Change the sparkplug
 

Since there wasn't a concise thread on this, I decided to post a few pics of how to get access to and remove the sparkplug from the GZ. This is detailed in the manual, with pictures even, but the scan quality isn't the best and it always helps a little having more detailed pictures.

I used the OEM toolkit for the procedure. The sparkplug wrench is 4th from the left, and when paired with the screwdriver extension (3rd from left), works very well and has no problems fitting into the relatively tight space. I added some cotter pins, a sparkplug gap tool and a pair of needlenose pliers to my kit.

http://www.postimage.org/gxyJ3C0.jpg

The sparkplug is accessed from the left side of the bike:
http://www.postimage.org/aVBM5gi.jpg

You have to remove the cylinder head cover plate with the small allen wrench.
http://www.postimage.org/aVBMpdr.jpg

http://www.postimage.org/PqCzYhi.jpg

http://www.postimage.org/PqCA2gA.jpg

Find the sparkplug wire boot and remove it by pulling up. You may have to finagle it a bit to get it to completely clear the plug top without binding up against the tank. Be careful not to crimp or break the wire or wire casing.
http://www.postimage.org/aVBNIx9.jpg

http://www.postimage.org/gxyKYkS.jpg

Use the sparkplug removal tool or a metric deep socket with a small extension to remove the plug. Remember, rotate counter-clockwise to remove it.
http://www.postimage.org/gxyLhi0.jpg

http://www.postimage.org/PqCAGaS.jpg

Clean the cylinder hole, and be careful not to drop dirt or grime onto the top of the piston. Notice the "shipping" stains on the heat dissipation fins. This is not an oil leak.
http://www.postimage.org/aVBOlrr.jpg

Reverse these steps to install a new plug. Don't forget to gap the new plug to the correct setting (0.6-0.7mm / 0.024"-0.028") before you install it. Tighten it with your fingers first, then torque it correctly (18N-m or 13 ft-lbs). This is generally only 1/8th turn of the plug past finger tight. NO MORE. You do not want to strip the plug threads nor damage your block.

Enjoy.

Re: Change the sparkplug
 

Excellent post. :2tup:

Just one comment from a REAL bad personal experience:

Clean around the base of the plug BEFORE you remove it. Compressed air is best. Loosen it and then blow again BEFORE removing the plug.

Wonder why I say this? Honda 550 Nighthawk. 4 plugs. 3 came out no problem. When removing the wrench and plug on the 4th, I see a small, round rock roll through the hole and INTO THE CYLINDER. One giant AW CRAP! :skull:

Re: Change the sparkplug
 

Very Helpful. Thanks for your help! I looked in the How section before I posted on it. Good to know that there is one now. This is a very helpful forum.

Re: Change the sparkplug
 

No problem.

Re: Change the sparkplug
 

Hi everyone I am new here and just got myself a 2005 Suzuki GZ250 just last week!
While here on the subject of sparkplugs does anyone know the sparkplug #for NGK ? thanks!

Re: Change the sparkplug
 

BR8HSA

Re: Change the sparkplug
 

Plug is a 17mm deep socket

Re: Change the sparkplug
 

Love, love, love the post and pics, Patrick! Thanks. Now, can you explaain what the "shipping stains" are and the cause? I thought mine were an oil leak.

Re: Change the sparkplug
 

Bikes (and cars) that come from Japan are often coated with a greasy or waxy substance to protect metal parts against salty seabreeze/etc. This coating is typically removed by the dealer. However I'm guessing that perhaps there are hard to get to places (on the fins perhaps?) where it is NOT removed but it eventually melts or puddles below the fins.

When I worked in an auto dealer all the Nissans (Datsuns back then) came off the truck with the wax on them. (It's name escapes me now, but I think it began with a "C")

Re: Change the sparkplug
 

Cosmolene. Mineral spirits will easily remove.

:)

Re: Change the sparkplug
 

I love the smell of Cosmolene in the morning.

Re: Change the sparkplug
 

Thanks Sarris, that's the stuff.

I sort of remembered that name but it sounded so stupid (kind of like a cross between Cosmo and Maybelline) that I thought I must have got my circuits crossed. In the early eighties (when Reagan imposed the "voluntary" quotas on the Japanese cars) we could (and had to) sell our meager monthly allocation of Nissans for well above list. Removing the Cosmolene was one of the many inventive fees we added on (along with pinstripes, floor mats, fabric protectant, paint sealant and undercoating. When you think about it, those last two are kind of like putting the Cosmolene back on.)

Re: Change the sparkplug
 

I remember back in 1973, buying a Datsun Sunny, & discovering that the floor appeared to be made out of baked bean cans, The first ( & real messy job!) was to underseal the car. I didn't keep it for long, because at 5' 10" I was too tall to fit in it comfortably. I subsequently found that the Japs hadn't realised that the Europeans were much taller than themselves, so had built cars that were only big enough for the small Japs. The build quality was also atrocious, & I Discovered that in Japan, their cars had to be tested annually, & at the seven year test they had to be virtually stripped down & rebuilt with new parts. This was so expensive that it was cheaper, in Japan, to scrap a seven year old car & buy another new one. This meant that they built cars that were built to fall apart at 6 years 11 months - not realising that in England cars were meant to last for a minimum of 15 years.

