Standard Spec YPVS 350 Barrels
Moderator: rztom
Standard Spec YPVS 350 Barrels
Where is the choke point/restriction on standard barrels ?
Looking at my tuned barrels (UK) the inlet windows are really opened up but after having to go up 3 sizes on the rebore due to wear, I feel I don't want the inlets made into Swiss cheese again !
So what is a good compromise to get a decent jump in power and not go to over the top, or you can't have both !
Looking at my tuned barrels (UK) the inlet windows are really opened up but after having to go up 3 sizes on the rebore due to wear, I feel I don't want the inlets made into Swiss cheese again !
So what is a good compromise to get a decent jump in power and not go to over the top, or you can't have both !
Last edited by Headcoats on Sat Sep 30, 2017 10:24 am, edited 1 time in total.
Cryin' In The Beer Of A Drunk Man
Re: Standar Spec YPVS 350 Barrels
Pipes ad K&N pods, big increase. Leave the porting alone. You gain huge power and still have reliability.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
Re: Standar Spec YPVS 350 Barrels
I have some standard barrels and after the premature wear on my tuned "swiss cheese" barrels , I'm now more inclined to have something not so radical but was just wondering if the barrels could maybe have a light clean up?
Cryin' In The Beer Of A Drunk Man
- OldTZracer
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Re: Standard Spec YPVS 350 Barrels
As Rory said, leave the porting alone - just clean them up...
"...its a 2-stroke ya twit - Its supposed to smoke..."
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Re: Standard Spec YPVS 350 Barrels
Would have to agree as well. Also don't polish anything on the intake side. So many barrels get destroyed with amateur tuning. The 2-stroke tuner handbook is a good resource if you do move forward.
- T.RexRacing
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Re: Standard Spec YPVS 350 Barrels
If ya want it ported let someone do it that's done the work to make it a worthwhile addition.
There is only one difference between a madman and me. The madman thinks he is sane. I know I am mad.
Salvador Dali
Salvador Dali
Re: Standard Spec YPVS 350 Barrels
I will if I decide going down that road again but the answer I'm after is how important is it that the inlets are opened right out ?
Cryin' In The Beer Of A Drunk Man
- Questo vecchio rz
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Re: Standard Spec YPVS 350 Barrels
You have several great tuners in the UK.
Why do you not just send them to Stan ? It's kind of a no brainier.
Why do you not just send them to Stan ? It's kind of a no brainier.
Banshee (Baja) race bike,+ 2 A Arms,L.E.Ds, Toomey, +4 stroker IMS tank, run flats.
96 GSXR SRAD, Future Yoshimura rep.
85 custom Tri-Z
RZ/YZR bike(project)
86 VFR750 RC24 Merkel replica (project)
Royal Enfield Bullet 500
96 GSXR SRAD, Future Yoshimura rep.
85 custom Tri-Z
RZ/YZR bike(project)
86 VFR750 RC24 Merkel replica (project)
Royal Enfield Bullet 500
- T.RexRacing
- Posts: 1318
- Joined: Fri Nov 01, 2013 8:34 pm
- Location: back in the hills
Re: Standard Spec YPVS 350 Barrels
It's my understanding the transfers require the most work so the inlet's likely secondary for mo powah.
There is only one difference between a madman and me. The madman thinks he is sane. I know I am mad.
Salvador Dali
Salvador Dali
- two-stroke-brit
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Re: Standard Spec YPVS 350 Barrels
pipes,carbs and zeeltronic Iggy.
will give the biggest improvements
mark
will give the biggest improvements
mark
350LC,Athena 392 big bore,stock porting,swiss cheese air box,stock reeds,spec11 pipes.(now TSA big bore pipes)
She might not be pretty but she will always be a fun ride
1982 YAMA RD350LC
98KDX 220R
1967 TRIUMPH TIGER
2001 TRIUMPH TT600
She might not be pretty but she will always be a fun ride
1982 YAMA RD350LC
98KDX 220R
1967 TRIUMPH TIGER
2001 TRIUMPH TT600
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Re: Standard Spec YPVS 350 Barrels
The transfers are the limiting factor on these barrels for flow. Thus why many of the aftermarket barrels can get substantially more power. Optimal transfer sizing. When you start messing with the size of the port windows you will majorly change power characteristics though.
