ESE's works engine tuner

[Bert]

So the bike has done plenty of hours now in various states of tune. After looking at the numbers again comp is sitting at 15.9:1.


Its time to update the cylinder head shape to the steeper bath tub profile. I can't see any sign of det anywhere. There is a ring in the squish band but that looks like its touching on some of the carbon build up on the piston. If anyone can see any major problems in the pics sing out.

Cheers Rich



Attachment 300567Attachment 300568

Really interesting stuff Rich. Looking forward to others feedback on this.

What's the other cylinder look like??

[Frits Overmars]

...perhaps theres a better simpler way to measure the port angles but the paper clip was always simple and easy for me. you may have good luck with wire or even solder.

When I do not have my own equipment at hand I use solder. Works fine.

[fatbastd]

Gate type power-valve on a Yamaha

I may have the wrong type of power-valve in mind, though I did see (about 5 years ago) an ex-works 500 Yamaha (across the frame 4, from about 1978 or 1979) in the UK with what I'd call a gate type valve - it wasn't a spool. Everyone at foist thought it was a TZ500 engine, though it was a0 too old (TZ500G came out in 1980) and had different cylinder stud spacing (I had several 500's to compare in the same shed). The engine came out of a hill-climb car...and had obviously fallen off the back of a Yamaha truck..

Barely relevant to the discussion, I know..

[senso]

When I do not have my own equipment at hand I use solder. Works fine.

If it isn't asking too much or crossing the line, could you show what kind of tools do you use to measure the ports angles?
Best regards.

[Drew]

If it isn't asking too much or crossing the line, could you show what kind of tools do you use to measure the ports angles?
Best regards.

Just make a beval, bevle, bevil. Nope, none of those spellings look right.

[merv]

Try bevel Drew.

[Frits Overmars]

If it isn't asking too much or crossing the line, could you show what kind of tools do you use to measure the ports angles?

It's not crossing the line at all but at the moment it's asking for the impossible because I haven't got them with me and I have no pictures or drawings, apart from my bent feeler gauge with which I measure port heights.
I use a 1 mm gauge, bent at 45°, that I pinch between the piston edge and the port edge in such a way that the bent end is vertical (parallel to the cylinder bore). Then I measure from cylinder top deck to piston edge and subtract 1,41 mm from the measured value. It works for every port as long as its axial angle is not steeper than 45°, even when both the piston edge and the port edge are chamfered or radiused.

[lodgernz]

the cylinders i ported the nikisil was removed before hand and replated afterwards. but you shouldnt have much trouble with the right bits. i think diamond impregnated ones should work although i havent actually tried them yet. maybe theres something even better ?

if you have a welder perhaps you can cut a chunk out of the side of the barell and weld the outer side portion of the exh in the water jacket area then weld the cylinder chunk back in. this should allow aux ports to be used. it has been done on other cylinders, maybe it can work for you

You can lift the Ex port on a Nicasil cylinder using a diamond impregnated burr to cut thru the plating and then use RexCut cotton impregnated
rotary "mops " to put a smooth chamfer and radius back on the bore.
But the issue is that the ring , no matter what the port width is, will always bulge out into the port, and the top corner radius is what smoothly pushes it
back into the groove.
The cylinder will last a while like that, but It doesn't take long for the ring to wear thru to alloy around the port top edge, as there is no Nicasil going around the corner
into the duct to support the ring.
Best long term fix is to have the chrome removed, cut the port and re Nicasil it.
But for dyno testing the porting result, doing it the easy way is fine.

Thanks Peewee and Wobbly, good advice.

[Muciek]

Few pages ago I have asked about adding aux transfer ports in cylinder liner. I have made them and there was nice gain since without them motorbike was making 0-100km/h in 11,8s and now it's around 10,3s. Mid range and top end is better and engine can easier get out of that torque dip just before powerband. Piston looks like this (picture at bottom of the post). Is it good or something is wrong? Could someone tell me what this "batman" (I really don't have better word for this ) at middle of piston crown means? I run 50% SAR , 0,8mm squish and 32msv (RZ 350 piston) it's a play bike (off road and stuff, not RR). There are traces on squish band because main bearings failed and piston started hitting the head at 9000 rpm....

[TZ350]

Rode in F5 last Sunday at Mt Wellington, and did a good job of keeping the rider coming second to last honest....

Great weather, great day and great racing.

The F5 (50cc) class lap record was broken again and the winning and second place times would have put those riders at 4th & 5th place in race 1 of F4 A grade and 6th & 7th in race 2.

To my surprise and delight, some anonymous person had pre paid my entry for me which is very nice. Thanks ... but because I don't know who they are I now have to be nice to everyone, just in case ..... .

Kel clocks a sub 30, F4 race one finishing order was 2T 2T 2T 4T and race two 2T 2T 4T 2T with 1st and 2nd running sub 30's and 3rd and 4th place recording laps either side of 30.


1415ABUC.xls

The results of the 3^rd round of the 14/15 season of AMCC bucket racing from yesterday are attached, for publication.
Tim will be updating the website & Mylaps.
There is a debate going over the sidecar points from the previous round which may result in a change. If so I will send an update.
F5 again delivered the closest racing & another new lap record.
Regards, David Diprose

Tim Frasers MyLaps results:- http://www.mylaps.com/en/events?sport=Bike&country=NZ

[TZ350]

Got my new RGV250 air cooled copper head back from being machined by Auto Flight today, looks good.

The copper was glued to the alloy block with the same high temp/thermal epoxy I used in the exhaust dam experiment.

The copper forms the squish area and is expected to draw the heat away from that part of the combustion chamber.

The combustion chamber was machined in true Wobbly Toroidal style with a sharp (no radius) transition from the squish band, it has also been machined so it takes a 3/4" reach plug.

At first glance the chamber looked to deep but a quick check with 10cc of kero soon left me re assured all was in order.

[wobbly]

So now you have stolen my head design where is the Blue Stilton.

[TZ350]

So now you have stolen my head design where is the Blue Stilton.

It was yummy .. .. will share next time ... promise.

Hope this air cooled RGV thing works, seriously trying for 30hp at 10k rpm.....

[chrisc]

Hope this air cooled RGV thing works, seriously trying for 30hp at 10k rpm.

[mr bucketracer]

It was yummy .. .. will share next time ... promise.

Hope this air cooled RGV thing works, seriously trying for 30hp at 10k rpm.....

free blowys