"Popping" noise when starting - Page 2

jsmeltser · 04-23-2009, 05:37 AM

Just got the bike out of storage and took it to a different dealer. The mystery of the pop/poot is solved. Quimrider was actually dead on, the head gasket was completely blown. It seems that the nut that holds it together had managed to work it's way completely off. Luckily the bike is still under warranty, so the repair was free. The guy who did the work said that it must be a known issue, because Suzuki sent a sort of locknut that he hadn't seen before, and asked him about my height/weight.

Sooooo glad that the cold weather appears to finally be over and I can get back on two wheels!!!

Quimrider · 04-23-2009, 10:04 AM

Glad you got it fixed under warranty! My fix cost me $330. The mechanic said that my head had slightly warped so they machined it down a very small amount. Hopefully they checked to see if yours had warped too. I'm 5'10" 200lbs and I rode about 50/50 freeway/city streets with a 16t front sprocket. If you don't mind me asking what are your riding habbits? I now ride a Vulcan 500 since I plan on making some long dist freeway trips this summer. I really want to keep my GZ, but i just can't justify the insurance/license plates for both

jsmeltser · 04-23-2009, 01:29 PM

I'm 5'9" 180 lbs. I ride about 80/20 highway/in-town. With all of the highway riding I do, I feel like I'm really pushing the limits of the GZ. I was actually planning on getting a Triumph this summer and passing the GZ on to my wife, but we had a very expensive emergency, so I'll be avoiding the freeway for awhile yet.

wdnavion · 07-19-2009, 03:37 AM

Popping noise when starting...I had this problem at about 25,000 miles..The head gasket layers were split apart at the left front and that was the causing the leakage. When I retorqued the large nuts on the cylinder studs...(27.5 foot lbs), the left front nut was loose. When I retorqued the small front hold down nut (underneath...the one that takes the 10 mm wrench), it would not tighten..just kept turning and I could tell that the stud was pulling out of the cylinder head...so I ordered the cylinder head gasket, the two copper gaskets, another stud (M6), and bought an M6-1 helicoil kit at the local AutoZone. You download the excellent GZ250 Service manual from this site and remove the valve cover, follow the instructions to remove the head which entails removing the camshaft, and get the cylinder head out on the bench. Remove the stud, carefully enlarge the hole with a 1/4 inch bit, being careful to not deepen the hole. Use the tap included with the helicoil kit, follow the instructions to turn in the insert and break the tang. Install the new stud with loctite making sure it is fairly tight in the insert. I would recommend not removing the cylinder until you get to the point where you need new piston rings which should be over 50,000 miles unless you are one of the rare folks who forget to change engine oil...

wdnavion · 07-19-2009, 04:01 AM

More Pictures

wdnavion · 07-19-2009, 04:06 AM

Yet another couple of Pix

wdnavion · 07-19-2009, 04:13 AM

Oops!

jsmeltser · 07-19-2009, 05:31 AM

Thanks for the info guys. Unfortunately this is an ongoing issue. About a month after having the head gasket replaced, the 10mm nut had worked its way loose again. The dealership mechanic put it back in and used loctite. After this I was a little paranoid about that stud and checked it before each ride. Sure enough, two weeks later, it was out again! The bike has been at the dealership for two weeks now. Had the head machined and they are replacing the gasket again. Currently waiting on the stud, which is on backorder...I can't imagine why! Luckily Suzuki is paying for the work again, even though the warranty ran out two weeks prior to this last incident.

