Need cam opinion

[dylandrew1]

OK. So, I've been flipping back and forth on cams for awhile now and its time to make a decision (sort of). I've been leaning toward 540/539's forever and I'm ready to pull the trigger. I typically ride a lot of trails, but also like riding in areas where you can open it up a bit. I've heard so much about losing bottom end with the big cams that I don't want to commit and be disappointed. However, I can get the low end back with gearing and can gear back up when I ride in the open areas. Another option is to go Biggie's route with the 536/540's. I've got a lot of mods and may do a stroker sometime down the road, but it isn't a priority. What do you guys think? As long as I don't lose anything that I already have with the NSHC's, I'll be happy. I'm ready to make a move.

[z455]

Do The 536/540 or 536/536. The second one is similar to the OSHC's and would give you a strong low and mid maybe a little more top than your current set up.

Just because you ride mostly trails I wouldn't go with the 540/539. You would loose too much bottom end.

Could post a pic of your Elites?

[kfxguy]

It's not like what your gonna lose is going to cause it to be unrideable or stall out alot. You can just go don't a tooth in the front. Was that you that called faith at web cams the other day? She called me. I had 540/540 in my 400cc motor and it had enough power to tow my buddys brute force 750 about two miles through the sand and river. You'll be fine. Your going to lose some bottom, but you'll more than make back up for it everywhere else.

[dylandrew1]

Yes, that was me that called Faith. The folks over there are great.
With a 13 tooth front sprocket, do you think I will have a similar feel (or better) to what I have now? The trails I ride now are 2nd and 3rd gear stuff. I get to open it up every once in a while, but a lot of it is low speed riding. I also plan to do a couple of trips where the riding will be wide open. This is where I believe the 540/539's will shine. Probably looking for the best of both worlds. If gearing can fix the low end loss, then I'm ok with it.

[kfxguy]

I doubt your going to be disappointed with it. Unless your one of those kind of people that like so much low end torque that you think it's fun for the bike to flip over on you when you nail it barely rolling. Me, I don't find that fun. I think what you'll have is more manageable power with a lot more higher end power and speed. Its not going to be down on torque compared to stock. The z engine is real tolerable to larger cams. Plus when you go stroker, you won't have to buy cams again.

[dylandrew1]

Understood. Should I do anything with the rear sprocket or will a 13/40 combination work OK?

[kfxguy]

Basically your the one that can answer that question once you get it together. Its all in what you want.

[biggiej42]

Couldn't be happier with my cams, only I don't do much top end riding. When I do, they hold out pretty well!

[TuckerHardRide]

I'm happy with my Yoshimira cams their great for track riding. And they work great everywhere else i use them too!

[dylandrew1]

Decisions, decisions. Hopefully, the Cam Gods will impart some wisdom to help me make a choice. Sounds like its a win either way. Thanks all for chiming in.

[icanzu]

440 bbk, NSHC's, 12.5-1 Wiseco, P/P head, FCR 41 w/taper-bored Noss, PWR radiator, full Trinity Stage IV exhaust, Dyna NP, Fastway/Elka steering stabilizer, full skids all around, Maxxis II's on Hipers all around, FCI, AC Nerfs on IMS pegs/heels, YFZ calipers up front on Typhoon discs, Houser +1.25 swinger, Elka Elites up front, Procycle flywheel less 9.5 oz, Runs like a bat out of hell.


At only 12.5:1 with a 41 FCR on a BB...and the lightened fly wheel...coming off of the NSHC and flipping to the 540/539 Webs will definitely knock the low end grunt down considerably for your riding appl. I've been where you are twice with the same result. As mentioned above, "low-end loss" can mean different things to different people...with different riding apps. After reading what seems like hundreds of posts in numerous threads regarding this topic, I have always found that the sand guys or desert riders, and GNCC or MX guys have a very different perception of what's too much, and what's acceptable.

If this helps you any, I can tell you the long version of how it affected my ride which was very similar to yours before the +4 crank went in. Being mostly a technical woods rider I also spend most of the time in 2nd and 3rd, but there are also a lot of steep, rutted, rocky, gnarly grades and tight stuff that require good torquey acceleration right off idle or close to it. When I had the my 440 with a 40mm FCR, (better bottom than a 41), 13.5 comp (point higher than yours), and the OSHCs (which have less bottom than your NSHCs), and 13/40 gearing I was real happy with the performance. Mind you that I was also on 22s in back...

When I decided that I wanted the best of both worlds (dunes/woods), which are basically polar opposites, and switched over to the 540/539 Webs I had to do way too much shifting and clutching to make the slow/technical stuff in the woods work c o m f o r t a b l e y. (The dunes were great!) I ran it that way for a while and it was certainly "ridable" without stalling a lot (with a stock fly wheel)...but I wanted better than "ride-able". I wanted optimal ride-ability, so I started with the gearing. First I went from 13/40 to 12/40...and then finally ended up at 12/42 in the woods and 14/40 in the dunes. 12/42 might sound like quite the stretch to some, but I needed a tractor for what we were doing. Not enough major azz haulin to need it geared much higher in our woods. Again, remember that I was on 22s in the rear. So since I didn't like mechanically gearing down THAT much, and having a huge sprocket in back and squishing the front....I actually went back to the OSHCs and was very happy!

