roller rockers which is best? Harley Evo Discuss roller rockers which is best? in the Motorcycles forums; have 91 Harley evo resurrected it. on a scale of 1-10 I'd say shes a solid 9. SE heads ev23 cam yoest carb kit daytona twin tech ignition and 6 ...

[HDisnewlife]

have 91 Harley evo resurrected it. on a scale of 1-10 I'd say shes a solid 9. SE heads ev23 cam yoest carb kit daytona twin tech ignition and 6 speed tranny can run 90 mph all day and shes really quick between 30 and 90. Now I want longevity. I am thinking of roller rockers to ease puah rod and valve stem wear and I find there are 2 ratios available 1.61 stock replacement and 1.75 the 1.75 gives more valve lift so my question is will this give me more top end without sacrificing the quickness does anyone know anything about this??

[evoKENevo]

Roller rockers are not a bad thing in any engine...but not really called for in engines with moderate lift and duration cams. In fact Donnie Peterson does'nt seem to think they're called for in EVO engines with less than a .550" lift cam...and your EV-23 cam @ .498" lift is only .003" higher than a stock '88-'91 EVO cam. Offset rocker arms will give you more lift...but will also change other aspects best left to experienced perf engine builders...especially if you're still running stock flat top pistons with relatively shallow valve pockets in them.

In fact,there's an excellent article on roller rockers ETC by Donnie in the May '04 issue of AIM you might want to back order before popping around $400 to $500** on them.

As far as longevity goes...I'd recommend keeping your stock rockers that're probably just fine for LOTS more miles the way your engine is set up and worry more about replacing your stock lifters (prone to failure) you did'nt mention doing...ass-uming (me) that your stock inner cam bearing (also prone to failure) would have been replaced with a Torrington bearing by a knowing wrench when the stock cam was replaced

As far as getting more top-end "without sacrificing the quickness" (low-mid range torque) goes...I'd recommend simply switching from EV-23 to an EV-27 cam (with slightly less lift but different timing & duration etc) for a broader power band while you're in the gear/cam case to replace lifters...and forget about off-set rockers...all of the above for around the same cost as roller rockers alone.

Just my opinions...but worth considering me thunks...especially the part about back ordering the AIM issue mentioned to answer all your questions on the subject...hoping this helps you some

[frisco-rigid]

Hi Newlife

I run 3 sets of heads with roller-rockers and 2 sets without (all stock ratio),, guess which ones I worry most about when I'm pullin 6K + Rpm's..

1.75 & 1.61,,, guess which one puts the most stress on the cam lobes and potential longevity..

Wise words from Ken..

Don't get tooo carried away with fancy sounding doo-dads cuz some of them will hurt your motor and some will only ah, do nothing at all..

[myt evo]

If you want gobs of torque without sacrificing reliability you may want to take a look at Bob Woods Knight Prowler W-6 cam. .510 lift quick ramp short duration. I would recommend roller rockers with this cam though.

[HDisnewlife]

Thank you all for your excellent suggestions. You truly helped me make my decision. (I did change out the cam bearing as well as numerous other bushings and bearings when doing the rebuild but I did not replace the lifters. I have decided to stay with flat top pistons and replace my rockers with stock parts in addition I am going to rebuild the clutch and replace the lifters as suggested Thank you all for your help