[BigDon]

...+/- 45 miles an hour in 5th.

As I told you all in a previous thread my new ownership experience is going very well. But I do have a question.

Background, 2008 cast iron 500ES, I have put all but the first 50 miles on the bike, the dealer ran up the first 50 during setup and prep at my request so the bike was ready for me to ride.

I have 625 miles on the bike now. I am still running it easy, however I have started taking longer and longer rides. Some of the rides include moderate grade increases. In order to maintain speed on these grades it is sometimes necessary to roll on the throttle. I am running at 45 and hit the grade and the bike starts to loose speed, I roll on the throttle and it stumbles, if I back off a little the stumble stops but I gradually loose speed say slowly down to 40.  I can stay in fifth or drop down to fourth and roll on the throttle again. It will then stumble a little but "push"  thru this and then continue to rev and pull smoothly.

Do I maybe be have a potential jetting problem or is this just part of the break in of the engine as it is being taken to newer RPM highs and load factors not yet experienced?

By the way on level roads this stumble does not happen and the bike starts, even cold (40 degree temps), with two to three kicks. It also idles fine after warm up.

Any advice??

[mbevo1]

Don - with my '07 iron lung, I've found almost any grade at or below 45mph is time to downshift... keeps the revs in the happy zone - 'specially during break-in. Loading up and lugging the motor isn't a "good thing".  BTW, I run about 145lbs soaking wet, so I don't think I'm that big a load on my Bullet...

I wouldn't worry much about flat spots - get a couple of thousand on it and it'll act like a different machine.



Mike and Stumpy in Michigan

[ace.cafe]

This is what's known as "lugging the engine". Not good.
It could possibly be combined with a jetting issue, which you notice when you try to open the throttle up to accelerate up from a relatively low rpm under load. If there is a lean-jetting issue, that would make the risk to the engine even worse.

Your rpms at that speed in 5th, with the added load of the hill are insufficient for the power curve to easily supply the needed power, so the engine starts to object.
Opening the throttle wider to get more power causes a condition where the ignition is too far advanced for that throttle opening at that rpm, causing piston heating, and is a recipe for an engine seizure in a Bullet engine which is not fully broken-in. The Bullet does not have a vacuum-operated ignition-retarding mechanism to deal with these kinds of circumstances.

Use the gearbox! That's what it's there for.
These bikes often need downshifting on any hills that are of any consequence.
If the hill creates a circumstance which interferes with your break-in limits, try to avoid that hill, and others like it until break-in is further along. If you get unknowingly caught on a hill that causes a circumstance like this, it is better on the engine to go ahead and downshift into a higher rev range, than it is to lug the engine at too-low of an rpm for the situation at hand. Even after break-in is completed, it is best to avoid lugging in any conditions, and best to keep the engine rpms in the "happy range" when going up hills, even if downshifting and higher revs are required. If the engine feels like it's objecting to the low rpms, then downshift.

This is a serious issue. There's been more than one Bullet that's bitten the dust in similar circumstances. I have an engine here in my workroom that has 3 large holes in the crankcases and a broken-off connecting rod in it. The previous owner seized the piston while lugging up a hill at 40mph. I bought what was left of it for parts.
Beware!

[jdrouin]

I have a similar experience on a certain part of the Brooklyn Queens Expressway. Even if I hit this spot at 50-55 mph, the combination of grade and headwinds from the harbor always slows me down to 45 and then 40, and the bike just doesn't want to pull faster unless I downshift to 4th. It doesn't look steep at all, so it must be an illusion caused by the fact that it's an elevated highway with the Brooklyn hillsides on the right and the distant harbor on the left.

Now that I have about 1,100 miles on the bike, I don't shift into 5th until about 45 mph. If I'm going steady at an even or downhill grade in consistent traffic, I'll put it in 5th as low as 40 mph, but I'm usually in 4th at that speed.

Jeff

[BigDon]

Thanks to all of you for your replies and for the reminder on lugging!

I don't let it get past the first indication of deceleration with out down shifting. But also need to be careful of overreving in the lower gears during break in. I will down shift and look to pull over if I am holding up traffic. It's hard to avoid hills in the area I live and ride in but that is what makes it a great place to ride. I just need to remind my self which bike I am riding!

The other part about the mechanical ignition advance is also one I need to keep in mind, I think I subconsciously was thinking about this as I would back off on the throttle and then down shift automatically.

So much to relearn after being spoiled by electronic ignition and massive amounts of torque.

Thanks again for your words of advice and warning

[ace.cafe]

General rule of thumb for a Bullet during break-in:

If you get caught in a situation where you have to decide to either rev higher than your break-in limits suggest, or lug the engine, then rev it. Don't lug it.

The possibility for engine damage is far higher with lugging, than it is with a short term rev increase beyond the suggested break-in rev range.
If in doubt, downshift.

[PhilJ]

The possibility for engine damage is far higher with lugging, than it is with a short term rev increase beyond the suggested break-in rev range.
If in doubt, downshift.

Sound sound advice!