Chapter 3: Must have the +4 crank now! Got it installed leaving all the rest as it was other than going down to 20s in back and to a 12.5:1 piston. Gearing now at 14/40 worked well again but went to 13/40 and found bliss...in the woods. Now the new problem with the crank, was that it fell on its face at 8500 in the sand. (see RCFAN's threads. Same exact prob).

Soooo....Yup...back to the 540/539s and and an FCI...and all was well!! Final build, as you see it in my sig, now works real well in both apps. In the woods on 20s I run 13/40 and have all the bottom I could possibly want in any sitch, and for the dunes on 22" 7 paddle Hauler Extremes 14/40 works great.

This was sorta long but I wanted you to get the detail of all the differences I experienced at different build stages to help you with your decision. I'm with KFXGuy in that I agree that you could go to the 540/539s now and be ...happy...but it'll really pay to already have them if you are going to add the crank at some point. If It was me...I'd stay with your cams or go to the OSHCs until you do the crank. Like I said RCFAN on this site has almost the identical motor as I do, and he and I went back and forth on this for a loooooooong time with tons of research, and his experiences were very similar to mine other than that he ended up with the 540/540 Webs witch totally kick azz for this build too!

Oh...and PS...with the +125 swinger, I think that flipping it over is gonna be the last of your concerns unless you like climbing buildings...

[dylandrew1]

Icanzu,

Thanks for the extensive write up. If OSHC's were available in my current build, that sounds like the way to go. Given that they are hard to to find, would the 536/536 or 536/540 provide enough of an improvement that it would be worth it?

I will do a stroker at some point, but only when I rebuild the the whole thing. Do you think any of the two cams mentioned would work well with a stroker? I don't want to buy another set of cams with a stroker, but if the upside was worth it, I'd consider it.

Thx.

[kfxguy]

Good explanation Icanzu. Dylandrew, in your situation, I'd either hold out on getting cams right, or get them and gear for your bottom end loss. I dunno, maybe the port job I keep doing has a positive effect on bottom end as well as top end, because I never really experienced a major loss of bottom no matter what cams I ran. I will tell you this tho.....I'm a over revving fool. Everything I build has to be able to spin unnaturally high. My rev limit on my 470 is 11,600rpm and I hit it pretty often (might explain the bent valves ). I shifted my stock bore motor at 11,800 and my old camaro had a stroker motor in it that I shifted off the rev limiter at 7800rpm. So me, I like hp or ron more than torque. So if your after stump pulling bottom end, maybe just keep what you have for now. Then get the 549/539 with your stroker. Now me on the other hand, I wouldn't be scared to run the 540/539 on a big bore motor. But that's me.

[icanzu]

Originally Posted by kfxguy

Good explanation Icanzu. Dylandrew, in your situation, I'd either hold out on getting cams right, or get them and gear for your bottom end loss. I dunno, maybe the port job I keep doing has a positive effect on bottom end as well as top end, because I never really experienced a major loss of bottom no matter what cams I ran. I will tell you this tho.....I'm a over revving fool. Everything I build has to be able to spin unnaturally high. My rev limit on my 470 is 11,600rpm and I hit it pretty often (might explain the bent valves ). I shifted my stock bore motor at 11,800 and my old camaro had a stroker motor in it that I shifted off the rev limiter at 7800rpm. So me, I like hp or ron more than torque. So if your after stump pulling bottom end, maybe just keep what you have for now. Then get the 549/539 with your stroker. Now me on the other hand, I wouldn't be scared to run the 540/539 on a big bore motor. But that's me.

You know, you may really have something there with your porting after all... I had my head ported by CT Racing out in Baja country. They typically build and port their motors for wide open desert screamers. Big carbs and the 540/539s in their BBKs. That's why I swapped their 540/539s back out for the OSHCs after a while.

I really know fairly little about porting as such, but isnt it true that you can flow for volume or for velocity, depending? My understanding is that CT's porting was geared toward velocity for WOT desert riding. Their motors are typically mid-toppers. Maybe that's why your experiences have been so different from many here who have perceived significantly more low end loss when switching to the high lift and looooong duration cams... I wish my motor would retain as much bottom as yours with the colossals you run!

As far as dyandrew1, Think about what you are going to invest in time and money to do a cam swap now, you know, depending on what you get. Ehh...maybe you'll get a good deal...but to answer your question...considering what I know I've spent, and learned through time and experience, if I were you, I'd save my clams until you do the crank and enjoy a real synergistic build then...and only pay once to get it there! If you're insane like me and have to do everything right away as you scrape the bucks together, then I'd say that you might wanna ask for a set of OSHCs here on the forum. They float to the surface again and again and they're getting even more reasonable. That would be a real conservative investment for a nice boost in the right direction...and you wouldn't have to eff with heavy duty springs blah blah blah..... If you decide to go Webs now, I'd recommend finding a grind that's fairly close to the OSHCs if the crank is still fairly far off in the future, or just get the 540/539s and put up with it till you snag the crank.

Do the math and check your sack. You'll find the answer there...

[dylandrew1]

Very good advice. Given the crank is far enough out there, I may look for something close to the OSHC's. I'll let you all know how it turns out. Again, thanks all for your input. This forum is great!