FMF Ti-4.1 or Pro Circuit T-4 for a 07 yz450f???

20 replies to this topic

Posted August 26, 2010 - 07:18 PM


Ok so I snagged what i believe was a good deal on two different set ups-
First I have just the slip on Pro Circuit T-4, bad thing about that is I need the mid pipe,springs and header-

or-- I have a fmf Ti 4.1 with the powerbomb header complete-

Question is which one would you guys choose and why? based on real experience please.

Can I expect to see any real difference in these two different pipes/set-ups?
Will one really out shine another? I could not afford to get an all new system so these I got really cheap, the PC is brand new but will need some additional parts to complete the system- which aren't cheap! , the FMF has about 6 hours on it-


Edited by TDUNCAN, August 27, 2010 - 06:35 PM.

  • grayracer513

Posted August 26, 2010 - 09:52 PM


My take:



Posted August 27, 2010 - 06:36 PM


Anyone else care to chime in? Thanks!

  • Polar_Bus

Posted August 28, 2010 - 05:26 AM


Do you race ? Forget about a pipe. Keep it stock, and get your suspension valved.

Do you ride in the presance of the public ? DEFINATELY keep it stock, and get your suspension revalved.

Do you get the feeling I don't like aftermarket pipes ?


Posted August 28, 2010 - 08:04 AM


Suspension is all done! No I don't race...yet--- been off since I was about 18, 37 now so just trying to get the best out of it.
Everything I have ever repiped has improved in some area or another so what I was looking for was an opinion based on the choices I have and real experience with those choices, that's cool that you don't like aftermarket pipes and I'm sure I could ride it the way it is, appreciate the input.

  • RMCoastie

Posted August 28, 2010 - 08:52 AM


I love loud aftermarket pipes that make your bike sound like a stupid ass quad and the people who hate them too...

Just kidding about the loud exhausts, i have a DR.D system though...

  • Polar_Bus

Posted August 28, 2010 - 12:21 PM


Suspension is all done! .

When you say "done" do you mean "done" as in specifically to your riding style, weight and experience level, or do you mean "done" as in simply "done by the previous owner" ? Two different animals...


Posted August 28, 2010 - 06:49 PM


MAN, tough crowd here! The suspension was "done" by the head mechanic for Honda here locally who is also Yami certified and yes it was set up for me and my experience level.
I grew up in California and remember the people bitching about noise level, here in the midwest and particularly where I live it's not as much of a concern, so pipe down- haha
So I guess this would be a good time to raise the question about db output on these two setups? Anyone know? I was thinking that one of the two and/or both would actually be quieter than stock?
Just gettin back into it so I apologize for the lame questions.
Looks like i'm going with the fmf for now since it's a complete system- anyone want to buy a PC T-4 slip on?


Posted August 28, 2010 - 06:53 PM


Tracen and Lance at Gretna Cycle did a fantastic job, only got to ride for about an hour today but I am impressed, honestly the first time I have ridden a bike that was set up correctly for me.


Posted August 31, 2010 - 04:41 AM


I got the 4.1 carbon with titanium Powerbomb. It definitely woke my 08 yz450f up after the jd kit.

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  • jrny426

Posted August 31, 2010 - 10:29 AM


Not sure if this helps but I put a fmf power core on mine and seemed make more usable power through out the power band (if it is still called that in a 4 stroker)

  • Slinkyman16

Posted August 31, 2010 - 04:44 PM


When it comes to exhausts it depends on two things.. What are u trying to do with the bike. And 2 sound.

That being said a full system will boast more power over a slip any day. But each system does things different to existing powerband.
I've always been a fan of the pc systems as they yielded smooth power and big gains in upper and over rev power.. While boasting the bottom to mid..

Fmf tends to take from the top and put it towards the bottom end..


