ESE's works engine tuner

[jamathi]

Yeah, it's about time you'd start producing something useful - like better pipes for TM kart engines .
Seriously though, a heat shield between those beautiful wobblypipes and those crankcase pre-heating cooling fins wouldn't be a bad thing.

I tried this on the Minarelli, in 1981, it worked: 300 rpm more on the Mugello straight....
But it was a lot of trouble fitting it.
Later we achieved the same result by wrapping the pipes with asbestos tape..

[wobbly]

In my defense , that engine ran on Methanol , so crankcase cooling wasnt a limiting issue at all.

[Matt@TYGA]

Thanks for the info on the rod lengths guys.

I'm hoping for more time this year to do some engine projects instead of just staring at my computer screen 24/7.......

I'm wanting to pull my Honda NSR150SP apart for a bit of a make over, using several of the ideas from this most informative site.

Wobbly, I read before that you'd used 3D printed reed stuffers. How about a 3D printed reed valve? I understand sealing and integrity would be an issue in the long term, but it might be enough to last a dyno run or three. my cheapo 3D printed does PLA and ABS without issue, and PETG at a stretch. Worth a shot maybe? I think with the incoming mixture helping with cooling that it won't just end up in a nasty blob in the bottom of the case, and should it fail catastrophically then hopefully no engine damage will occur. I'm just thinking about Wobbly's work with thick and thin reed petals to direct flow. Maybe worth a shot at actually having an angled valve to direct flow instead of relying on the petals.

Got the extendo, water cooled exhaust port stub to try also. Looking forward to seeing what that does. Only got the 3D printed version at the mo which was just to test fit. Will knock something up in aluminium for a dyno test. Been using the oval to round transition since 1994 for my NSR250s, so I know that works.

NSR150SP rod length is 110mm. Perhaps this length would have been a better choice for the 250, based on other info here ;-)

Anyway, here's hoping that I can get these other projects done and dusted so that I can have some fun!

[husaberg]

thanks for the info on the rod lengths guys.

I'm hoping for more time this year to do some engine projects instead of just staring at my computer screen 24/7.......

I'm wanting to pull my honda nsr150sp apart for a bit of a make over, using several of the ideas from this most informative site.

Wobbly, i read before that you'd used 3d printed reed stuffers. How about a 3d printed reed valve? I understand sealing and integrity would be an issue in the long term, but it might be enough to last a dyno run or three. My cheapo 3d printed does pla and abs without issue, and petg at a stretch. Worth a shot maybe? I think with the incoming mixture helping with cooling that it won't just end up in a nasty blob in the bottom of the case, and should it fail catastrophically then hopefully no engine damage will occur. I'm just thinking about wobbly's work with thick and thin reed petals to direct flow. Maybe worth a shot at actually having an angled valve to direct flow instead of relying on the petals.

Got the extendo, water cooled exhaust port stub to try also. Looking forward to seeing what that does. Only got the 3d printed version at the mo which was just to test fit. Will knock something up in aluminium for a dyno test. Been using the oval to round transition since 1994 for my nsr250s, so i know that works.

Nsr150sp rod length is 110mm. Perhaps this length would have been a better choice for the 250, based on other info here ;-)

anyway, here's hoping that i can get these other projects done and dusted so that i can have some fun!

vf3 cr125......
Not as much fun but well tested.
Out of interst what are the differences with the SP to the Std.
Shame those Those NSR 125 and 150 need such long inlets to clear that rear top engine mount.

[Matt@TYGA]

vf3 cr125......
Not as much fun but well tested.
Out of interst what are the differences with the SP to the Std.
Shame those Those NSR 125 and 150 need such long inlets to clear that rear top engine mount.

Hi Husa,

Yes, well tested indeed, but we do because we can. And I could whittle a reed valve from granite with a tooth pick for less than VF charge

I haven't had anything much to do with the std NSR150, but I do know that the cylinder is totally different. Still a bridged exhaust port, but tiny in comparison to the SP. no data on the timings as all I did was look at one in the Honda shop. The head is also different and I think that the piston is different too.

The old model NSR150R was a single port with a single flap exhaust valve. We cut auxiliary ports when I raced one back in 1995. Also welded up the valve and trimmed it to a nice snug fit. What was noted then has been well documented here in that the wider one went with the auxiliaries, the more power it made. Right up until we broke into the water jacket. the way to go would have been to cut in from the outside, weld up and fit a patch, but we weren't allowed to alter the outside look of the cylinder. Crying shame.

We ended up at about 40hp at the rear wheel, on avgas. Honda gave us the bike at 21hp.......

The piston and crank had to be stock. As did the reed valve, but you were allowed to modify the reed valve. Had a PJ34mm carb.

I didn't really fit that well on it and much preferred the 250.

Yes on the intake. Fitting an MC21 carb boosts things at the top end, but need to make a spacer block to get clearance, which is a pain.

Matt.

[ken seeber]

While we're on about crankcase cooling, I reckon that the Vortex KZee thru flow ventilation system is pretty good. One might even say cool. Certainly couldn't do any harm.

