engine build: SYM dd50.

[Jwhood]

Yeah I got a sef ramp plate for free and I think a keli vari can't wait to get my Honda put together money is tight right now but soon enough I'll find out what this Honda scene is like myself lol

[repherence2]

did some porting on the intake. I widened the port and deepened it, but I did not open it up height wise, I only faired it in. It was filed by hand, no power tools used.











also did some porting of the CT reed box. just basically smoothing the sharp casting transitions.

[repherence2]

finally installed the Taiwan bearings into the cases and pulled the crank into the cases.

bearing installation tool




Dio MHR replica bore (right) and a Jog Motoforce mid race (left). the areas marked with black marker is the contact area of the MHR base gasket. the base gasket was trimmed to match the area where the base gasket mates to the engine case. I still need to port the transfer tunnels on the MHR and cut away some of the skirt that partially blocks the transfer areas in the case, where the intake charge comes in.



I marked the Motoforce with the MHR gasket that I have prepped. this was to see how much more the transfers open up on the Dio as opposed to the Jog in regards to the cases. I must clarify that this is a SYM DD50 block though.


here I a picture of 2 KELI variators. one for the Jog90 and the other for the Dio.

I am thinking of doing the Jog transmission mod on this CVT.


this is how much of the Jog transfers would have to be opened up to for it to match the case of a SYM dd50.

now I am starting to see why the Hondas are so fast here. the transfer ports, if port matched between the bore and the case, they end up larger than any of the Jog bores can be opened up to.

[repherence2]

bought some parts

oil pump plug
clutch nut wrench
stock SYM dd50 drive belt
tuning weight set
105mm stud kit
KOSO fan shroud
rubber carb boot to adapt big carb to airbox

[repherence2]

wrapped the Arrow pipe with thick fiberglass "tape". much thicker than the stuff from DEI, thermal/heat wrap.

with KOSO fan shroud

[190mech]

WOW!Strange that pipe wrapping just came up on KiwiBiker,,the latest is to only wrap the diffuser and belly as Wobbly stated here;
"Effective cooling of the Ex duct is certainly effective , with the proviso that using the coldest water entering under the duct is NOT the way to go.
Wrapping the header is proven to promote deto due to the returned mixture in front of the piston being overheated , ruining the trapped charges effect.
But wrapping the diffuser - and then wrapping the mid or tailcone , would for sure have a positive effect , if and only if , the result was that the average pipe wall temp
was maintained close to that as was tested on the dyno.
You could then extrapolate that, and I agree Ken , that designing , then testing pipes already wrapped on the dyno , would increase retained heat energy as well as protecting the pipe
surface from wind effects.

Edit - wrapping most of the pipe would result in one downside , backing off into a corner the surface will remain hotter for longer, this may affect off corner acceleration
helped by lower wall temp generated by heat loss from radiation."

This was copied from page 2223 here;
www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page2223

[goodkat]

I'm wondering if the engine / fan shroud of the sym dd would fit a vertical honda engine (AF18, 24, 27, 28)...mine it's all battered up and I cannot buy a new OEM replacement since it's discontinued.

[repherence2]

Jan 15, 2020 5:25:42 GMT -5 goodkat said:

I'm wondering if the engine / fan shroud of the sym dd would fit a vertical honda engine (AF18, 24, 27, 28)...mine it's all battered up and I cannot buy a new OEM replacement since it's discontinued.

My block is a SYM dd50.
The Koso fan shroud is for a "DIO".

It will work. The dd50 engine is a Taiwan copy of the af18 type engines.

[goodkat]

Great news then! Can you post a link where did you got yours? Why did you picked KOSO over the OEM one?

[repherence2]

Jan 15, 2020 9:22:48 GMT -5 goodkat said:

Great news then! Can you post a link where did you got yours? Why did you picked KOSO over the OEM one?

I bought it from a local shop yesterday (808 Cycles). It was the only Koso left in stock. He also had replacement aftermarket shrouds. They look like stock af18 covers. He had chrome, blue chrome, and fake carbon.

