YZ 250 EFI

[Uniflow]

Stu, put it this way, the EFI bike was by far the best bike for the conditions yesterday.
It's still early days in understanding what we have got, it would seem that the injection timing has a big influence on the way the power is delivered, bottom, mid range. I think from what we have found so far that the power curve can be manipulated at this lower middle range with still the same top end. Yesterday it seemed the "power band" as such was gone!

I think the bit of metal in the last picture was from a casting disaster some years back, I'm not sure how that got in there.

[Uniflow]

I had the Kawasaki at Epic Events ride yesterday but didn't fire it up, too busy with the YZ's. We got to talking about how hard it would be to run the yz on ethanol fuel. Unlike a carb where it IS a drama to change, the YZ will only need the push of a few buttons, that instant.

[Stusmoke]

Stu, put it this way, the EFI bike was by far the best bike for the conditions yesterday.
It's still early days in understanding what we have got, it would seem that the injection timing has a big influence on the way the power is delivered, bottom, mid range. I think from what we have found so far that the power curve can be manipulated at this lower middle range with still the same top end. Yesterday it seemed the "power band" as such was gone!
I think the bit of metal in the last picture was from a casting disaster some years back, I'm not sure how that got in there.

Really? I thought it might have been the remains of a 250F silencer after 10 minutes of idling 

Very cool what you've done here mate. On the off chance I'm wrong and the big four truly believe that four strokes will continue to rule motocross forever and the sport will never change back to two strokes and they DON'T all have their designs working perfectly and locked up in company vaults, I know who I'd be calling if I was Yamahas two stroke R&D department.

[Uniflow]

This project was undertaken as " non profit " , a hobby, because I would like an EFI twostroke myself but no one offer an EFI bike. I waited for the OSSA, but noting seem's to be happening there so I decided to have a go myself and so far so good. I would be happy if Yamaha started to produce an EFI towstroke. Perhaps like this one or perhaps DI either way it would be a good thing, until this happens I'll continue on experimenting with what we have ( and with a bit of spare time perhaps finish the new 360 )!
I think manufactures still have a **** load of valves to sell yet.

[TMKIWI]

I must have missed the meassage to come ride the bike Neil.
I bet the track was interesting. It has been raining here for 5 days now and I am over it.

[Uniflow]

Didn't you get the message, I sent the pigeon two days ago . After yesterday I'm more than happy for anyone to ride it, with Wayne's permission, I've been a bit nervous as to how it might perform in the real world.
Yes a bit muddy but central plateau drains well so still plenty of grip. TM, do you do any of the Epic Events rides? Be happy to meet you at the next event with a view to do a " bike test ". If you give it a bad review you will have to ride the Kawasaki for the rest of the day and I invite you to review that

[Stusmoke]

If its ever around the brisbane area, let me know! I'd be more than happy to test out the upper RPM and rev limiter for you 

[TMKIWI]

I do a few of the epic rides but was a bit soft for this 1.
Will let you know when I do the next one.
I doubt I would give the bike a bad reveiw, but I can be persuaded with beer to give an excellent one.
You can thrash the TM as much as you want as well.

[GerbilGronk]

 It was freezing, snow on the Desert road, muddy, wet but the most  fun I have had in a long time.
 Heaps of two strokes as people see the light and the only bike I saw getting a tow in was a four stroke.

[Stusmoke]

This project was undertaken as " non profit " , a hobby, because I would like an EFI twostroke myself but no one offer an EFI bike. I waited for the OSSA, but noting seem's to be happening there so I decided to have a go myself and so far so good. I would be happy if Yamaha started to produce an EFI towstroke. Perhaps like this one or perhaps DI either way it would be a good thing, until this happens I'll continue on experimenting with what we have ( and with a bit of spare time perhaps finish the new 360 )!
I think manufactures still have a **** load of valves to sell yet.

And look what you've managed to produce in your spare time as a hobby! Imagine what Yamaha or Honda could accomplish if they threw their engineering department and half a billion dollars at it! Honda made good two strokes, whether they admit it or not.

