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Post by wangwang on May 2, 2019 21:07:22 GMT 1
First of all, I know nothing about tuning/porting etc. so need some advice. I have a pair of barrels in nice shape, but are tuned/ported, what I need to know if possible, what scale of tuning has been done, and how good a job it is. cheers wang  20190502_182340 |
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Post by midlifecrisisrd on May 2, 2019 21:17:44 GMT 1
Looks quite mild to me The tell tale is the exhaust port height. How many mm from top of port to top of barrel Here's mine Steve  |
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Post by tacky1 on May 4, 2019 8:17:09 GMT 1
They look pretty mild. Not much gone off the top of the ports. I usually bring mine right up to the bottom of the boost port. What does the bottom of the cylinders look like. What’s the distance of the top of the exhaust port to the top of the cylinder.
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Post by tsa on May 4, 2019 9:50:00 GMT 1
Not a lot in the inlet the windows dont appear to have been touched just the entries to them and not ported to modern standards either. So old school porting.
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Post by wangwang on May 4, 2019 13:39:26 GMT 1
Apart from what you can see in the pic, everything else looks pretty standard.
Would this benefit from making the adjustments smooth? looks quite rough to me.
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Post by midlifecrisisrd on May 4, 2019 14:02:46 GMT 1
Still better than standard
Get them on 😄
Steve
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Post by marrcel on May 4, 2019 19:42:24 GMT 1
Not a lot in the inlet the windows dont appear to have been touched just the entries to them and not ported to modern standards either. So old school porting. That makes me wondering what is my next step to get more power at 10krpm with the porting of the barrels. Vforce4, ignitech cdi and spannies already.  |
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Post by 4l04ever on May 4, 2019 21:05:06 GMT 1
Not a lot in the inlet the windows dont appear to have been touched just the entries to them and not ported to modern standards either. So old school porting. That makes me wondering what is my next step to get more power at 10krpm with the porting of the barrels. Vforce4, ignitech cdi and spannies already. What make are those exhausts? |
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Post by marrcel on May 4, 2019 23:02:13 GMT 1
gR espangol ole😜
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Post by tsa on May 5, 2019 14:32:57 GMT 1
Not a lot in the inlet the windows dont appear to have been touched just the entries to them and not ported to modern standards either. So old school porting. That makes me wondering what is my next step to get more power at 10krpm with the porting of the barrels. Vforce4, ignitech cdi and spannies already. The things for more power @10,000rpm would be as follows 28-30mm pwk carbs Head volume and squish set to give 7:1 comp and 1mm squish for safety I cannot say about the pipes you have as I have never measured a set of those. As for porting widen the exhaust port Chordal width to between 69-71% of bore diameter, but only widen the top width and flow the top into the bottom radius. Widen the inlets and raise the port roof as the port areas are far to small to flow what the VF and a larger carb can flow. The transfer ports really need the most work to get the correct area and direction. Always remember that porting will need more frequent piston and ring changes usually 2 sets of rings then change the piston too on the 3rd set. Approx 5000 miles between pistons. Yes I know people will say I have done xxxxx thousand miles on a xyz porting but changing them regularly will keep the engine at it's best. I do not and will not accept any responsibility if you have any issues with the above advise. Take it up with your tuner as I know this all works and works well. |
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Post by bare on May 7, 2019 17:01:41 GMT 1
Firstly.. the porting work on those inlets (first pix) is crappy ..some twit has widened the ports And even Narrowed the centre bridge ..Not terribly but not great either.. Pointlessly !
Inlet is..the Thrust (heavily loaded) side of the cyl. Inlet Widths should be limited to stockish And that bridge needs to be there.. width intact.
Secondly.. at 10K rpms the Engine is Close to it's limits and Wear/loadings increase geometrically with rpms.
Even 500 rpm lower will notably increase engine life.
In My world 5k betwixt pistons is short .. for a non race engine.. used with passable reason.
Setup and Parts quality is Key though
Yama rings and pistons (and all else) are a whole world better quality than Any aftermarket items. All brochure babbles aside.
That said, a rebore for the 3rd set of rings... is expected.
Good luck.
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