150sx cylinder porting?

dbx33
Profile picture for user dbx33
Posts
247
Joined
8/13/2020
Location
USA
dbx33
How good are the stock cylinders? ive head from a few people that the gains on this are MINIMAL. That theres plenty gains to be had on the 250/300 cylinders but not the 125/150 cylinders. Anyone have dyno's to back up claims?
2
|
Bruce372
Profile picture for user Bruce372
Posts
6329
Joined
4/1/2008
Location
USA
Bruce372 5/18/2021 7:04pm
5/18/2021 7:04pm
When I did a top end, I was surprised the squish was ok the larger side, so I used a slightly thinner bade gasket.... so there might be some improvement, but maybe only slight.

The bikes make great power, and it's easy to loose power with aftermarket bolt on.

Good jetting helps, and the stic pwk carb makes good power and gives the bike a different perspective.
1
tsmitty2661
Profile picture for user tsmitty2661
Posts
95
Joined
2/15/2017
Location
Pittsburgh, PA, USA
tsmitty2661 5/20/2021 5:03am
5/20/2021 5:03am
Sent my 2019 top end to Lynks. Totally different bike. I had complaints of the 150 signing off if you tried to over rev it like a 125. Sent it to him and it’s unreal now. Used the ktm jetting thread from here, changed slide and needle and made a noticeable difference when I did that as well. My bike now is not even in the same category as when it was stock
2
Rickyisms 5/20/2021 7:18am
5/20/2021 7:18am
tsmitty2661 wrote:
Sent my 2019 top end to Lynks. Totally different bike. I had complaints of the 150 signing off if you tried to over rev it like...
Sent my 2019 top end to Lynks. Totally different bike. I had complaints of the 150 signing off if you tried to over rev it like a 125. Sent it to him and it’s unreal now. Used the ktm jetting thread from here, changed slide and needle and made a noticeable difference when I did that as well. My bike now is not even in the same category as when it was stock
What did it run you?
tsmitty2661
Profile picture for user tsmitty2661
Posts
95
Joined
2/15/2017
Location
Pittsburgh, PA, USA
tsmitty2661 5/20/2021 12:37pm
5/20/2021 12:37pm
tsmitty2661 wrote:
Sent my 2019 top end to Lynks. Totally different bike. I had complaints of the 150 signing off if you tried to over rev it like...
Sent my 2019 top end to Lynks. Totally different bike. I had complaints of the 150 signing off if you tried to over rev it like a 125. Sent it to him and it’s unreal now. Used the ktm jetting thread from here, changed slide and needle and made a noticeable difference when I did that as well. My bike now is not even in the same category as when it was stock
Rickyisms wrote:
What did it run you?
I think work itself was 450 then I got everything for a new top end off him too. Total was $675
1

The Shop

See All »
swatdoc
Profile picture for user swatdoc
Posts
1095
Joined
6/29/2014
Location
Temecula, CA, USA
swatdoc 5/20/2021 8:34pm
5/20/2021 8:34pm Edited Date/Time 5/20/2021 8:35pm
Tsmitty - I have a '22 150 on order. I just called Lynks two days ago and inquired about this very issue. Asked if it was possible to broaden the powerband via porting and head mods so the bike pulls longer, and they told me absolutely. I'm a big guy so i really want the added torque, but would like a little wider powerband than what guys usually describe with the 150. Already have the FMF Fatty with a PC R-304 silencer. George is shipping out my 38 PWK w/STIC this coming Tuesday. Smitty I think you just confirmed for me I'll be sending my cylinder and VHM head to Lynks for a little work. Curious - did they recommend a single ring piston by any chance?

Anything else you can tell us about how the power is now?

Also curious what a GET ignition could do. These bikes don't have a TPS or EFI, so I'm thinking all the GET could do is just alter advance/retard, correct???? Not sure how much difference that could make. Would be kind of cool to have 2 maps though. But it would be a pain to find someone with the tuning software and a dyno to get it optimized. From what I understand, the stock cpu is locked and cannot be flashed.

BTW - I was quoted $420 for the port and head work - plus shipping of course.
3
Bruce372
Profile picture for user Bruce372
Posts
6329
Joined
4/1/2008
Location
USA
Bruce372 5/20/2021 9:09pm
5/20/2021 9:09pm
swatdoc wrote:
Tsmitty - I have a '22 150 on order. I just called Lynks two days ago and inquired about this very issue. Asked if it was...
Tsmitty - I have a '22 150 on order. I just called Lynks two days ago and inquired about this very issue. Asked if it was possible to broaden the powerband via porting and head mods so the bike pulls longer, and they told me absolutely. I'm a big guy so i really want the added torque, but would like a little wider powerband than what guys usually describe with the 150. Already have the FMF Fatty with a PC R-304 silencer. George is shipping out my 38 PWK w/STIC this coming Tuesday. Smitty I think you just confirmed for me I'll be sending my cylinder and VHM head to Lynks for a little work. Curious - did they recommend a single ring piston by any chance?

Anything else you can tell us about how the power is now?

Also curious what a GET ignition could do. These bikes don't have a TPS or EFI, so I'm thinking all the GET could do is just alter advance/retard, correct???? Not sure how much difference that could make. Would be kind of cool to have 2 maps though. But it would be a pain to find someone with the tuning software and a dyno to get it optimized. From what I understand, the stock cpu is locked and cannot be flashed.

BTW - I was quoted $420 for the port and head work - plus shipping of course.
Hahaha, this bike is gonna rip.

Btw, my dyno dude ran single ring and it lost power! Some say it improved power tho..... I wouldn't bother, the 150 runs good and is reliable.