[TrackTen]

My experience with isolating the cylinder from the crankcase was that the crankcase/gearbox and oil by them self run very hot. Maybe as much as 80-90 or even 100 deg C in a long race when the water cooled cylinder was only ever at 40-45 deg C.

Next time you run your bike, afterwards feel the flywheel, it will be quite hot. That heat is mostly transmitted out to the flywheel and comes from the crankcase. I think that anything to cool the crankcase would be worth the effort.

Attachment 340085Attachment 340086Attachment 340087

Speedpro took the copper head fin idea a step further and made a clutch cover copper gasket/fin that picked up heat from the hot gearbox oil and transmitted it to a large cooling fin on the outside.

That is very interesting , is the base gasket made of 3 parts / sheets ? No problem with leaking ?

[Frits Overmars]

While we're on about crankcase cooling, I reckon that the Vortex KZee thru flow ventilation system is pretty good. One might even say cool. Certainly couldn't do any harm.

Never say never, Ken. Having air flowing between crankcase and gearbox is a good thing for sure. But then this air exits right under the exhaust header. Not under the first part of the duct, that should be cooled, but under the remainder of the header, where gas energy should not be used for global warming, but for efficient wave action. A heat shield wrapped around the header would be the obvious solution in my opinion, but I could not discover any trace of it on the Vortex documentation.

[yatasaki]

As air cooling question is more or less elaborated, next question about added transfer ports. On the drawing is common moped/old timer arrangement. Easiest is to drill/grind finger B ports. But, because of intake port there is very little or no space for adding finger-C port ,then additional "bypass" C ports are fed from B ports.
So cross section of B duct untill starting of "bypass" should be equal B+C ports after junction to spread the flow more or less equally.
Is it better to have only B ports with uninterrupted flow or to use as much area as possible with C port?

The other issue is that all added B and C ports are aiming upward cyl head which is good for overrew as I could see on my test track and mychron. Lowering upward angle of B ports to 10°( which is sometimes achievable)like on "modern" cylinders added some power but lost a bit of overrew.
Any comments?

[pete376403]

Never say never, Ken. Having air flowing between crankcase and gearbox is a good thing for sure. But then this air exits right under the exhaust header. Not under the first part of the duct, that should be cooled, but under the remainder of the header, where gas energy should not be used for global warming, but for efficient wave action. A heat shield wrapped around the header would be the obvious solution in my opinion, but I could not discover any trace of it on the Vortex documentation.

Isnt this the best argument for reversed cylinders, with the heat up and out the back where is doesn't mess with the rest of the engine, and intakes on the cold side?

[andreas]

As air cooling question is more or less elaborated, next question about added transfer ports. On the drawing is common moped/old timer arrangement. Easiest is to drill/grind finger B ports. But, because of intake port there is very little or no space for adding finger-C port ,then additional "bypass" C ports are fed from B ports.
So cross section of B duct untill starting of "bypass" should be equal B+C ports after junction to spread the flow more or less equally.
Is it better to have only B ports with uninterrupted flow or to use as much area as possible with C port?

The other issue is that all added B and C ports are aiming upward cyl head which is good for overrew as I could see on my test track and mychron. Lowering upward angle of B ports to 10°( which is sometimes achievable)like on "modern" cylinders added some power but lost a bit of overrew.
Any comments?

If your drawing is somewhat to scale. I would have a piston-window fed single c port.

[TZ350]

That is very interesting , is the base gasket made of 3 parts / sheets ? No problem with leaking ?

The question is, do you want to shield the cylinder from the heat generated in the crankcase or isolate the cylinder heat and keep it away from the crankcase. Which side needs the extra cooling the most?



No problems with sealing when you use copper head gasket sealing paint/glue.



Copper under the exhaust tract to improve cooling in that area.



Crankcase air cooling, you can go as crazy as you like.........

[husaberg]

Isnt this the best argument for reversed cylinders, with the heat up and out the back where is doesn't mess with the rest of the engine, and intakes on the cold side?

Engine further forward better handling
Straighter pipe

[husaberg]

The question is, do you want to shield the cylinder from the heat generated in the crankcase or isolate the cylinder heat and keep it away from the crankcase. Which side needs the extra cooling the most?



No problems with sealing when you use copper head gasket sealing paint/glue.



Copper under the exhaust tract to improve cooling in that area.




Crankcase air cooling, you can go as crazy as you like.........

Maybe check the rules rob does it say liquid cooled or water cooled.
if it says Water oil is on the table
nope has to be air cooled
https://www.mnz.co.nz/docs/default-s...ses-(road).pdf

[TZ350]

Maybe check the rules rob does it say liquid cooled or water cooled. if it says Water oil is on the table, nope has to be air cooled
https://www.mnz.co.nz/docs/default-s...ses-(road).pdf

......... whats the answer if the aim is to air cool the base of the cylinder and the transfers and any extra air cooling of the crankcase and its oil is just collateral damage.