Throttle lag: underpowered engine, or mechanical problem?

11920 Views 26 Replies 20 Participants Last post by Travisty, Feb 17, 2009

giusage80

Discussion Starter · Nov 4, 2008

Please hear me out, because I know some people may think they know the answer to this question without reading my explanation.

I am fully aware that the Ninja 250R is a smaller bike and the engine is only 250cc; it is only capable of so much. However, I have been noticing some throttle lag that I don't remember being there when I first purchased the bike. Here's what happens:

I shift into neutral (since I have the problem in neutral and it is not engaging any gears at all, it leads me to believe there may be something mechanically wrong)

*** From an idle of about 1,000 RPMs, I give the throttle a slow 1/4 turn to reach about 6,000 RPMs, leading me to believe there is nothing wrong...

*** Next, I give the throttle a very fast 1/4 (again, from neutral), but there is a delayed response for the engine to open up and rev to 6,000 RPMs. Its almost as if something is "stuck" and prevent the throttle from opening up with the motion of the throttle grip. I can only describe it as feeling like the cable is made out of rubber, and it takes some time for the cable to catch up with the throttle's manipulation.

*** It seems to only happen in the low 1,000-4,000 RPM range, as opening up the throttle very fast at higher RPMs does not produce an throttle lag. Mostly from idle.

I apologize if I did not use all of the correct terminology. Also, if you have any questions or would like me to elaborate further, please let me know. I try to be as descriptive as possible, but its different if you're not the one actually experiencing it.

Does anyone have the same problem or know what this could be caused by?

Thank you,
--Eddie

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1 - 20 of 27 Posts

Jester

· #2 · Nov 4, 2008

Did you do any mods that could have affected this? (Exhaust, jetting carbs, shimming needles, etc.)

Is the bike fully warmed up when you do this? Is the choke (fuel enrichment to please RedRider) off?

I know what you're saying is happening, the same thing happens with my weed wacker (don't laugh ahaha i can't drive). I don't hitnk anything is wrong with the throttle, because my weed wacker throttle opens just fine (i can see the cable and the actual throttle opening and closing).

What octane gas are you using?

Maybe the carbs need to be cleaned.

giusage80

Discussion Starter · #3 · Nov 4, 2008

I don't have any mods. The bike is stock from wheel to wheel.

Yes, I make sure the bike is warmed up; I first noticed it when after I rode home from work one day (about a 10 mile trip)

I am using 91 Octane gas, the highest available in California.

The bike has just under 2,000 miles on it and I brought it in for the initial maintenance at 700-800 miles (I believe it was suppposed to be 600 miles, but who's counting?

.

Based on the above info, do you still think it is the carbs? I suppose it can't be the cables, because there is an immediate response to my throttle manipulation at anything above 3k-4k RPMs.

Thanks,
--Eddie

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Steezy McBreeezy

· #4 · Nov 4, 2008

:-\

man thats kinda weird.. i only have that lagging problem when i try to get on the throttle when the motor is still cold..

weth56

· #5 · Nov 4, 2008

Well you also have to remember its a 2 cyclinder engine and there isnt that power there. And its a carbed bike so thats a little bit too. These are just my opinons. Its like you dont pay attention to something untill is is brought to your attention. So this might have been doing this and you were to happy to be on the bike and out riding to where you werent payin attention. But try using more clutch coming out of first and see if that helps.

Felix

· #6 · Nov 4, 2008

Slack in throttle cable? Which I guess you would feel from idle but not once reving.

Once mine was shimmed it lost that 'hesitation' at takeoff. Not sure if that is the same thing you are talking about.

Felix

ccy

· #7 · Nov 4, 2008

i kinda had the same problem when i first got my bike...
a few time i was trying to make a left turn into a major street on a stop (stop sign), i throttle up and the bike moved a little and the engine sounded like it stalled, but it's not, it's just not going...i was more like rolling across the road more than and then other cars started honking at me...pretty scary!
i realized it helps by warming bike completely...and when it happened again...just release the throttle immediately, and throttle up gently again

Outinthedark

· #8 · Nov 4, 2008

kkim said:
have the temps been noticeably colder there lately? if so, how much colder? to me, it sounds like a lean jetting condition. I'd shim the needles, if you have not done so, and see if that fixes the problem.

+1 to kkim...even though he hates me...

Sounds like you are not fully warmed up and running a little lean. Same issue with me. Shim the needles and you are good to go. Let that 250 warm all the way up too!

spooph

· #9 · Nov 4, 2008

The owners manual says idle should be set at 1380, I personally run it at 1500. adjust it and see what happens. If it doesn't fix it, and it's not a cable issue, nor a choke issue, it might be running too lean or rich, which means we're gonna have to get you to start sniffing the exhaust...

giusage80

Discussion Starter · #10 · Nov 4, 2008

ccy said:
i kinda had the same problem when i first got my bike...
a few time i was trying to make a left turn into a major street on a stop (stop sign), i throttle up and the bike moved a little and the engine sounded like it stalled, but it's not, it's just not going...i was more like rolling across the road more than and then other cars started honking at me...pretty scary!
i realized it helps by warming bike completely...and when it happened again...just release the throttle immediately, and throttle up gently again

Yup, that's exactly what happens, except it also happens when the bike is fully warmed up as well (AND in neutral).

As I said, I realize this is a two-cylinder, underpowered bike. But what puzzles me is that the engine should rev as desired when in neutral, right?

@ spooph, my bike is stock, straight from the showroom floor, and it idles at about 1,100 RPMs. I see how this could cause the issue, seeing as it should be higher. I'll look into shimming the needles, whatever that means (no worries, I'll use the search feature so you guys don't have to waste your breath)

nrhampton

· #11 · Nov 5, 2008

I could be mistaken...But doesn't lower octane fuel usually burn faster than higher octane?
If I'm right you should also try putting some 87 or something in it, see what happens.

camicwrath

· #12 · Nov 5, 2008

same thing ewith my bike I found it was a mixture of being run with 91 oct then switch to 87 oct an also when it wasnt fully warm. It still does it a little so I might attempt to shim the needles.

littlemike

· #13 · Nov 5, 2008

In my opinion, your bike is perfectly normal. Remember this bike is build for beginners so it will have a little lag so to not intimidate new riders. Like others suggested, shim the needle with one washer since your bike is stock and go test ride if you can tell the difference. If you don't like it, you can just remove the washers and put your bike stock again.

My bike does the same thing as you describe but only when its cold, once warm, I have no hesitation.

I used two washers, got a full exhaust, snorkel remove and I used 86 octane. We only have 86, 88 and 90 octane gas here in the Texas panhandle.

gummybear

· #14 · Nov 7, 2008

my bike did the lag thing too. happened a few times in an intersection, not fun. releasing the throttle and coming back on it helped. but REALLY what helped was shimming the needles. i used only 1 washer and it took away that dead spot of throttle lag. give it a try maybe? or maybe change your riding style to start out with more throttle and clutch control to keep the rpms higher, and avoid that lag area

StockWall

· #15 · Nov 7, 2008

giusage80 said:
I don't have any mods. The bike is stock from wheel to wheel.

Yes, I make sure the bike is warmed up; I first noticed it when after I rode home from work one day (about a 10 mile trip)

I am using 91 Octane gas, the highest available in California.

The bike has just under 2,000 miles on it and I brought it in for the initial maintenance at 700-800 miles (I believe it was suppposed to be 600 miles, but who's counting? .

Based on the above info, do you still think it is the carbs? I suppose it can't be the cables, because there is an immediate response to my throttle manipulation at anything above 3k-4k RPMs.

Thanks,
--Eddie

Maybe the octane is your problem. 91 octane is NOT needed for these bikes. Unless the temp outside is over 100 degrees, 91 is more than likely hurting your bike than helping. I bet your spark plugs are fouled up. If you are running gas that is not need for something it will basically kill your plugs and you wont get the right spark to get a good combustion. Maybe some one else can explain it better. Hope this helps.

nrhampton

· #16 · Nov 8, 2008

so in other words....what everyone else already said StockWall.

haha

StockWall

· #17 · Nov 8, 2008

Yea, but I had to get my 2 cents in too. haha.

mia-ninja

· #18 · Nov 14, 2008

I have the same problem dude. I use the mid grade gas. which actually improved my gas mileage from the 93 or 91 octane..i cant remember now. I was told that I didn't need to use the higher grade. So, I went mid grade. I'm gonna try the 87 and see if it does anything. If not. I'm shimming needles and so forth. But first I must fine washers

and get some money and find some time. Damn, seems everything is against me.

crushedcamber

· #19 · Nov 15, 2008

Spooph said:
The owners manual says idle should be set at 1380, I personally run it at 1500. adjust it and see what happens. If it doesn't fix it, and it's not a cable issue, nor a choke issue, it might be running too lean or rich, which means we're gonna have to get you to start sniffing the exhaust...

+1 my bike is actually set from factory at 1500 and i wouldnt change it for anything, i havent experieced any hesitation unless it is not fully warmed up.

Stanley168

· #20 · Dec 10, 2008

Just wondering did eddie solve the problem.........

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