ESE's works engine tuner

[Frits Overmars]

Yes but its firing earlier in the stroke btdc so you would subtract the advance not add it wouldn't you.

No, TZ350 is right. You may want to look at it this way: let's say ignition occurs at 20° before TDC. The spark before that came 120° earlier; that's 140° bTDC.

it already has 3 cdi circuits so thats not an issue. However if you decide to use one pick up it then fires all three at the same time. Im pulling 8000 so i guess thats the same as 24000 rpm for the coil so quite a bit

How difficult can it be to add two pickups? The coils will thank you for it by not becoming fried.

welding up the angled existing threads and putting in a new straight setup would make all the problems go away.

The toroid chamber layout aggravates the disadvantage of the angled plug, so straightening it will be more important than before; otherwise all your other efforts may be more or less canceled out. I would not work on an engine with the plug shrouded like that.

[TZ350]

The toroid chamber aggravates the disadvantage of the angled plug. I would not work on an engine with the plug shielded like that.

Would I have been better off leaving it with the original hemispherical chamber shape?

Starting with another NSR head I could make one with a bath tub shape if that would be better then my attempt at a toroid. I can un shroud the plug a bit more.

[Frits Overmars]

Would I have been better off leaving it with the original hemispherical chamber shape?
Starting with another NSR head I could make one with a bath tub shape if that would be better then my attempt at a toroid. I can un shroud the plug a bit more.

I'm not criticising the toroid; I'm criticising the angled plug. 'Unshrouding the plug a bit more' is not the way to build a winner. Don't compromise. Sorry if I'm being blunt.

[speedpro]

Im setting up an engine, it is a triple engine with three lumps on the flywheel and one pickup.

Why not one lump? Configure the one lump as TDC on whatever cylinder and tell the ECU you need 2 other sparks, on 2 other ignition channels, 120deg apart. Sorry, not familiar with Zeeltroinic so not sure that can be programmed or if the channels are available. Certainly the Link ECU I'm currently playing with can do it.

Or a multi tooth trigger wheel with a missing tooth to identify where in the crank revolution it is. Again, identify TDC for a cylinder in relation to the missing tooth and the others 120deg apart. Still assuming seperate ignition channels.

[speedpro]

I have straightened up a RGV 250 plug in a head I was using, reshaped the chamber, exactly the same compression, and got instant horsepower everywhere.

As Frits said - 3 pickups would be the simplest answer, mounted on a nice billet backing plate for symmetry.

[JanBros]

One way arround the angled plug is to cut the top off and weld in an incert

don't weld it in, just transform it so you can use replacable inserts. Have done it with a KR1S head

[Matt@TYGA]

Or one of these:
https://www.vhm.nl/en/catalog/engine.../g+c+a+nr+view

If you contact Matt at Tyga, he can possibly get you one, so you don't have to buy the pair. Still expensive, but solves that problem.

I can certainly get the individual parts that you need from VHM, but they're not particularly cheap as you'll know. But then you can experiment with head shapes by turning up new inserts. So the head cover is a one time deal.

I'd say that you're on the right track with welding in an insert, as long as you don't disrupt the coolant flow through the head.

I have a few MC21 heads kicking around with deto damage that could be used for your project.

The NSR's through the years were restricted in different ways. The MC16 has small carbs and small ports. Makes around 40hp peak at the wheel in a not particularly exciting way, but does have reasonable midrange. The MC18 '88 was restricted by limiting the opening of the exhaust valves. Simply pull a plug apart and get decent mojo. The MC18 '89 needs a splice of the wiring to change ignition timing and exhaust valve operation, as does the '90~'93 MC21. The MC28 needs a pocket full of cash to derestrict by way of an HRC ignition card.

Going back to the MC18. The cylinders are pretty good and will make reasonable power right off the bat. The heads (as stock) have angled plugs to compensate for various clearance issues, but if you do a lot of searching then the HRC F3 kit used central located plugs. This may well be what you're looking for. I don't have any MC18 barrels handy as just used the only undamaged one I had to rebuild an engine recently. May have a head but unlikely to be the kit type.

All cylinders from MC16 through to MC28 share the same stud pattern on the bottom side.

You could try Gecko Motorcycles in the UK. Dan has a lot of NSR F3 stuff and may have what you need. He's a good chap and I'm sure that you could work a decent deal with him.

Hope that helps.

Matt.

[jasonu]

Would I have been better off leaving it with the original hemispherical chamber shape?

Starting with another NSR head I could make one with a bath tub shape if that would be better then my attempt at a toroid. I can un shroud the plug a bit more.

Why not completely weld the buggar up then re drill and thread the SP hole and re cut the dome?

[jbiplane]

Hi guys. I want produce some pistons by 5-axe CNC milling.
I know piston should be conical from the side and oval from the bottom. Somebody could help me to find production drawings, formulae or whatelse?

[Haufen]

Hi guys. I want produce some pistons by 5-axe CNC milling.
I know piston should be conical from the side and oval from the bottom. Somebody could help me to find production drawings, formulae or whatelse?

I think a general guideline can only get you so far. Personally, I'd try to get a piston which works well in a similar application, have the material analyzed and the shape measured to the detail you need. Use high Si content to make the pistons resistant to cold seizure (as they don't expand that much).

[husaberg]

I can certainly get the individual parts that you need from VHM, but they're not particularly cheap as you'll know. But then you can experiment with head shapes by turning up new inserts. So the head cover is a one time deal.

I'd say that you're on the right track with welding in an insert, as long as you don't disrupt the coolant flow through the head.

