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SJMC_DON

Got YZ cams on your 07'? With what exhaust?

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I have a problem with e-starting my 07' after a YZ cam swap. I have researched and believe I have my jetting spot on... the bike will kick start everytime first kick but when cold it will not e-start at all when it's warm I get lucky sometimes and after 5 - 10 cranks with the button it will start. I just did some jetting changes and put the bike back together less the back half of the exhaust. .. one touch of the button and "berooom" started right up with the button... put the exhaust can back on and I'm back to the same old sheet of not starting.

I have the stock WR exhaust with the GYTR enlarged end cap and screen still in. I like this exhaust, it's quiet and still makes great power but I am considering taking the endcap off all together to see if the starting improves:excuseme:

Any input would be greatly appreciated.

Thanks:ride:

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having the stock WR can is probably not a good idea, it probably creates too much "back pressure" making it difficult to start. Try using a stock 06 yz muffler, it's got pretty good air flow. Besides the starting issue, how do you like the cams now? Removing the end baffle altogether is a good idea too, it will allow significantly more air flow and won't be that loud, the screws allow the spark arrestor to stay in place too. I'm thinking that bike is going to be a monster once coupled with a better flowing exhaust.

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Besides the starting issue, how do you like the cams now?

I like it:banana:

could you elaborate on that please? :thumbsup:

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Besides the starting issue, how do you like the cams now?

could you elaborate on that please? :thumbsup:

What.... the dancing bannana is not enuf?:ride:

The low end power is stronger... not the hard hit I expected but more linear and grunt like if that makes sense... it can be a handful if I am tired and in the tight stuff but it's something that I can definitely get used to and have already learned to appreciate while trying to loft the front wheel over something from a stand still it just seems more effortless.. 1st gear seems taller and more useable, I can't explain why or how but it's true.

Mid pull is harder, 4th gear 3/4 the way through the roll on and the front tire is lifting, acceleration here is far better than the stock set up.

I have yet to really wring it out but I have a GP on Sunday and I am expecting big things provided the dead engine start does not bring me heartache.

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What.... the dancing bannana is not enuf?:thumbsup:

The low end power is stronger... not the hard hit I expected but more linear and grunt like if that makes sense... it can be a handful if I am tired and in the tight stuff but it's something that I can definitely get used to and have already learned to appreciate while trying to loft the front wheel over something from a stand still it just seems more effortless.. 1st gear seems taller and more useable, I can't explain why or how but it's true.

Mid pull is harder, 4th gear 3/4 the way through the roll on and the front tire is lifting, acceleration here is far better than the stock set up.

I have yet to really wring it out but I have a GP on Sunday and I am expecting big things provided the dead engine start does not bring me heartache.

hhahaha, I should have stared at the banana a little longer. :ride:

Sounds like you're making some progress there with the power delivery, still, I insist that you should consider at least a yz stock can. I think you're not getting the brutal low end you expected because the stock wr can is killing the low end, just like the restrictive stock can kills the power on 08 yz's. If you lived closer I'd lend you my yz pipe so you could try out the difference.

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If you lived closer I'd lend you my yz pipe so you could try out the difference.

I'll pick it up in 25 min

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I'll pick it up in 25 min

hehehe, good one joe, only problem is your bike doesn't have 06 yz cams...:thumbsup:

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One of the biggest thing I noticed when I threw a 08 YZ exhaust system on my 07 WR was the header size difference. It just make's the bike seem to breathe so much better. The stock header is just too restrictive.

I don't have a YZ cam on my bike, but it really fires up easy on the e-button now, even cold.

The power gains I got from this pipe sound really similar to how you're explaining yours from the cam.

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I have a full fmf pipe on my o7 with a yz cam . and mine starts with the e-z button . just not as e-z as it used to . I still think your pilot jet is 1 size fat . but I can't be sure . when my bike was rich it was very hard to start . because it was too rich when choked and too lean when not choked to start ez . I used to be able to start my bike with the stock jet with the bike covered with snow and no choke. try a smaller pilot .

