question about the zong? motor rattles at higher rpms

alan566 · 03-14-2010, 12:38 PM

while ridding at low to mid rpms it runs smooth but out on the road i have to get on it alot more and when higher rpms and a lot of throttle (like riding up a hill in 5th gear at 55) the motor sounds like it rattles some, like it does in a car that is spark knocking. i filled it up with reg gas (87) so i added a little octane booster, not much probably brought the octane to the low 90's. it runs smoother and rattles a lot less. i have under 100 miles on it and have changed the oil 2 times, 1st time was before i started it, 2nd time around 25 miles. Is the rattling normal?

katoranger · 03-14-2010, 02:23 PM

Spud? I wonder if the valves need adjusting? Also maybe fuel mixture?

Allen

FastDoc · 03-15-2010, 11:21 AM

I always only use premiun in all my motorcycles. Cheap insurance against knocking. Stock spark plug? Different heat range maybe?

Weldangrind · 03-15-2010, 11:48 AM

The fact that the rattling calmed down with octane booster puts a finer point on detonation. Try super unleaded at you next fill and see if the problem goes away.

BTW, you can make just about any car or bike detonate if you load it up in too high of a gear.

alan566 · 03-15-2010, 08:37 PM

Do i need to change the stock spark plug? it came with a NGK D8EA and the gap is set to .70 mm.

about the gas, i always used premium also years ago but its hard to find gas stations around here with 3 pumps on each machine at the station. if you go to a gas station that only has one pump then there is probably around a gallon (no sure how much) of gas left in the line and pump coming out to the bike. I will try to get 93 in it.

its not real bad and it does the same thing if i lug the motor also.

FastDoc · 03-15-2010, 10:25 PM

Quote:

Originally Posted by alan566

Do i need to change the stock spark plug? it came with a NGK D8EA and the gap is set to .70 mm.

about the gas, i always used premium also years ago but its hard to find gas stations around here with 3 pumps on each machine at the station. if you go to a gas station that only has one pump then there is probably around a gallon (no sure how much) of gas left in the line and pump coming out to the bike. I will try to get 93 in it.

its not real bad and it does the same thing if i lug the motor also.

Your plug is correct.

Weldangrind · 03-15-2010, 11:07 PM

I would agree that the plug is the correct type, but if it is the stock plug, it might be a fake. There are some clever NGK forgeries out there, but you can spot one next to the genuine article. Did you buy and install the plug, or was it original to the bike? If it is the original, I'd buy a new one.

I'm with you on the separate fuel hose issue. That's the reason why I buy dirt bike fuel from our local Chevron with a dedicated super unleaded pump.

TheRealWorld · 03-15-2010, 11:32 PM

See if you can duplicate the noise in a lower gear, It might be some vibration. Look for any thing that might vibrate at a higher rpm.

SpudRider · 03-16-2010, 12:50 AM

If your Zong is like mine, you got a real NGK spark plug. Also, the spark plug is correctly gapped. Therefore, I don't think you have a bad spark plug.

I always burn 87 octane fuel in my Zong, and this fuel has not caused any problems for me after riding 22,000 miles. Therefore, I don't think you need higher octane gasoline, either.

I don't think anything is loose, since the Zong comes well assembled from the factory. However, it certainly doesn't hurt to check all the bolts.

I think all single-cylinder, air cooled engines make a bit of noise. If you listen carefully, you will also certainly hear the valves opening and closing. You say the noise is not too bad, therefore, I think the noise you hear is probably normal. However, it certainly wouldn't hurt to check/adjust the valve clearance.

If you can, I encourage you to test ride someone's Yamaha TW200; I wouldn't be surprised if the engine sounds the same.

Alternatively, you could have someone else ride your Zong, and see if he thinks the noise is abnormal.

Spud

SpudRider · 03-16-2010, 01:01 AM

Quote:

Originally Posted by Weldangrind

...BTW, you can make just about any car or bike detonate if you load it up in too high of a gear.

Exactly.

After all, this is only a 200cc motorcycle. Also, the Zong is geared way too high from the factory.

