Sluggish Throttle Response

[Bikergeek]

This is my first summer season riding this bike and I have noticed a sluggish throttle response when the engine gets hot.

When the bike starts to run hot, oil temp around 250+ degrees and outside temps around 80 degrees, my throttle seems to get less responsive. It feels as if there is a lack of fuel or maybe just the opposite, a rich mixture but the engine really lags only when trying to start rolling from a stopped position; no other time. When engine is cooler, 150 - 200 degrees, it feels "normal".

But please don't tell me to get the Dobeck EFI device. I went that route already. I would rather get the engine running properly without any add-ons.

Any ideas what's going on? What to look for? What to do?

 

[glider]

250* with out any added fuel and running lean will be a bit sluggish in 80* temps. Do you have any engine light coming on after a start?

What intake do you have? Do you have the TFI hooked up, or did you?

You mention that you are running V&H Big Shots Staggered exhaust. Do you have baffles in them?

What's the last thing you did to the engine? What fuel octane are you running?

We need more info to help you out.

 

[Jack Klarich]

This is my first summer season riding this bike and I have noticed a sluggish throttle response when the engine gets hot.

When the bike starts to run hot, oil temp around 250+ degrees and outside temps around 80 degrees, my throttle seems to get less responsive. It feels as if there is a lack of fuel or maybe just the opposite, a rich mixture but the engine really lags only when trying to start rolling from a stopped position; no other time. When engine is cooler, 150 - 200 degrees, it feels "normal".

But please don't tell me to get the Dobeck EFI device. I went that route already. I would rather get the engine running properly without any add-ons.

Any ideas what's going on? What to look for? What to do?

More info would be a big plus here, you had a TFI and it did not work? You now are back to stock?

 

[glazier]

This is my first summer season riding this bike and I have noticed a sluggish throttle response when the engine gets hot.

When the bike starts to run hot, oil temp around 250+ degrees and outside temps around 80 degrees, my throttle seems to get less responsive. It feels as if there is a lack of fuel or maybe just the opposite, a rich mixture but the engine really lags only when trying to start rolling from a stopped position; no other time. When engine is cooler, 150 - 200 degrees, it feels "normal".

I'm no expert and don't claim to be, as there are many more folks on this board with much more experience and knowledge than myself, but if your bike is getting to 250+ degrees in 80* temps, you need to get it to run cooler, especially if you say it feels normal between 150-200 degrees. 250* in 80 degree weather sounds really hot to me. Mine is a 2000 Heritage and used to run about 250* on the highway in hot Texas summers, before I recently upgraded to the high volume oil pump (which yours should have already), and switched to Mobil 1 V-Twin 20W-50. Went for a long ride yesterday afternoon in mid 90* temps and never got over 235*-240* on the highway at a steady 75-80 mph. What oil are you using??? Is it too lean??? Get that thing running cooler and see what happens. Mine is a carb and I don't know a thing about fuel injection on bikes, so I can't help you out there. Just seems to me it's running too hot, but maybe these later model bikes just run hotter. I also have one of those little slip on things with fins that go over the oil filter to help get rid of some of the heat. Harley used to have them but discontinued them. I got mine on Ebay. Not sure how well it works, but it can't hurt. The ad said you can run your bike with this thing on your oil filter, and after 15 minutes of riding, you can rest your knuckles on the rocker box covers without getting burnt. I'll give this guy $100 for every minute he can keep his hands on my rocker box covers after 15 minutes of riding. There's no way.

 

[Bikergeek]

Sorry folks,

Here is some additional information on my bike. I bought it used with 4300 miles. It came with the V&H pipes (I believe there are baffles in them) and the Stage 1 upgrade (as per the original owner implied). No engine lights remain on while running. Everything appears "healthy".

I did try the Dobeck EJK but didn't find it satisfactory. It wasn't providing any information as to what the settings represented and/or how much fuel was being injected at different stages so I returned it. And I found it ridiculous to make an adjustment on the EJK and then go road test the settings and if not satisfied do it again and again and again. Not for me, thank you!

Where I live we have more traffic and when I am riding on local roadways I tend to ride about 30-40 MPH and that's when the engine starts getting hotter. Lots of stop and go riding. Highway riding should allow the engine to run cooler but haven't done any long runs yet. And what really bothers me is the temps here have only reached the low to mid 80's. What's going to happen to the engine when the temps start hitting the 90+ range?

I did an engine oil change when I first got the bike, using H-D regular 20W-50 oil. I just bought Mobil1 20W-50 and plan on changing it again even though the oil has only 1500 miles on it since that oil change.

Hopefully this helps the real "experts" here with solving my problem. Thanks for the replies and hopefully some helpful solutions.

 

[glider]

Question:

How do you arrive at the 250* temp? Is it with an analog or digital temp gauge and have you verified the accuracy of the gauge with boiling water?

 

[Bikergeek]

Question:

How do you arrive at the 250* temp? Is it with an analog or digital temp gauge and have you verified the accuracy of the gauge with boiling water?

Good question.

Answer: I have the Harley Oil tank analog temp gauge as well as my friend. I tested mine using boiling water and the gauge read very close to the 212 degree mark at the boiling point. So it's close enough to being accurate.

I also swapped out my gauge with my friend's gauge and the gauges seem to read correctly during our last run together. We logged our bike's temp and then did the gauge swap when the temp was up near the 250 degree mark on my bike. His bike was around 210-220.

Oh yea,

I am using as required: Premium fuel - 92 octane with the 10% ethanol added.

 

[glider]

Have you checked for any intake leaks that in itself would lean out the fuel and run hotter than normal. Do it when the bike is at the 250* so you would be able to see if the hotter temps were contributing to the problem, possibly an intake leak.

 

[doctordoug]

Good question.

Answer: I have the Harley Oil tank analog temp gauge as well as my friend. I tested mine using boiling water and the gauge read very close to the 212 degree mark at the boiling point. So it's close enough to being accurate.

I also swapped out my gauge with my friend's gauge and the gauges seem to read correctly during our last run together. We logged our bike's temp and then did the gauge swap when the temp was up near the 250 degree mark on my bike. His bike was around 210-220.

Oh yea,

I am using as required: Premium fuel - 92 octane with the 10% ethanol added.

Has your friend added an aftermarket fueler of some sort? I would assume he has. A stock Harley with stage 1 is going to run hot. If you have the money add a Thunder Max and an oil cooler. That will drop the temps. You can see your AFR with the Thunder Max and not with the TFI. TFI is all you need with your mods.

 

[Bikergeek]

Have you checked for any intake leaks that in itself would lean out the fuel and run hotter than normal. Do it when the bike is at the 250* so you would be able to see if the hotter temps were contributing to the problem, possibly an intake leak.

Exactly where would I look for intake leaks? Everything "appears" to be normal. Are these just clamps that require tightening?

I will also check for exhaust leaks by the exhaust pipe clamp at the engine exhaust port. It was loose at one time.