I am on Rory's team when it comes to tuning. Bigger carbs are of no value on a stock motor. Throw on some pods and call it a day. Zeel may be worth some power but I didn't really see it. Of course if you have piles of tuning and dyno time then sure there are gains to be had. Stock carbs can even work on 396 granted they may cut a bit of top end.
I am on Rory's team when it comes to tuning. Bigger carbs are of no value on a stock motor. Throw on some pods and call it a day. Zeel may be worth some power but I didn't really see it. Of course if you have piles of tuning and dyno time then sure there are gains to be had. Stock carbs can even work on 396 granted they may cut a bit of top end.
- T.RexRacing
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- Joined: Fri Nov 01, 2013 8:34 pm
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Re: Standard Spec YPVS 350 Barrels
I have dyno access anytime as it's my office. However a bike I own hasn't seen a pull in 10 years. That may change when I get my GPL pipes......
There is only one difference between a madman and me. The madman thinks he is sane. I know I am mad.
Salvador Dali
Salvador Dali
Re: Standard Spec YPVS 350 Barrels
Very nice T! Very nice.
The dyno is the best way to tune. Porting should only be considered by an expert rider. The general public are not expert riders. There are so many sacrifices from porting, to get the big numbers. Ridability on the street goes out the window fast.
Everyone knows about "chicken strips". I had a track day about a month ago on a 2009 KLX250SF. Every street bike you look at, has chicken strips. Get on the track, and it's like magic, the strips are gone...even on the Kwacker 250. So, if you must port your bike, do us all a favour and track your bike first. Going fast, does not require porting. It requires corner speed, comfort with your bike and ease of operation. The RZ does that in spades. That's why they are so popular. Fun! Fun! Fun! Porting offers a very experienced rider other challenges.
The dyno is the best way to tune. Porting should only be considered by an expert rider. The general public are not expert riders. There are so many sacrifices from porting, to get the big numbers. Ridability on the street goes out the window fast.
Everyone knows about "chicken strips". I had a track day about a month ago on a 2009 KLX250SF. Every street bike you look at, has chicken strips. Get on the track, and it's like magic, the strips are gone...even on the Kwacker 250. So, if you must port your bike, do us all a favour and track your bike first. Going fast, does not require porting. It requires corner speed, comfort with your bike and ease of operation. The RZ does that in spades. That's why they are so popular. Fun! Fun! Fun! Porting offers a very experienced rider other challenges.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
- T.RexRacing
- Posts: 1318
- Joined: Fri Nov 01, 2013 8:34 pm
- Location: back in the hills
Re: Standard Spec YPVS 350 Barrels
Yeah but having the powah isn't about track daze or racing. Common sense has no place here dood.
Shit my Tuono doesn't really have any "chicken strips" and it's never been tracked. I know it's not acceptable to ride fast on the street but that's never stopped me. It's why I ride and always will be. I don't wheelie through town,there's a time and place for everything and in traffic ain't it. I live in the mountains and ride roads where 70 MPH is terrifying. Tight technical and tons o' fun.
The RZ is ported by Ed Erlenbach. Quite streetable and well behaved on pump gas. It's a matter of degree.
Shit my Tuono doesn't really have any "chicken strips" and it's never been tracked. I know it's not acceptable to ride fast on the street but that's never stopped me. It's why I ride and always will be. I don't wheelie through town,there's a time and place for everything and in traffic ain't it. I live in the mountains and ride roads where 70 MPH is terrifying. Tight technical and tons o' fun.
The RZ is ported by Ed Erlenbach. Quite streetable and well behaved on pump gas. It's a matter of degree.
There is only one difference between a madman and me. The madman thinks he is sane. I know I am mad.
Salvador Dali
Salvador Dali
Re: Standard Spec YPVS 350 Barrels
It sure is.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine