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That Lag and Leap problem

76K views 202 replies 66 participants last post by  KiwiHOG 
#1 ·
A few of us on here have experienced problems concerning a lag when you take off from a dead stop and then an immediate acceleration. It throws you off balance and is very alarming. Some of us have experienced fuel light problems. I had both.
The problem? The fuel pump.

After having my fuel pump replaced last week and riding it until one or both of these problems reoccurred, I am happy to say it is fixed.

I rode my 750 until something happened and I am pleased to say the fuel light came on at precisely the correct time. I fueled up with 2.8 gallons which means that there was approximately .7 gallons in the tank,....perfect !
No lag and leap problem was encountered.
I am now a happy camper,..er, rider. :)
 
#3 ·
A few of us on here have experienced problems concerning a lag when you take off from a dead stop and then an immediate acceleration. It throws you off balance and is very alarming. Some of us have experienced fuel light problems. I had both.
The problem? The fuel pump.

After having my fuel pump replaced last week and riding it until one or both of these problems reoccurred, I am happy to say it is fixed.

I rode my 750 until something happened and I am pleased to say the fuel light came on at precisely the correct time. I fueled up with 2.8 gallons which means that there was approximately .7 gallons in the tank,....perfect !
No lag and leap problem was encountered.
I am now a happy camper,..er, rider. :)

About how many miles did you go before your light came on? I am trying to gage. My light came on when I had 40 miles on my odometer and I thought I was having issues, because I was told that they delivered my bike with a full tank, it was only when I ran out of gas on my second ride that I knew it was not a mechanical issue but a lying tongue issue.
 
#7 · (Edited)
I really wonder how it could be the fuel pump that is the problem... For it to only happen under certain conditions, I just don't see the logic.
Makes perfect sense to me. That Lag-and-Leap thing we were experiencing was only happening when I was low on fuel,...of course I didn't know I was low on fuel because my light never came on.
The light sensor (fuel sensor) is in the fuel pump and when the fuel level gets low enough the pump can't pick up enough gas to supply the engine. Starting from a dead stop sends all the fuel towards the back of the tank and since the pick-up is towards the front of the tank it is momentarily starved of gas. (hence the lag). When the fuel is pushed back towards the front of the tank due to that lag crap, it leaps out from under you once the pick-up has a supply again.
It scared me to death a couple times when it did that and it is dangerous because when it lags like it did you have a tendency to give it more throttle and then when the gas is sloshed back up to the pick-up,....VRROOOOMM !
A novice rider would have been in trouble with a problem like that, and if I hadn't had a firm grip on the handlebars that 750 would have slung me off the bike.

Anyway,....there ya go. Problem solved.
 
#12 ·
I have talked to the service manager at my Harley dealer and requested that he look at the fuel pump that he removed from my machine and see who the manufacturer is. I was told that there are NO identification markings on the pump, so who makes the pump? I have no idea.

However,......If you have a pump problem you can call Harleys' toll free number @ 1-800-664-7762 and give them your VIN and they will overnight a fuel pump (I assume to the dealerships service department).
Harley IS aware of this problem.
 
#19 ·
It isn't the end of the world... and if the bike isn't pushed to its current limits, either performance, or fuel level wise - you'll probably be fine, and probably wont ever experience it.

My issue is that when I pay 8+ grand - its going to work as it should. I dont care what costs they incur in fixing the problem. They've made enough profit from me already - time for them to hold up their end of the deal.
 
#31 · (Edited)
I am grateful to you guys for hammering out these issues. I'm looking at the new Harley Street carefully...It seems like a good bike. I want to support the US economy, have a reliable simple machine to get to work and be a part of something. Honda, Triumph and BMW seem to put out fairly strong bikes but we (my wife and I) are trying to focus our resources on the local economy, the local produce and support things in our community. The new Harley Street is one of the few things still made in the US. I know, I know, the Kansas City plant doesn't forge all the parts there but the principal is in place. I've been reading so many awesome posts, I had to chime in. The fuel issue (with the pictures of the internal fuel pump) is very helpful. Thanks Old Dawg! I'm going to be riding a Harley, I can feel it...
 