[bearorso]

Imagine what Yamaha or Honda could accomplish if they threw their engineering department and half a billion dollars at it! Honda made good two strokes, whether they admit it or not.

The thing is, 1/2 a billion is not needed. Not even 1/2 a million would be needed for development. As I feel it's just sitting there, gathering dust, in quite a few company archives. Of course, you've then got tooling up / manufacture costs, but strict development costs, from right now .....

Yamaha have their DFI sorted in their Outboards - it, as it stands, may, or may not be suitable for bike use. Honda, you can guarrantee, have every damned aspect of 2ts sorted - and probably from a lot longer than decade and a half ago. Just their AR tech, could have been applied to real performance applications , and not just the Asian (and later, at a tiny scale, Australian ) trail bike / dual sport market. AR, with an electronic carb (EFI) - since it's got so cheap it's now on Postie Bikes (saw the new ones the other day - Wot, they are Green and White, not Racing Red?      It's just not right, I telz Yuz  ) -  would probably pass "whatever" these bloody Euro 3 specs are, whenever (2017) they bloody well 'have' to be met ...........

No, Honda = All Four Strokes, All The Time. Therefore, Honda, can well and truly, go **** themselves. 

[Stusmoke]

Imagine what Yamaha or Honda could accomplish if they threw their engineering department and half a billion dollars at it! Honda made good two strokes, whether they admit it or not.

The thing is, 1/2 a billion is not needed. Not even 1/2 a million would be needed for development. As I feel it's just sitting there, gathering dust, in quite a few company archives. Of course, you've then got tooling up / manufacture costs, but strict development costs, from right now .....

Yamaha have their DFI sorted in their Outboards - it, as it stands, may, or may not be suitable for bike use. Honda, you can guarrantee, have every damned aspect of 2ts sorted - and probably from a lot longer than decade and a half ago. Just their AR tech, could have been applied to real performance applications , and not just the Asian (and later, at a tiny scale, Australian ) trail bike / dual sport market. AR, with an electronic carb (EFI) - since it's got so cheap it's now on Postie Bikes (saw the new ones the other day - Wot, they are Green and White, not Racing Red?      It's just not right, I telz Yuz  ) -  would probably pass "whatever" these bloody Euro 3 specs are, whenever (2017) they bloody well 'have' to be met ...........

No, Honda = All Four Strokes, All The Time. Therefore, Honda, can well and truly, go **** themselves. 

Well said. And I have to wonder just how much more beneficial this all four stroke all the time thing is working out for the big four. For gods sake Yamaha doesn't even field a factory effort anymore! Last time I heard anyway. Yamaha had the motocross market in the palm of their hand once upon a time with their old school YZs. Sales have plummeted too. They might make alot more off of four stroke parts than two stroke parts, but has it really balanced it out? I guess it must have otherwise they would stop and rewind.

[TMKIWI]

The Japs are a very proud people and will not admit that maybe they got it wrong.
Jumping on the green band wagon was very easy for them to do and now the hole they have dug is rather large.

[bearorso]

The Japs are a very proud people and will not admit that maybe they got it wrong.
Jumping on the green band wagon was very easy for them to do and now the hole they have dug is rather large.

You're not wrong there, on both points.

I still have a bit of , faith in Yamaha - they at least have kept producing, and supplying to most world markets, 2t MXers. I live in hope, that the company that put reed valves and good porting into their production 2ts, of all types, over 40 years ago, then the single shock, and so many other things - including having the balls to mass produce 4ts that were not Foo Foo bikes, will be the first Japanese manufacturer to give us a modern 2t.

[Stusmoke]

The Japs are a very proud people and will not admit that maybe they got it wrong.
Jumping on the green band wagon was very easy for them to do and now the hole they have dug is rather large.

You're not wrong there, on both points.

I still have a bit of , faith in Yamaha - they at least have kept producing, and supplying to most world markets, 2t MXers. I live in hope, that the company that put reed valves and good porting into their production 2ts, of all types, over 40 years ago, then the single shock, and so many other things - including having the balls to mass produce 4ts that were not Foo Foo bikes, will be the first Japanese manufacturer to give us a modern 2t.

x2. And Sushi kicks arse when its fresh.