Big Bore, or Cams?

[dylandrew1]

I’m looking to do some engine mods on my 06 kfx 400. I’m considering adding stage 1 or 2 cams to my current engine or going a different route and adding a 470 or 485 BB kit. Which is better from a reliability, power and cost standpoint? I have a Motorworks slip-on, FCR 39, K&N with no airbox, and Big Gun rev box. I ride primarily in the desert and on trails.

[knoxville9]

Cams are fool proof if you shim your valves occasionally and have it timed correctly its about the safest and cheapest route even if you get both its like 350$ and BBK of any size runs 400-1000 and with out cams their useless so cams is a great start

[dylandrew1]

Thanks for your reply. I've read on other forums that the valve springs need to be replaced (on some I've read the valves should be replaced too). Is this true? Can I run stock springs/valves with aftermarket cams?

[knoxville9]

I believe so, I'm sorry i don't have a more accurate answer, I'm sure you definitely could but the after market cams would probably cup your old valves and wear your valve springs. Personally I'm running stock cams with kibble white valves and valve springs, and its very good for my riding style the only problem I've had is that their still being broken in and I shim my valves like once a month and it gets annoying.

[drzoo2]

Depends on how aggressive they are. Obviously any aftermarlet will be more aggressive and will shorten the life of the valve train. OSHC it is recommended the valves, springs and chain are upgraded. I ran these for a season and never had a problem but recently down graded to a new style Hotcam.

For sale btw.

z

[dylandrew1]

I planned to go with a stage 2 cam (but if the reliability isn't good, I could go with stage 1). It sounds like springs and valves might be worth the investment if the head is off anyway. I really appreciate the advice. I'll let you know how it turns out. Thanks!

[quad97]

I don't think the reliability is that much different between stage one and stage two hotcams. I think stage one is intake cam only and stage two is both cams from hotcams. I would change the valvesprings out to an aftermarket set along with the cam chain. I've always had good luck with the stock valves on these motors.

[airmobile101]

I would do the cams first,One being its alot cheaper and your gonna notice it right from the start. You can do the big bore later. And since you already have the FCR, thats gonna complete the wow factor once you have the big bore installed. I personally have never had a issue with the stock valves,but I did replace them when I did the DRZ upgrade.

[dylandrew1]

It sounds like cams are the way to go. I may look at a BB down the road. Again, I really appreciate the help. As soon as I get it done and get a few rides in, I'll post some comments.

[drzoo2]

I have a set of oldschool hotcams for sale. I guess technically they would be a stage 3. Let me know if your interested.