stock vs mod

[Ron Hamp]

This is a comparison of an 07 stock to a 07 with the RHC porting ,RHC piston and RHC carb mods .the bike has a CHM pipe with a 1 5/8 out let and was run on pump fuel compresion is about 12.9-1

[grayracer513]

Uh,....Wow!

Look how far down the rev range you've brought the power peak, too. Most impressive, Ronald.

What were the cams? You didn't mention them.

[Ron Hamp]

stock 07 cams .i was suprized @ the power curve also and very happy with it im sure thesrs more to be done i just put it up on the dyno to check fuel air ratio and it was @ 14.2 very dangerous It had a 160 main in it and i took a quess and installed a 185 the FA went o 12.5 and i called it good as i put it on the dyno for free .with good fuel and some more tuning it would have been making 55-56 hp very respectable for a serious pro mx bike i was impressed with the 30 pounds of torqe @ 5000 rpm.

[grayracer513]

OK, now I see. The image was fuzzy, and I misread it earlier. Still a good gain, though, and a nice fat lift in the torque curve. Good work.

[grayracer513]

The reliability is only impacted by the extra force the engine will produce. Nothing about port work puts any additional physical stress on the valve train, etc.

For pricing questions, use a PM, please.

[grayracer513]

Gray did I catch you talking about prices not in a PM https://www.thumpertalk.com/forum/showthread.php?t=597508:p

Yes. The difference, however, is that I don't sell the Zip-Ty mod, nor am I associated with Zip-Ty, so my discussion of their prices does not put me in violation of the rules which state that non-sponsors may not promote their products. ?? :worthy:

In RHC's case, however, this situation may have actually changed just today. Film at 11:00.

[Ron Hamp]

I may @ some point list a manufactures price for a part on here .any body can email or pm me and when i have a chance i can quote a price to them on my parts and services .im not here to take advantage of the bryans i have to admit this forum has increased my income though.

[Ga426owner]

In RHC's case, however, this situation may have actually changed just today. Film at 11:00.

hmmm you have my curiousity now

[King_Air]

See his post in the General section for more info.

[Clarkie49]

Here is one of mine (disclaimer, as anyone that owns their own dyno knows, the number is just a refernce, every dyno reads differently blah bah blah)

before (blue) is bone stock '06 YZ450F, stock piston, pipe, cams, pump gas etc etc.

After (red) is the same bike with a 13.75:1 CP Piston, Hotcams, I ported the head, closed up the piston-head clearance (was 0.055" stock, now running @ 0.030), still running on pump gas with the same stock exhaust.

Question for you Ron, I am not really happy with the over-rev of the curve, this is a Supermoto, will your cams (or any that you know of) help flatten the curve out above 9,500rpm?

I asked if anyone knew the stock lobe centers but got no response, I will probably install the stock cams just to find the lobe centers. Thanks in advance for any help/comments from someone that has been inside these engines a lot more than i have

[Ronin 26]

Here is one of mine (disclaimer, as anyone that owns their own dyno knows, the number is just a refernce, every dyno reads differently blah bah blah)

before (blue) is bone stock '06 YZ450F, stock piston, pipe, cams, pump gas etc etc.

After (red) is the same bike with a 13.75:1 CP Piston, Hotcams, I ported the head, closed up the piston-head clearance (was 0.055" stock, now running @ 0.030), still running on pump gas with the same stock exhaust.

Question for you Ron, I am not really happy with the over-rev of the curve, this is a Supermoto, will your cams (or any that you know of) help flatten the curve out above 9,500rpm?

I asked if anyone knew the stock lobe centers but got no response, I will probably install the stock cams just to find the lobe centers. Thanks in advance for any help/comments from someone that has been inside these engines a lot more than i have

hhhhhhhhhhmmmmmmmm Ron I've seen that chart before,.......

Be careful at .030" she wiil kiss the head that tight. Did you adjust the compression ratio or are you running the 13.75 and the milled cylinder which will bring the comp ratio well over 14:1. Makes allot of heat but not really anymore power than 13.5:1 (in my experience). Run the intake around 106/107 LC

Sumo's are hard on bottom ends, with a quench that tight she had better come apart often.

Nice work.

[Ronin 26]

Here's a YFZ i did recently. I removed a 480 BB kit and hotcams and installed my package which included a stock bore and a cam grind from Ron.

The red run is the 480 with HC.

The brown run is Ronin built.

The final blue run is Ronin built with a velocity stack and intake i fabbed for it.

[Clarkie49]

hhhhhhhhhhmmmmmmmm Ron I've seen that chart before,.......

Be careful at .030" she wiil kiss the head that tight. Did you adjust the compression ratio or are you running the 13.75 and the milled cylinder which will bring the comp ratio well over 14:1. Makes allot of heat but not really anymore power than 13.5:1 (in my experience). Run the intake around 106/107 LC

Sumo's are hard on bottom ends, with a quench that tight she had better come apart often.

Nice work.

Thanks, up here in Colorado we need to squeeze them as tight as possible (on my Superbike I run 0.018 p-h) and the actual rwhp is down around 15-20% from sealevel so hopefully it wont be as bad as you say. I actually tightened it up without milling the cylinder or head, I didnt want to change the combustion chamber shape too much and I can easily go back to stock. The heat doesnt seem to be too bad but it's cool out, i will keep an eye on that though so thanks

What is your opinion of the hotcams vs stock cams, I can press the sprockets off and on without too much trouble, will probably tack weld them on once i have found a good combo. Would you leave the hotcam exhaust at around 103 (claimed) or open that up a little?

Road Race bikes are so much easier with adjustable sprockets Thanks for your comments and help

[Ronin 26]

Thanks, up here in Colorado we need to squeeze them as tight as possible (on my Superbike I run 0.018 p-h) and the actual rwhp is down around 15-20% from sealevel so hopefully it wont be as bad as you say. I actually tightened it up without milling the cylinder or head, I didnt want to change the combustion chamber shape too much and I can easily go back to stock. The heat doesnt seem to be too bad but it's cool out, i will keep an eye on that though so thanks

What is your opinion of the hotcams vs stock cams, I can press the sprockets off and on without too much trouble, will probably tack weld them on once i have found a good combo. Would you leave the hotcam exhaust at around 103 (claimed) or open that up a little?

Road Race bikes are so much easier with adjustable sprockets Thanks for your comments and help

I'd open it up a bit for sure (EX cam timing). I run the in line four stuff way tighter as well (quench). I've had the 450's kissing at .030 inches. Kissing is ok, smacking is not I would also suggest modifying the camshaft tensioner to manual operation one less thing to worry about.

I also tack the sprockets when finished. I JUST finished timing a YZ 250 F EX cam, the sprocket comes on and off a few times, and i like to sleep at night. Stinken decomp set up is a PITA but it works well. On the 250's you can remove it but i like to keep it there.

The Hot Cams are good stuff, i usually use Web grinds I've had better sucess with them. I have used the HC stuff quite a bit as well. There is tonnes of PtoV in the Yami's so that's not really an issue.

Yeah the RR stuff rules. Lotsa stuff available, and adj. sprockets are easy to get. Web makes a full adjustable kit for the Yami's that retains the decomp set up you might want to think about it if you're going to be messing with timing often. The EX sprocket is kinda a nightmare (3 pcs design to retain the decomp) PM me if you pick up a set and I'll fix there install instructions for you. Falicon makes the kit so you could get it from them as well. If you're not careful you can break the decomp shaft.......................but I can help you avoid that.

[Clarkie49]

Awesome thanks for all the info!