DIY portmapping HOW?

[tz375]

Correct. And because of geometry, it's a reduction in degrees of blowdown. Not by a lot, but it's measurable. And that tends to cause us to raise the exhaust more and that in turn tends to push the rev peak higher, but in reality the pipe and port dimensions work together and if they are out of step, it costs power and flexibility.

[dyrberg123]

I am learning every day here Guys. As said i am currently installing packhouse equipment here in Chile, cant wait for the day to be over, getting to my hotel room and on the sundial site . THANKS

[Vintageman]

I have a set of GT750 barrels that were professionally ported that are 1-2mm too wide and are basically useless unless I find pistons with wider intake skirts.

Did you ever consider usual the older style T500 piston with the window cut out not full slot (if it fits?). I think the skirt is wider at inlet ( I have one somewhere but damned if I can find now). Also OS would help little too

Here look at this picture. There are two side by side and you'll see what I mean

http://www.ebay.com/itm/Pistons-and-Rin ... 46&vxp=mtr" onclick="window.open(this.href);return false;

[tz375]

Thanks for that link. I do have a set of oversize old style WISECOs that will work fine in a lower revving motor, and after all that work the porter managed to change an L block into not much different to an MAB which was not the idea. The plan was to get later type exhaust time with earlier intake timing.

Now I have to use a thin spacer/thick base gasket to get the inlet timing back without pushing the exhaust too high. If all else fails I can add a little Devcon F to the port floors and re-shape them to get what I want. There's usually a way to get to where you want to get to.

[Vintageman]

little Devcon F to the port floors and re-shape them to get what I want.

I have noted that people use JB Weld too

dyrberg123,

ARE YOU OK? I heard Chile had an EarthQuake


Yamaha Rd350/r5/ds7/350/Banshee all have the same rod length 110mm (http://www.vitosperformance.com" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;)
So assuming near same deck height and offset between Suz and Yam, just compare Ex height wtih Yam

This is true for T350/T305/T250/GT250/GT380.

As far as intake we need info of R5 piston dimensions which so far I can not find mine and may have thrown out.

My R5 lugs real well low 3000 rpm and very very interested in timing intake since piston ported too

My T350 Ex. was almost 31mm with 0.002" shim slid slide between piston and port (and see light across all port top). It maybe got that when I smoothed up exhaust port and/or just mfg tolerance.

I know 29.5mm Ex on GT250A sure is exciting, but a little too radical for street (IMO). Again only 250 so 100cc sure must help when trying to run easy and hold a grade without need to shift.... maybe not

[dyrberg123]

Hi Vintageman,

Yes i am really great, thanks for asking. We felt it a Little here where i am staying, but not alot though. But the quake alarm went on all night, i just hate that sound as you know some people are at danger.... Must be same feeling as those living in the tornado zone i imagine.

Can't wait to be home so i participate in the discussion Again... I forgot to bring my engine

[dyrberg123]

Hi Guys, hereby some updates from the garage.

It's been a while since i last posted, been really busy in the shed.

Most of the ordered porting tools have arrived and i am learning by doing (MAYBE )

First the exhaust, half way done. IT IS EQUAL TO BOTH SIDES-BAD CAMERA ANGLE Needs to polished up a bid and then some chamfering:



Still needing the angle die grinder to reach the transfers, but it will arrive later this week, not for the roof of the transfers but for the bottom after fitting base plates.

Spacers are also made, and the top of the barrels are matched to be flush... On to the lathe..





To add a Little extra Work i have read about modding the DG's with a real stinger and a real silencer / can..

So i decided to cut my new DG





Sort of funny Construction. when baffel removed the end of the last cone can bee seen through the outer pipe, that connection to the perforated tube can't be optimal.



Here all stripped, they are extremely lightweight, now i only need to make new cones to accommodate the stinger OD on 22,4mm



More to come..

[dyrberg123]

Almost forgot Pictures of the intake Also some finishing off and chamfering still needs to be done..