Longevity of Japan 2 strokes over Chinese 2 strokes

FNTPuck

Well-Known Member
Joined
Jul 2, 2018
Messages
427
You can build a reliable HT engine, but the cost outweighs the benefits.

The real weak link is the crappy chrome plated cylinder, so a sleeved jug with quality piston rings goes a long way to increasing longevity. They are hard to find though and $100+ just for the cylinder. Then I would look into a balanced/welded crank (~$70), and a CNC head that won't warp (~$50). Two part "Supercharge" CDI is more reliable than the stocker and only $20. CNC adapter to prevent worn out/wobbling rag joint sprocket setups is another $40-50.

When all is said and done you are at like $350 for what is still just a chinese 2stroke and at that point you could have gotten three spare Triple40s to swap at the first sign of trouble or did the smart choice and went with a 4stroke for longevity for a commuter and put the savings into HD wheels and a triple tree fork.
 


LewieBike

Active Member
Joined
May 21, 2014
Messages
496
I have a 1980's Kioritz 32 cc weedwacker engine that has been thoroughly used with it's weedeater attachments that still starts and runs like new, Very quiet, lots or rpm and decent power for a tiny engine. I was my first engine on my friction bike. But mounting it was a big problem. The Italian McCullough I now use on that bike is also pretty old and well used too, but it's a nice engine. They both run well, I'd think any Echo, Honda, Tanaka, Mitsubishi, type of Japanese made industrial garden implement engine is miles ahead of a HT Chinese bike engine if not power, longevity.
 

LewieBike

Active Member
Joined
May 21, 2014
Messages
496
You can build a reliable HT engine, but the cost outweighs the benefits.

The real weak link is the crappy chrome plated cylinder, so a sleeved jug with quality piston rings goes a long way to increasing longevity. They are hard to find though and $100+ just for the cylinder. Then I would look into a balanced/welded crank (~$70), and a CNC head that won't warp (~$50). Two part "Supercharge" CDI is more reliable than the stocker and only $20. CNC adapter to prevent worn out/wobbling rag joint sprocket setups is another $40-50.

When all is said and done you are at like $350 for what is still just a chinese 2stroke and at that point you could have gotten three spare Triple40s to swap at the first sign of trouble or did the smart choice and went with a 4stroke for longevity for a commuter and put the savings into HD wheels and a triple tree fork.
The HT engines are not hard chrome bores, they're Nikasil. An alloy of Nickle and Silver, Nikasil is plated onto the aluminum bore, MotoGuzzi uses Nikasil on most of their modern V twin motorbikes now, It's a good substitute for chrome but not quite as durable.

I still think iron or steel liners are best.
 

FNTPuck

Well-Known Member
Joined
Jul 2, 2018
Messages
427
The HT engines are not hard chrome bores, they're Nikasil. An alloy of Nickle and Silver, Nikasil is plated onto the aluminum bore, MotoGuzzi uses Nikasil on most of their modern V twin motorbikes now, It's a good substitute for chrome but not quite as durable.

I still think iron or steel liners are best.
No they are not Nikasil, they are chrome plated AL. You can literally see the chrome peel on a damaged cylinder or if you race and let one hit ~425*. One Vendor is trying to get Zehe to do a run of true Nikasil bores but has not made any progress on it.

I agree an iron sleeve would be best, they are available but expensive.
 

junglepig

Active Member
Joined
Oct 30, 2018
Messages
218
No they are not Nikasil, they are chrome plated AL. You can literally see the chrome peel on a damaged cylinder or if you race and let one hit ~425*. One Vendor is trying to get Zehe to do a run of true Nikasil bores but has not made any progress on it.

I agree an iron sleeve would be best, they are available but expensive.
Not to hijack thread, but I'm planning on installing a thermocouple to measure CHT soon. Do you have some experience with that?
I'm planning on installing the TE at the base of the spark plug. On a slant head, would this make sense, and what temperature at that point would indicate danger? I may set it up with a temp display, or maybe just a warning light.
 

FNTPuck

Well-Known Member
Joined
Jul 2, 2018
Messages
427
Not to hijack thread, but I'm planning on installing a thermocouple to measure CHT soon. Do you have some experience with that?
I'm planning on installing the TE at the base of the spark plug. On a slant head, would this make sense, and what temperature at that point would indicate danger? I may set it up with a temp display, or maybe just a warning light.
Most just use a relatively cheap laser thermometer after a run to get a rough idea, but I have seen people on the zeda group who use the temp ring under the spark plug to monitor it and I'm sure the more serious racers likely do as well.

