Pro Circuit Vs Lynk's YZ125 motor

Check  out vet build thread . He runs a JM Racing engine yz125 in 50+ LL .  He built a long list  of 125,s that won the 125 classes.  Dungee ,s 125, Gieger,s 04 cr125 that equal to any 25 125.

I have run Pro Circuit engine YZ125’s and I have had a JM racing stock bore 125 and a stroked YZ134. They were both great and much better than stock but I like the 134 better. I don’t know anything about Lynk’s.

Lynks is pretty much the top engine builder for the top amateur kids. His engines were on the podium several times the last few weeks at the Texas nationals. WTT, EBR, HP, all make good 2 stroke engines as well.

There's no wrong choice here. Lynk's builds some solid engines and they have a very strong presence and Loretta's. I think the concerning part of the PC engine is that it was built for RV and they used his input to develop the spec. How many kids can ride a bike like Ryan? I haven't personally ridden that engine or put my kid on it though, it may be developed to be very easy to ride. 

I Used to run Lynks engines on KTM superminis.  Great engine builder, is pretty much the top builder for amateur two stroke stuff.  His work is top notch.  Most 2 stroke engines that are built solely for a race bike are going to be pretty aggressive and "pipey", but from what I've heard the RV spec is even more so than average.  

Wow. A stroked 134. That would be an interesting bike to ride 👍

Sounds like you should do Lynks 

Prices ???

Have you looked at the GYTR kit?

My 1st 04 cr125 was decked , ported, diff carb taper bore bigger . JM racing . Then I got his 2 mm ovr 134with a 2mm stroker crank, 1 mm up, 1 down in 2010 I think.  Hoho that thing pulled Super hard & quick .  It was stolen along with 2 5 hr 06,s.  I hv the TG replica 04 champion ship engine spec , no stroker crank .  It’s soo quick and strong .  I like it better than a stroker crank bike because it’s quicker.  It’s equal or stronger than a yz125 LL championship bike . That yz only ran for a little bit then 2 riders where trying to figure out why it wouldn’t run.  Too modified they don’t last long .  Stroker crank bike I had built for Millville.  Local tracks it had too much or u couldn’t use all of it.  In 2010 it would pull any mod 250f.  Both bikes r similar stab the clutch & a strong hit had all the power & torque.  Non striker u get going quicker I say that’s an advantage.  

I woukd stick with John,s engine maybe get a small tweek of porting. And try different pipes pc has 2 the rv is probably better for LL. Quick to build power then goes flat .  Hgs is a Really good pipe too just run a pc shorty instead of the long euro silencer. Rad valve for off corner quickness . LL is a small track non of the 125,s run like 125 emx upper mid top end screamers.  And he doesn’t build engines where they blow up .  

John at JM Racing built me a YZ134 via 2mil overbore.(not the newer motor)  Hands down the best money I ever spent on  a motorcycle, still my favorite bike of all time.  I am Vet racer so no displacement issues for me though.

I do see that the newer YZ motor has a LOT of jetting issues, and I am fairly close to some top 125 riders.   I believe the power jet carb to be the issue.

My 125sx has a full engine job from PC and it’s one of the easiest to ride and most forgiving 125s I’ve ever ridden. Plenty of bottom end (for a 125) with a smooth transition into the mid range and then just doesn’t stop pulling through the top end. It loves to be ridden up top but is so forgiving. 

Dyno charts > anecdotes

yeah but they gotta be run on the same dyno, has anyone tested both of these together?

Ideally yes, but curves are still representative of characteristics. 

Dynos mean nothing on a track. JM engines are Very impressive on the track.  98 I had Jeff Wilohs 97  national yz125 bike.  It ran clean bottom to a very high pulling top. He holeshot a national . 98 at Byron Chad Johnson team green With a JM racing engine . Pulled me hard 100 feet off a corner a straight. I had it screaming in the strongest part .   Weight is huge on a 125 I was aprox 165 lbs.  My 04 DBP cr125 would anilate the Noleen yz125.  JM engines hit and pull quick with a super strong & long mid range . That goes to the ovr rev , a perfect track engine. And Very exciting & fun to ride.  U can short shift or rev a gear out .  I,m dropping a tooth no doubt it will pull that gearing.  U know the left& rights threw hills where u want to keep it on the pipe but off cambers u don’t want to ovr power it.  Just keep power & grip going. Just  keep it on the pipe this engine makes that soo easy .  Sorry I,m mega beat oh man a cave today I think was worse than nyc . And so many problems.  Dungee, J. Grant 02 cr125 & Jeff Dement he ran his engine in the GP,s.  Talon Vohland FMF 99 too but here. 

you mean peak power means nothing on a track. that's not what you use the graph for. you mentioned overrev, dyno graphs will show that..

Dynos are important, they show the relative difference between mod and stock. 

A dyno with 30hp stock and 33hp  mod, shows 10% increase.

Same model bike, different dyno with 40hp stock and 44hp mod shows rhe same relative 10% hp increase vs stock.

Plus, dynos also show that half of rhe expensive stuff you can buy looses power over stock. In 2018, the only ktm150 silencer that didn't loose power over stock was pc shorty. 

Vforce made no difference that model also.

On track testing is very subjective,  even without the placebo effect and power of suggestion. 

No one spending $1400 on a Ti pipe will admit they can't feel it, or whether it made bike worse.

One thing to consider that hasn't been mentioned yet is track-side support. Out of the aforementioned engine builders, how many of them actually show up to Loretta's to support their riders? EBR, HP, and Pro-Circuit are the one's I know that provide this service at Loretta's. This can be a huge deal especially if you guys run into engine problems or jetting issues. Walking the bike over to the people that built your motor at a high stress event to help diagnose and dial it in I feel is more important than HP numbers. 

Looking forward to hearing a ride report. I’ve seen tons of Lynn’s built Austrian bikes, but not a ton of YZs. 

So……..Lynk”s is based out of VT I believe..pretty close to where I live….thinkin* about getting a carbed 125SX built…..

Simply install the STIC Super X PWK 38/40mm. @traktor built a $4k TC125 for his boys and the boys and their race buddies always chose to ride/preferred the STIC carb'd 2nd TC125. Nothing will pull harder from bottom to top. I know a dad that installed the Super X on his sons 125SX with with only head work and a pipe. At Ponca Nat his son pulled holeshots against fully pro built engines. Been stoked on my 200SX with STIC PWK carbs for 5+ years. 

Thanks…I will investigate further