Loose cylinder head bolt
 

Noticed bike was leaking oil earlier this week. Now trying to tighten up the nut but I'm not having any luck getting the wrench into the area. Pretty sure its a 10mm bolt since it fits on the back one. Thinking the leak is from the bolt being loosened over time and not needing a new gasket. Only a 2007 with 5,800 miles on it and oil change was done last month with replacing the oil filter.

Sounds like you are using the factory tool kit. A box end wrench would be better. 6 or 12 point box end. 12 would be better in this case.

I'll have to pick one up tomorrow. No clue where some tools are and no light doesn't help.

Ah............the familiar no light syndrome. I went half nuts with the lack of light and tried almost everything to brighten up the underground parking here. Finally found a clip on LED light that clips onto the beak of a baseball cap. It points where I look and far better than a strap on light for my head.

I would have a better light source if it wasn't for the mosquitoes love for my blood. I've got a fan blowing to keep them away and a small battery operated light to go by. Husband has no clue where one is either. lol

Holy crap! That bolt is flat missing on my bike. Gonna rob parts and replace it :eek:

Ok. That nut replaced.

Well tightening the bolts up fixed one leak but a new area started leaking oil.

My bike leaked at that bolt next to the spark plug, too. I took the bolt off, cleaned it up real good, and re-torqued it (the German standard, 'Guten-tight'!).

It wasn't leaking a lot, just a bit over the course of a couple hundred miles. I've traveled another 100 or so miles since, and it hasn't leaked again as far as I can tell. Definitely no more leakage on the fins / front like I was experiencing.

This nut was completely missing from my son's bike, seems to be a common issue with these. Wonder why Suzuki doesn't use some sort of lock washer arrangement?

Andrew

A couple drops of Blue Loktite would solve the problem.

Not sure the blue Locktite would stand up to the heat?

Give it the benefit of the doubt, nothing ventured nothing gained.

I've got blue loctite on the other set of bolts. Red you have to take a blowtorch to heat it hot enough to break loose. So far since tightening the last bolt it hasn't leaked. Also noticed that it started running better.

You could likely build a battleship with red stuff. No welding needed.

Thought I'd give an update on my leak. Looks like my issue wasn't the bolts being loose but the valve cover gasket was needing redone. Hopefully fixing that will work. The old gasket could be wiped off with a paper towel.

It's called SUZUKI BOND. I went with some sort of SILICONE GREY i got at the autoparts store and used it very sparingly.
So far so good.

PS: I've used the blue stuff too on these motors.

The blue stuff works, the bolts that were lose haven't since so that's good. I used the silicone black gasket stuff since gray said not to use around gas. Looking like it had been done before but they didn't wait for the stuff to set.

I've got 30,000 km on my GZ. In that time I've noticed oil on the fins twice. The bike shop mechanic tightened the head bolts both times, and cured the problem. Seems like loose head bolts is a common Suzuki problem.
:(

I wonder if it might be a case of unequal expansion and contraction of the head and cylinder that might have a bearing on the head bolts coming loose. A little Loktite on the bolts may help. Just a guess from me since we never had a problem with Lynda's bike.

An air cooled engine may exceed optimal operating temps while a liquid cooled engine upper operating temp is governed by the thermostat. Food for thought.

When the weather gets hot here in Las Vegas, I switch to 20/50 weight oil. I have right at 16,000 miles on my bike with no leaks so far and when I checked my head bolts after detailing my bike recently, everything looked good. Just changed to the heavier oil this week as it will be 100 degrees + this week. Trying to stretch my baby's life out as far as possible.

Permatex Motoseal is what you want for sealing the valve cover. You can get it at most auto parts stores, it's designed for motorcycle engines and it is cheaper than Suzuki bond (probably the same stuff anyway) I used it to seal up mine and it has been leak free.

https://www.permatex.com/products/un...et-maker-grey/

So far the black gasket stuff has worked. No leaks so that's a good sign. Bike only has a little over 8k miles on it but was in rough shape last year when I got it. Looked like it had been taken apart before. A couple of bolts we had to undo had the blue loctite on them, while one in the same area didn't. Now to figure out the other issue that started up for the past month.