looking for people interested in top end performance modifications

[Zorge]

Heh, for those programmable I've heard right here, on this forum. Our "insider", guy we know as "humanbeing", few years ago left few "Taobao" links to those CDIs. Where are those links, I really don't know.

Basically, you get CDI box with USB interface and some software to do the job (it seem to me like something I could manage myself). There are three different preloaded ignition patterns (kinda, first has constant angle for triggering spark, second varies angle depending on revs in that manner, third has some other twist, and the last is left for user to custom fit it. As I said, this procedure, creating custom made ingition curve, didn't look to me like "mission impossible" even for noobs. Price? Um... it was long time ago, but i think it was low three figure.

And there are those adjustable CDIs. As I understand, they have variable angle and some more or less generic ignition timing curve, but you can move this curve in amplitude of 4 or 5 degrees with a plaing tiny screwdriver. It is not much, but IMO, it will do the magic. They look like this - http://www.aliexpress.com/item/Gy6-r...74_75,201409_1 .

About surging. Here, in my neighborhood, this happens after too tight boring of a cylinder, when someone rebuild engine, especially when it is two-stroker. Simply, piston doesn't have enough space to expand. Plus, most of our C-motos are air cooled so thermal strains are different comparing to liquid cooled engines. Do you know, how much differs diameter of your piston and cylinder? And than, there is this urban legend about strange thermal properties of a alloy in Chinese pistons (if you so far didn't fit this "Wiseco" you mentioned), and when you add increased compression... Sh...Surge happens. Bottom line: I think that problem is in those two.

I fit some bolt-on oil cooler (take-off plate on a head, pair of hoses and a radiator) on my lil' 50 cc horizontal engine. And you know - thing works! It really takes out the heat and dissipates through radiator. I couldn't quantify how much this thing decrease oil temperature, but I know that oil hose fittings and radiator can be pretty hot. At the end, you can monitor oil temperature before and after fitting oil cooler with those handy dipstick thermometers.

About "no pump": I thought the same thing about my horizontal, that this is engine with a bath splash lubrication, but there is a small trochoidal pump that pumps oil into two lines toward head and crankshaft. Yes, it is low pressure pump (my engine pumps app. up to 2,5 Bar when the oil is cold, and about 1 Bar on working temp, but still, pumps oil nicely. Plus, internal volume of a oil cooler "appendix" (radiator and hoses), on my engine is relatively small - just around 100 cc, so this is not so big "detour" for the oil flow. IMO, if are the is no "bottle necks" (narrower passages that is) inside inlets and oultlets, radiator and hoses, this contraption should work nice even on a low oil pressure engine.

Here's one of oil cooler sets for OHV "Honda" based clones: http://www.aliexpress.com/item/Mediu...74_75,201409_1 .

One more thing. We talked about valve seat cutters in their hand tool version. One word - "Neway". Oh, they are sweet, great for DIY, but their pricing knock me down.

[axa]

Heh, for those programmable I've heard right here, on this forum. Our "insider", guy we know as "humanbeing", few years ago left few "Taobao" links to those CDIs. Where are those links, I really don't know.

Basically, you get CDI box with USB interface and some software to do the job (it seem to me like something I could manage myself). There are three different preloaded ignition patterns (kinda, first has constant angle for triggering spark, second varies angle depending on revs in that manner, third has some other twist, and the last is left for user to custom fit it. As I said, this procedure, creating custom made ingition curve, didn't look to me like "mission impossible" even for noobs. Price? Um... it was long time ago, but i think it was low three figure.

And there are those adjustable CDIs. As I understand, they have variable angle and some more or less generic ignition timing curve, but you can move this curve in amplitude of 4 or 5 degrees with a plaing tiny screwdriver. It is not much, but IMO, it will do the magic. They look like this - http://www.aliexpress.com/item/Gy6-r...74_75,201409_1 .