Are you possibly hearing noise coming from the drive chain?

Spud

katoranger · 03-16-2010, 07:56 AM

I ran 87 in my lifan with no problems too. The zong may be higher compression though. Spud, we are about 1100 ft of elevation here in GA. It may be that he needs to jet up the carb some.

Allen

FastDoc · 03-16-2010, 11:27 AM

Higher elevation you jet down, leaner mixture. A richer mixture, although suboptimal, would cool the engine and actually help prevent detonation/preignition. They are not exactly the same thing, but there is overlap.

TurboT · 03-16-2010, 04:16 PM

Could you have the bike in fourth in that speed? If going up a hill or needing more power? It sounds to me like you might be overtaxing the motor. You mentioned it makes the same sound when it lugs, could the amount of power you're requiring at that speed up a hill essentially be doing the same thing?

I think about this at a distance, 55 MPH is a pretty good clip on a 200cc Air cooled motorcycle. I'm not sure the top speed of the Zong, but I thought I'd read here about 65 mph. If you're going up hill at that speed, sounds to me like you're at the end of the tourque/hp/speed limit. The noise you hear might just be the bike/motor telling you I need more revs for this.

SpudRider · 03-16-2010, 04:29 PM

Quote:

Originally Posted by katoranger

I ran 87 in my lifan with no problems too. The zong may be higher compression though. Spud, we are about 1100 ft of elevation here in GA. It may be that he needs to jet up the carb some.

Allen

Based upon my experience, and the experience of others, I think Alan's carburetor main jet is fine, Allen.

The stock, Teikei, size 132, main jet is pretty much optimal for your altitude; if anything, this main jet is a little rich.

Spud

SpudRider · 03-16-2010, 04:38 PM

Quote:

Originally Posted by TurboT

Could you have the bike in fourth in that speed? If going up a hill or needing more power? It sounds to me like you might be overtaxing the motor. You mentioned it makes the same sound when it lugs, could the amount of power you're requiring at that speed up a hill essentially be doing the same thing?

I think about this at a distance, 55 MPH is a pretty good clip on a 200cc Air cooled motorcycle. I'm not sure the top speed of the Zong, but I thought I'd read here about 65 mph. If you're going up hill at that speed, sounds to me like you're at the end of the tourque/hp/speed limit. The noise you hear might just be the bike/motor telling you I need more revs for this.

This is exactly what I also believe.

I think you will notice a definite improvement if you switch to a smaller countershaft sprocket. I recommend either a 14-tooth, or a 13-tooth countershaft sprocket.

http://chinariders.net/modules.php?n...ewtopic&t=7565
http://chinariders.net/modules.php?n...er=asc&start=0
http://chinariders.net/modules.php?n...ewtopic&t=9240

Spud

03-14-2010, 12:38 PM	#1
alan566 Join Date: Feb 2010 Location: Hartwell, GA Posts: 187	question about the zong? motor rattles at higher rpms while ridding at low to mid rpms it runs smooth but out on the road i have to get on it alot more and when higher rpms and a lot of throttle (like riding up a hill in 5th gear at 55) the motor sounds like it rattles some, like it does in a car that is spark knocking. i filled it up with reg gas (87) so i added a little octane booster, not much probably brought the octane to the low 90's. it runs smoother and rattles a lot less. i have under 100 miles on it and have changed the oil 2 times, 1st time was before i started it, 2nd time around 25 miles. Is the rattling normal?
	0

03-14-2010, 02:23 PM	#2
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	Spud? I wonder if the valves need adjusting? Also maybe fuel mixture? Allen __________________ You meet the nicest people on a Honda Clone.
	0

03-15-2010, 11:21 AM	#3
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	I always only use premiun in all my motorcycles. Cheap insurance against knocking. Stock spark plug? Different heat range maybe? __________________ Happy to serve.
	0

03-15-2010, 11:48 AM	#4
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	The fact that the rattling calmed down with octane booster puts a finer point on detonation. Try super unleaded at you next fill and see if the problem goes away. BTW, you can make just about any car or bike detonate if you load it up in too high of a gear. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

