Problem with exhaust system on HD trike

[trikerman]

Hi there to you all, could anyone give me any advice about my exhaust system that I have fitted to my 2000 Road King Classic 1450 trike, as you can see from the photo I have 4 straight through mufflers on the rear, I have a screaming eagle high performance air filter, and a power comander fuel injection package, the problem is that the trike sounds good, but it seams to be all noise and no go, 70- 75miles per hour and thats pushing it, and only 33 miles to the gallon. Before I had the Harley triked it used to do 110mph and 50 mpg. Do you think that fitting some baffles to the exhaust would improve things, something to do with back pressure.
kind regards,

John.

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[rocker bri]

Hi John,
now i had the same problem with my road king when we triked mine and i ended up doing a big bore up-grade ie biger pistons ,pots and cams and a stage 3 this made one big improvement to the speed etc yes i also droped in fuel comsumption but then the roadking had become a trike and i put that down to she had put a few pounds on like her owner... now the trike does well over the ton...with regarde to your pipes ,how are these confugired ? from the picture it looks like you are running to down pipes into a twin rear barrel silencer ? (opps sorry john you do say )you may do better running 2 down pipes into one that will give you a better air flow out etc and i find a better power set up , also it sounds like you only have a stage 1 set up ? with the fueler and air filter think of a stage 2 or 3 much better, it never ends John making the HD better the above does sure cost a bit but it gives back the performance to the trike that i think is lost in the conversion, you may just wish to change the cams that makes a big difference..
what ever you do i wish you luck buddy.....
RB

 

[Mr.Wizard]

I'm going to take a shot that your EFI system is Magneti Marelli EFI and not a Dephi system?

Next, are all four pipes open or do you only use the inner two?

 

[trikerman]

Hi John,
now i had the same problem with my road king when we triked mine and i ended up doing a big bore up-grade ie biger pistons ,pots and cams and a stage 3 this made one big improvement to the speed etc yes i also droped in fuel comsumption but then the roadking had become a trike and i put that down to she had put a few pounds on like her owner... now the trike does well over the ton...with regarde to your pipes ,how are these confugired ? from the picture it looks like you are running to down pipes into a twin rear barrel silencer ? (opps sorry john you do say )you may do better running 2 down pipes into one that will give you a better air flow out etc and i find a better power set up , also it sounds like you only have a stage 1 set up ? with the fueler and air filter think of a stage 2 or 3 much better, it never ends John making the HD better the above does sure cost a bit but it gives back the performance to the trike that i think is lost in the conversion, you may just wish to change the cams that makes a big difference..
what ever you do i wish you luck buddy.....
RB

Thanks Bri, not even stage 1 they are things that I've tried, (screaming eagle air filter and pro fueller plus)

 

[trikerman]

I'm going to take a shot that your EFI system is Magneti Marelli EFI and not a Dephi system?

Next, are all four pipes open or do you only use the inner two?

#
thanks Mr Wizard, yes It's the early 2000 EFI and all four pipes are open, I was thinking of capping off the 2 outer ones, do you think that this would make an improvment, or as I've said earlier fit some baffles into the system.

My mate has had his 2001 Road King converted by a different company to me, and he easily reaches 95 Miles per hour.

John

Ps I've also fitted a Screaming Eagle heavy duty clutch as well, so clutch is not slipping.

 

[Mr.Wizard]

#
thanks Mr Wizard, yes It's the early 2000 EFI and all four pipes are open, I was thinking of capping off the 2 outer ones, do you think that this would make an improvment, or as I've said earlier fit some baffles into the system.

My mate has had his 2001 Road King converted by a different company to me, and he easily reaches 95 Miles per hour.

John

Ps I've also fitted a Screaming Eagle heavy duty clutch as well, so clutch is not slipping.

Clutch slippage would be apparent when pulling WOT as the motor would increase RPM's with no movement of the vehicle. Since you didn't mention it at 75 MPH it actually didn't cross my mind.

My main concern is the MM EFI system and the PCIII. Working with countless PCIII systems I've found the MM and the PCIII not to be a good match for making torque. I believe the dual venturi and the throttle body neck restriction along with the small injectors just will not produce good results. There are few tune guys that have the skills to properly map the PCIII to a MM EFI system.

I would assume your Mate has a Delphi system. Visual inspection can tell you which is which. The Delphi has only one large venturi butterfly and the MM has two small ones under the air filter.

When relieving exhaust pressure you also are adding to the loss of bottom end torque. Adding fuel will help but you will have a greatly reduced MPG average on top of adding the trike kit weight.

Immediate remedies would be to add exhaust restriction and remap the PCIII to lean the mixture in the cruising ranges then above 3500 RPM's increase the fuel to make HP at WOT.

Other things to consider would be to upgrade to a Delphi system then beef up the motor in small steps until you accomplish what you are looking for. Cam's can make a large difference in the pull and economy of your motor as long as you don't over cook the replacement cam. Start small and speak with the Cam company for the positive results in the RPM ranges you need improvement. That would be a great place to start.

 

[trikerman]

thanks very much Mr Wizard.

John.

 

[Mr.Wizard]

John, I hope this helps even if just a little.

This forum is a great friendly place with a wealth of information from riders to trike builders. Continued comments will help to narrow down your prognosis.

I've been told that when questions are asked and properly answered it takes an average of $500 US to add 1 HP on a Harley. $1000.00 US to those uninformed.

Cheers