ESE's works engine tuner

[Grumph]

Pretty sure wob was talking about a 4t as well
What modern 2t have pressure fed big ends?

Where did he say it was modern ? LOL. Could have been something continental...

[husaberg]

Where did he say it was modern ? LOL. Could have been something continental...

Could have but i think he was sneaking 4t stuff in the thread.
notifce the pin on the later Honda F1.
Windage?

i am guess the DLC and Crn2 are the coatings
so diamond like coating and hard Chromium nitrate
https://pubs.acs.org/doi/abs/10.1021...nalCode=aamick
https://en.wikipedia.org/wiki/Chromium_nitride

[TZ350]

What modern 2t have pressure fed big ends?

Well maybe not "pressure" feed but my 2T is direct feed through the drive side crank shaft half ......

[husaberg]

Well maybe not "pressure" feed but my 2T is direct feed through the drive side crank shaft half ......

Anyone know what the aprilia D1 bottom end looks like?
looks pretty normal

[Michael Moore]

Crap will eventually build up in the hollow crank pin, so therefore perhaps the leading side.

The 750 Laverda twin had oil slinger shrouds as on some 2T engines, and mine had sediment built up to the outside of the pin oiling gallery almost to the point of starting to block oil flow. Replacement shrouds that were held to the face of the flywheel with screws were made so cleaning would be easier (no need to scrub around with a bit of wire to try and loosen the sediment so it could be flushed out).

Small Hondas have a better arrangement with their oil filter cans that take the centrifuged oil out at the rotation axis, so there is a lot of space available to store sludge before having problems.

[wobbly]

Im oh so sorry guys - yes the question was 4T related.
Real old XR200 being bored and destroked to pull 14,000 reliably.
The KTM up to 07 had the good roller setup, after that they went plain bearing as do the 4T Honda's but changing
the oil pump for plain bearings on an old XR is just too hard.

[TZ350]

Anyone know what the aprilia D1 bottom end looks like?
looks pretty normal

The Aprillia DI direct injection SR50 crankshaft has a cam on one web to drive the DI air pump.



Aprillia SR50 DI crankshaft

[Grumph]

Im oh so sorry guys - yes the question was 4T related.
Real old XR200 being bored and destroked to pull 14,000 reliably.
The KTM up to 07 had the good roller setup, after that they went plain bearing as do the 4T Honda's but changing
the oil pump for plain bearings on an old XR is just too hard.

Went through that with the mighty GN a couple of years back. Roller diameter is the major factor with the small 4T singles.
Going from a 4mm roller to a 3.5mm one made a massive difference in reliability.
Your next problem with the XR will be top end lubrication. You need a pressure feed into the cam with holes onto the lobe surfaces.

[wobbly]

Yea, the XR has oil fed around a stud up to the head.With the big overbore and resleeve that will go.
Will use an external hose and cooler.

[TZ350]

.
Success ....... https://youtu.be/xAp77XQx9R8


I have finally got the pseudo 2S EFI MAP co processor working well with the output smoothed. Now I have something useful to work with to explore the possibilities of using MAP and VE table with two stroke fuel injection.
.

[TZ350]

.
Ok, it is starting to look like I may have a winner.

Fueling is real rubbish but its what you would expect with a first cut.

The great news is that the Pseudo MAP value behaves like I hoped. It increases as the motor starts making power and drops in areas where the TPS increased but the motor did not fire. You can see that in the middle of the picture where the TPS (green line) increases but the RPM (white line) decreases because the motor did not pick up and the MAP (yellow line) and rpm dropped. To the right of the graph you can see where the motor picks up and the MAP follows suit. Fueling is crap so the traces are not very neat.

Altogether it looks like the concept is going to work.

In this graph the motor reeves out to 12,000+ RPM so I claim a world first, a 2S EFI successfully running in the 10/10 death zone with MAP and VE table.

Now all I have to do is figure out how to use Tuning Studio to improve the fueling. Get it running properly and ride it around the track ...... Lots to do yet.


.

[husaberg]

Im oh so sorry guys - yes the question was 4T related.
Real old XR200 being bored and destroked to pull 14,000 reliably.
The KTM up to 07 had the good roller setup, after that they went plain bearing as do the 4T Honda's but changing
the oil pump for plain bearings on an old XR is just too hard.

Destroking one is easy insert XL125s crank 57mm becomes 49.5mm
For the hondas you can go down to a 3.5mm bearing using the Yamaha XT200 rod and Prox do a suitable bearing. From Memory
The DR200 is a longer rod option with 3.5mm rod bearing a well
Using a Yam rod allows you to either bush the little end or use a DR200 piston which is domed and about $200 cheaper than a wiesco.
Some of the odball Honda singles were also 30x37mm rod bearings but a little thinner generally.
GL145 has bigger valves pus roller bearing cam.

If tjhe rules are open i would just buy the franken motor off Drew.
Give it a decent bottom end and ignition.

Grass Kart?

[husaberg]

Im oh so sorry guys - yes the question was 4T related.
Real old XR200 being bored and destroked to pull 14,000 reliably.
The KTM up to 07 had the good roller setup, after that they went plain bearing as do the 4T Honda's but changing
the oil pump for plain bearings on an old XR is just too hard.

Grass Kart?
Destroking one is easy insert XL125s crank 57mm becomes 49.5mm
For the hondas you can go down to a 3.5mm bearing using the Yamaha XT200 rod and Prox do a suitable bearing. From Memory older cattledogs TKRJ do a siler 3.5mm 30x37mm silver plated no idea what design
The DR200 is a longer rod option with 3.5mm rod bearing a well
Using a Yam rod allows you to either bush the little end or use a DR200 piston which is domed and about $200 cheaper than a wiesco.
Some of the odball Honda singles were also 30x37mm rod bearings but a little thinner generally.
GL145 has bigger valves pus roller bearing cam.
What would worry me with destroking one would be the loss of comp that wil be unrecoverable
a flatt top gives 10:1 12 to one with a 125 shaped dome these engines love compression.
it will take a mighty big bore to get a decent lick of compression, going past 70mm is bloody hard

If tjhe rules are open i would just buy the franken motor off Drew.

Give it a decent bottom end and ignition.



I always preferred the CB100 gearbox over the XR200 6 speed, Much nicer ratios esp for racing.
but you would have to use 5 speed cases and the oil gallery is even closer on the 125's. no worries if you were intending on running it externally.

[TerraRoot]

Since we've mentioned a few foul-stokes here, (i'm in the middle of thinking about the conrod problem, and this talk reminded me) i'm converting 4T bottom end to take a 2T topend because the rules never said i couldn't.

what method would you use to block up all the holes in the 4T oil soaked crankcase? JB weld, braze, MIG, TIG? only really concerned about making an oiltight seal and not structural work.

[Michael Moore]

If you want to avoid welding then small tapped holes with plugs or tap bearing balls into an interference fit hole and then peen the edges over. I've seen the latter in some OEM applications.