Compression/Jetting

[Balaz_73*00]

Just wondering if you raise compression or lower it does it make you leaner or richer? Trying to get my bike dialed in, I just went from a 13.5 to a 13 and not sure if I should change the jetting

[RobRacing]

Correct my theory if its wrong but I am pretty sure when you lower the compression it will get richer and when you raise it it gets leaner. This is because the higher the compression the more vaccum is created causing more air to get sucked in causing your bike to run leaner. The opposite occurs when you lower compression. Its tuff to say if you should re jet or not it just depends on how the weather is that day.

[WilRideAnything]

It doesn't affect the jetting.

[Balaz_73*00]

Yea that's kinda how I was theorizing. The motor feels so much weaker now that I've rebuilt it since it blew. I was running a 13.5:1 piston, port and polished head, stock cam and that's about it. Now since the rebuild I got a 13:1 piston, dropped a 02crf cam in and it feels weaker. Before the rebuild I was running a 190 main and when it blew my builder told me it looked like I was running real lean...the top of my piston was pretty much white/tan. Anyway, when the motor was getting done I put a 200 main in it and told myself that I'd stop running the leaded AV100LL fuel. So that's pretty much where I'm at. Running that 13:1 cp, added the cam, and started running 100 torco from the local gas station. I didn't think I'd lose that much power considering I put in that cam. I guess that's why they say lean is mean! Ha Any imput to where my power went would be great!

[Red Juggernaut]

I have the same mods done to my 04 but a 12.5 and a stage 2 cam with no lid. my main in that is a 182 and the bike is strong, carb is dialed in nicely. I think your main is to big try a 180.

[Balaz_73*00]

O man 180 seems small. My builder said with my previous setup I was running real lean. I didn't mention I have a sparks full system, open air box with a uni. I'm thinking I'l throw in this 195 first and see how that is then try my 190. I don't wana be running lean again and blow it. I'm curious if me changing gas will effect things too? I guess trial and error is the only way to tell. Or should I have just left the 190 and with the lower compression and different gas would it have put me spot on? I guess its hard to say til I try things out

[SHIFTx450]

Sounds like someone beat you for your cam... You had a ported head with a "stock cam" ? Who told you that, your builder? Did you buy the bike used?

[RobRacing]

The gas probably has something to do with it. You are just going to have to play around with the jetting until it is running good. If you are not getting power around mid range try adjusting the needle and see if that makes a difference.

[Balaz_73*00]

I actually think the stock cam worked better with my setup then the crf. Im going to put it back on. I dont like how the power comes on with the crf. Definitely not all it cracked up to be

And yes I've been playing with the jetting the past few days. I definitely think the gas makes a big difference. Someone around here told me AV gas makes you leaner so I've just been tinkering and plug checkin like crazy. I have a 195 in it now and shes pullin alot better than the 200. Im pretty content where I'm at now, just gota get that cam outa there

[Ruf Racing]

Originally posted by Balaz_73*00
I actually think the stock cam worked better with my setup then the crf. Im going to put it back on. I dont like how the power comes on with the crf. Definitely not all it cracked up to be

And yes I've been playing with the jetting the past few days. I definitely think the gas makes a big difference. Someone around here told me AV gas makes you leaner so I've just been tinkering and plug checkin like crazy. I have a 195 in it now and shes pullin alot better than the 200. Im pretty content where I'm at now, just gota get that cam outa there

A stock cam with no mods, is borderline acceptable. Try a HCII.
:D

[Balaz_73*00]

I dono man, with the 02crf it has tons of torque down low but nothing in the upper rpm's. Seems like I have to short shift to keep it in the power band. With the stocker it felt like I had alot more on the top. Maybe its just my riding style but having to short shift just doesnt fit me.

[Scro]

The HCII is more of a mid-topend cam. However, it will still give you more power across the board compared to the stock cam.

[SHIFTx450]

Hotcam Stg 2 all the way... I dont feel an ounce of bottom end lost when i put mine in... And thing f'n rips. Just pulls harder all the way.

[Balaz_73*00]

Yea that's prob what I will try eventually. I'm at least gona leave this one on for a few races, haven't got a chance to race one it yet but I will tomarrow. Well see how it goes. I've been riding all through the week and gettin a feel for how to ride on it..short shift for sure at least imo

[Ruf Racing]

Good luck, let's us know if you make the switch.