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I have an 08 WR450 with a YZ exhaust cam and a DR. D pipe. It was hard to e-start until I leaned out the fuel screw.

I noticed that my bike fired right up after stalling with the hot start pulled in so I figured it was a bit lean.

My bike runs really good.

I had WB E2 pipes on my other WR's and liked them. I don't know who makes them now that WB went under. I heard Vance & Hines.

My DR. D pipe runs good but is too loud.

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I have a full fmf pipe on my o7 with a yz cam . and mine starts with the e-z button . just not as e-z as it used to . I still think your pilot jet is 1 size fat . but I can't be sure . when my bike was rich it was very hard to start . because it was too rich when choked and too lean when not choked to start ez . I used to be able to start my bike with the stock jet with the bike covered with snow and no choke. try a smaller pilot .

Using Eddie Sinsero's method for setting the pilot circuit I realized I was too fat... so I opened it up and actually found a 50 in there:bonk: Installed a 45 and now it will start when cold but nothing after it has warmed up. Edddie continues to help me over in the jetting forum but it looks like my old JD fuel screw (was installed on my 04', 4 years ago) might be the culprit :thumbsup:

I opened the exhaust a little bit last night and it really had no effect...

Thanks for the input guys, keep it coming if you can :ride:

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If it starts when cold but not when warmed up that means you are still rich on the pilot I think.

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I'm running a 42 pilot because that's what the wide band said I needed . the 45 is what I took out . It was stock. But be sure your accel pump is working proper ,because with a 42 and a crappy accel pump it goes way lean when cracked on. mine did not work until I put on the rd powerbowl on. you could try and o-ring mod.

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I'm gonna try the 42 on mine.

I put a Merge accelerator pump on mine and it did get rid of a nasty bog.

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I'm running a 42 pilot because that's what the wide band said I needed . the 45 is what I took out . It was stock. But be sure your accel pump is working proper ,because with a 42 and a crappy accel pump it goes way lean when cracked on. mine did not work until I put on the rd powerbowl on. you could try and o-ring mod.

Hmmmm... I am now in uncharted waters with the AP but maybe thats the direction I am headed in..

Thanks for the info TWEAV:ride:

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Hmmmm... I am now in uncharted waters with the AP but maybe thats the direction I am headed in..

Thanks for the info TWEAV:ride:

I'd try using two small o-rings on the ap mechanism and a 40 leak jet. that's what I'm using and it works wonderfully.

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I think you should stick a wide band on it just to get a good base line tune . I screwed around with mine for a month trying to get it right . then I put it on a dyno and found my pilot jetting was off . now I'm running the 42 pilot and a 155 main and it's very very close to right . now for the bad news mine is due for a new piston I can hear it slapping a bit . it only has 3500 miles at W.O.T. I Kind of surprised it only lasted this long . Damn short piston skirt . Who would think you would ever complain about any skirt being too short ?:thumbsup::ride: Anyhow I'm going to change it when I get so time and the other bike going.

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I think you should stick a wide band on it just to get a good base line tune . I screwed around with mine for a month trying to get it right . then I put it on a dyno and found my pilot jetting was off . now I'm running the 42 pilot and a 155 main and it's very very close to right . now for the bad news mine is due for a new piston I can hear it slapping a bit . it only has 3500 miles at W.O.T. I Kind of surprised it only lasted this long . Damn short piston skirt . Who would think you would ever complain about any skirt being too short ?:thumbsup::ride: Anyhow I'm going to change it when I get so time and the other bike going.

Wow your main is what I would consider lean to... I am going to try and find a shop that can provide this service.

Thanks

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Yes I know It's way leaner then more people say to run , but at Wot it's at 13.4 to 1 so it's right there . I'm running a dynajet jet kit , I don't know if that is what is different about mine . Most people are running a jd kit.

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