Running awesome! Just have to nail down the jetting.

[turbowrenchhead]

After $1800 in repairs this spring the bike is hauling ass! I was running 350 mains last year per dyno tuning and on the safe side of jetting. I'm did some wot runs tonight and I feels very strong. I put in 370's with this years new additions thinking thats all it would need.

Upgrades:

66X54 Stock crank and pro lites

DIY dune porting. intakes 6mm longer/1mm wider, exhaust 3mm wider/1.6mm raise port over last years pair.

DIY case porting with roughed up trench surfaces.

V4's

22.5 cc custom domes with a .048 squish 10mm band and 140 cranking psi.

 

I ended up with the largest I had on hand, 420's. I'm starting to see brown in the color. Up to the 420's is was all grey plug chops. I even have my idle jet a 1/2 turn out on the richest setting.

I was worried that I might have an air leak. So I put the leak tester back on it. Holds 7psi for 20 mins. I'm good!

Now the next challenge, finding bigger jets locally. Too late to order them. I have to be ready by 5pm this Friday for the biggest ride of the year.

This year even the DS650 will get left in the dust! Raptor 660's didn't pose a threat last year.

For me to go up 7 sizes and still lean I must have made a significant increase in power. How much would you guys guess? I'm thinking I between 65 and 70hp

 

 

 

[WINDYCITYJOHN400]

 I'm thinking I between 65 and 70hp

 

I'm thinking NO.  (The pulse strength thru the carb has probably dropped from the large porting. So the jets aren't flowing as much fuel as before)

 

In the end, hitting a big HP number with THAT kind of build just robbed your bottom end torque.

 

Besides…..I smell a burndown coming. 

[turbowrenchhead]

Bottom end feels just fine.

[WINDYCITYJOHN400]

Bottom end feels just fine.

 

You didn't have any bottom end with the last motor. LOL  (You forget…I've seen all your dyno curves.)

[oldskool]

Wow 420 ' s and need more. 350 with stock carbs?

[turbowrenchhead]

You didn't have any bottom end with the last motor. LOL  (You forget…I've seen all your dyno curves.)

 

Doesn't bother me. I can still ride it just fine.

[driftingbanshee]

I'm on 340s with stock carbs and only bolt ons.

 

dont talk to morons you only educate them..

[turbowrenchhead]

Wow 420 ' s and need more. 350 with stock carbs?

 

Yeah, stock carbs.

[sstaton1983]

Im thinking ring snag on the exhaust port....Good luck and you get an A+ for effort.. I have ruined a couple sets of cylinders when I thought "the bigger the ports the better"....

[turbowrenchhead]

Rings are fine. Ports were champhered

[Nieskes]

Are you the guy who advertises on cl for atv repairs and power mods?

[sstaton1983]

All the chamfer in the world won't help if the ring pops out due to the port being to wide....Not saying you will have an issue... Also depends on how the port is shaped to help the ring seat back in the groove.

[WINDYCITYJOHN400]

Doesn't bother me. I can still ride it just fine.

I can ride a Raptor 80 or Suzuki 230 shaft drive "just fine".

 

Your last build with your DIY porting made less overall power than if you just stuck $200 Vito's Super Stock pistons in a stock cylinder.

That motor ate itself and you spent (according to you) $1800 in upgrades (you could have a 421 Serval/Cub by now)

Now you're onto cylinder/crank/piston/port job #2.

You did a pretty aggressive exhaust port on a motor that will be running DNR/FORESTRY FRIENDLY trail pipes........

And JUST LIKE LAST YEAR, you're in a rush to get ready for a big ride.

I'm noticing a trend......you aren't very receptive to advice.... and spend way more time thinking about the "right now" than picturing a good long term plan.

Watching you find your own way......is like watching someone try to climb the BACK of very high extension ladder.

[03DMshee]

^^^^^verbal assults being handed out on the daily!

[sstaton1983]

Word to yo mom...