Jump to content
Sign in to follow this  

Honda CRF250L with 286cc Up kit,Yoshimura pipe and EJK

Recommended Posts

Has anyone on here got a Honda CRF250L with 286cc Up kit,Aftermarket pipe and EJK fuel controller and had it on the Dyno??

I would imagine you should have around 30BHP at the rear wheel??

Share this post


Link to post
Share on other sites

I would imagine you should have around 30BHP at the rear wheel??

 

You would also need cams, valves and porting to hit 30. I have 26hp running  what you said with a 305 kit. I think some of the guys have reached 32hp 

  • Like 1

Share this post


Link to post
Share on other sites

You would also need cams, valves and porting to hit 30. I have 26hp running  what you said with a 305 kit. I think some of the guys have reached 32hp 

 

It is now a Honda CB300R engine and Honda quote stats of over 30Bhp for this model,With EJK and Yoshi i would have thought that would bring it up even more,I will

get it Dyno'd some time for my own curiosity.

  • Like 1

Share this post


Link to post
Share on other sites

It is now a Honda CB300R engine and Honda quote stats of over 30Bhp for this model,With EJK and Yoshi i would have thought that would bring it up even more,I will

get it Dyno'd some time for my own curiosity.

 

oh ... I thought you were talking about a big bore kit not the stroker parts upgrade.  I do not know enough to comment on that.

Edited by gnath9
  • Like 1

Share this post


Link to post
Share on other sites

rear wheel HP and crank HP are two different things, manufacturers like to list crank numbers, they sound better. cars used to be rated the same way, basic bare engine numbers also known as gross HP they switched to net ratings with accessories and such in 1973.

 

the crf250l is rated at 23.7hp (motorcyclespecs.co.za) but when strapped to a rear wheel dyno they typically are producing in the 18hp range.

the CBR300 is rated at 30.4hp and likely puts around 25hp to rear wheel.

 

still a quite healthy gain from just 37 extra CC's the torque peak climbs up the scale a pretty good ways pointing towards much hotter cams.

 

a person could see a pretty good gain from swapping in CBR300 cams.

  • Like 2

Share this post


Link to post
Share on other sites

Read up in the 349 thread. Bored, stroked, ported, cam'd, full FMF and reworked FI I got 31.5hp at the wheel with a knobby.

  • Like 2

Share this post


Link to post
Share on other sites

Read up in the 349 thread. Bored, stroked, ported, cam'd, full FMF and reworked FI I got 31.5hp at the wheel with a knobby.

Same here 32,6 HP , guess more needs seriously head porting and bigger valves.

Had mine also running with stock cylinder and Piston with 286 cc .

No dyno run, but Buttdyno say much weaker.

  • Like 1

Share this post


Link to post
Share on other sites

By the way, Schrauberklaus what is the outcome after you swapped the Tagekawa for the BB 305 kit. Any improvements issues ? How many km did you manage to put on it yet ?

Share this post


Link to post
Share on other sites

I am since 23 of november on tour with the CRF349 and the BB Kit .

About 11500 km since i install the bb kit , no issue so far .

 

Dit 10 Days ago a 70 Km offroad section in the mountains of north Thailand and swap

for this day from my 15/39 T road setup to 13/39T .

The only thing that stop the Bike is my offroad riding ability and ruts on very steep sections deeper as the front achsle.

 

Never stall , but rear break out more often then i like .

Edited by Schrauberklaus
  • Like 1

Share this post


Link to post
Share on other sites

Sounds good. How about vibrations with this heavy Wiseco piston as compared to the original Honda ?

 

Mine is not built near as you guys but, I did notice a little more vibs with the 305 and here is where it gets weird and I do not understand why but, DuckyDog made me a head pipe that I compared to the FMF megabomb and it actually out performed the FMF by 1.5hp down low and only lost .5 up top ... and for some reason the bike feels much smoother/less vibs ... 

  • Like 1

Share this post


Link to post
Share on other sites

The guy in Bangkok who tuned my air/fuel ratio said everyone he knows who has tuned/bored or Dyno'd a CRF get the best results throughout the rev range with the Yoshi pipe,he says the FMF has similar at low to middle but the Yoshi always has more at the top end,he puts this down to more money being spent on the research and development side of things by Yoshimura but i've had Yoshi's on my bike for years and they've always been as good if not better than other race pipes!

  • Like 1

Share this post


Link to post
Share on other sites

The guy in Bangkok who tuned my air/fuel ratio said everyone he knows who has tuned/bored or Dyno'd a CRF get the best results throughout the rev range with the Yoshi pipe,he says the FMF has similar at low to middle but the Yoshi always has more at the top end,he puts this down to more money being spent on the research and development side of things by Yoshimura but i've had Yoshi's on my bike for years and they've always been as good if not better than other race pipes!

 

If Yosh would have let us keep our number/side plate I would have bought Yoshimura  ...  👍  also, I was an early adopter and started modding right away before many of these parts were available that we have now ...  🤦

  • Like 1

Share this post


Link to post
Share on other sites

Sounds good. How about vibrations with this heavy Wiseco piston as compared to the original Honda ?

Vibrate a little more then original but nothing i am worry about so far .

I have a XR280 , a XR440 and a XL636 . They all vibrate more then the CRF and the 104 mm Piston in the XL is ,5 gr, lighter then stock .

Its not only the balance its also the higher Power that create more vibration in a thumper.

  • Like 2

Share this post


Link to post
Share on other sites

Mine is not built near as you guys but, I did notice a little more vibs with the 305 and here is where it gets weird and I do not understand why but, DuckyDog made me a head pipe that I compared to the FMF megabomb and it actually out performed the FMF by 1.5hp down low and only lost .5 up top ... and for some reason the bike feels much smoother/less vibs ... 

I guess the hit of the Pressure wave coming out of the Exhaust Port hitting the 180 degree Bend in the Header adds to the vibs.

different bend/diameter , different vibs

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...