wdnavion · 07-19-2009, 12:47 PM

Mr. Smeltser,
This does sound like the same issue that I addressed in the earlier post from yesterday. The GZ250 is not liquid cooled and when it is ridden fast and hard in hot weather, the head material around the exhaust valves gets pretty darned hot. Lugging the engine i.e. running in a higher gear at lower RPM at high throttle settings exacerbates this high temperature situation. Also lots of almost WOT operation at near top speed especially on very hot days hastens the issue. This causes the aluminum head to expand between the cylinder and the big stud nuts. This results in a lot of pressure on the head gasket. The repeated thermal cycling which results from going to cool to hot and back again eventually results in compression of the head gasket...it actually gets a little thinner and then allows the leakage to start. When the gasket first starts to fail, it is only noticed when the engine is cold at startup and then symptoms go away as the engine warms up. If you are having an ongoing issue with head gasket failure, I suggest my previous post concerning installing the M6 "helicoil" threaded insert in the hole for the front cylinder stud. This provides a much stronger mounting for the stud than the original fine threads in soft aluminum situation. It is important to do a good job with drilling and tapping this hole so that you do not have problems later. Because the insert kits run about $30 to $40, you can probably take the head to a reputable machine shop and have the whole thing done right for not much more than the ridiculous price of the insert kit at the local car parts shop! And no, you do not have to use loctite on a permanent "helicoil" repair...that is just something I do but not a normal or necessary thing. Now, on to my second suggestion, I highly recommend that you use a special sealant on the head gasket when you put it back together. It is called Hylomar Advanced Formulation Gasket & Jointing Compound. You will probably not find it at run of the mil car parts shops but it is available from engine rebuilding suppliers. If you have problems finding it, call a local engine rebuilder to see if they can get it for you. When you put the cylinder head back on, ensure that the parting surfaces are absolutely clean and dry and free of oily residue. Take a plastic spatula or small plastic scraper and carefully "squeegee" a thin film of the compound onto both sides of the new head gasket. When you reinstall the head, make sure that you do not over-torque the heads beyond 28 foot pounds because all you are doing is crushing the new gasket and reducing its resistance to thermal cycling. You can also use the Hylomar compound on the valve cover..just make sure that you clean any oil from the parting surfaces and use just a thin coating. I hope this helps.....

Water Warrior 2 · 07-19-2009, 04:43 PM

Excellant pics and info. Could this be made into a "Sticky" for future reference ??

04-23-2009, 05:37 AM	#11
jsmeltser Junior Member Join Date: Jul 2008 Location: Fort Madison, Iowa Posts: 10	Re: "Popping" noise when starting Just got the bike out of storage and took it to a different dealer. The mystery of the pop/poot is solved. Quimrider was actually dead on, the head gasket was completely blown. It seems that the nut that holds it together had managed to work it's way completely off. Luckily the bike is still under warranty, so the repair was free. The guy who did the work said that it must be a known issue, because Suzuki sent a sort of locknut that he hadn't seen before, and asked him about my height/weight. Sooooo glad that the cold weather appears to finally be over and I can get back on two wheels!!! Login or Register to Remove Ads
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04-23-2009, 10:04 AM	#12
Quimrider Senior Member Join Date: Jun 2007 Location: Toledo, OH Posts: 198	Re: "Popping" noise when starting Glad you got it fixed under warranty! My fix cost me $330. The mechanic said that my head had slightly warped so they machined it down a very small amount. Hopefully they checked to see if yours had warped too. I'm 5'10" 200lbs and I rode about 50/50 freeway/city streets with a 16t front sprocket. If you don't mind me asking what are your riding habbits? I now ride a Vulcan 500 since I plan on making some long dist freeway trips this summer. I really want to keep my GZ, but i just can't justify the insurance/license plates for both
	0

04-23-2009, 01:29 PM	#13
jsmeltser Junior Member Join Date: Jul 2008 Location: Fort Madison, Iowa Posts: 10	Re: "Popping" noise when starting I'm 5'9" 180 lbs. I ride about 80/20 highway/in-town. With all of the highway riding I do, I feel like I'm really pushing the limits of the GZ. I was actually planning on getting a Triumph this summer and passing the GZ on to my wife, but we had a very expensive emergency, so I'll be avoiding the freeway for awhile yet. Login or Register to Remove Ads
	0

