Coming Soon
Home > Forum


Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - Jeram

Pages: [1] 2 3 ... 31
1
Non-Moto / Re: My 380 road racer project
« on: January 09, 2017, 02:38:20 PM »
First test ride

Jetting still needs some work though.

https://youtu.be/_MpUW7NH8Jc

2
Non-Moto / Engine oil: Mineral, semi-synthetic and synthetic
« on: March 13, 2014, 09:37:34 AM »
^ That's a spam post ^

yes. indeed it is.
why only discus synth, mineral and blends?
there are other options.... other much better options.


I can get you castor/synth/ceramic oil for $35/L in Melbourne ;)
Let me know if you want some, its amazing stuff

As much as I would love to spend $35 a litre on what is apparently liquid gold, doesn't that kinda defeat hte purpose of me saving money?

$35 a litre is the cheapest oil Ive ever purchased. The last oil I used was 50!

And I mix at 25:1 ratio...

It may add $10 to the cost of a tank of fuel, but thats still $500 cheaper than new Nikasil and new piston, and $300 cheaper than a new rod and a crank rebuild.

If you only use the best then the only thing you can blame an engine failure on is yourself ;)

3
Non-Moto / Engine oil: Mineral, semi-synthetic and synthetic
« on: March 05, 2014, 07:13:10 AM »
why only discus synth, mineral and blends?
there are other options.... other much better options.


I can get you castor/synth/ceramic oil for $35/L in Melbourne ;)
Let me know if you want some, its amazing stuff

4
Technical / Painting exhaust
« on: November 17, 2013, 10:34:10 PM »
I was asked about painting the exhaust pipes, so I'd thought I'd ask the group.  Has anyone has painted their exhaust.  I'm not a fan, but was wondering if anyone has done it, and if so did the like the outcome, and how did it hold up over time.  Lets assume the paint will be high temp paint.  I don;t think it would stand up to the abuse, and would look bad over time.

Thoughts???

Easily scratched, but at the end of the day, you paint it and then repaint it as necessary.

But if you want to try an avoid rust. Just put some cooking oil on the bike and bake it on. it will turn a lovely caramel color.

I've tried cooking oil and Lanolin.
Lanolin seems to work best when a pipe is sitting in storage without use.
Cooking oil works best when it can be baked on

5
Technical / Piston/Cylinder diagnosis
« on: October 26, 2013, 07:40:43 AM »
buy your self a ball hone stu, http://www.brushresearch.com/flex-hone.php?gclid=CNSq6enBtLoCFc6j4AodpS4AWw, just spray with wd-40 three passes and shes looking good.

pistons are cheap and disposable, so just pop a new one in!
bore looks ok, just clean it up a little yourself and whack her back together.

PS: your bore might be glazed which is stoppping the new rings from seating, hence the ****ty compressioon

6
Technical / New YZ Project
« on: October 17, 2013, 08:36:03 AM »
good thinking with the athena kit... no point spending money on ported gore cylinders if you dont need it :)

Just on a side note: I think that now Gore is part of Millenium Technologies (Nikasil Platers), You might see a present increase in service and reliability as Millenium are simply great.

7
General Two Stroke Talk / YZ 250 EFI
« on: September 19, 2013, 06:14:07 AM »
I thought I was using an Ignitech EFI ( ordered through Wobbly ) but it appears they might be no more! Wobbly's ordered is now five months old and no news. Not even contact from Emails. They have taken the money for the order. Unfortunate as it seemed like it might have been a good unit.
We will stick to the LINK ecu at the moment, we now have total control over injection timing.

This is totally off subject but my own YZ now has a Rekluse clutch in it, with a left handle bar rear brake. Foot brake is totally gone ( for old people with a worn out right hip ). It's a bit like a mountain bike with both leavers on the handle bars operating front and rear brake. Much better entry to the corner control.

That's very disappointing!

Ignitechs quality was lacking in a big way over the last 2 years, I've had numerous faults and very poor customer support. So its not suprising that theyve gone belly up. (I dont know whether they have or not, but what your saying doesnt sound good)



8
General Two Stroke Talk / YZ 250 EFI
« on: September 05, 2013, 08:55:43 AM »

There is quite some arguement that 2ts will go to more oversquare engines, especially with such techs as DFI, as the fuel component of the charge, will be less dependent on the 'whole engine' concept.

I disagree with the idea that a DFI two stroke would require an over-square engine configuration. Its still a two stroke, it still relies on crank case induction and exhaust scavenging, just like almost all other DFI two strokes (with boats being the exception).

However a DFI trapping valve two stroke would probably make good use of a short stroke as it does not need the long stroke for additional exhaust time area.


Disagree all you want young fellow.

As I wrote "There is quite some arguement that 2ts will go to more oversquare engines, especially with such techs as DFI". Therefore, there will be disagreements.

I don't believe there is a need for 2ts in Motorcycles to go that route - chasing revs to get HP, as naturally aspirated 4ts do. That's through my own, perhaps 'old timers' viewpoint, on what I want from a 2t.

2ts can keep relatively long strokes, whilst doing battle with 4ts.  Simple maths / time calculations show that 4ts "big bang advantage", so to speak, is gradually being negated by the revs they must go for, for power to compete against a 2t, at least for now. Though, Moto 3 rules (well, the max. bore rule of 81mm - shared with Moto 3 - is a somewhat of a 'control' in Moto GP) , are keeping a cap on revs.

But, as I wrote, there have been, and will remain to be, quite a varied opinion on what bore / stroke ratio is 'optimum'.

One Engineers "Optimum", will be anothers "Dud".

I gave the Evinrude dimensions as an example of what has been done, with a certain, pretty successful application of DFI  2 strokes.