They were also velly clafty! In 1980 I was working in a factory, in Sheffield, that made springs & anti roll bars for world wide car manufacturers. The guys there told me that they used to make these parts for Datsun, but, a few years back, the Datsun bosses asked if they could visit the factory. These Wily Oriental Gentlemen duly arrived, armed with the ever present cameras, & proceded to photograph everything. Guess what! When the contract came up for renewal, it was found that they had quietly built a spring/anti roll bar factory in Japan, & didn't need our services anymore.

Just as an aside - We used to have bumper stickers to put on our Jap cars - "I'm backing Blitain" (sic)

Re: Change the sparkplug
 

Yes, English cars have always been known for their quality and reliability here stateside. :whistle:

Re: Change the sparkplug
 

I just wanted to say Thank you for this valuable information.

I am trying to get my '03 Suzuki GZ250 up and running again after 2 or 3 years of sitting and found this information very easy to follow. I replaced the dead battery Friday with one of those new tech Acid-Gel media types and viola, I have power, it cranks but no turnover. I investigated some more and found that the spark plug was not the issue prevening it from starting (but hey, I learned how to change a spark plug on my bike! :). There is something preventing the spark, possibly a broken wire some where? I guess that would mean removing the tank in order to find the damage? Or could there be another (easier) explanation and fix?

I would appreciate any leads offered as I have my Motorcycle Ohio class beginning this Friday at 6PM.

Thanks

Re: Change the sparkplug
 

Did you drain the tank and put in fresh gas ? Did you put the fuelcock in the prime position for a minute to prime the carb ? The GZ normally has carb problems when left to it's own devices for a long period of time.

Re: Change the sparkplug
 

ok, but what would explain the no spark to the spark plug?

Re: Change the sparkplug
 

I would pull the tank and start tracing the wires. Also check the fuses first with a meter to verify they are good. Was the bike in storage where mice and other rodents could get at the wiring ? Oh yeah, check the air filter for a small nest too. You may have to displace some small neighbors.

Re: Change the sparkplug
 

Yes, I did find evidence of furry critters and this is not the first time these pests have invaded where they weren't welcome(they nested on my in-line 4 between the spark plug wires and chewed through the insulation)...so then you would say it is pretty likely they chewed a critical wire? Ok, well no easy fix but that is ok...at least I know what I will be doing tomorrow. :)

Thank you
PS the spark plug wire looks to be in good shape from what I can see...until it gets lost behind/under the tank.

Re: Change the sparkplug
 

Keep us informed about your progress. Good hunting.

Re: Change the sparkplug
 

I changed my spark plug today and it was super easy thanks to this post... thank you for posting this Patrick!

Re: Change the sparkplug
 

I follwed your steps but when replacing w/ a new plug I can only turn w/ fingers a few turns. It appeared to start properly but I had to use a socket to get it to turn further.

I immediately found your post, read it and tried it again. I can only turn the plug a few turns before it gets hard to turn unless using a socket. I checked the threads on the original plug as well as the new plug after removal and the threads look clean so I seriously doubt any kind of striping of the threads. Can I use some WD-40 on the threads?

Thanks!
Chandler

Re: Change the sparkplug
 

Yes,you can use some WD-40 on the threads.Did the old plug come out easily? If so there may be some carbon on the threads.
:) :cool:

Re: Change the sparkplug
 

The head threads will strip or cross thread before the plug.

WD 40, oil, or anti seize will work.

Re: Change the sparkplug
 

Thanks for the replies! I used WD-40 and it did thread a bit easier.... Tightened it w/ the socket and good to go...

Unfortunately my starting problem is more battery related that plug but the plug was due for a change anyway....

Thanks again for the great resource!
Chandler

Re: Change the sparkplug
 

I thought the spark plug wrench was 18mm. This post says 17mm. Can anyone straighten me out on this?

Re: Change the sparkplug
 

18mm thin wall socket will fit.That's all I ever used. :) :cool:

Re: Change the sparkplug
 

Thanks guys, that's what I thought.

Re: Change the sparkplug
 

Great tip ! Me personally STRONGLY advise using a dab of antisieze on the plug threads. My personal rule of thumb "almost" any bolt that comes out and I observe the imfamous "white powder" on the threads gets antisiezed. The only bolts I don't antisieze are sprocket bolts and brake caliper bolts, those get Loctited ! :2tup:

Re: Change the sparkplug
 

now that bike has a nice paintjob, is it from factory or did you painted it? silver+black+a red line, thats beautyful

Re: Change the sparkplug
 

my issue is removing the tank to get access to the plug. i could not get the rubber gas hose off, completely stuck. any tips or tricks for safely removing the hose without damaging it?

Re: Change the sparkplug
 

Why do you want to remove the tank? To access the plug, you just need an allen key to remove the two allen bolts, holding the left hand cover above the engine. Remove this plate, and you can get straight to the plug.

Re: Change the sparkplug
 

according to my manual i need to do so to get at the plug. and i tried what you suggested but the angle is such that the tank is in the way. i have a 2009. please advise

Re: Change the sparkplug
 

[attachment=0:3tl584de]img113.jpg[/attachment:3tl584de][attachment=1:3tl584de]b36.jpg[/attachment:3tl584de]It would appear that the manual is wrong!!!!!!!!! Using the spark plug wrench that Susuki supply, is awkward, but you certainly don't have to remove the tank, and the owner's manual that came with the bike certainly didn't tell you to remove the tank - just the plate. I've included a picture of the wrench, and a picture of the page in the manual. Bujia is the Spanish word for plug. The section on the right shows the two bolts holding the plate, then how to remove the plug.