I’m looking for a little cam selection guidance. I want to try some different cams/pistons to bring the torque on sooner and drop my CR a bit. The reason for this is I’m doing a lot more 2-up loaded touring and realize I won’t always be able to get the 93 octane which is readily available in my area (MI).

Current build
98” at 10.5
9.17 corrected / 185.4ccp
CP 6cc pistons
well prepped heads (84cc 1.9 I/1.62 E w/grooves)
.030hg
Kury WT 26g cams
48mm HPI TB
TMAX AT
Timken conversion
Dark Horse prepped crank
3.37 gears.

This thing really screams from the mid to high rpm’s but I’d prefer to have more torque in the lower rpm range. It’s my personal opinion this build is better suited for a lighter bike or maybe a solo bagger not used primarily for 2-up touring.

My previous build (98”) was with Andrews 37g’s @ 9.7 and heads with mild (if any) cleanup and aftermarket stock valves. This was a real easy motor to live with as far as tune and lower octane when that’s all that could be found and scooted along pretty good.

What cams would give me the characteristics of the 37's yet take advantage of the head work and throttle body? I’m thinking I want to get the compression down into the 9.7-10 range.

Thanks,
Rick

 

Who did your head work? Best place to start is him. You also don't mention exhaust. I am very impressed with the improved low/mid torque I have with my recently fitted SuperMeg 2-into-1.

 

Give Tman a call. He might be able to recommend something with what yuo have and what you want.

 

I plan to talk to the guy who did my heads but am exploring options at this point so I have some info to discuss with him.

I'm currently running V&H Power Duals with 4" Jackpots. I've been through a couple of 2-1's and plan to stay with what I've got.

This is a mid to high rpm build, no getting around that. I'm just looking for some input on which route to go to turn this around. I'll make whatever changes are neccessary to accomplish my goal.

Rick

 

Earlier torque and lower compression generally don't go together. In order to bring the torque on earlier, you probably want to look at cams which close the intake valve earlier than what you currently have. An earlier intake close will raise you ccp. It's really not something you should be scared of as long as your tune is spot on with AFR AND timing. Are you good with tuning the timing aspect with you TMAX? If not, can you get it to someone that is.

As others suggest, probably want to talk to whoever worked on your heads. Need to understand what kind of lift you can get away with and what kind of flow you are getting to best match a cam.

I run the T-Man TR590's and get 100 tq and 2250 and 120 tq at 3000 in my 103". I'm right at 200 ccp. I'm a believer in T-Man. Give TR a call, he's a great guy to talk to.

Zach

 

I would say that some of these figures came from an engine calculator and there is nothing wrong with that. Bigboyzheadporting.com has a good one. It looks like you haven't actually measured your ccp unless you have a digital gauge. The dials are pretty acurate, but not within a tenth of a psi. If you haven't it would be a good thing to do and do a leak down while you're at it. The ccp number should be pretty close to what the calculator estimates. That said, I agree with Biggzed that the TR-590 would probably do for you what you desire. It will increase your dynamic compression at lower rpm by closing your intake sooner. This should bring your torque on at a lower RPM. You may see it hold on longer also which could translate into more HP. If you do drop your compression you might want to go with a cam that closes the intake at 40 degrees or sooner.

 

I run the Cyclerama CR-575 cams , call Wes and talk to him , I'm over 100 trq at 2500 rpm's , but I have a 2-1 exhaust too that helps

 

Yep, the ccp was checked and is dead nuts on to what it was calculated to be when I did the build. I'm aware of the effect of lowering comp and earlier closing intake and the 590 is one I'm considering. I'm just hoping to hear from some who have experience with the type of build I'm looking to do and what their experiences were and what parts were used.

A lot of care was taken to make sure this build came out as expected and it did. It's a real screamer running through the gears which is a lot of fun but in reality it's a bagger and I'm starting to use it like one. I considerd going back to 37's and just adding 1.75 rockers and I still may but if I can find the right cam to give me the power in the same rpm band and take advantage of the head work and throttle body so much the better. It's not a high dollar thing to do this as I'll have the domes cut down a little to get my compression in line with what I need. What do the 590's like?

Another one I'm considering is Woods 5g. Has anyone run this?

Thanks,
Rick

 

This one is on my list. What comp do you run?

Thanks,
Rick

 

The heads are capable of taking any cam I'll be using and I'm waiting to hear back from the porter on his thoughts. I've spent a couple of years playing with the TMAX on a couple of builds. This build is just a little to finicky for my liking.

One other problem I have. I can't leave anything alone and enjoy working on bikes and trying different things. My plan was to build a low comp 117" this winter before I got my wake up call. I need to put a new roof on my house before winter and as anyone can guess that ain't cheap.

Rick