From what I have seen on the group chats from builders like Rob and Kurt is that between 250-350* is safe cylinder head temps for continuous running, 350-400 is hot but should be OK if the setup is right(filed rings, proper end gap, good quality oil, retarded ignition timing, etc), and ~450+ even for relatively brief periods you have to start worrying about the cylinders peeling. Your average build won't be anywhere near there, but when the kids run those cheap $20 pancake heads with 100:1 oil ratio, lean jets for top end, and a milled head with 1 base gasket for 200psi compression, they are the ones who run into those issues. They brag about hitting 50+mph on a Monday and complain that the motor was defective and lost all compression by Friday :LOL:.

I mostly build commuters to resell so don't go that crazy with mods that sacrifice reliability for performance, but if I did I would go with the spark plug mounted thermocouple and a cheap temp display to keep an eye on it.
 

junglepig

Active Member
Joined
Oct 30, 2018
Messages
218
Most just use a relatively cheap laser thermometer after a run to get a rough idea, but I have seen people on the zeda group who use the temp ring under the spark plug to monitor it and I'm sure the more serious racers likely do as well.

From what I have seen on the group chats from builders like Rob and Kurt is that between 250-350* is safe cylinder head temps for continuous running, 350-400 is hot but should be OK if the setup is right(filed rings, proper end gap, good quality oil, retarded ignition timing, etc), and ~450+ even for relatively brief periods you have to start worrying about the cylinders peeling. Your average build won't be anywhere near there, but when the kids run those cheap $20 pancake heads with 100:1 oil ratio, lean jets for top end, and a milled head with 1 base gasket for 200psi compression, they are the ones who run into those issues. They brag about hitting 50+mph on a Monday and complain that the motor was defective and lost all compression by Friday :LOL:.

I mostly build commuters to resell so don't go that crazy with mods that sacrifice reliability for performance, but if I did I would go with the spark plug mounted thermocouple and a cheap temp display to keep an eye on it.
Sounds good. I'm just waiting for a couple of components from China. I have some 14mm ring terminals that I think are suitable for the type K thermocouple mount.
I'm going to mount either a Raspi or Aduino to do some data aquisition and display. Just because it's the sort of thing I like to do. I love hard data.
I'm thinking some temperature, rpm, and vibration data will be useful. Since it will likely be a small display if any, for the temperature, I'll probably set up an RGB LED temperature status light. Maybe mounted in the lower part of the speedometer or tachometer dial face. That could give me a Green "OK" plus some statuses of yellow/orange/red blinking etc. Maybe even a 10-segment bar graph for temp. But I'm just talking and not building for now...
 

Will'smotobikes19

Well-Known Member
Joined
Apr 9, 2018
Messages
1,583
Well I guess I will get no personal mileage to go by for Japanese engine setups on bikes. Everyone seems to be set on Chinese engines I either get people that say yep Jap engines last forever or guys saying Chinese is better. I realize not everyone with the Jap engines have a speedo/odometer. I think I recall someone saying they got 20k but I'm not sure. With small Jap engines on bikes most times guys sell the bikes before the motor goes which is a good thing. Fixing motorized bikes gets annoying after a while and I just want to ride tbh. If I got a job in a nearby town I would ride the crap out of a properly built bike with a good engine.
 

mark20

Active Member
Joined
Sep 26, 2018
Messages
441
Well I guess I will get no personal mileage to go by for Japanese engine setups on bikes. Everyone seems to be set on Chinese engines I either get people that say yep Jap engines last forever or guys saying Chinese is better. I realize not everyone with the Jap engines have a speedo/odometer. I think I recall someone saying they got 20k but I'm not sure. With small Jap engines on bikes most times guys sell the bikes before the motor goes which is a good thing. Fixing motorized bikes gets annoying after a while and I just want to ride tbh. If I got a job in a nearby town I would ride the crap out of a properly built bike with a good engine.
if you got the money go for it, it will most likely be truble free, we have a hasquvarna chainsaw ( closet thing i have to a japaense engine)
it starts first pull every time, we sold it to are neigbor becuase we dont use it anymore, its a 455 rancher
plus a quality name brande engine will hold its value. we sold it for 300$.
 
Last edited:
Top