New to me 07sumo


7 replies to this topic
  • sito

Posted May 04, 2009 - 06:00 PM

#1

Hey guys,

Quick word of thanks and intro. Just got my 07 WR450 supermoto with extensive mods. With this site's faq's and search and such, I can look at the old parts supplied and know what's been done that wasn't on the listing==so good stuff.

I did do my first mod==gray wire. Curious that it wasn't done as it has a VL slipon can, airbox cleaned up, etc. Does pull better through the gears. I am dealing with the steady throttle sputtering/popping/surging, though, and about to pull the trigger on a vortex x10 to see how that helps. I'm certain it would only improve the bike, if not fix the sputtering issue. Comments??

Tonight, on my 4th ride, figured out the high end bogging is prob the rev limiter and not the main! Stupid boy, but that's me.

This week I'll verify the jetting and fuel/air turns (think that may help the popping prob)--there's a jd kit on it so I'm reasonably sure the jetting is ok as I'm about at the same elevation as the PO. but will verify.

Anyway, I'm in Austin, have a couple of buds who take their SMs and sportbikes to harris hill, and can't wait to run the WR there--probably in 1-2 weeks.

Again, thanks a lot--great forum, as good as my Porsche forum (pelicanparts).

Jack

  • mikeythefokker

Posted May 04, 2009 - 06:57 PM

#2

I believe that some pictures are in order.

  • davidl9999

Posted May 04, 2009 - 09:16 PM

#3

Hmmm...
The power should fall-off before you hit the rev limiter. I'd be surprised if that was the problem, but I'll take your word for it.

Question: Have you check the main jets so you found one that pulls hard in WOT and 1 size up and 1 size down doesn't pull as hard*? If you haven't gotten there yet, it might be worth another look at the MJ.

* If you get 2 MJs that pull equally hard 1 richer pulls less, use the richer MJ that still pulls hard.
If you get 3 MJs that pull equally hard and 1 richer pulls less, use the one in the middle.

  • sito

Posted May 05, 2009 - 04:44 AM

#4

Hmmm...
The power should fall-off before you hit the rev limiter. I'd be surprised if that was the problem, but I'll take your word for it.

Question: Have you check the main jets so you found one that pulls hard in WOT and 1 size up and 1 size down doesn't pull as hard*? If you haven't gotten there yet, it might be worth another look at the MJ.

* If you get 2 MJs that pull equally hard 1 richer pulls less, use the richer MJ that still pulls hard.
If you get 3 MJs that pull equally hard and 1 richer pulls less, use the one in the middle.


Thanks, definitely going to chk the mains. The power dropoff at high revs actually feels like a too-small main to me but at lower revs, WOT, it pulls like a freight train--hence the rev limiter theory. Never felt it on this bike and coming from larger CC bikes. Just ordered the vortex x10, btw, so looking forward to some drivability improvements.

Seller's pic below. Will provide a proper pic in my garage later...

Posted Image

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • davidl9999

Posted May 05, 2009 - 07:54 AM

#5

Something else came to mind on this, Sito.

If the bike is jetted properly, it could be that you're feeling the normal droop in the power curve that happens at high RPMs. In the dyno chart below (thanks to Two Brothers Racing), the power curve falls off around 8.5k RPM and the bike is about 10HP lower at 11k RPM than at the peak. It's entirely possible that if you've tuned the bike well to get a sharper peak, then you'll likely have more "droop".

Along with this is that volumetric efficiency (VE) or how well you can stuff air/fuel mixture into the engine suffers at high RPM primarily due to valvetrain limitations, and secondarily due to intake and exhaust pulse timing from the intake and exhaust system geometries. It may simply be the case that the intake and exhaust systems aren't tuned to maximize VE at high RPMs in your case and again you'll feel a sharper fall-off in power at high RPMs than you otherwise would.
(It looks like an FMF pipe on there, and I don't know how "extensive" your powertrain mods are).

http://www.twobros.c...a-YZF450_SO.pdf

Anyway, nice looking bike! I'd be interested in what you find out is going on. :excuseme:

  • sito

Posted May 05, 2009 - 08:13 AM

#6

Something else came to mind on this, Sito.

If the bike is jetted properly, it could be that you're feeling the normal droop in the power curve that happens at high RPMs. In the dyno chart below (thanks to Two Brothers Racing), the power curve falls off around 8.5k RPM and the bike is about 10HP lower at 11k RPM than at the peak. It's entirely possible that if you've tuned the bike well to get a sharper peak, then you'll likely have more "droop".

Along with this is that volumetric efficiency (VE) or how well you can stuff air/fuel mixture into the engine suffers at high RPM primarily due to valvetrain limitations, and secondarily due to intake and exhaust pulse timing from the intake and exhaust system geometries. It may simply be the case that the intake and exhaust systems aren't tuned to maximize VE at high RPMs in your case and again you'll feel a sharper fall-off in power at high RPMs than you otherwise would.
(It looks like an FMF pipe on there, and I don't know how "extensive" your powertrain mods are).

http://www.twobros.c...a-YZF450_SO.pdf

Anyway, nice looking bike! I'd be interested in what you find out is going on. :excuseme:


Interesting and I love being a noob on a bike or car and trying to figure this stuff out (with good help, of course). Big drop off on HP after 9k but what I'm experiencing is like a "throttle-off" rather than subtle drop in power. My buddy races a YZ but hasn't had a chance to come over and ride mine--he should be able to help identify that.

As far as mods, here's what was listed/known for sure:

Leo Vince slip-on Muffler
JD Jet kit
R&D adjustable Leak jet
Gray wire (I did this)

Looking at the spare parts, I believe that:

- Yam gytzr (forgot the nomenclature) kit-AIS gone, throttle stop, airbox etc.
- YZ cam sprockets (looks like 2 sprockets in the box, need to count the teeth, I guess)

Think that's it. I have a call into the PO to go over some of this stuff. Now investigating an alarm system...

Tonight I'll check the fuel/air (adj screw installed) and tomorrow the jets.

Oh--and thanks to the sticky on the board wrt the air filter hole through the filter--checked mine first thing last night and all is well..

Jack

  • odlaw19

Posted May 09, 2009 - 06:48 PM

#7

The sputtering is because of the TPS. I've disconnected mine while the SM wheels are on and its 50 times better at constant throttle!!!!

Try it!

  • sito

Posted May 10, 2009 - 04:03 AM

#8

The sputtering is because of the TPS. I've disconnected mine while the SM wheels are on and its 50 times better at constant throttle!!!!

Try it!


I'll try it. I installed the vortex x10 cdi yesterday (ridiculously easy) and it helped tremendously.

I have to admit that I've looked for the damn tps 5x and not been able to find it. If anyone had a pic that would help me a lot, but I suppose I'll eventually stumble upon it.

Good chance I may have figured out the over rich condition: adj leak jet. I checked the powerbowl setting for the first time yesterday and it was +2 turns out (60+ jet). I adjusted to 40 (1.5 turns) and will test ride this a.m. but the idle was lower.

Report around noon but fingers crossed. Also popped my first wheelie yesterday--WOOHOO!!!!

Jack




 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.