Owning your mistakes is good for the soul. (Cylinder Head Removal)

PeterE

Getting there...
Location
California
Hi All. Ownership of my new (to me) 2021 Himalayan is off to a rough start. I was in the process of doing my first valve adjust (3k) and was using a guide that recommended saving time and using a wood dowel to find TDC. Bad idea. The dowel grabbed the threads in the spark plug hole and the bottom 3" of dowel is now in my cylinder.

I'm now learning how to remove and replace my cylinder head. I've downloaded a copy of the engine manual and am going to go at it slowly and carefully. Any advice, tips or even ridicule will be gladly accepted.
 

Laserman

Well travelled
Staff member
Oof! Yeah, I've always used a drinking straw or stirring straw to find TDC on my old VWs and small engines. Because a valve adjustment must be done cold, there is no danger of the straw melting, either. Pretty sure most of us have bungled something while wrenching at one time or another, sometimes we learn things the hard way!

The single most important thing for you to do (and work around with) is keeping tension on the timing chain after you remove the camshaft. If you're going to completely remove the head, you'll have to feed the head out of the chain while making sure the chain doesn't jump around on the lower timing gear. Watch some YT videos, there's a few dealing with LS410 disassembly.

I would also recommend replacing the camshaft with an aftermarket one like TEC or Hitchcock's since you're gonna have the upper end apart anyway, but waiting an extra week to ride might not be for you :D
 

OldGuy

Well travelled
Location
Seattle,WA
OOF(!) is right. I'm sorry to say that there have been a number of posts here about NOT sticking something down the cylinder to find TDC, because the spark plug hole is at a bit of a steep angle to the top of the piston. Sorry you had to learn the hard way.

Other than what you're doing, no other thoughts. If you're not happy with the stock performance, ok, replace the cam. Since your warranty is already history, you have nothing to lose.
OG
 

Guzziot

Total noob
Location
Centralia, WA
Few will admit having done it but it's more common than you'd think. At a recent motorcyclist gathering I sat with two other guys who'd done the same. Credit goes to the most interesting solution & the ability to laugh about it later.
 

PeterE

Getting there...
Location
California
Thanks. I gave up trying to be clever and just stripped it down. It felt really good to grab that pencil piece out of the cylinder. Now waiting for parts to arrive...

On the plus side, I've found lots of bolts that weren't torqued properly.
 

OldGuy

Well travelled
Location
Seattle,WA
I've done in the past too (luckily I did it on a single cylinder 2 stroke!). At least pencil won't damage anything, and from some other experiences voiced here, it's probably a good idea to check the torque on everything whenever you can.
OG
 

sqeeezy

Well travelled
Location
Southern Spain
Erm...Is it not sufficient just to determine the correct TDC by the marks without sticking anything in? That's why I have done. Also... because there's a number of degrees of rotation during which there is play/slack/clearance, I reckon you can be a few degrees off without that messing up the freeplay adjustment. I am open to reasoned polite argument. The tricky bit is getting the feeler gauges in and judging the fit as you push/pull them.
 

Jester

Well travelled
Location
Northants, UK
Many years ago I owned a GPz 305-the belt drive overbored Z250. As each time I took off the timing cover some oil came out I had the bright idea of putting a bit of wood under one side of the centre stand-and a good idea it was too up until the point I used the impact driver to loosen the cover fixings and knocked the bike over.

My flash of brilliance for doing the timing was a shoelace. As the engine was high compression it would easily drop over TDC so I used a ratchet and as I got near the mark choke hitched a shoelace around the handle of the ratchet and wrapped it around the gear lever linkage, I could then gradually pull the shoelace until the TDC mark was lined up with little risk of going over and the crank couldn't turn backwards as the ratchet was holding it.

Personally the only thing I would put down the sparkplug hole is a sparkplug. It's not just the risk of dropping something in but the chance of getting some random stuff in that the engine won't like.
 

Laserman

Well travelled
Staff member
Erm...Is it not sufficient just to determine the correct TDC by the marks without sticking anything in? That's why I have done. Also... because there's a number of degrees of rotation during which there is play/slack/clearance, I reckon you can be a few degrees off without that messing up the freeplay adjustment. I am open to reasoned polite argument. The tricky bit is getting the feeler gauges in and judging the fit as you push/pull them.
Sure one can remove that bolt on the LS410's LHS cover and see the timing marks for TDC. Might take a light and some head-cocking that would make a bird proud to see the marks inside , but they are there.

I've done 3 valve checks on mine without doing that, however. My method is to put bike on centerstand, pull the spark plug and valve access covers, put bike in 4th or 5th gear, and hand-turn the tire/rotate engine so that piston is just past highest point after intake valve closes. I was taught (in the late 1980s) to use a straw to determine piston stroke position by a guy who had already been doing this kind of stuff for at least 20 years then. He also taught me things like using a match stick to set distributor points which has never failed me on any vehicle unfortunate enough to still have points. (PerTronix or wtf)

Anyway, some old methods still work just fine. My truck, automobile, and motorized bicycle all require regular valve adjustments as well as my Himalayan, and I've always used a straw and visually observed the valve rocker position to indicate when I should attempt to adjust each valve. Not saying my way is superior to any others, just that I was taught this way over 30 years ago and it works for me. YMMV of course, over time we all have our way of repeating a job.
 

PeterE

Getting there...
Location
California
Well, I've learned my lesson and won't be sticking anything down the spark plug hole except for the spark plug.

Update: cylinder head is off, pencil fragment is out, and I'm waiting on gaskets to arrive. While I wait, I'm cleaning the sealing surfaces. I can't believe how much silicone sealant was used on that valve cover.
 

MikeM

Well travelled
Location
So Cal USA
Well, I've learned my lesson and won't be sticking anything down the spark plug hole except for the spark plug.

Update: cylinder head is off, pencil fragment is out, and I'm waiting on gaskets to arrive. While I wait, I'm cleaning the sealing surfaces. I can't believe how much silicone sealant was used on that valve cover.
If you can score a tube of yamabond 4 its about the best Ive ever seen. Back in the day we used Yamabond at the Kawasaki shop.
 
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