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Boricua

07 YZ450F Bottom Power

32 posts in this topic

I like my 07' YZ450F, but the bottom power sucks compared to my frind's 07'CRF450. I just found that I am faster on the CRF than in my bike (I don't like that..) The only mods on the bike are: FMF Power Bomb header & FMF Speed muffler, 13/51Th sprockets, Uni 2 stage air filter. What can I do to increase the bottom power?

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get a 49 or 48 tooth rear sprocket.

You would want to go up in size not down to get more low end.

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You would want to go up in size not down to get more low end.

he's topping out the gear too fast with the 51.

get a 48 or a 49 and you will feel like you have more low end to play with.

bike has plenty of torque but a 51 tooth gets you there way too quick.

get a 48 and you have a little more time and more throttle to play with.

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That bike is faster on the bottom than you think. I went from an 07 YZ450 to an 08 CRF 450. The Honda feels faster but if you ever follow a Yamaha you will notice pretty quick you cant close the gap coming out of deep corners and that is a sign of true bottom power.

My 07 Yamaha had a megabomb, R&D powerbowl, correct jetting and one more tooth on the rear sprocket. I was never down on power to anyone or anything in the +40 expert class. My problem with my Yamaha was flat turns and pushing the front end. The problem with my Honda is that it takes twice the energy to ride as the Yamaha.

I rode an 09 Yamaha last week and it went well. I am hoping I get to ride it through some flat corners soon to get the final impression.

All the bikes are better than 99% of the riders.

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I would try going with a 50T rear sprocket. It will still have that bottom end power you want but will also give you a little more room to play with. Also, with that speed exhaust , are there any performance gains with it? or is it just for sound regulation, exc. If so, try saving up for a Factory 4.1...then you'll notice some low end power...I also found with my bike, that my jetting was off so the bike was running much more richer than it should. Once I got the correct jetting, it was like night and day:thumbsup: :)

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I dont get it,my 07 pulls off the bottom like a Kenworth,infact I am thinking going to a 47 rear to smooth it out.Then again my jetting is just about dead on. Stock everything,that has to do with the motor and pipe.

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I like my 07' YZ450F, but the bottom power sucks compared to my frind's 07'CRF450. I just found that I am faster on the CRF than in my bike (I don't like that..) The only mods on the bike are: FMF Power Bomb header & FMF Speed muffler, 13/51Th sprockets, Uni 2 stage air filter. What can I do to increase the bottom power?

Are you running stock jetting? This is not a fact,but that FMF could be hurting the bottom end,I am a big fan of oem pipes,a lot of aftermarket pipes are just that aftermarket.The 08 can does not count.

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I run a MRD full system ,carb jetted for the MRD

1 tooth up rear

I can keep my bike in 3rd gear on most track

every once in a long straight ill go to 4th .

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I am a big fan of oem pipes,a lot of aftermarket pipes are just that aftermarket.
I can tell you for a fact that the DRD is an improvement over the stock system.

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I can tell you for a fact that the DRD is an improvement over the stock system.

If the DRD makes a pipe for the 06 and 07 and the pipe is identical for both yrs,but the oem pipes changed because of the cams. I would like to test that,it is hard to believe that a aftermarket pipe made for a 06 will work on a 07 dealing with cam changes. I have tried the whole OEM 06 system on my 07 and it choked it up everywhere,HAD NOTHING TO DO WITH JETTING. Did DRD change pipe designs from 06-07? If I were to go aftermarket it would be MRD no doubt.

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If the DRD makes a pipe for the 06 and 07 and the pipe is identical for both yrs,but the oem pipes changed because of the cams. I would like to test that,it is hard to believe that a aftermarket pipe made for a 06 will work on a 07 dealing with cam changes. I have tried the whole OEM 06 system on my 07 and it choked it up everywhere,HAD NOTHING TO DO WITH JETTING. Did DRD change pipe designs from 06-07? If I were to go aftermarket it would be MRD no doubt.
I know that you did say that, but I said that I know for a fact that the DRD is an improvement over the stock exhaust , and by that I meant that I know of quite a few bikes of all 3 years, '06-'08, '07 included, that have installed the DRD and found it to work better than the OEM systems. That's what I meant, and I stand by it.

I also know of at least two guys on this board, and one IRL who have put '06 systems on their '07's and were generally pleased with the results, although the gains were not as great as they thought they would be, and were mostly in the form of moving the power around, rather than adding any anywhere. In any event, you're the only one who has had the experience of the pipe "choking up" the engine. Don't know what to tell you.

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I know that you did say that, but I said that I know for a fact that the DRD is an improvement over the stock exhaust , and by that I meant that I know of quite a few bikes of all 3 years, '06-'08, '07 included, that have installed the DRD and found it to work better than the OEM systems. That's what I meant, and I stand by it.

I also know of at least two guys on this board, and one IRL who have put '06 systems on their '07's and were generally pleased with the results, although the gains were not as great as they thought they would be, and were mostly in the form of moving the power around, rather than adding any anywhere. In any event, you're the only one who has had the experience of the pipe "choking up" the engine. Don't know what to tell you.

You are telling me 2 guys you know of on this board put a oem 06 system on there 07 and were pleased. If that is correct they are not in tune with there motor. The OEM 06 system was a total mis-match POWER WISE when mounted to the 07. THAT IS A FACT!! If there is a cam change with 2 same bikes just different years and a pipe manufacture has the same pipe that works for both years,one bike is going to run better with that pipe than the other.

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Whatever. I know what they reported, and I rode the one I know of personally myself. There was no problem.

The cam difference you keep mentioning is very minor, and has to do with a slight change in lobe centering with the same lobe profile.

And the same DRD pipe absolutely works fine across all three years, '06-'08.

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My WB alum pro II is a 06/07 model pipe...definite and noticeable improvement over stock...

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I have an 07. Put a 50t on the rear and send your carb to Zip Ty. You will be amazed. I hardly ever shift from 3rd gear.

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I never tested the OEM exhaust , It was bend when I got the bike. So I can't tell if the current set-up is the problem. The jetting still stock. I did try the 50 sprocket, but I got more out of the 51.

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