Help with a vacuum leak

steviejfredricks · 05-25-2013, 08:34 PM

My Diamo ls200 has been running really bad of late, I noticed the problem when I took the carb off and put it back on to figure out why the throttle was sticking. Some chain lube shot into the cable fixed that problem. But now the bike is running like crap, It sputters and runs really rough at idle and then after I ride for a bit I pull in the clutch and the engine revs like crazy. I'm pretty sure its a vacuum leak. I sprayed the seal where the throttle cable goes into the carburetor and the bike revved up so I was assuming that that I'd found the problem. I wrapped the seal with some electrical tape and It didn't seem to do a whole lot. So now I'm not sure whats going on. I don't know if theirs jus a place I overlooked or if the electrical tape just isn't providing a good enough seal. I know that when I sprayed the taped seal with carb cleaner, nothing happened so I would guess that it isn't the culprit. If anybody has any other possible spots that the leak might live I'd be glade to hear them. I've checked the boots, the outlet from the air filter, the carb itself. I don't know whats up. Does anybody know what else this could be. This bike is giving me gray hair at 19

MICRider · 05-25-2013, 10:43 PM

Was the boot between the carb and engine in good shape? Sometimes they deteriorate and crack up rapidly and cause air leaks and overly lean running. It's possible that the removal and re installation of the carb could have worsened the situation. Lot's of folks here with tons of knowledge (lol, way more than me!) so hopefully they can help you out

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zingshoen · 05-26-2013, 12:57 AM

sth went wrong when you took the carb off. maybe sth loose, or sometimes overly tight bolts can crack something. i would take it off again and inspect all the parts. if unsure, whether something is iffy, post photos, then moderators and forum members will be able to advise.

steviejfredricks · 05-26-2013, 04:20 AM

hhhhhhm, I sprayed the boots pretty good (and carefully, I like my eyebrows) and didn't notice any raise in rpm. I guess I could have missed a spot though. I'll take everything apart and do a thorough check come monday, post some pictures as well.

zingshoen · 05-26-2013, 04:50 AM

before u do: is ur tank full? being out of fuel can give those symptoms.

Weldangrind · 05-26-2013, 12:50 PM

I had a vacuum problem with TurboT's atv, and it turned out to be the o-ring seal that mates with the head. There is a groove that the o-ring sits in, and the groove was cut too deeply; the hillbilly solution was to stack two o-rings. It ran fine after that.

That was with a steel intake tube on a low-mile atv. Your bike probably has an intake tube with rubber in the middle, and it could be cracked (like MICRider says). Like zingshoen says, maybe a mounting bolt is too tight.

Did you remove the intake tube from the head, or just remove the carb from the intake tube?

steviejfredricks · 05-26-2013, 02:16 PM

I removed the intake tube from the head, the way the bike is setup its the only way to get the carburetor off. I also feel that its important to mention that the problem isn't the carb itself. I have two, (got the other one on ebay for $30) and the bike had problems with both. I've been running the bike to see what wrong with it for a while so I sort of doubt its the lack of gas. I'll take the carb off tomorrow and post some pictures if I see anything weird. Thanks for the suggestions all.

05-25-2013, 08:34 PM	#1
steviejfredricks Join Date: Feb 2013 Posts: 9	Help with a vacuum leak My Diamo ls200 has been running really bad of late, I noticed the problem when I took the carb off and put it back on to figure out why the throttle was sticking. Some chain lube shot into the cable fixed that problem. But now the bike is running like crap, It sputters and runs really rough at idle and then after I ride for a bit I pull in the clutch and the engine revs like crazy. I'm pretty sure its a vacuum leak. I sprayed the seal where the throttle cable goes into the carburetor and the bike revved up so I was assuming that that I'd found the problem. I wrapped the seal with some electrical tape and It didn't seem to do a whole lot. So now I'm not sure whats going on. I don't know if theirs jus a place I overlooked or if the electrical tape just isn't providing a good enough seal. I know that when I sprayed the taped seal with carb cleaner, nothing happened so I would guess that it isn't the culprit. If anybody has any other possible spots that the leak might live I'd be glade to hear them. I've checked the boots, the outlet from the air filter, the carb itself. I don't know whats up. Does anybody know what else this could be. This bike is giving me gray hair at 19
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05-26-2013, 12:57 AM	#3
zingshoen Join Date: Jun 2009 Location: Brisbane, Queensland, Australia Posts: 648	sth went wrong when you took the carb off. maybe sth loose, or sometimes overly tight bolts can crack something. i would take it off again and inspect all the parts. if unsure, whether something is iffy, post photos, then moderators and forum members will be able to advise. __________________ 1971 Garelli Gulp 50cc with open ports and 16 mm Bing Carbie + 1980 Honda XL 223 ZS + 2007 Zongshen LZX200G + DR400SM
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05-26-2013, 04:50 AM	#5
zingshoen Join Date: Jun 2009 Location: Brisbane, Queensland, Australia Posts: 648	before u do: is ur tank full? being out of fuel can give those symptoms. __________________ 1971 Garelli Gulp 50cc with open ports and 16 mm Bing Carbie + 1980 Honda XL 223 ZS + 2007 Zongshen LZX200G + DR400SM
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05-26-2013, 12:50 PM	#6
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	I had a vacuum problem with TurboT's atv, and it turned out to be the o-ring seal that mates with the head. There is a groove that the o-ring sits in, and the groove was cut too deeply; the hillbilly solution was to stack two o-rings. It ran fine after that. That was with a steel intake tube on a low-mile atv. Your bike probably has an intake tube with rubber in the middle, and it could be cracked (like MICRider says). Like zingshoen says, maybe a mounting bolt is too tight. Did you remove the intake tube from the head, or just remove the carb from the intake tube? __________________ 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
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05-25-2013, 10:43 PM	#2
MICRider Join Date: Oct 2009 Location: Alberta, Canada Posts: 3,274	Was the boot between the carb and engine in good shape? Sometimes they deteriorate and crack up rapidly and cause air leaks and overly lean running. It's possible that the removal and re installation of the carb could have worsened the situation. Lot's of folks here with tons of knowledge (lol, way more than me!) so hopefully they can help you out .
	0

05-26-2013, 04:20 AM	#4
steviejfredricks Join Date: Feb 2013 Posts: 9	hhhhhhm, I sprayed the boots pretty good (and carefully, I like my eyebrows) and didn't notice any raise in rpm. I guess I could have missed a spot though. I'll take everything apart and do a thorough check come monday, post some pictures as well.
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05-26-2013, 02:16 PM	#7
steviejfredricks Join Date: Feb 2013 Posts: 9	I removed the intake tube from the head, the way the bike is setup its the only way to get the carburetor off. I also feel that its important to mention that the problem isn't the carb itself. I have two, (got the other one on ebay for $30) and the bike had problems with both. I've been running the bike to see what wrong with it for a while so I sort of doubt its the lack of gas. I'll take the carb off tomorrow and post some pictures if I see anything weird. Thanks for the suggestions all.
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