The STIC imo will do more than the porting.... when setup the stic keeps building revs and really rips on top
3
swatdoc
Profile picture for user swatdoc
Posts
1095
Joined
6/29/2014
Location
Temecula, CA, USA
swatdoc 5/20/2021 9:21pm
5/20/2021 9:21pm Edited Date/Time 5/20/2021 9:22pm
Bruce - yea hard to argue with pretty much 100% positive feedback on the STIC mod. I'm talking to George about running the STIC on my '79 CR250, and my Mugen '76 CR125 as well.

Should be a really fun bike. Gonna throw on my Cone Valves and Trax too. Got a Rekluse on the way in addition to a bunch of other goodies. I'll have to do a bike build thread
4
alien
Profile picture for user alien
Posts
125
Joined
4/1/2008
Location
USA
alien 5/21/2021 12:52pm
5/21/2021 12:52pm
The 150 sx comes with two maps stock . You plug in or unplug a wire under the tank to switch from map to map. I added a toggle switch to the bars to make going from one map to the other easier. I like the slow map better most of the time, it slows down the revs and makes the power feel a little longer. Moto guys, you must change to the red PV spring if you want a nice hit off the bottom to clear jumps out of corners.
tsmitty2661
Profile picture for user tsmitty2661
Posts
95
Joined
2/15/2017
Location
Pittsburgh, PA, USA
tsmitty2661 5/21/2021 1:28pm
5/21/2021 1:28pm
alien wrote:
The 150 sx comes with two maps stock . You plug in or unplug a wire under the tank to switch from map to map. I...
The 150 sx comes with two maps stock . You plug in or unplug a wire under the tank to switch from map to map. I added a toggle switch to the bars to make going from one map to the other easier. I like the slow map better most of the time, it slows down the revs and makes the power feel a little longer. Moto guys, you must change to the red PV spring if you want a nice hit off the bottom to clear jumps out of corners.
Personally wouldn’t put a red spring in my bike. It would be way too tiring and hard to control. I’ve found like 1.75-2 turns in is good for me. I’ve tried riding the bike with the PV screw all the way out and it’s way too hard to control and tired me out pretty quick. I’ve seen two people talk about the pc silencer and fatty pipe combo, what’s the reason for that? I have one in the garage cause I switched to fmf fatty and shorty since I couldn’t get a pc pipe

I’ve been very curious about the stic pwk set up. It’s on my list but the mikuni hits pretty damn hard and runs great now that it’s tweaked (leaner slide, yz needle). I just have a hard time justifying a 600$ carb and stic when I don’t have any complaints. When I asked lynks about a single ring he said just stick with double ring. Risk of piston cocking in the bore isn’t worth what little power if any it would gain (he’s said he saw a couple instances of that happening). I don’t have an aftermarket head, stock head and whatever he did to it. Didn’t take it apart to see yet
1
romain524
Profile picture for user romain524
Posts
756
Joined
1/14/2015
Location
Newport Coast, CA, USA
romain524 5/24/2021 8:26pm
5/24/2021 8:26pm
That Lynks mod sounds exciting! It makes me want to buy an Austrian little bore! How it all felt on the track? Stronger everywhere?
swatdoc
Profile picture for user swatdoc
Posts
1095
Joined
6/29/2014
Location
Temecula, CA, USA
swatdoc 5/24/2021 10:50pm
5/24/2021 10:50pm
TSMITTY - would you mind if I give you a call to chat about the porting you had done? Was trying to send you a PM, but it's not working for some reason
thanks
John
Tracktor
Profile picture for user Tracktor
Posts
2343
Joined
8/17/2006
Location
The RTF/Amboy, WA, USA
Tracktor 5/25/2021 1:12pm
5/25/2021 1:12pm
swatdoc wrote:
Bruce - yea hard to argue with pretty much 100% positive feedback on the STIC mod. I'm talking to George about running the STIC on my...
Bruce - yea hard to argue with pretty much 100% positive feedback on the STIC mod. I'm talking to George about running the STIC on my '79 CR250, and my Mugen '76 CR125 as well.

Should be a really fun bike. Gonna throw on my Cone Valves and Trax too. Got a Rekluse on the way in addition to a bunch of other goodies. I'll have to do a bike build thread
Im running a STIC on 18 TC125, 96 CR125 & 87 Cr250 amongst other bikes we have owned. On every bike the difference is mind blowing.

We had a stock TC125 & a full mod ported/cases stuffed etc TC125. I had a STIC on the stocker & got the mod running perfect with the stock Mikuni & had my boys ride them back to back. They had no interest in riding the mod. The difference wasn't even close. We also tested the stocker against a PC full mod 125 with similar results. I just ahd a good friend try one after messing with a Lectron for months & never getting it to run quite perfect. I gave him an extra STIC carb to try and haven't got it back yet!

A couple things about the STIC on the KTM engine especially - These run better with stock or so squish. Like Bruce I've always tightened our bikes up from stock but on the newer KTM's you lose over-rev and don't gain any bottom end. Dyno runs back this up. Also, this setup runs best with a silencer with a larger diameter outlet. We saw noticeable gains going from an FMF shorty to a PC setup. The extra power gained from the STIC allows you to dial in the PV even more to pick the best power delivery for the rider/track.

I would start with a stock bike & just add the carb & STIC. I am betting you will be happy with that setup and then there is no reason for expensive fuels/porting/high strung engines. I've pulled pistons at 35+ hours from a B rider who hammers his engines and they have looked like they have maybe 5 hours on them. I would also advise against running oxygenated fuels with the STIC as the baseline jetting is with regular fuel & oxy changes this up & can make tuning difficult..........
2

Post a reply to: 150sx cylinder porting?