#34 ·
I am not at all convinced it is a fuel pump issue. The lag and leap only happens when there is low fuel, and the fuel is displaced on launch or in a lean. As soon as the fuel level stabilizes, everything works as normal. When my bike is full of fuel, there is no lag and leap.
 
#36 ·
I am really upset after reading all this and what I learned today...for us it is not a low fuel issue. Apologies if read some of this in another post I just left.

My wife has been trying to learn to ride on the 500 after successfully taking a rider course. She has been having a lot of difficulty, ...then the last time she was on it, still has not left the neighborhood, she took a spill very unexpectedly. She is frustrated and has not been back on the bike in a few weeks. It had the fuel light indicator problem (has been lit since about the 30 mile mark) so today I drove it to the dealer to have that checked. Boy was I surprised. The throttle on this bike is extremely erratic. I wasn't sure I would make it to the dealer. I was suspecting it was some fuel delivery issue, or injectors, or maybe it really was low on fuel but with only about 40 miles of cul de sac riding that couldn't be! I am really pissed this bike threw my wife due to the erratic throttle and I was totally oblivious. Until today. I had taken a few rides early on but mostly she has been in the neighborhood riding circles, practicing uphill starts, coming back into our driveway, about a 400 yard route.

This is very upsetting. Someone said the tank was replaced? Well ours sure needs it after she was thrown down on the sidewalk. I hope our dealer will be able to find the whole story.
 
#38 ·
My street 750 is going in for work soon. My place has told many many times its nothing and that the lag and leap thing would just work itself out. Well after it happen to me yesterday and i almost got run over in the middle of the road i think its time they did something about it.
will keep everone posted on the findings :(
 
#44 ·
I'm nervous about the lag and leap problem.

because I'm something of a novice rider.. a few years back i picked up a 69 Yama 125 Enduro and learned to ride on that. Moved to DFW and raped a local harley dealer on an '02 Honda Rebel which I loved and learned about the Street

I planned on the Street for my next upgrade and got scared when I learned about this problem. the thought of 750 cc's screaming a full throttle unexpected scares the pi$$ out of me..

Well, the Honda has been stolen and I've found a screamer deal on a Streeet in a neighboring state...

Emotionally i want to drive over, write a check, and bring that baby home... But my common sense is saying stay the "F" away...

:-( Is anyone still fighting this problem?
 
#45 ·
because I'm something of a novice rider.. a few years back i picked up a 69 Yama 125 Enduro and learned to ride on that. Moved to DFW and raped a local harley dealer on an '02 Honda Rebel which I loved and learned about the Street

I planned on the Street for my next upgrade and got scared when I learned about this problem. the thought of 750 cc's screaming a full throttle unexpected scares the pi$$ out of me..

Well, the Honda has been stolen and I've found a screamer deal on a Streeet in a neighboring state...


Emotionally i want to drive over, write a check, and bring that baby home... But my common sense is saying stay the "F" away...

:-( Is anyone still fighting this problem?
I have almost 5K miles on my Street750 since July of last year when I bought the bike brand new. I haven't had that issue with the lag and leap. Only occasional hitting the Rev Limiter when running in one gear too long during excessive acceleration...:) The only thing I had to have checked on my bike was the fuel cap from a recall notice. My bike is still under warranty. I've had good luck with my bike. I run premium gas only and I can get the non alcohol blend just up the road 6 miles away. Otherwise I just premium grade gas. Honda's and Harley's will always be a target for thieves.
 