Posted August 31, 2010 - 06:13 PM


THANKS! I really appreciate the info- actually the low end will work better for me since I probably won't see much of the real top end until I improve my skills. The bike still scares me a bit to be honest! Having the suspension set up for me really has made a huge difference, went with Eibach springs in the front and race tech rear- about 100mm-105 mm sag, still trying to get it dialed in, just about looped out yesterday and about had a goon crash endo the day before that. Just replaced the clutch basket and hub (hinson) and I think it was kg plates. Fun trying to relearn, oh just snagged some Gaerne SG10 off ebay too for 175 lightly used- should be better than the quadrants with the huge toebox etc..I'm a tall bastard too so i put a sdg tall seat on and really like it so far- need to replace the pegs- not lower just new the ones on it are worn down pretty good, any sugestions? Should get the fmf exhaust on Thursday. Think i'll keep the stock bars on for now, bike seems kinda hard to turn in the sand not sure if RC high bars would help? I really hate the long clutch lever too was looking at asv shorty-


Posted August 31, 2010 - 06:17 PM


I grew up in Redlands California if I still lived there I would be concerned more about noise but I live on the river in Nebraska and no one seems to far- my kids 97 honda cr80 is louder than my stroker, I think! The reason for the exhaust for me was just to even out the power, cure or help with the off throttle responce and I figured aftermarket would be better than stock-

  • trailsweep

Posted September 01, 2010 - 08:21 PM


I race a 07 450 and hands down the best thing I did for that bike was to get the Megabomb header for that bike along with the 4.1 and a JD jet kit . The header woke the botom end up very well and actually made the bike seem to run alot smoother, o and get the stailess one if you do cause the ty seems to dent VERY easily when hot , have fun with the bike there a blast!!

  • trailsweep

Posted September 01, 2010 - 08:22 PM


Also FMF sells a quiet core insert for that pipe if you need and it is also a spark arrestor

  • Polar_Bus

Posted September 02, 2010 - 07:17 AM


Tracen and Lance at Gretna Cycle did a fantastic job, only got to ride for about an hour today but I am impressed, honestly the first time I have ridden a bike that was set up correctly for me.

Excellent !

Many years ago a very wise NESC expert rider schooled me on an aftermarket exhaust. "Many times you end up slower with a faster pipe" He meant more hp in many cases actually fatigues a rider and allows other riders to take advantage of a rider who is racing tired. Granted this was years ago racing 125cc 2 strokes, when you added a pipe the power became ballistic, but ONLY ballistic at above 11K rpm's. No doubt pipes today offer a far more broad power increase, but you understand my point...

There was a performance company back in the early 80's called PSI. They were famous for KILLER hp ported cylinders and pipe combos. The dumba$$ I was I bought a PSI setup for my already too fast , peaky 1984 KX125. After the mods my bike was so hard to keep on the pipe, after a few months I put the bike back to stock, added a 2 teeth larger rear sprocket instead (also upon the advice of the wise old expert), and sold the PSI stuff to another racer who claimed he was "so fast" after the PSI setup, I personally never saw any of his "additional" speed. I did however see him on his a$$ lowsided in many soft loomy corners ! LOL

Edited by Polar_Bus, September 03, 2010 - 01:15 AM.


Posted September 04, 2010 - 06:28 PM


WOOOO HOOOO man I put on the powerbomb header and fmf 4.1 Ti exhaust yesterday aand let it sit for 24 hours- i/2 turn out on the air/fuel screw holy shit did this thing come alive!!!

I get a little pop on decel and a little on acccel which I thought was strange- pretty sure stock jetting? maybe go a little further out? Really seemed to smooth it out low to mid throttle, bad thing was going around the block an old timer stepped out and chewed my ass for going too fast around the mile loop I live on(dirt) that didn't go too well so I'll be paying the association horseshit fine and riding out on the sandbar on the river. my fault for sure I was just trying to see what it would do and whether I would notice the difference between stock and aftermarket pipes.
So I'll be going back through the old posts on this set up and trying to figure out if I can get the pop out or if it's normal. suggestions welcome, midwest 60-80 degrees now and elevation at or around what 2300?


Posted September 04, 2010 - 06:29 PM


oh yeah first time the bike ever started on the first kick too!

  • trailsweep

Posted September 06, 2010 - 12:25 PM


JD jet kit for that bike. No guess work and great results.

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