Low & Slow's Ninja 250 project

[sendler]

Originally Posted by HHOTDI

I was looking for the link to the info on the Oct 17th Barstow/Vegas meet and no longer see it, is it still on? :{)

Looks like it is still on.
.
2013 Craig Vetter Fuel Economy Challenge, Las Vegas

[renault_megane_dci]

Originally Posted by low&slow

Alan has had the valve timing changed for more low-end torque.

I wish Alan was on this forum to tell us more about this mod ...
That is the best route to take engine wise on a Ninja 250 if one is willing to trade off top end power for FE.

Did you guys took some pics to refresh our memories of both your bikes ?

[low&slow]

Here you go:[/IMG]

[godscountry]

Originally Posted by low&slow

Thanks Jay!

I had been busy since getting back from the Mid-Ohio Vetter Challenge and hadn't ridden the streamlliner much since the competition. This week I worked on a couple of refinements: a new bellypan and I raised the windscreen so that the passing air wouldn't hit my shoulders. I finally hit reserve today after more than 400 miles on this tankfill. I completed my errands and refueled: 437.3 miles/3.79 gal. of fuel for a result of 115mpg.

The weather has been hot here and the engine temperature got past halfway after a 50mile ride. I may need to open up the air inlet in the nose for long uphill runs in hot weather . The next competition is Las Vegas next month but it probably won't be super hot then. Alan Smith and I are planning to do a some testing with our streamliners later this month and we hope to produce some good results.

Very impressive,have you seen the guy building a cabin bike at cabinbike.com,pretty interesting.

[B440]

Originally Posted by renault_megane_dci

I wish Alan was on this forum to tell us more about this mod ...
That is the best route to take engine wise on a Ninja 250 if one is willing to trade off top end power for FE.

Did you guys took some pics to refresh our memories of both your bikes ?

I'd like to know more also. The only thing I could find was setting the valve lash on the loose side. I recall something on valve timing for another bike where it could be changed by one or two teeth for more power... I'll have to look for it.

[renault_megane_dci]

Originally Posted by B440

I'd like to know more also. The only thing I could find was setting the valve lash on the loose side. I recall something on valve timing for another bike where it could be changed by one or two teeth for more power... I'll have to look for it.

I made a post about atkinsoning a bike engine that involved retarding the inlet cam two teeth.
A member tested it and it does not work with carbs.

The target was not to gain power but to trade power for efficiency.

Unfortunately there are no beater that you can get for peanuts in the injected bike world so we still don't know if it is indeed efficient for FE

[sendler]

We will start to see better pricing on used CBR250R's now that Honda has changed the bike to 300 with all new bodywork. I expect to see CBR250R's in the $2,500 range.

[jjackstone]

Originally Posted by renault_megane_dci

I wish Alan was on this forum to tell us more about this mod ...

Perhaps if Craig is monitoring this forum he could weigh in on this topic. He has worked fairly closely with Alan and may know how he made the adjustment.

JJ

[sendler]

It might be possible to just move the torque peak lower in rpm by changing cam timing by one tooth instead of going for a full Atkinson esque late closing with the requisite back flow out the inlet valve which tends to disturb the carburation.

[renault_megane_dci]

Originally Posted by sendler

It might be possible to just move the torque peak lower in rpm by changing cam timing by one tooth instead of going for a full Atkinson esque late closing with the requisite back flow out the inlet valve which tends to disturb the carburation.

Actually the testing was done with a single tooth changed and it already disturbed the carb (not beyond help though)

Loose valve lash has the result of a little less overlap and shorter duration : sounds a better way to boost torque