Non specific motorcycle repair page.

Joined
Apr 2, 2008
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Nashville Tn.
Great source.


Now if I can just diagnose clogged jets is what my problem is...

I have checked the fuel strainer but not yet the compression. I get surges of power at low speed, 1st & 2nd gear crawling with traffic. And stumbling at high speed when I do a roll-off, to roll-on.

I would have thought with the gas I'm using (Shell 91 only) the 10% ethanol would have cleaned the jets? :confused:

The air filter was caked, but removing it entirely has not had an effect on it, and it's getting worse. It won't run at top speed.


It was barely noticeable at high RPMs (8-9,000 rpms) a few weeks ago, now it's noticeably lower starting around 5. It seems like if I harp on it a few times it's better at the moment, but over all it's getting worse.


Gonna check for cracks too, once the weather gets nicer...


Chokes, starts and idles great. Runs good, but not great.



UPDATE: The octane I was using wasn't 91 as said above...it was 93. I checked the strainer and it was spotless so it's highly probable the jets are clean to (Ethanol is a cleaner). The numbers on the plug I have don't correspond with the one in the Honda FSM. It's one # off and I asked the guy when I bought it to give me the best plug, and a hotter one (oops, when will I learn to leave stuff alone). Weather or not it's the same IDK, BUT....Going off the theory it is hotter, I guessed my stumbling could be fluttering and the octane is too high...or the plug is too hot. So, I ran 89 in my next tank and the problems seem to have vanished...

Not entirely, but mostly. Oddly, my mid range now has a very faint stumble/ flutter, and my low and high RPM ranges are smoother. Once again it will run at top speed, but overall I think it's lost about 5% power. It's hard for me to tell exactly, I ride with earplugs, so associating seat of the pants with that the engine sounds like is hard(er). I'll prolly try and get the exact plug and then go back to 93.
 
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Joined
Mar 23, 2003
Messages
485
Location
Vancouver, WA
Great source.


Now if I can just diagnose clogged jets is what my problem is...

I have checked the fuel strainer but not yet the compression. I get surges of power at low speed, 1st & 2nd gear crawling with traffic. And stumbling at high speed when I do a roll-off, to roll-on.

I would have thought with the gas I'm using (Shell 91 only) the 10% ethanol would have cleaned the jets? :confused:

The air filter was caked, but removing it entirely has not had an effect on it, and it's getting worse. It won't run at top speed.


It was barely noticeable at high RPMs (8-9,000 rpms) a few weeks ago, now it's noticeably lower starting around 5. It seems like if I harp on it a few times it's better at the moment, but over all it's getting worse.


Gonna check for cracks too, once the weather gets nicer...


Chokes, starts and idles great. Runs good, but not great.

Could it be an ignition problem? Have you checked timing? Spark plug? Is it CDI? Do they have control modules?
 
Joined
Apr 2, 2008
Messages
2,160
Location
Nashville Tn.
Could it be an ignition problem? Have you checked timing? Spark plug? Is it CDI? Do they have control modules?

It's CDI...and guess what Dual Sport, Honda...250cc...motorcycle... *HINT* has CDI issues....



Will check timing as soon as the weather warms.

Just changed the plug...and according to the link in the above source, it's at a good mix.


Don't know about what's in it now though. An Autolite came out, and a NKG with only one # off, went back in.

I'm thinking it's a hot (too hot) plug but won't know for sure until I pull it.

Also, the air filter has NOT been in since I replaced the plug. Gonna do that ASAP.




BTW, it's a Honda Nx250:D
 
Joined
Apr 2, 2008
Messages
2,160
Location
Nashville Tn.
Surging...

what about the chain? :frown:


...I was gonna go for a ride....how safe is this?







only place I can find on it, so far....
 
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Mace

rock scientist..
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Joined
Feb 17, 2002
Messages
21,460
Location
Las Vegas
I can't tell what would be wrong with the chain from that pic...

Is it worn through?

Pull off the car and rebuild it. The Ethanol won't clean a gummed up jet..
 
Joined
Jan 4, 2009
Messages
277
Location
Idaho-208
x2 on the carb rebuild. I would never run my bike without an air filter on it as that's the only protection from debris getting into the engine. Also if you are running a higher octane fuel you have to re-jet the carb either up or down depends on elevation and octane. I was running TRICK racing gas (101 octane) and the bike ran hot and had great throttle response!! Jetting was a nightmare and the 55 gallon drum that held the fuel was rusting....tons of debris in the float bowl...so back to 93 octane and re-jetted again. What's wrong with the chain? Is it worn on that link? How old is the chain? How bout the sprockets? I'd replace the chain before it binds up on the front sprocket and causes some case damage.
my .02
 
Joined
Apr 2, 2008
Messages
2,160
Location
Nashville Tn.
I can't tell what would be wrong with the chain from that pic...

Is it worn through?

Pull off the car and rebuild it. The Ethanol won't clean a gummed up jet..

I don't know what to call it but the outer piece is broke in a tiny section, revealing the inner piece.

On the Eth,,,yeah, I'm about to pull my hair out on ethanol period...ya hear one thing...you hear another.

I was told in chat by numerous people that Ethanol breaks the tar and junk loose in the fuel system...

I was under the assumption it was not all that great in low-tuned motors and to get the best out of it, you needed a high compression, tuned motor. And the mpg would still suffer in both those motors.

Wiki: "Ethanol (E100) consumption in an engine is approximately 51% higher than for gasoline since the energy per unit volume of ethanol is 34% lower than for gasoline.[13][14] However, the higher compression ratios in an ethanol-only engine allow for increased power output and better fuel economy than could be obtained with lower compression ratios.http://en.wikipedia.org/wiki/Ethanol_fuel#cite_note-autogenerated6-14"


It's a motorcycle so MPG is of little importance to me.

Mine has a 11:1 c/r... I am/ was thinking the Etoh. is a better fuel to run and will breakdown any tar or junk in the system but a guy at the local shop has been telling me otherwise to.






x2 on the carb rebuild. I would never run my bike without an air filter on it as that's the only protection from debris getting into the engine. Also if you are running a higher octane fuel you have to re-jet the carb either up or down depends on elevation and octane. I was running TRICK racing gas (101 octane) and the bike ran hot and had great throttle response!! Jetting was a nightmare and the 55 gallon drum that held the fuel was rusting....tons of debris in the float bowl...so back to 93 octane and re-jetted again.

Put the AF on as soon as I could. It's been on, and running fine w/ the 89 and a (confirmed) hotter plug.

Going back to stock ASAP.




What's wrong with the chain? Is it worn on that link?
Yes.


How old is the chain? How bout the sprockets? I'd replace the chain before it binds up on the front sprocket and causes some case damage.
my .02

Don't know. I've got a local shop trying to special order me a 39 tooth sprocket. Getting a chain to. Stock is 41 and 1st gear on my bike is useless. Fronts have no AM. It is a special spline that no one has ID'd to another bike yet.
 
Joined
Apr 2, 2008
Messages
2,160
Location
Nashville Tn.
All these problems stated with the original parts. I was riding 90 miles one way, for about 3 weekends, about three times.

I thought the AF was the problem so I yanked it till I could get back home. While I was where I was, I spotted a Honda place and got a plug...the return trip netted the same results.

Got home, started thinking, cleaned the AF and ran 89. The problems are almost nonexistent...I just H8 run the risk of messing something up, if that's not the problem to start with.

I'm thinking the RON is too high but don't yet know for sure.
 
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