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Post by Tobyjugs on Sept 29, 2019 11:53:44 GMT 1
That is a nice dyno graph no stutter to be seen. Yes it will pull WOT from 3k Before the v4 reeds it wasn't as much of a flat spot but there seemed to be a slight lull before the power rush Here's the earlier dyno graph Steve Are both dyno graphs with the large reed spacers you have? i noticed that reed spacers help to boost the midrange a little and took 3-4 Pk off the top in my case. (no power valves in engine)
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Post by midlifecrisisrd on Sept 29, 2019 15:56:00 GMT 1
[/quote]Are both dyno graphs with the large reed spacers you have? i noticed that reed spacers help to boost the midrange a little and took 3-4 Pk off the top in my case. (no power valves in engine)[/quote]
The first run was 10mm spacers and tzr250 6 petal reeds
The second was 10mm spacers and v4's
As the v4's are thicker it gives another 5 or 6mm on the inlet tract
Made a big difference
Steve
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Post by midlifecrisisrd on Sept 29, 2019 16:00:36 GMT 1
You can see the difference on the torque curve between 5 and 6k
They both start the same but the early graph shows flat to 6k where the later is climbing
Steve
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Post by ferox100 on Sept 29, 2019 17:47:02 GMT 1
Am leaning towards a 385 now, especially with the powervalves still in use and 75-80 bhp! That sounds like the best road bike set up with good spread of power. Steve, can a standard head be used on these? And I take it oring head set up would be best to save opening up head gaskets ID's? It's a recut standard head on mine with single inner o rings, long rod crank and wiseco 795 pistons on +1mm I did see Wiseco made a batch of ultra stroker pistons with a 6mm pin offset that allowed a standard head and gasket to be used but not sure how that affects the port map I'm hoping if it's dry at the weekend I can get it out the workshop and fired up. May even run it to the mot place if all ok but think the rear brake may have seized up 🙁 If you were closer you could have had a go lol Steve So I take it that the pistons actually protrude a little above the cylinders, hence the machined head,Did you need to go to 65mm bore for piston availability?
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Post by midlifecrisisrd on Sept 29, 2019 18:52:30 GMT 1
It's a recut standard head on mine with single inner o rings, long rod crank and wiseco 795 pistons on +1mm I did see Wiseco made a batch of ultra stroker pistons with a 6mm pin offset that allowed a standard head and gasket to be used but not sure how that affects the port map I'm hoping if it's dry at the weekend I can get it out the workshop and fired up. May even run it to the mot place if all ok but think the rear brake may have seized up 🙁 If you were closer you could have had a go lol Steve So I take it that the pistons actually protrude a little above the cylinders, hence the machined head,Did you need to go to 65mm bore for piston availability? Yes they protrude a little. Hence running with no head gasket and effectively lowers the exhaust port As the piston strokes 2mm lower the exhaust port and transfer floors are lowered to the piston crown at bdc so increases the port area Think the piston crown angle may be different too Mine is on 65mm by accident, it was supposed to be on 64.5mm but the head had been cut for 65mm piston with some clearance so decided to bore it to that The 795's are available from 64mm to 66.5 but only in 0.5mm increments. Steve
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Post by midlifecrisisrd on Sept 29, 2019 18:54:17 GMT 1
Here's the head Steve
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