#48 ·
Does anyone have a link to the recall info? I've only had my 500 for a week but I have experienced the lag and leap from fuel starvation with no fuel indicator light illuminating. Pretty crappy since I have a lot of hills and banks on my commute and high traffic areas. When I fueled up I'd gone 126 miles (the dealer did give me a nice full tank with purchase) and the tank was completely full with 2.6 US gallons in the tank. No more issues as soon as I filled the tank up but since I first experienced the lag and leap issue mid sharp bank before having to go up hill leaving work, I have zero desire to replicate it. It could have been bad if this were my first week on a motorcycle.
 
#51 ·
The is no recall for this issue. The only recall is for filler cap fitting the gas tank.

If one were to follow the thread(s) carefully, one would see the issue is the fuel "sock" attached to the fuel pump inside the tank. That's how mine was fixed. No more lag and leap. The fuel sock was partially separated from the fuel intake port, sucking in air at low fuel conditions.
 
#52 ·
The is no recall for this issue. The only recall is for filler cap fitting the gas tank.

If one were to follow the thread(s) carefully, one would see the issue is the fuel "sock" attached to the fuel pump inside the tank. That's how mine was fixed. No more lag and leap. The fuel sock was partially separated from the fuel intake port, sucking in air at low fuel conditions.
Thanks again for this info. i will let me local dealer know in the morining when i call that this is may be my problem or the fuel pump.
 
#53 ·
Questions for everyone experiencing this lag and leap problem

@Obtuse please check your private message. I send you some questions to see if i am indeed having the lag and leap problem or if mine is totally different.


Im just going to post my questions on here so that everyone else can maybe guide me to see if this is my issue.

When you experienced this lag and leap did it feel as the engine tries to rev up but it doesn't until you feed it way too much gas? Does it feel as if the engine is like stuttering on you? If you turned the bike on and off did it continue until you filled it with gas? If you didn't fill it with gas but turned the bike off did the problem persist consistently as soon as you turned the bike back on or did it start sporadically and random again?
I really dont know if the issue of the lag and leap is the same as what i am experiencing its very random it happened to me on multiple gears but i have noticed on a first gear stop or a first gear roll it does it even more.
 
#54 ·
@Obtuse please check your private message. I send you some questions to see if i am indeed having the lag and leap problem or if mine is totally different.


Im just going to post my questions on here so that everyone else can maybe guide me to see if this is my issue.

When you experienced this lag and leap did it feel as the engine tries to rev up but it doesn't until you feed it way too much gas? Does it feel as if the engine is like stuttering on you? If you turned the bike on and off did it continue until you filled it with gas? If you didn't fill it with gas but turned the bike off did the problem persist consistently as soon as you turned the bike back on or did it start sporadically and random again?
I really dont know if the issue of the lag and leap is the same as what i am experiencing its very random it happened to me on multiple gears but i have noticed on a first gear stop or a first gear roll it does it even more.
I can tell you what happens to me. Its usally happens when im low in gas. But the light is not on. when i take off it feels like the bike just dies and it throws me forward and then catches and really throws me back. 1st time really caught me by surprise and almost caused me wreck. So now i always fill up around the 120 mark just in case. but my last time happened around the 90 mile mark. I was right in the middle of traffic when it happened. scared the sh*t out of me. i was not ready for it and came with in a few feet from getting hit by the car behind me.
hope this helps you.
god bless
 
#55 ·
The lag and leap problem, I experienced, was only when the fuel tank was low on gas, starting just before the low fuel light came on. It happened only when accelerating hard, in 1st gear and also in second gear for me. Apparently I did not accelerate hard enough in higher gear to experience that problem. The bike would accelerate and suddenly it cut out (no power) for a second before it resumed acceleration. The result was that you were jerked forward and back during hard acceleration. This was not intermittent problem, it was easily reproducible. The dealer fixed it by replacing the whole fuel pump assembly, which is located inside the gas tank. Theoretically, there was some separation happening between the pump and the tube/sock, which is at the bottom of the tank and as the gas swooshed back during hard acceleration it sucked air for a second.
The fix resolved the issue completely, I never experienced that problem since the fix.
Hope it helps.
 
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