Hi all,

I'm Ken here from Malaysia. I just got my 1990 Heritage Softail last week. I found the bike is great , however, it is not as powerful as compare to my friend Softail Custom 1997 and FXR 1989.

I found my bike engine is not so smooth as well, when I throttle it, it seem to have lagging power for a second before the torque came in..and the vibration is very heavy when travel on more than 90mph..

BTW, the bike is running with Screaming Eagle Carbs now, may i know what should i need to check? The mechanic has helped to tune the Carb and he told me my bike is OK, but I just dun feel satisfy as compare to my friends' bike..

Pls share your thought..is Heritage Softail 1990 doesn't as torquey as Softail Custom 1997? Is the vibration normal? What is the top speed of the heritage 1990?

Pls advise.

Thanks in advanced.

Ken

 

no one can help bros?

 

First off, how many miles are on it? If its got a lot of miles on it and it wasn't maintained properly, like regular oil changes. Or its been abused, reved up excessively or too often it may be a bit worn and sloppy.
Have your mechanic do a compression test on the engine and double check the timing. If the cams have been changed have him check that timing too.

Yes EVO engines do vibrate, its normal and due largely to the uneven firing order of the V-Twin engine design. Unless you want to loose the unique Harley sound and spend a ton of money on a custom crankshaft, and a lot of other parts your stuck with it.

 

Ken-

Welcome man.. I used to own a 90 Heritage as well..

Make sure your top motor mount is tightened securely as well as the motor & tranny bottom bolts..

The vibes are part of it being HD.

The compression test (as mentioned) is key to the shape of Ur motor..
If it is low, then it will be less powerful..

If your bike is all stock, (meaning air breather & pipes) that isn't helping either..

Give us more details about it & we can try to help more..

PS: My '90 did vibrate at 90 mph as well.. But I could run it over 100...
Just wasn't comfortable doing that..

Congrats on yer new ride !!!!

 

hi bro, thanks for the reply..this give me an idea what should i ask the mechanic to check..the compression seem ok..and we suspect on the carb..

actually, i could accept the vibration, as i know Vtwin vibrate and it is part of Harley!! The idling of my bike is good..u can really hear the rythmes of Harley...

But my doubt is on the throttle side..I would say the bike is powerful, however, I could always feel the lag when I throttle it especially running on first gear..the lagging is like the turbo lag, when you throttle it, the power come later a few second..so may i ask if this is due to the carburator setting? I'm running with Screaming Eagle now which changed by the previous owner..the bike is running at 60,000 miles..so i believe the engine still running strong..hopefully any HD guru here can shall with me what should we do before I change the Carb back to original?

BTW, besides the Screaming Eagle Carb, all the parts are still original since 1990(what is breather? pipe are still original )...what else I need to upgrade to gain some power? as I dun want to left behind during convoys...Screaming Eagle Carb is not good??


pls advise, best regards
Ken

p/s..i hv shared some photo here..

 

The SE carb isn't a bad one, but it sounds a little like the one you have may be a bit too big for your applicaion. A carb that's too big will bog the engine because the air flow velocity drops to far at low rpm's and wide open throtle positions. If that is what's happening the carb can't mix the fuel and air properly, so it hesitates until the rpm's climb up a bit.
An easy way to 'test it' would be to find a nice long stretch of road and try twisting the throttle slower to see if it pulls hard, then turn around and just jam it on all the way. If it bogs when you jam it on its most likely to be either the acceleration pump not being setup right or the carb is just too big for the engine.
I am not familiar with that carb so I don't know if it has an acceleration pump or how to adjust it. But if it doesn't, or it can't be adjusted put the old carb back on because the one you have was probably setup for high rpm power and not everyday ride-ability.

 

thanks bro Citoriplus!! I will visit the workshop again this noon!! will feedback if any improvement!!

Thanks again for the help!

 

"BTW, besides the Screaming Eagle Carb, all the parts are still original since 1990(what is breather? pipe are still original )...what else I need to upgrade to gain some power? as I dun want to left behind during convoys...Screaming Eagle Carb is not good??"

The breather is a hose coming from the moror case going (originally) to the air cleaner, that allows the motor to exhale crankcase pressure, when pistons are on the downstroke.

If your air cleaner filter is still stock, a K&N is a good upgrade for inhaling.
Also it is washable, & after re-oiling, re-usable...

Your motor is like an athelete, if it can NOT inhale & exhale to it's best, the performance will be suffer..

Good K&N air filter & good performance mufflers & re-jet carb to match, is a good start..
New Performance Spark Plug wires also..

Sounds like your mufflers are still original, that could be improved on, better performance mufflers. Lots of options here, but Cycle Shack has some good mufflers & are very low cost..And make some more power.

I would agree, that SE carb just may be too big for Ur stock bike..
But make sure first..

 

first thing i would do is check the compression.... 60K on a evo is a lot....
take a look at your plugs... you can tell a lot about what is happening in the combustion chamber....
what does the exhaust smell / look like?
hopefully you just running fat....

just an fyi I bought a sportster from a guy who could not get it to run correctly... he had overfilled it with oil... the blow by clogged the air filter and it ran super rich... an oil change, new af, and a jet and I'm cooking with propane!

 

"60K on a evo is a lot...." That depends on how it has been maintained..

My '97 RK (I bought it new) has over 77,000 & only thing I did was change the inner cam bearing before any problem. also K&N,pipes & good ign..

My '94 Fat Boy (owned since '98) now has almost 130,000 miles on her...
Still runs fine..Good compression & etc..(slightly modified) but still stock bore & stroke..