I had originally posted this message as a reply to another post but I need some info if anyone esle has had the same problem as the one I'm having.The whole adventure is a little more in depth then what I have listed below but all the details would just be too long so here goes.....


I bought my Heritage new in 06 and I have had a power issue ever since.The first time was at the second service . When I left the dealer it seemed as though the bike had an extra 20 HP. I was loving it.I called the dealer to find out what they had done and they said nothing out of the ordinary. This extra power lasted for about a month and the all of a sudden one day it was gone, I took it back and they checked a few things and said the bike was runnig good which it was....idled great ...started great, but the extra power was gone.They said it was running normal for a mostley stock bike.I only have Vance & Hinds Big Radius exhaust and Screaming Eagle air kit.Anyway I accepted it as all in my mind. at least that's what my friends told me even though I knew different. The following season I took it to another dealer and had a mechanic take it out to see what he thought...he came back and said it was a slug and he knew what the problem was. He said he sprayed around the intake with oil and it stalled hence an air intake leak. No problem...replace the intake seal with a new one. WOW what a difference, That EXTRA power was back, so of I go back to the other dealer to see why they couldn't find the probem.They said no way it was the intake seal.After trying to explain to them that I didn't know one way or the other if that was the problem or not, but how could they explain the power coming back.Darn if I didn't leave there and half way home the power was gone again.
I August of this year I took it back to the same mechanic who had replaced the intake seal the year before and he changed out the jets as I was going on a 6 day trip down state side and wanted it running better.It had tons of top end power for all six days and for about a week after that.I even went back to let the mechanic know that things were runnig good.Believe it or not 2 days later and it was back to being a slug again. I have gotten to the point where I am just accepting the fact that the bike has some sort of Gremlin. I think that something just isn't right. My wife has a completely stock XL 883 and most of the time if she is ahead of me I really have to twist the throttle and bang through the gears to catch up to her. A 1450 trying to keep up to a 883 ...ah it just aint right ...Ha Ha.. Any one ever even remotely have the same issue. I think that if the bike ran like crap then at least the dealer would would at least be able to see that there was a problem, but that isn't the case.It seems to run good so how can they fix what isn't broke, but why and where does this increase in power come from and why does it just dissappear????? I'm at a dead end...

 

Right, lets be logical about this.

Any dealer/workshop would need a place to start from, and as this is a 'seat of the pants' thing, my advice would be to treat your bike to a dyno run. You would then have a level playing field to work from & it only costs a few dollars.

Assuming you haven't got any fault codes showing, and the bike is down on power, it's a signal to methodically work through three things - intake, exhaust & ignition and the dealer will also check the lamda sensors (if fitted) or the exhaust contents.

If it's an intermittent fault. be prepared to do some work yourself as it's notoriously expensive to pay for diagnosis of something that only happens when you're standing on one leg on the saddle, or something daft.

Good luck!

 

Perhaps your wife did an engine swap on you?

 

I agreewith Reverend. Dyno run would tell you just how real the power loss is. Intake leaks can cause some serious power loss.

 

Had a very similar situation with an older Yamaha. Amazing power fluctuation from one day to the next and then back again. Ended up rebuilding the carb and got the power back for good. Somebody may have goofed up your carb before you bought the bike. I sent my carb from my 99 Heritage to Bob Wood of cam fame and had him build it to his specs. Was very happy with the results.

 

I hate to be the one to tell you this but you won't outrun a Sportster with a Heritage. My Sportster will run circles around my Heritage.

 

Thanks for the suggestions. Actually the bike was on a dyno the summer I bought the bike because it was coughing throught the carb after the dealer installed the Big Radius. The Dyno guy told me he " drilled out the main jet".It did get rid of the backfiring through the carb and it only happened again a couple times after that and the Dyno results were76.07 Max power and 80.45 Max torque. I had it back there in Sept of 06 ( I think it was because of the power fluctuation) and back on the Dyno it went with the end result being 78.42 Max power and 83.37 Max torque. If I remember correctly it did run great for a time after the last dyno until the power increase disappeared again.

It seams that when ever the carb comes apart to be worked on it runs good with lots of power and even the sound of the pipes sounds much better with what "seems to me like more compression from them.I remember jumping on the hi-way and thinking...Wow this sounds great..just touch the throttle a little and the thing wanted to scream".Then a week later ,gone again.

In August this summer when I had it in before going State side( I live in Ontario Canada) the mechanic said the 185 main jet was Too large and that he knew the Dyno guy very well, as the dyno guy worked at the same dealership for a time doing strickely dynos.He said the Dyno guy liked to put in Too large of a main jet and it was just dumping in too much fuel.I think the mechanic then changed it out for a 180...and as I previously mentioned it ran great for my whole trip with exceptional top end power. Then it dissappeared again.While he was doing the work I asked the mechanic if it could be an intake leak and he said he didn't think so because the plugs looked great. I don't know if this a correct assumption or not and he didn't seemed too concerned if this was the case


Remember this all started after my second service from NEW and they didn't do anything with the carb at that time.

As far as the sporty doing circles around the Heritage I have rode the wifes bike on a few occasions and the thing is very quick for a totally stock bike but when my bike is running top shelf ( which seems to be rare these days ) I can smoke past her no problem.Hey ...maybe she did do an engine swap on me.

With the riding season coming to a close very quickly in in the far North I think that I will have to leave this plaguing problem until spring...save some bucks and search out someone who can diagnosis and fix this problem once and for all.

 

You could try the old WD 40 trick for a leaking intake.

 

Normally, when something breaks mechanically, it breaks for good. IF I had to wager a guess, I would say that it was electrical, probably a ground wire that isn't making good contact, or perhaps seeking another path to ground. Just a guess, if it comes and goes.

 

From what you say, the power figures are spot on. You've had two seperate dyno runs, so it's basically sound.

I'd plump for a careful exploration of the carb internals. I'd be looking very carefully at any rubber 'O'-rings or gaskets internally. I haven't got much experience of Harley carbs, but when I worked on BM's the symptoms you describe could easily be caused by poor gaskets, poor inlet sealing (the WD40 trick) or flooding of the float.

If the carb's good to go (and be very logical here - they're basically simple, but look horrendous!), I'd try the ignition side.

If your plugs are in good condition, and identical condition, it's likely not ignition but double check connectors very, very carefully, especially the low tension side of things.

My money's on the carb internals..

Don't leave it til next year - you'll forget & get put off by the negatives of leaving a poor running bike. Fix it & you won't be able to wait to fire it up again.

:-)