About surging. Here, in my neighborhood, this happens after too tight boring of a cylinder, when someone rebuild engine, especially when it is two-stroker. Simply, piston doesn't have enough space to expand. Plus, most of our C-motos are air cooled so thermal strains are different comparing to liquid cooled engines. Do you know, how much differs diameter of your piston and cylinder? And than, there is this urban legend about strange thermal properties of a alloy in Chinese pistons (if you so far didn't fit this "Wiseco" you mentioned), and when you add increased compression... Sh...Surge happens. Bottom line: I think that problem is in those two.

I fit some bolt-on oil cooler (take-off plate on a head, pair of hoses and a radiator) on my lil' 50 cc horizontal engine. And you know - thing works! It really takes out the heat and dissipates through radiator. I couldn't quantify how much this thing decrease oil temperature, but I know that oil hose fittings and radiator can be pretty hot. At the end, you can monitor oil temperature before and after fitting oil cooler with those handy dipstick thermometers.

About "no pump": I thought the same thing about my horizontal, that this is engine with a bath splash lubrication, but there is a small trochoidal pump that pumps oil into two lines toward head and crankshaft. Yes, it is low pressure pump (my engine pumps app. up to 2,5 Bar when the oil is cold, and about 1 Bar on working temp, but still, pumps oil nicely. Plus, internal volume of a oil cooler "appendix" (radiator and hoses), on my engine is relatively small - just around 100 cc, so this is not so big "detour" for the oil flow. IMO, if are the is no "bottle necks" (narrower passages that is) inside inlets and oultlets, radiator and hoses, this contraption should work nice even on a low oil pressure engine.

Here's one of oil cooler sets for OHV "Honda" based clones: http://www.aliexpress.com/item/Mediu...74_75,201409_1 .

One more thing. We talked about valve seat cutters in their hand tool version. One word - "Neway". Oh, they are sweet, great for DIY, but their pricing knock me down.

Zorge I finally figured out what the cause of the engine surges were.... as i reported it happened during stress, on climbing , but also quick roll of throttle. it was simply because my clutch was slipping.

immediately recognized it when I mistakenly dragged my hand on the lever during acceleration, I then loosened the cable and no more surges.
now I can roll WOT while on incline and hold a good speed.


I'm quite relieved as the surges started soon after all my engine mods, i want sure if i over did things... I'd like to think I gave it more power but probably i just misadjusted the tension and forgot about it.

I might need to find stiffer clutch springs though. I hadn't looked into it yet, are these available?

[Zorge]

Oh, that kind of surge! I thought that you experienced surge with full stop of a engine.

About clutch: you know, if those stock springs are bit tired, maybe "Honda's" (note this - "Honda's" (or gooooood substitute, from reputable manufacturer)) genuine CG springs will do the job.

Or, you could, for the sake of the experiment, play with washers to get bit stronger preload of those springs, or to add some extra ring in a "sandwich" made of metallic discs and friction plates.

Unfortunately, I do not have in front of me this clutch assembly, and I can not weigh - to do by the book, or to try"something completely different".

[axa]

Oh, that kind of surge! I thought that you experienced surge with full stop of a engine.

About clutch: you know, if those stock springs are bit tired, maybe "Honda's" (note this - "Honda's" (or gooooood substitute, from reputable manufacturer)) genuine CG springs will do the job.

Or, you could, for the sake of the experiment, play with washers to get bit stronger preload of those springs, or to add some extra ring in a "sandwich" made of metallic discs and friction plates.

Unfortunately, I do not have in front of me this clutch assembly, and I can not weigh - to do by the book, or to try"something completely different".

genuine springs seem like a reasonable solution. With each new set of valves I noticed springs of different strengths, seems to me clutch consistency wouldn't be any different.

I've heard of adding plates before but that seemed a solution for too much power... surely don't have that problem here

[Zorge]

Adding extra plates (or some other way to keep them tighter), in case with C-motos, is also to compensate worn friction plates or new plates thinner than stock (it seems that it is not so rare occurrence).