove the head and perform the proceedure on the bench.

If you are at all uncomfortable about this, give the head to a machine shop for thread repair.

Future reference....if you cannot install the plug till it seats against the head by hand, it is cross threaded.
Anytime any fastener resists install it is either cross threaded or the threads are damaged...either bent or debris.
But as you have found out, aluminum is not one bit forgiving.

Good news though, it is repairable at minimal expense.

Good luck,
Rob

SYMbionic Duo · Post by **SYMbionic Duo** » Thu Jul 12, 2012 9:43 pm

Thanks, I was already considering a helicoil.

I always thread by hand, and only use a tool to make sure it is tight.
So maybe i over-torqued.

Hmm, I think that the universe is telling me to get a torque wrench.