whats up guys....I just want to get some input from anyone out there who is running an Ultima motor..I have a 1988 FXRS and I'm lookin to replace the engine with a 107 inch Utlima..a friend of mine has a 127 Ultima in a 1998 Fatboy and it runs great and he hasn't told me of any problems..I chose the 107 because I like the HP..not too much but more than enough for me..my concern is the fitment..I know Ultima says its .010 taller than stock..which is nothing...but the FXR frames are tight in the back..I have the S&S hot set with the heads and its very tight..but I don't know how much taller those S&S heads are over the stock heads..if the 107 is the same height as my evo now I should be okay,just lookin for some advice...thanx guys.

Vince

 

I am sure you have read the Ultima threads and there is a lot of good info in there. I have a 113" Ultima in a 92 Fatboy and it was tight on the front but it did fit without cutting or grinding the frame. Plenty of room on the top. The 127" is the only motor that they say may need to have the frame modified for it to fit. Good luck with your purchase and let us all know how you make out.

 

LG,
you know that the Ultima engines from 107"-120" are all the same price?? There is no replacement for dispalcement. We use a lot of the 120" and they run strong!! If you have any questions E-Mail me and we can help you.

 

What would be the better fitment into the FXR frame..96,100,107?..everything I've read on the this forum about the Ultima's has been mostly positive..I want to get reliablity with performance...I'm not guy who is constantly hammering my bike but I do like to know the power is there if I need it..I just want to make the best choice on the engine size for fitment..also I figure I will need to get a new Alt/Rotor as I've read about the oversized shaft..what exhaust do you guys recomend to use?..I have 34 inch 1/34 drags now..wondering about my clutch too...Barnett kevlar..all input is greatly appreciated guys..thanx.
Vince

 

Sounds like your current engine is already far from stock. Any idea what its power and torque are?

You have probably the best handling Harley frame there is, so don't hold back on the cubes!

 

I never put the bike on a dyno...I had it set up for low/mid range..S&S superstock heads w/matching pistons(10:1) S&S 520 lift cam,super e carb,1/34 drag pipes,..she ran great..until it pulled a stud..I figure I would just replace the engine with something totally new..and rebuild the 80" from the cases up..it does have over 50,000 on the bottom end and the cases are seeping at the seam...that S&S hot set-up is a good kit for anyone on a budget and does their own wrenching..I'm just looking to upgrade..everything else on the bike is NEW...trans built w/JIMS gears and shafts,the whole primary inside is brand new why not just get a whole new engine I figure.