Messages

31

General Two Stroke Talk / YZ 250 EFI

« on: September 05, 2013, 03:11:28 PM »

I would think EFI (and DFI) would give engineers more freedom to work with other engine parameters. If a really oversquare piston would be prone to hot spots and pinging at specific throttle settings and RPM ranges it may be easier to compensate with the computers than it would be on a carb. So one would expect EFI/DFI engines to push the envelope in this regard (ratios further away from 1.0 than we are use to seeing). Maybe.

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Photos & Videos / My 380 nets some additional attention

« on: August 27, 2013, 02:46:47 PM »

Thread jack alert.....

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Photos & Videos / My 380 nets some additional attention

« on: August 27, 2013, 05:25:29 AM »

Yeah, that hill was pretty cake for the Great Pumpkin... 

That was ridiculous.

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Photos & Videos / My 380 nets some additional attention

« on: August 27, 2013, 04:19:08 AM »

All I wanted to do was climb that there hill.   Sheesh....

35

General Two Stroke Talk / What are the symptoms of the big end bearing worn?

« on: August 15, 2013, 12:18:43 AM »

Mostly for con rod but really shot crank bearing could introduce rotational slop -- but will also allow the crank to wobble a bit.

Bottom line here with this check -

- if you feel sloppyness then you have a problem. You need to tear it down. End of story.
- if you don't feel slopppyness then you still *might* have a problem.  If there is other evidence then pull the jug. Otherwise, go ride.

Do you mean, crank bearings or conrod bearing?
The only way to correctly determine wear is to check the specs and measure with correct instruments as per manual.

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General Two Stroke Talk / YZ 250 EFI

« on: August 14, 2013, 09:42:13 PM »

Write a book, I hate writing!

Then what the heck are you doing with all this posting? If I am not mistaken it qualifies!  ;-)

So I can't believe that LINK can't wait for a full rotation (or at least till that gap comes around) to start sparking. Who the heck wrote the firmware???

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General Two Stroke Talk / Had a little epiphany at the track today.....

« on: August 14, 2013, 03:45:34 PM »

I am orienting my dual sport KTM250 a bit more towards street with a 42 tooth rear sprocket (replacing the 48 that is on there now). THAT ought to test the limits of this theory!

38

General Two Stroke Talk / YZ 250 EFI

« on: August 14, 2013, 03:42:42 PM »

you could write a book on your experience with the BigHorn, and this YZ. I have a great time reading about these technical details. An ignition problem that breaks the shaft. Who would have thought? Does the flywheel have a "TDC" pin such that on start the LINK can wait for that and then start sparking? Or maybe thats how it was supposed to do it anyway?

Can you refresh my memory -- you were looking at a more reasonably priced computer. I don't think that is the LINK. Did that ever go anywhere?

Ha Ha Ha, sell the idea to Yamaha, their NZ technical guy seems not even interested. It's been waved under his nose. They are not interested!
That's the encouraging thing about this " conversion" there has been almost no problems. I made the throttle drum too good a fit and sometimes the throttle would hook up for a moment, not nice going into a corner with trees everywhere. Giving it a little clearance has fixed that problem. I gave the head too much compression ( if some is good, more must be better ) but that was quickly rectified, my fault. We have broken two kick start shafts now with the original ignition ( through the LINK ), at kick over the computer looses count of the flywheel pins and gets mixed up and then fires at the wrong time. We fixed this by fitting an Ignitec and using the LINK for fuel only. I made a new kick start shaft out of EN39B and case hardened it. Something else will bust now because the shaft never will anyway there is no kick back problem now with the Ignitec. I'm waiting on an Ignijet computer to try out, this should do the same job out of a much smaller package and much smaller price! That's about it, ride it in the rain, doesn't bother it. We are using a crude oiler system still, runs 60 to 1 oil in the fuel plus after 60% throttle a small valve opens to a fixed jet in the throttle body.

39

General Two Stroke Talk / YZ 250 EFI

« on: August 14, 2013, 01:51:45 AM »

The DFI folks claim about 30% savings so you are getting half of that, sounds like a win to me! Congrats on your progress to date.