I have a few MC21 heads kicking around with deto damage that could be used for your project.

The NSR's through the years were restricted in different ways. The MC16 has small carbs and small ports. Makes around 40hp peak at the wheel in a not particularly exciting way, but does have reasonable midrange. The MC18 '88 was restricted by limiting the opening of the exhaust valves. Simply pull a plug apart and get decent mojo. The MC18 '89 needs a splice of the wiring to change ignition timing and exhaust valve operation, as does the '90~'93 MC21. The MC28 needs a pocket full of cash to derestrict by way of an HRC ignition card.

Going back to the MC18. The cylinders are pretty good and will make reasonable power right off the bat. The heads (as stock) have angled plugs to compensate for various clearance issues, but if you do a lot of searching then the HRC F3 kit used central located plugs. This may well be what you're looking for. I don't have any MC18 barrels handy as just used the only undamaged one I had to rebuild an engine recently. May have a head but unlikely to be the kit type.

All cylinders from MC16 through to MC28 share the same stud pattern on the bottom side.

You could try Gecko Motorcycles in the UK. Dan has a lot of NSR F3 stuff and may have what you need. He's a good chap and I'm sure that you could work a decent deal with him.

Hope that helps.

Matt.

How do the JC20 and JC22 Ports stack up against the various NSR250s Matt.

My old port maps for the various 125 NSRs are on an old external hard drive that is not working.

As they are straight plug but as i mentioned they fit the bottom stud paterens but not the top.

One way arround the angled plug is to cut the top off and weld in an incert





http://forums.everything2stroke.com/...he-Shop/page46


Another is to use a NSR125 Cylinder head which is a straight plug
However to use that you have to use a NSR125 Cylinder as well for some reason the head bolt pattern is different from the 250.
(Bren learnt this after i said no i think it will fit)

Some models of the NSR are restricted and i don't really know how well the others stack up against the MC 16/18/21
the bottom stud partern is the same but the water cooling deck is slightly different.
I do have some port maps somewhere.

don't weld it in, just transform it so you can use replacable inserts. Have done it with a KR1S head

.

[/QUOTE]
As was shown above by Janbros you could also make the inserts removable and make sure the water flow is even arround the plug.

[Matt@TYGA]

How do the JC20 and JC22 Ports stack up against the various NSR250s Matt.

My old port maps for the various 125 NSRs are on an old external hard drive that is not working.

As they are straight plug but as i mentioned they fit the bottom stud paterens but not the top.

I don't have the port maps for the JC20 or 22, but I gather that the case stud pattern is the same as NSR250 and also NSR150. I've been asking a couple of blokes in France if they have the port maps, but so far not forthcoming. They're using our 150 pipe on their 125's, but would rather be able to compare the porting and possibly think of something a little different.

[husaberg]

I don't have the port maps for the JC20 or 22, but I gather that the case stud pattern is the same as NSR250 and also NSR150. I've been asking a couple of blokes in France if they have the port maps, but so far not forthcoming. They're using our 150 pipe on their 125's, but would rather be able to compare the porting and possibly think of something a little different.

I had the French ones they were very restricted i remember that bit.
Grumph i think was given a flash drive that i think had them on it?
From what i seen it was like a lot of the different euro makets had different specs.
I think a lot of the euro ones were made in Italy engine parts and all.
the JC22 had longer studs on the top as the JC22 had a thicker head casting.
th bottom stud parrn is the same as i have a 250 cylinder sitting on one here but the water feed is slightly different but nothing major.
I had a good google and i cant find anything at the moment other than the stuff in the TRX project.
I had the French ones they were very restricted i remember that bit.
Grumph i think was given a flash drive that i think had them on it?
From what i seen it was like a lot of the different euro makets had different specs.
I think a lot of the euro ones were made in Italy engine parts and all.
the JC22 had longer studs on the top as the JC22 had a thicker head casting.
th bottom stud parrn is the same as i have a 250 cylinder sitting on one here but the water feed is slightly different but nothing major.
I had a good google and i cant find anything at the moment other than the stuff in the TRX project.

Malossi do a 65mm bore kit and cylinder for them not sure if they have a operational PV
http://www.2strokeparts.de/shop/prod...-nsr-125&SESS=
which would make a 360 NSR twin

[wax]

No, TZ350 is right. You may want to look at it this way: let's say ignition occurs at 20° before TDC. The spark before that came 120° earlier; that's 140° bTDC.

How difficult can it be to add two pickups? The coils will thank you for it by not becoming fried.

The toroid chamber layout aggravates the disadvantage of the angled plug, so straightening it will be more important than before; otherwise all your other efforts may be more or less canceled out. I would not work on an engine with the plug shrouded like that.

The confusion is i am talking atdc and you and tz are talking before lol, I think we are both saying the same thing.
why am i doing it this way ? i already have the ignition, im just saving money if possible

[wax]

Why not one lump? Configure the one lump as TDC on whatever cylinder and tell the ECU you need 2 other sparks, on 2 other ignition channels, 120deg apart. Sorry, not familiar with Zeeltroinic so not sure that can be programmed or if the channels are available. Certainly the Link ECU I'm currently playing with can do it.

Or a multi tooth trigger wheel with a missing tooth to identify where in the crank revolution it is. Again, identify TDC for a cylinder in relation to the missing tooth and the others 120deg apart. Still assuming seperate ignition channels.

The flywheel has three lumps and one pick up. The ignition i have is a 3 channel ignition. I can buy another but i am just trying to make what i have work