Running at high RPM after full port and a great deal of blow by

[rkstew]

First post guys so don't be too hard on me... I haven't been into four strokes in a while and got a 400ex with a 416 that was a bit neglected.

First ting I did was get a full port on the intake and exhaust and a rejet and twist throttle and controls off a CRF450 since I'm a old 125b racer and can't stand a thumb..

elevation is at 450 roughly and now she acts like she's getting way too much air and winding out instantly like an extreme lean situation

Once again it has, full port and blend, rejet, Full HMF K&N and No lid. Main jet is a 185. Any suggestions? I'm a 2 smoke guy :devil:

[rkstew]

also has web stage 2 cam

[punk rock kiel]

i have a 426 with port and polish, stage 1 hotcam, full lrd exhaust, ehs air box lid, and twin air air filter with same elevation 172 main, 42 pilot, 3rd clip with slight pop on decel and airfuel 2.5 turns out.

[honda400ex2003]

give it a plug chop and see how it looks jetting wise. it sounds slightly rich but its hard to say exactly.

http://www.exriders.com/vbb/showthread.php?s=&threadid=445695&highlight=jetting+placement

the plug chop info is down just a bit.

welcome to the site!
steve

[honda400ex2003]

also give it a compression test and see how it does. normal is around 125 psi or a bit more.

steve

[rkstew]

Originally posted by honda400ex2003
also give it a compression test and see how it does. normal is around 125 psi or a bit more.

steve

Compression is around 140:ermm:

It will just take some fiddling with the carb I think and I've been real short on time lately so thanks for the suggestions fellas:D

[DragonGunner]

406EX with 11:1 compression, Intake port job with no exhaust porting, open air box, K&N, stock carb without choke, 185 main jet at 725'....sounds like your close, raise your needle an adjust an play with the air screw.

[rkstew]

Thanks for all the input guys..

I'm working all weekend as usual so I should have it figured out by monday.

Battery wasn't too bad at $55 for a 12 amp:D

Something Chrome, It's on the trickle right now.

Forgot to list static compression ratio; 11:1


I'm wondering if the 450 carb conversion is just the way to go at this point:lmao

Bad news is a I have leak out of the already cracked cam cover so I'll be on the look out for one of those or a TIG better than I have access too:devil:

[rkstew]

Originally posted by honda400ex2003
give it a plug chop and see how it looks jetting wise. it sounds slightly rich but its hard to say exactly.

http://www.exriders.com/vbb/showthread.php?s=&threadid=445695&highlight=jetting+placement

the plug chop info is down just a bit.

welcome to the site!
steve

Thanks man, I'm more of a lurker than poster and have the 500R bug too:devil:

We'll see plug testing tomorrow after I fiddle with the carb a tick:D

[trxPOWER]

hey man, it sounds like you have a air leak somewhere, sounds like the carb boot to me. if you spray starting fuel around the boot when its running and it revs, you have a air leak.

[rkstew]

Originally posted by trxPOWER
hey man, it sounds like you have a air leak somewhere, sounds like the carb boot to me. if you spray starting fuel around the boot when its running and it revs, you have a air leak.

Already done my man, they ported the intake to the head:D

My ether says no leaks...

My gut tells me the float might be sticking and causing it to flood...

Def too rich though because It's popping on decel like it was it's job:lmao

I think I'll throw my 178 or 175 main in there just to see what happens. I have no advance key so no worries

[rkstew]

And thanks to all you fuggers and the replies for real.:cool:

It had it's maiden voyage tonight and the plug is wayy dark. Don't y'all love fixing other people's crap?:devil:

[chronicsmoke]

Originally posted by rkstew
And thanks to all you fuggers and the replies for real.:cool:

It had it's maiden voyage tonight and the plug is wayy dark. Don't y'all love fixing other people's crap?:devil:

But at least you'll have a mean machine by the time you're done in the ER :p

Good Luck! Welcome to the site

Post some pics up later too :chinese:

[JOHNDOE83]

In 4 strokes, popping on decell is a sign of a lean pilot jet.

[CJM]

Originally posted by JOHNDOE83
In 4 strokes, popping on decell is a sign of a lean pilot jet.

x2 lean pilot jet. Sounds liek your main jets to large-too rich.

[rkstew]

I figured it out this afternoon, the float wasn't seating the needle and filling the bowl causing it to constantly flood.

I was amazed they stopped making metal floats and these are plastic.

It's all gravy now and just fine tuning, pics are coming. Bet on it ;) Now for the clutch issues:lmao

[rkstew]

That is after I popped a new fuel pump into my Jeep ZJ:devil:

I'm sure it's possessed by now and needs killing lol. 2 hours and $200 later she purs again:)