Yes it runs real well. They are different to ride, my standard one feels a little sharper up to about third / half throttle but then the EFI one doesn't hit as hard when coming on the power. Same top end power. I hate to compare but the EFI bike feels more 250F ish but just more power, everywhere.
In saying this Wayne has just today changed the injection timing peramaters and it's crisper at the up to third / half throttle now. Still way more to be learned about this transfer port injection.
Citabjockey, I too am astounded at how clean the engine runs throughout it's rpm range with so little tuning time. I'm sure this tells us that transfer port injection is the way to go, short of full DFI. Remember we are getting an approx 14% fuel saving under the same conditions, this must point to less fuel short circuiting out the exhaust port.
Racer X, any time, just come on down, winter is best time although there are good rides on throughout the year. Summer is generally too dry to allow forest rides.

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General Two Stroke Talk / YZ 250 EFI

« on: August 13, 2013, 10:13:14 PM »

Sounds like its running VERY clean bottom to top!
So this DFI stuff really works, eh?

Looks like a fun trail.

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General Two Stroke Talk / Charles how are you holding up through this stage of the season???

« on: August 12, 2013, 02:59:58 PM »

JS7 so far this year:

Hangtown, 2rd
Thundervalley, 7th
Tennesee, 4th
High Point, 19th
Budds Creek, 12th
Southwick, 11th
Redbud, 2nd
Washougal, 3rd
Spring Creek, 1st
Unadilla, 11th

So yes, if you are after the championship this is not your guy. But this is an impressive record nevertheless. And if he could pull these same placings on a 250SX? It would be fun to see the Conniptions the big four would go through in that situation! He just has to get out of the money making mode and back into the fun mode (or any other speedy rider that wants to stir the pot).

This year has been better for him than last. Not crashing out near as much, seems to be much more careful. And he used to be a master on the two stroke bikes.

How about signing Bubba?

This might have been intended as a joke, but it might not be come contract renewal time. Bubba has delivered nothing but disappointment to his Rockstar Energy/Suzuki team. They must be kicking themselves for signing him. Add to that the extremely poor sportsmanship he showed when bagging out hte YZ450F and I think hes gonna find it a little harder to pull a high end contract out of the hat. And so he should. His performance these last couple of years has been nothing short of disgraceful by the standards he is judged, that is, one the of the best riders in the world. I think his career peaked in 09.

This year has bee nthe better year? Last I checked he was SECOND LAST in points and he crashes out roughly 60% of his races. and THIS is the better year? In that case, my point is even more valid... I feel sorry for RE/Zooki though. He REALLY hasn't delivered. Not like a guy with his rep should anyway. Maybe he'll get a taste of his own medicine and they will break contract to get away from him and then piss on his rep on radio. But if it gets anymore piss on it the fire may go out...

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General Two Stroke Talk / Charles how are you holding up through this stage of the season???

« on: August 12, 2013, 06:24:23 AM »

This year has been better for him than last. Not crashing out near as much, seems to be much more careful. And he used to be a master on the two stroke bikes.

How about signing Bubba?

This might have been intended as a joke, but it might not be come contract renewal time. Bubba has delivered nothing but disappointment to his Rockstar Energy/Suzuki team. They must be kicking themselves for signing him. Add to that the extremely poor sportsmanship he showed when bagging out hte YZ450F and I think hes gonna find it a little harder to pull a high end contract out of the hat. And so he should. His performance these last couple of years has been nothing short of disgraceful by the standards he is judged, that is, one the of the best riders in the world. I think his career peaked in 09.

43

General Two Stroke Talk / What are the symptoms of the big end bearing worn?

« on: August 11, 2013, 11:13:59 PM »

You can negate the warn piston issue by sticking a screwdriver down the spark plug hole. Feel that go up and down while you rotate the flywheel back and forth. Get the piston at about 1/2 stroke which maximizes the pistion travel per rotation of the flywheel. Now while feeling the screwdriver for up and down motion rotate the flywheel. If you get any discernible rotation out of it without the screwdriver moving then you have a bad big or little end bearing or bearing surface.

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General Two Stroke Talk / Charles how are you holding up through this stage of the season???

« on: August 11, 2013, 10:40:21 PM »

How about signing Bubba?

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General Two Stroke Talk / YZ 250 EFI

« on: August 11, 2013, 10:39:45 PM »

It's only me riding it, no "special" riders yet.

Given you description of the edits maybe you ARE a special rider!  (ducking now)

Looking forward to the video!

Now if we could just get that 360EFI going. And have Robbie Marshall ride it at Monster Energy Cup!