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Post by ekim1847 on Oct 22, 2012 13:25:04 GMT -5
I have a 2006 linhai 300, 12k miles on it. At lower speeds in runs great, but it will not go facter than 55 mph. On the interstate when I want to go faster than 55 mph and I give it more throttle, it starts to backfire and stutter not going faster than 55. at lower speed when I give it wide open throttle it will climb to 55 mph no problem. I have the vales adjusted, does not help.
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Post by inuyasha on Oct 22, 2012 13:35:34 GMT -5
Hi
Welcome aboard
Pleased to meet you
Is this a carb or efi version? sounds like it could be either an intake or exhaust leak or if a carb version that may need to be cleaned and adjusted properly as it sounds like your running lean ( Getting too much air, not enough fuel)
Take care and ride safely
Yours Hank
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Post by 12string on Oct 22, 2012 13:48:11 GMT -5
Check fuel delivery... The vacuum fuel pumps are often the culprit, sometimes the vacuum lines are at fault, (kinked twisted or too small T's)
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Post by ronlee on Oct 22, 2012 14:30:04 GMT -5
I suspect it is starving for fuel at higher speeds because the fuel pump may not be delivering fuel as it should. I have a Linhai 300 that was acting up and finally quit because of fuel shortage from either a weak fuel pump or an air leak in the fuel line somewhere. New hoses and replaced the vacuum pump with an electric fuel pump and it now flies. Another benefit of the electric fuel pump is that it fills the carb. before starting so starting is instant.
Be sure to get a pump that only puts out 2 pounds of pressure or less as a higher pressure one will force fuel past the carb. needle valve and flood the carb.
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Post by scooteritch on Oct 24, 2012 21:13:49 GMT -5
I have a 2006 linhai 300, 12k miles on it. At lower speeds in runs great, but it will not go facter than 55 mph. On the interstate when I want to go faster than 55 mph and I give it more throttle, it starts to backfire and stutter not going faster than 55. at lower speed when I give it wide open throttle it will climb to 55 mph no problem. I have the vales adjusted, does not help. ekim1847 - Did you by chance replace your back tire recently? The reason I ask is that I replaced my rear tire not too long ago and had to remove the muffler and the rest of the items attached to the swing arm. When I put everything back, it seems that my muffler did not produce a solid seal when I reattached it to the exhaust pipe coming out from the engine. For few weeks, I felt like I was not getting the top speed that I had before but I contributed it to maybe a another tuneup was needed. Basically, make sure your muffler is completely sealed. If you feel any exhaust escaping around the connection area, seal it. Once I did this, I now have a nice acceleration and can jump back up to 65MPH without any issue. I hope this and the rest of the suggestions can help you find your problem. Thanks |
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Post by spandi on Oct 24, 2012 22:00:20 GMT -5
I popped in a Mikuni fuel pump and clear yellow Tygon hoses, as Chinese fuel pumps have a reputation for failing.
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Post by prodigit on Oct 24, 2012 22:24:03 GMT -5
I'd say it could be the rollers. Probably stock rollers with 12k miles on it, needs replacement (belt too).
Your 300 should hit 70 with ease, probably top out at 80MPH (~90 on the speedo if it's chinese).
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Post by unclebuggies on Oct 25, 2012 10:49:43 GMT -5
I thought the 2006 linhai 300 had an electric fuel pump. They started using vacuum pumps with the 2008 model. Can any owners confirm?
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Post by ekim1847 on Oct 25, 2012 16:03:42 GMT -5
Thanks everyone for all the good advise. At the scooter shop thay think changing the carb at $400.00 will take care of the problem. But at $400.00 and no guarantee......I can live with it as it is now.
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Post by scootnwinn on Oct 25, 2012 23:08:57 GMT -5
About the only thing that would cause you to need a new carb is excessive shaft play. You can check that by attempting to wiggle the shaft the throttle butterfly attaches to. If it moves a lot you need a new carb if not you can replace just about every other part for far less than $400
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Post by ekim1847 on Oct 30, 2012 8:30:46 GMT -5
Thanks prodigit, I change the rollers and put on a new belt. Problem solved! Had it on the interstate the other day top out at 75 mph. No backfiring or sputtering!
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Post by jlee on Oct 30, 2012 15:01:35 GMT -5
Thanks prodigit, I change the rollers and put on a new belt. Problem solved! Had it on the interstate the other day top out at 75 mph. No backfiring or sputtering! Glad you solved the problem, but scratchin' my head over how rollers & belt got rid of backfiring... |
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Post by prodigit on Oct 30, 2012 16:44:54 GMT -5
Rollers and belt need to be changed after 10k, that probably took care of the speed issue.
Another is he might have a gasket leak in the exhaust; having the correct gear (increased load) on the engine might make the exhaust run less rich, resulting in less back firing.
