I am putting together a CVO based 103 (HD 103 stroker kit) in a RK. From my last post regarding piston to valve running clearances I have now skimmed 40 thou from the CVO 103 heads as suggested by hdm88. Whilst the engine is in bits would it be beneficial to change out the stock CVO253 for an alternative cam i.e. 37g. Is this cam suitable for a 103 displacment, are there any others I should consider, I would like to have a build which is torque orientated.
CVO253 cams or 37g gear drives
1 - 12 of 12 Posts
The 37g would be good, the woods tw5g also....but remember that big motors tend to "shrink" cams some what. Just more chamber volume to fill so lifting the valve higher will help...the 253 is at .530 lift but the late intake open and especially the real late close at something like 53 abdc just isnt for making low end numbers. I would think the red shift 557 might be a good choice...the stock CVO springs are rated to .550 lift but there is normally a .015 fudge factor there so the .577 lift of the red shift should still be ok. Lets wait for DOC , GROCK, BULLET to respond.olly said:
As Chuck said you need to find out the compression ratio with the milled heads, I take it your running the CVO flat top pistons. The compression will be higher in the 103'' vs. a 95'' so you have to be carefull with the 37 not to exceed 10:1.olly said:
As Syclone said the stroker can use a longer duration and higher lift cam, the .557 redshift and TW5 are good selections for higher compression engines. If you want some good torque and good power look at the TW6H, TW8, TW9B or the Andrews 67. The CVO cam is an EPA cam and it stinks. The CVO 103'' engine puts out around 84 HP and 92TQ, GRocks Weed Wacker puts out more than that.
Doc..He's running the CVO 103 heads which average about 95cc (Ya, I know!) . the CVO's whith their flat tops are advertized as 9.0:1 but with 165ccp they are really around 8.7:1. He's not gonna get to 10:1 with .040 off those heads...so that should eliminate the tw8 and tw9b , the 67 and the 257's. More like 9.4-9.5:1 is where he should be at now .hdmd88 said:
Joined
·
780 Posts
The Andrews 44 or 50 would be my choice. With 9.5-1 comp. in a 103 ,the 44G would come on early .
Syclone, CR 9.4/9.5:1 is similar to what I have calculated. What are you thoughts on a cam to match this CR. Heads are good for about 550" lift. Dependant on your suggestions for cam what additional depth clearance pockets would I need to put in to my std CVO flat top pistons, if any ?. Can you suggest a good retailer to contact for the part you suggest.
For an andrews cam..for your application..I like the tw50g better than the 44g because it's got a little more lift at .510 and more duration ..It will come on a little later, but a 103 motor in itself at 9.5:1 will already have more low end grunt than a 88 or 95.olly said:
The red shift 557 reminds me of the wood tw6gh cam...but with lower lift at .557 its ramp shape means it will be much quieter. It's a bolt in high torque cam that will work anywhere from about 9.0-9.7:1 It may require some case clearancing though. Tdc lifts should not be of concern with these cams.
those would be my choices right now....I say MY choices because one of my bikes is an 05 CVO E-glide ...that I'm loooking for a bolt in cam to simply rid myself of the tensioners.
I'm going to hold off for a while because first..It's snow season for me...and both Zippers and Freedom cycles are curently developing bolt in cams for the CVO motors that will offer modest performance gains...
As a point of reference...my stock CVO 103 with slipons.,a/c and race tuner made 101/103..on a dj250. I would think you should be able to achieve low to mid teens in torque with lots of area under the curve. Hp will be what it will be.
for a supplier...directparts.com , Jp Cycles, Zippers...and check with HDWRENCH on this forum..he's a great guy and can also give you some direction and well as parts sources.
1 - 12 of 12 Posts
Join the discussion
Join now to ask and comment!