Need some help with mods

[red01400ex]

I have a 01 w/ slip on wb,k&n,jetted. i was told from a friend the best thing i could do for more power is get a higher compression piston,stock bore and a drop in cam. is that true? if so what the best route to go? any suggestions would be appreciated. i'm not sure i trust him he rides a rapturd

[Leo]

That's what I did, and so far I'm very happy with it!

Leo

[red01400ex]

hey leo thanks for the response. is this something you did yourself? also do you still run on pump gas? as far as the xr cam is it a low/mid range cam? one other question, what did you spend ballpark also where can I get the best price?

[Ex'r Marlin]

Yeah, I am going to have to agree with your friend with the Raptor.....

Going with a higher compression piston alone will be noticeable, but adding a cam.... I am told to hold on!:D :D :D (depending on what cam you have).

I guess it depends on how much power increase you want. If you want to continue running pump gas, I have been told on this forum to get a 10.8 to 1 or 10.5 to 1 comression ratio or lower. Some say that when they went to the 10.8 to 1, they mixed with the pump gas with race gas.... So a 10.5 to 1 might be a wiser choice.... Yet I have not had a problem running 94 octane.

Depending on how much power you are looking for, keeping the stock bore is the most economical, probably the most logical, and the least time consuming compared to having the cylinder bored. Logically though, the more cc's you have, the more power gain.

About the price.... It depends on who is going to do this mod. Parts alone may cost you over $300.

Good luck!:)

[red01400ex]

ex'r marlin thanks for the info which hot cam do you have? does it give you more low/mid or mid/high? i'm in california and ride at glamis so I need something low/mid to help me pull the hills. also how is your 416/ cam? thanks

[red01400ex]

forgot one thing is this something I could do myself? I have access to the tools and have someone with a little motorcycle knowledge but the last thing i want to do is start it then have to take it to someone else to put back together

[airheadedduner]

For the money you might as well get a 416 piston.

[Leo]

Originally posted by red01400ex
hey leo thanks for the response. is this something you did yourself? also do you still run on pump gas? as far as the xr cam is it a low/mid range cam? one other question, what did you spend ballpark also where can I get the best price?

I did the work myself, but I turn wrenches for a living.. It's a pretty easy procedure if you have basic mechanical knowledge AND a good shop manual..

I would probably say the XR is a bit of a mid-range cam.. It's not radical by any means. I wasn't trying to build a super racer though, I just wanted something with a little more go all the way around while keeping the nice wide, rider friendly powerband.

It runs fine on pump gas, but it did have enough pre-detonation going on under certain conditions to make me nervous before I had the jetting dialed in (any pre-detonation is a bad thing).. I think if I was riding in high heat / high load conditions (dunes, etc) I'd be running a pump / race mix just to be safe. On the trails I haven't had a bit of problem.

If your going to do it yourself, I'd recomend taking the jug off, and having a machine shop check it out before spending the $$ on the piston.. If you've got some wear then it's time to bump it up a bit. Having the cylinder bored should only add $25-$30 to the total cost. I got lucky and my cylinder was as true as the day it rolled off the line w/ no wear/scratches/etc..

Whatever you do make sure to get a good headgasket, I personally don't like the composite style gaskets.. The stock MLS style gaskets are the only way to go.. I got an OEM 400EX gasket set, along with an XR400 headgasket.. You don't have to re-torque the MLS gaskets like you do with the composite style.

If I remember right I got the parts for ~$300 including the OEM gaskets / loc-tite / etc.. If you have to invest in a torque wrench (don't try it without one!) figure another $80-$100 for a decent one.

Leo

[red01400ex]

great info thanks leo. did you have to change the valve springs? my bike is an 01 with maybe 7 trips to the dunes so hopefully it doesn't have to be bored yet. you said it helps to have a good manual? I have the one from honda is that a good one? it seems pretty detailed but what do i know.one last question, did you get your parts at a local shop or did you get them online? if online could you recommend a place. thanks