I would also suggest to use 2 ounces of sea foam in a full gas tank. It should get rid of valve deposit. After that, do a valve adjustment, and your bike should run just as new.
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Post by jlee on Oct 30, 2012 16:53:29 GMT -5
Sounds plausible I guess, though he may have masked the underlying problem rather than solved it...
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Post by ekim1847 on Oct 30, 2012 18:32:59 GMT -5
I'm thinking the old rollers would not let me go over the rpm to go faster than 55. I had plenty of throttle so when I put more gas in the engine to increde the speed the rpm would not increase causing the backfiring and sppudering. All I know it's working well with no issues.
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Post by jlee on Oct 30, 2012 18:45:41 GMT -5
I'm thinking the old rollers would not let me go over the rpm to go faster than 55. I had plenty of throttle so when I put more gas in the engine to increde the speed the rpm would not increase causing the backfiring and sppudering. All I know it's working well with no issues. If the rollers were maxed out, and you had plenty of throttle left, it would simply have turned the belt faster until you got to WOT. Unless you have a rev limiter of some sort. |
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Post by prodigit on Nov 2, 2012 0:59:15 GMT -5
I'm thinking the old rollers would not let me go over the rpm to go faster than 55. I had plenty of throttle so when I put more gas in the engine to increde the speed the rpm would not increase causing the backfiring and sppudering. All I know it's working well with no issues. If the rollers were maxed out, and you had plenty of throttle left, it would simply have turned the belt faster until you got to WOT. Unless you have a rev limiter of some sort. Most bikes are rev limited. Even if not, they usually start losing torque beyond 7k RPM, so much that at 9k RPM they might not be able to overcome any wind or other resistance. If the rollers are really worn out, the gearing might be so low, that it forces the engine to make eg: twice the RPMs, to get at the same speed. eg: if you're doing 6k RPM to get to 60MPH, but the rollers are worn so much that the variator only allows a gearing of 1/2 of before, then the engine needs to do 12k rpms to reach to 60MPH. Most engines, even if they are rev unlimited, are still limited to ~9 or 10k RPMs max. Once the engine gets to 9 or 9,5k RPM, it has almost no more torque left to go any faster; in such case the bike would only go upto 45MPH instead of 60. |
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Post by jlee on Nov 2, 2012 2:08:45 GMT -5
If the rollers were maxed out, and you had plenty of throttle left, it would simply have turned the belt faster until you got to WOT. Unless you have a rev limiter of some sort. Most bikes are rev limited. Even if not, they usually start losing torque beyond 7k RPM, so much that at 9k RPM they might not be able to overcome any wind or other resistance. If the rollers are really worn out, the gearing might be so low, that it forces the engine to make eg: twice the RPMs, to get at the same speed. eg: if you're doing 6k RPM to get to 60MPH, but the rollers are worn so much that the variator only allows a gearing of 1/2 of before, then the engine needs to do 12k rpms to reach to 60MPH. Most engines, even if they are rev unlimited, are still limited to ~9 or 10k RPMs max. Once the engine gets to 9 or 9,5k RPM, it has almost no more torque left to go any faster; in such case the bike would only go upto 45MPH instead of 60. Hmmm, most bikes are rev limited? I've heard the opposite. Anyway, your explanation is non sequitur. The original poster said his bike sputtered and backfired when trying to go past 55mph. That would have nothing to do with a rev limiter or worn rollers. |
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Post by prodigit on Nov 2, 2012 3:26:06 GMT -5
Most bikes are rev limited. Even if not, they usually start losing torque beyond 7k RPM, so much that at 9k RPM they might not be able to overcome any wind or other resistance. If the rollers are really worn out, the gearing might be so low, that it forces the engine to make eg: twice the RPMs, to get at the same speed. eg: if you're doing 6k RPM to get to 60MPH, but the rollers are worn so much that the variator only allows a gearing of 1/2 of before, then the engine needs to do 12k rpms to reach to 60MPH. Most engines, even if they are rev unlimited, are still limited to ~9 or 10k RPMs max. Once the engine gets to 9 or 9,5k RPM, it has almost no more torque left to go any faster; in such case the bike would only go upto 45MPH instead of 60. Hmmm, most bikes are rev limited? I've heard the opposite. Anyway, your explanation is non sequitur. The original poster said his bike sputtered and backfired when trying to go past 55mph. That would have nothing to do with a rev limiter or worn rollers. 1- Ever done 43k RPMs on your engine, or even more than 12k rpm? 2- Well seemingly the rollers did take care of his issue, so... |
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Post by jlee on Nov 2, 2012 3:54:53 GMT -5
1- Ever done 43k RPMs on your engine, or even more than 12k rpm? 2- Well seemingly the rollers did take care of his issue, so... 1. No, and neither have you. Guaranteed. 2. As I said before, that may have only masked the real problem. |
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