03-15-2010, 11:07 PM	#7
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	I would agree that the plug is the correct type, but if it is the stock plug, it might be a fake. There are some clever NGK forgeries out there, but you can spot one next to the genuine article. Did you buy and install the plug, or was it original to the bike? If it is the original, I'd buy a new one. I'm with you on the separate fuel hose issue. That's the reason why I buy dirt bike fuel from our local Chevron with a dedicated super unleaded pump. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

03-15-2010, 08:37 PM	#5
alan566 Join Date: Feb 2010 Location: Hartwell, GA Posts: 187	Do i need to change the stock spark plug? it came with a NGK D8EA and the gap is set to .70 mm. about the gas, i always used premium also years ago but its hard to find gas stations around here with 3 pumps on each machine at the station. if you go to a gas station that only has one pump then there is probably around a gallon (no sure how much) of gas left in the line and pump coming out to the bike. I will try to get 93 in it. its not real bad and it does the same thing if i lug the motor also.
	0

03-15-2010, 11:32 PM	#8
TheRealWorld Join Date: Jun 2008 Posts: 817	See if you can duplicate the noise in a lower gear, It might be some vibration. Look for any thing that might vibrate at a higher rpm.
	0

03-16-2010, 12:50 AM	#9
SpudRider Join Date: Jul 2008 Location: Idaho Posts: 25,054	If your Zong is like mine, you got a real NGK spark plug. Also, the spark plug is correctly gapped. Therefore, I don't think you have a bad spark plug. I always burn 87 octane fuel in my Zong, and this fuel has not caused any problems for me after riding 22,000 miles. Therefore, I don't think you need higher octane gasoline, either. I don't think anything is loose, since the Zong comes well assembled from the factory. However, it certainly doesn't hurt to check all the bolts. I think all single-cylinder, air cooled engines make a bit of noise. If you listen carefully, you will also certainly hear the valves opening and closing. You say the noise is not too bad, therefore, I think the noise you hear is probably normal. However, it certainly wouldn't hurt to check/adjust the valve clearance. If you can, I encourage you to test ride someone's Yamaha TW200; I wouldn't be surprised if the engine sounds the same. Alternatively, you could have someone else ride your Zong, and see if he thinks the noise is abnormal. Spud __________________ Spud "Never argue with an idiot. He will drag you down to his level, and beat you with experience." Mark Twain 2015 Zongshen ZS250GY-3 (RX3) 2006 Zongshen ZS200GY-2 (Sierra 200) 2005 Honda XR650L 2004 Honda CRF250X 1998 Kawasaki KDX220 Mods made to my Zongshen ZS200GY-2: http://www.chinariders.net/showthread.php?t=6894
	0

03-16-2010, 07:56 AM	#11
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	I ran 87 in my lifan with no problems too. The zong may be higher compression though. Spud, we are about 1100 ft of elevation here in GA. It may be that he needs to jet up the carb some. Allen __________________ You meet the nicest people on a Honda Clone.
	0

03-16-2010, 11:27 AM	#12
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	Higher elevation you jet down, leaner mixture. A richer mixture, although suboptimal, would cool the engine and actually help prevent detonation/preignition. They are not exactly the same thing, but there is overlap. __________________ Happy to serve.
	0

03-16-2010, 04:16 PM	#13
TurboT Join Date: Sep 2008 Location: Surrey, B.C., Canada Posts: 2,185	Could you have the bike in fourth in that speed? If going up a hill or needing more power? It sounds to me like you might be overtaxing the motor. You mentioned it makes the same sound when it lugs, could the amount of power you're requiring at that speed up a hill essentially be doing the same thing? I think about this at a distance, 55 MPH is a pretty good clip on a 200cc Air cooled motorcycle. I'm not sure the top speed of the Zong, but I thought I'd read here about 65 mph. If you're going up hill at that speed, sounds to me like you're at the end of the tourque/hp/speed limit. The noise you hear might just be the bike/motor telling you I need more revs for this.
	0