I'll have to have a squizz at what the 2t Snowmobiles tend to use. It may be comparable to the
Outboards, as they may be more of a 'steady state' engine than a Motorcycle Engine ( but, I'd think, less so than an Outboard) would be. It, of course, may not be comparable, at all.

The 2T snowmobiles have a large bore/short stroke configuration, but the main point is that the bore/stroke rations did not change when the bikes went from carbied to EFI and then to DFI. The DFI two strokes did not alter their bore/stroke ration when they swapped from carbied to DFI either.

The bore/stroke rations remained constant because gas flow dynamics and power characteristics do not care how and when the fuel enters the engine, only that its there and dispersed in time for ignition to occur ;)

So therefore I can only assume, and rightly so, that the bore/stroke will stay constant for two stroke motorcycles regardless of the fuel delivery type.

9
General Two Stroke Talk / YZ 250 EFI
« on: September 03, 2013, 11:06:05 AM »

There is quite some arguement that 2ts will go to more oversquare engines, especially with such techs as DFI, as the fuel component of the charge, will be less dependent on the 'whole engine' concept.

I disagree with the idea that a DFI two stroke would require an over-square engine configuration. Its still a two stroke, it still relies on crank case induction and exhaust scavenging, just like almost all other DFI two strokes (with boats being the exception).

However a DFI trapping valve two stroke would probably make good use of a short stroke as it does not need the long stroke for additional exhaust time area.

10
General Two Stroke Talk / YZ 250 EFI
« on: September 02, 2013, 11:36:06 AM »
20% less fuel burn this weekend. It depends on the type of usage, at lower speeds ( tighter track ) there is a larger benefit, more top end running = less fuel saving. I would imagine top out both bikes would be similar fuel consumption ( similar power ). Now it's getting exciting, every time out on the EFI bike is a little better as we change settings slightly. This weekend we got the raspy original feel back ( like my standard bike ) but we soon tuned that back out! It's much better / faster to ride with the smooth program installed. We even had a 250F rider have a go on the bike, he was quite shocked at how it went, it was hard to pry him off the bike after that. 

With this torquey, tractable powerband, would it be possible to increase the revability of the 250 two stroke? Most are typically the midrange monsters as we know, but how about revving them out to their redline? And possible a slightly shorter stroke/bigger bore design to increase said redline?

MX seems to be the exception to the two stroke bore/stroke rule of thumb.

square bore/stroke is almost always optimal except for in moto-cross.

I always wonder why the didnt build the optimal 68x68mm 250-2T and then achieve the required bottom end/mid range/top end balance with pipe design and porting....

I am sure there is a very valid reason and it likely has nothing to do with HP, but more likely about usability and traction... and even more likely; laptimes.....

I always thought it was a traction issue. Whats the standard bore/stroke of the 250t offroad motor? 66.4x74 or something? 6mm off the stroke compensated for by a 1.6mm increase in bore, wouldn't that mean an increased turnover speed? 250 2ts struggle for traction in alot of places as they are, I always just put it down to a turnover speed too quick for the dirt. Four strokes can get away with it because they deliver a power stroke half as often.

72


11
Non-Moto / My 380 road racer project
« on: July 12, 2013, 12:16:35 PM »
Dayum. Is all I can say. Going to go electric start? Also, when do these 380 motors redline?

Going to be using roller starter and push starting for this bike. Elec start would only add weight and cost :)

the std 380 motor redlines at 7000-7500 i beleive, but we are pushing this motor to peak at 8750 with the rev limiter at 9250.

12
Non-Moto / Electric bike wins pikes peak event. Whhhuuuuttt???
« on: July 05, 2013, 01:58:13 PM »
Battery tech will be phased out soon and replaced with supercapacitors.

it is feasible that in 10 years time, your bikes chassis will also be its battery, made from a graphene matrix.

That will bring the costs down big time.







graphene is freaking awesome stuff. Once in mass production the possibilities are nigh on endless. Imagine a motorcycle that weighed less than 2 kgs... Where a 50 cc engine replaces a 500. Infastructure, farming, bullet proof vests that could stop a .50 barret round dead in its tracks and still be a tenth the weight of todays vests. So psyched for the future, glad its happening in my life time.

Not sure about the 2kg bikes though ;)

Problem is that Graphene at this point in time only has the energy storage capacity similar to a chemical battery. It may become better over time however.

The greatest think will be that instead of having a frame and batteries, you will instead have a chassis which is the battery which will reduce the bikes mass by the weight of the chassis (about 10-20kg)

13
Technical / Piston Diagnosis
« on: July 02, 2013, 07:44:39 AM »
whats the CR head like? same marks?


Burn pattern is ****

Skirts look good

weird scratch marks (or maybe cracks, cant tell from photo) on dome

edges of the piston erroded (or broken away)


Most clues point towards detonation, and I would supect the piston dome marks are from a previous situation.

=too much ignition advance for the given fuel/air/engine setup

so either back off the advance, increase the fuel quality or back off the engine tune.

14
Non-Moto / Electric bike wins pikes peak event. Whhhuuuuttt???
« on: July 02, 2013, 05:35:29 AM »
The majority of our electricity comes from Coal/Crude oil/Natural Gas! What savings? Solar/wind are going bankrupt!

Solar and wind are going bankrupt because they didnt bother to develop new technology in the last 10 years and as a result now the chinese have reverse engineered the current tech for half the price!

15
Non-Moto / Electric bike wins pikes peak event. Whhhuuuuttt???
« on: July 02, 2013, 05:33:08 AM »
Battery tech will be phased out soon and replaced with supercapacitors.

it is feasible that in 10 years time, your bikes chassis will also be its battery, made from a graphene matrix.

That will bring the costs down big time.



Pages: [1] 2 3 ... 31