07-19-2009, 03:37 AM	#14
wdnavion Junior Member Join Date: Jul 2009 Location: Lancaster Ohio Posts: 12	Re: "Popping" noise when starting Popping noise when starting...I had this problem at about 25,000 miles..The head gasket layers were split apart at the left front and that was the causing the leakage. When I retorqued the large nuts on the cylinder studs...(27.5 foot lbs), the left front nut was loose. When I retorqued the small front hold down nut (underneath...the one that takes the 10 mm wrench), it would not tighten..just kept turning and I could tell that the stud was pulling out of the cylinder head...so I ordered the cylinder head gasket, the two copper gaskets, another stud (M6), and bought an M6-1 helicoil kit at the local AutoZone. You download the excellent GZ250 Service manual from this site and remove the valve cover, follow the instructions to remove the head which entails removing the camshaft, and get the cylinder head out on the bench. Remove the stud, carefully enlarge the hole with a 1/4 inch bit, being careful to not deepen the hole. Use the tap included with the helicoil kit, follow the instructions to turn in the insert and break the tang. Install the new stud with loctite making sure it is fairly tight in the insert. I would recommend not removing the cylinder until you get to the point where you need new piston rings which should be over 50,000 miles unless you are one of the rare folks who forget to change engine oil...
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07-19-2009, 04:01 AM	#15
wdnavion Junior Member Join Date: Jul 2009 Location: Lancaster Ohio Posts: 12	Re: "Popping" noise when starting More Pictures Login or Register to Remove Ads
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07-19-2009, 04:06 AM	#16
wdnavion Junior Member Join Date: Jul 2009 Location: Lancaster Ohio Posts: 12	Re: "Popping" noise when starting Yet another couple of Pix
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07-19-2009, 04:13 AM	#17
wdnavion Junior Member Join Date: Jul 2009 Location: Lancaster Ohio Posts: 12	Re: "Popping" noise when starting Oops!
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07-19-2009, 05:31 AM	#18
jsmeltser Junior Member Join Date: Jul 2008 Location: Fort Madison, Iowa Posts: 10	Re: "Popping" noise when starting Thanks for the info guys. Unfortunately this is an ongoing issue. About a month after having the head gasket replaced, the 10mm nut had worked its way loose again. The dealership mechanic put it back in and used loctite. After this I was a little paranoid about that stud and checked it before each ride. Sure enough, two weeks later, it was out again! The bike has been at the dealership for two weeks now. Had the head machined and they are replacing the gasket again. Currently waiting on the stud, which is on backorder...I can't imagine why! Luckily Suzuki is paying for the work again, even though the warranty ran out two weeks prior to this last incident.
	0

07-19-2009, 12:47 PM	#19
wdnavion Junior Member Join Date: Jul 2009 Location: Lancaster Ohio Posts: 12	Re: "Popping" noise when starting Mr. Smeltser, This does sound like the same issue that I addressed in the earlier post from yesterday. The GZ250 is not liquid cooled and when it is ridden fast and hard in hot weather, the head material around the exhaust valves gets pretty darned hot. Lugging the engine i.e. running in a higher gear at lower RPM at high throttle settings exacerbates this high temperature situation. Also lots of almost WOT operation at near top speed especially on very hot days hastens the issue. This causes the aluminum head to expand between the cylinder and the big stud nuts. This results in a lot of pressure on the head gasket. The repeated thermal cycling which results from going to cool to hot and back again eventually results in compression of the head gasket...it actually gets a little thinner and then allows the leakage to start. When the gasket first starts to fail, it is only noticed when the engine is cold at startup and then symptoms go away as the engine warms up. If you are having an ongoing issue with head gasket failure, I suggest my previous post concerning installing the M6 "helicoil" threaded insert in the hole for the front cylinder stud. This provides a much stronger mounting for the stud than the original fine threads in soft aluminum situation. It is important to do a good job with drilling and tapping this hole so that you do not have problems later. Because the insert kits run about $30 to $40, you can probably take the head to a reputable machine shop and have the whole thing done right for not much more than the ridiculous price of the insert kit at the local car parts shop! And no, you do not have to use loctite on a permanent "helicoil" repair...that is just something I do but not a normal or necessary thing. Now, on to my second suggestion, I highly recommend that you use a special sealant on the head gasket when you put it back together. It is called Hylomar Advanced Formulation Gasket & Jointing Compound. You will probably not find it at run of the mil car parts shops but it is available from engine rebuilding suppliers. If you have problems finding it, call a local engine rebuilder to see if they can get it for you. When you put the cylinder head back on, ensure that the parting surfaces are absolutely clean and dry and free of oily residue. Take a plastic spatula or small plastic scraper and carefully "squeegee" a thin film of the compound onto both sides of the new head gasket. When you reinstall the head, make sure that you do not over-torque the heads beyond 28 foot pounds because all you are doing is crushing the new gasket and reducing its resistance to thermal cycling. You can also use the Hylomar compound on the valve cover..just make sure that you clean any oil from the parting surfaces and use just a thin coating. I hope this helps.....
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07-19-2009, 04:43 PM	#20
Water Warrior 2 Senior Member Join Date: Dec 2006 Location: Squamish B.C Canada Posts: 11,409	Re: "Popping" noise when starting Excellant pics and info. Could this be made into a "Sticky" for future reference ??
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