So I posted a question a few months ago about wether this mod would be worth while. In any case I went ahead and did it. To be clear its the stage 4 kit sold by hd/screaming eagle.

In short, no it was a waste of money. It feels faster but it took a few rides for the difference to really settle in and you have to work it right to feel it. Should have listened to folks on here. The power is all up top which is partly down to my configuration, shortshots and that massive 58mm throttle body. But even if I changed to a different pipe if i am disappointed with how 91hp feels up top comp to 65(confirmed on dyno) Im not gonna be happy with an extra 5 torques down low if I spend the extra to make the change. The tune was excellent by Doc's performance in Claremont fl. Would recommend him to anyone. But I would not recommend this upgrade.

Question. I dont like the look of the heavy breather which is the only option I have found for the 58mm throttle body. Do I even need it? will the stock throttle body produce as much power? I have read its excessive in size at the very least. I prefer the look of a round air filter.

 

Stock throttle body can handle over 100 ponies.

 

ditch the walmart pipes and get you a patriot defender or a road rage (or some other 2-1).

 

Sorry to hear that it was not what you expected. I went through the same thing with the Zipper's 88" kit. It never produced the power they said it would even with the Patriot Defender. You can't beat Hammer Performance. That's why I'm going with their kit when I eventually get around to upgrading the Roadster beyond a stage 1.

 

Curious, what would you do to get bang for the buck as you would not be pumping an 883 to 1250 as is so often discussed. I was looking at Hammer' s site and wondering about that. If you get headwork and cams can you really just do that or would New springs, valves, pushrods, etc be needed. Seems it could get quite expensive.

 

I think the Heavy Breather that sticks out up front looks goofy as well.

A smaller intake will reduce horsepower, but increase torque as I recall. Perhaps going back to a smaller throttle body will help the low end pull. 58mm seems pretty big for a 91 hp motor. But, I'm far from expert.

John

 

yeah.. at that point.... it's twin cam, xr1200x, or ducati M1200R time

a/c: ness and others offer 58mm cleaners for the touring bikes. not sure how the bolt patterns are though.

 

I am sorry you are disappointed with your conversion.

I am beyond pleased with my 883 to 1250 upgrade. The increase in power is across the entire RPM range, and it was not expensive.

I will be doing some dyno runs after the first of the year that I can post up to show the improvement on paper.

Below is the improvement in real life...those wheelies are roll on power only, no clutch work.(obviously not high RPM power, but low end).

The 1250 upgrade is complimented by a Performance Plus Stage I upgrade.




To answer your question...the 58mm TB is too big for your build. It is even too big for a Twin Cam Stage IV build. We have consistently seen more power out of the stock TB than the 58mm HD TB.

 

When I do this I'm looking at the 110+ HP kit which comes with all of that etc. you speak of. Pushrods, springs, tuner, cams, porting. To take my stock Roadster to a hellacious 1250 will be half the cost of the Zipper's 88" kit I had on the 48, not including the labor costs of having an HD shop do the install, and it kicks the crap outta the Zipper's 88" kit as far as power output. I will do the install myself this time.

The 88" kit was expected to produce over 110 hp and I was told it was a very conservative estimate. It ended up producing 97 hp and 94 ft/lbs of torque and it required more work with case boring and a bunch of other mods to fit the big bore kit. Then the problems began...

To me, going from around 60 or 70 hp to 110+ outta a 1250 bolt on kit is a hole lotta bang for the buck, especially on a light Sportster.

OP, Not sure what u spent on that HD kit but seems like you would have gotten more for the money going with Hammer. I hope you get it cranking somehow and become satisfied with your purchase. I know the feeling of being unsatisfied with a big upgrade like that all too well. It blows, to say the least, to look back and say I shouldda listened to the suggestions or done some more homework. Good luck.

 

ah, warranty and women is why there was no hammer or decent pipes:

https://www.hdforums.com/forum/sport...m-upgrade.html

i guess you can hold on to it until the warranty goes then maybe hammer it but, you'll probably get rid of it before then like that poor scrambler. with the work you've done to it. the dealer will probably cut you a good deal on a low rider s. you missed on on a crazy deal. a guy in the dyna forum built one out to 117, powdered thos ugly poo brown wheels and more, then sold it for less that he paid for the bike! for giggles.

https://www.hdforums.com/forum/motor...-for-sale.html


it may not have sold, unlikely at that price... but, send him a pm and see.


sorry you aren't happy. sporty is a good round town bike though.