Posts
2343
Joined
8/17/2006
Location
The RTF/Amboy, WA, USA
Edited Date/Time
12/3/2020 2:41pm
So I never have our cylinders done by anyone I like to do minor porting & cleaning on them myself and combined with reworking the powervalve linkages plus tuning our bikes have always ran amazing. I know enough to not grind away without having a dyno or flow bench at my disposal.
So I bought a couple 2017 Husky TC125’s from a friend who was getting out. One was a “Lorettas stock” build and the other a full race port job. Both done by a reputable company. Neither had been ridden when I got them. Both had minor problems in the first few hours like a powervalve retaining bolt coming out. I got such a good deal none of this matters money wise. I have a 150 kit sitting in box.
The full race one didn’t seem to run that well so I decided I better tear it down and see what was actually done. Maybe it doesn’t really matter but the porting looks terrible, grinder grooves everywhere and very non symmetrical. Even the case stuffing looks tacky. Any builders on here have an opinion?
He paid a good amount for it over a year ago. I will say we ran our stock bike with STIC Keihin carb against the full mod running their modded Mikuni and the stocker blew it away. More power for a tenth of the cost...
So I bought a couple 2017 Husky TC125’s from a friend who was getting out. One was a “Lorettas stock” build and the other a full race port job. Both done by a reputable company. Neither had been ridden when I got them. Both had minor problems in the first few hours like a powervalve retaining bolt coming out. I got such a good deal none of this matters money wise. I have a 150 kit sitting in box.
The full race one didn’t seem to run that well so I decided I better tear it down and see what was actually done. Maybe it doesn’t really matter but the porting looks terrible, grinder grooves everywhere and very non symmetrical. Even the case stuffing looks tacky. Any builders on here have an opinion?
He paid a good amount for it over a year ago. I will say we ran our stock bike with STIC Keihin carb against the full mod running their modded Mikuni and the stocker blew it away. More power for a tenth of the cost...
Port height is very important, take your calipers and measure the heights and see the differences between cylinders.
I am looking for a 150 complete kit, how much was yours?
The Shop
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Luxon 4-Post Bar Mounts
$189.95 - $239.95
The fact that both engines had parts fall out within a few hours adds to my concern.
Like said above these 125 cylinders pretty damn good from factory. I spend more time “porting” on the powervalve linkages than anything. Figured out a few tricks so they work smooth as butter..
Bruce, the 150 kit came with bikes so no idea what cost was.
From what I can gather, there is very little parts required to transfer over from the 125 setup. People say ktm parts are expensive but I dont get that at all.
Fun fact, Eric Gorr is left handed, and had to teach himself to port with his right hand because of the availability of porting tools. The last 144 kit he did for me, I measured the port heights and they were within 0.1mm, probably more accurate than one could actually measure.
For my own edification I spent some time cleaning up the ridges & craters/gouges throughout the whole thing. May not make a difference but I feel better knowing it all matches side to side and has a uniform rough finish.
Waiting for my updated STIC to get it all back together.
Overall I am pretty unimpressed by the work that was done. Both engines needed a decent amount of reworking to get running to my satisfaction. Maybe that's why this company has mostly gone in a different direction over the last couple of years?...........
I'm a machinist, I own/operate a small CNC shop, so I have an eye for detail. I also think there are people who don't need to operate manual machines like die-grinders and whatnot. After a six pack of my favorite cold ones I can hold a better straight line or smooth arc with a carbide burr than that... I wouldn't hire whatever shop that is to do any actual work.
A related story: A buddy recently had a problem with some KTM suspension from a well known shop. They installed the Race-Tech spring conversion in his Factory Edition AER fork. They cranked his pre-load all the way tight and failed to correctly set the length of the spring-cartridge (which is an inherently bad design from Race-Tech already). The result was two forks of different lengths and overly harsh suspension. There was what I considered clear evidence that they used a pair of channel-lock style pliers to tighten the preload nuts as well as a rebound adjuster hammered in with an impact gun so tight that the threads were galled beyond repair.
My thoughts on both of these situations (your porting and my buddy's forks) is that perhaps the shop hired a new helper without the mechanical and technical experience necessary to do the work unsupervised, or without the integrity to do good work unsupervised. Either of these hypothetical "new helper" explanations reflects on the judgement of the shop owner / management. I'd find another shop for future work and do my best to repair what you have there.
I’ve cleaned it all up as best I could. Frankly at this point I would rather have it stock but we will see what we can do. I think i have a pretty good grasp of engines for an amateur. If you were at the Dream Race my youngest holeshot & won supermini on a home built bike & finished 3rd at Top Gun on it. Oldest was 5th at 125 All Stars on another home built bike. KTM’s don’t really need much to rip. It’s more in the tuning, imo....
Man, some of those supermini kids are fast and beating them all is awesome! Fifth in the 125 class is a real accomplishment. I missed Top Gun this year as my wrist has been injured since the end of July and I've done minimal riding since the two stroke weekend and it's getting better slowly.
My boy rode the bike yesterday after I cleaned things up and it seems to run better. Not as strong on bottom as the other one with my work but strong on mid-top. Some tuning on PV may help this.
For the money a stock cylinder with STIC in carb is hands down the best set-up, IMO. Truly insane what they do to these bikes...........
Pit Row
The dig marks on the sides of the port ducts is terrible work, as is the side to side marks, although rough, for god's sake make it a cross hatch or something slightly appealing to the eye!
I used to just remove the casting marks inside the ducts and then bead blast all the channels. To avoid all the beads hitting the plating, I would shove towels down in the bore and mask off certain areas. When done, it looked great and performed amazing. Also gasket match the boost port on the cyl base, match up the chordal width of the windows as well as the height and a few other small things.
The KTM 125 did not like a lot of compression, on the dyno it started to take off power on the upper rpm range, I ended up lowering the cyl base by .015" and then cutting the head a little bit to get 1.0mm of squish.
The Bill's Pipe seem to be the only pipe that cured a small dip in the power curve right around 10k that helped transition the engine from pv closed to pv open.
I also made a special cocktail of Renegade 110+93 e-free and a small oxy (about 5%) with some nitromethane and straight castor oil..although gummy, (hence the pv cleaning and polishing), the engine never got hot enough to burn off all the oil so there was always a small film of it all over the bearings and cyl walls, that's why you hear a lot about film strength. It smelled good to :-)
These bikes dont need 120 oct to run but when done in small stages, somewhere around 102 oct is fine to keep detonation away and have a strong runner all day.
Good luck, J
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