I dont really order stuff online so i dont know which direction to point you in.

All the covers were priced at $50. The Koso was the least flashy as opposed to the chrome and fake carbon shrouds.

[repherence2]

Jan 15, 2020 2:46:21 GMT -5 190mech said:

WOW!Strange that pipe wrapping just came up on KiwiBiker,,the latest is to only wrap the diffuser and belly as Wobbly stated here;
"Effective cooling of the Ex duct is certainly effective , with the proviso that using the coldest water entering under the duct is NOT the way to go.
Wrapping the header is proven to promote deto due to the returned mixture in front of the piston being overheated , ruining the trapped charges effect.
But wrapping the diffuser - and then wrapping the mid or tailcone , would for sure have a positive effect , if and only if , the result was that the average pipe wall temp
was maintained close to that as was tested on the dyno.
You could then extrapolate that, and I agree Ken , that designing , then testing pipes already wrapped on the dyno , would increase retained heat energy as well as protecting the pipe
surface from wind effects.

Edit - wrapping most of the pipe would result in one downside , backing off into a corner the surface will remain hotter for longer, this may affect off corner acceleration
helped by lower wall temp generated by heat loss from radiation."

This was copied from page 2223 here;
www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page2223

From what i gathered from research and a video i seen, i did not wrap the headder. I tried to leave 1 bore volume coming off the bore unwrapped.

So basically, i started the wrap at the beginning of the slip-fit portion of the pipe itself. It has a separate flange/headder section which is not wrapped.

[islandscrub]

Love that koso cover, good tough plastic. That chrome bit has to go though, better with a scoop, just swapped mine out the other week.

[190mech]

Jan 15, 2020 10:09:09 GMT -5 repherence2 said:

Jan 15, 2020 2:46:21 GMT -5 190mech said:

WOW!Strange that pipe wrapping just came up on KiwiBiker,,the latest is to only wrap the diffuser and belly as Wobbly stated here;
"Effective cooling of the Ex duct is certainly effective , with the proviso that using the coldest water entering under the duct is NOT the way to go.
Wrapping the header is proven to promote deto due to the returned mixture in front of the piston being overheated , ruining the trapped charges effect.
But wrapping the diffuser - and then wrapping the mid or tailcone , would for sure have a positive effect , if and only if , the result was that the average pipe wall temp
was maintained close to that as was tested on the dyno.
You could then extrapolate that, and I agree Ken , that designing , then testing pipes already wrapped on the dyno , would increase retained heat energy as well as protecting the pipe
surface from wind effects.

Edit - wrapping most of the pipe would result in one downside , backing off into a corner the surface will remain hotter for longer, this may affect off corner acceleration
helped by lower wall temp generated by heat loss from radiation."

This was copied from page 2223 here;
www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page2223

From what i gathered from research and a video i seen, i did not wrap the headder. I tried to leave 1 bore volume coming off the bore unwrapped.

So basically, i started the wrap at the beginning of the slip-fit portion of the pipe itself. It has a separate flange/headder section which is not wrapped.

Glad to see you are doing your homework!!I didnt see the lead pipe extension..There is no reason to be stupid in 2stroke tech these days as the masters are more than willing to help the next generation keep these 'simple' engines going strong..My favorates are KiwiBiker ESE thread; www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner
and the French pitlane 2stroke section; www.pit-lane.biz/f34-gp125-et-250-snif

[repherence2]

Jan 15, 2020 17:17:17 GMT -5 islandscrub said:

Love that koso cover, good tough plastic. That chrome bit has to go though, better with a scoop, just swapped mine out the other week.

Islandscrub,
You must be psychic, that is exactly the plan. Remove the chrome piece and mount a scoop on it.

And yes, the Koso plastic looks pretty tough.

[jackrides]

Guys, this writing on pipe insulation really advances everyones knowledge base on exhausts. Supercool! I think the wrapping started with large 4T motors and maybe it helped there. 2T just ain't the same.