Help needed 4-stroke tuning

[Eoin70]

Hallo, ik heb een vraag,
i know maybe this isn't the correct place for my question, but i need some information from the Dutch forum members.
I am looking for a 4-stroke tuner for CRF250 moto-x bike we want to get the head ported, does anyone know some good tuner in Holland?

Thanks Eoin

 

[Wieger]

moved to the english section of this forum. But this is a scooterforum, so your question isn't really suitable. But the folks on this forum aren't that bad and know something about motorbikes. So for this 1 time I won't delete it. If you don't get your answer, I refer you to a motorforum

gr, wieger (crew)

 

[Eoin70]

ok thanks no problem. But i was hoping that some Dutch members could answer, i'm living in Ireland so its very easy for me to send parts to Holland for tuning.
And dont worry im not just some guy who only posted this topic, i used to be a very very active member here on the english scootertuning section.

Lets see who knows a good tuner for me

 

[Wieger]

Ah i see, sorry , But we (dutch people) Often look at this english section. It's just a separation of language, Not a wall between Dutch and foreigners

ABTuning is a good 2stroke tuner and they are currently working on a 4stroke engine.

Gr, wieger

 

[JohnB]

I think you should google for car tuners in ireland or the rest of the UK
The basics are al the same.

Poorting isn't always better.
It should comply with the camshaft , carb/injectorvolume etc etc

 

[scootertrog]

...... But the folks on this forum aren't that bad.......

gr, wieger (crew)

MHR,
lol..... just a little bad?


I know I've said this before, and I'm sure the others here feel the same way. This IS a great forum and I really appreciate the administrator's giving us this section.

scootertrog

 

[tiba_karotsu]

4stroke tuning? i can be of help to you as i used to be an import car tuner but i am active in 4stroke tuning as i have tuned bikes for the Kawasaki factory racing team (roadrace) and countless other customer bikes.

here's some pics of my work, it's a cylinder head for Team Kawasaki's 125cc motorcycle for roadracing.

btw what's up dude, it has been a while since you posted here, so this is what you've been up to.

 

[Eoin70]

maybe you are the man for the job

well i've been pretty busy, i spent my winter in Austria skiing and now im just starting to build up my sprinter again, i had a box coming from holland with many parts and it has been delayed for about 3 weeks now:S

but about the crf250, i can already see on the intake ports there are big restrictions there, we already had it on the dyno, and from STD only 31.5
but with a White bros exhaust and HPI cdi we had it up about 33hp

i guess 38 is our goal , now we also have a Pro Cicruit high compression piston fitted. Some guy has pm'ed me so i hope hes the one that will be able to help me

 

[tiba_karotsu]

what are the valve sizes of the CRF250? can you post a pic of the intake & exhaust ports like the ones i posted? i'm very curious to see how it looks like on the inside.

 

[Eoin70]

ok here you go some pics for you, this head is damaged by the way, the valve seats need to be re-cut

the exhaust port diameter is 26 mm on both ports and on the intake its 31mm

and here another

 

[tiba_karotsu]

wow now those are really big valves judging from the inside diameters of teh valve seat throats, that head is begging to be ported, damn i want to get my hands on that head it be like tuning a Honda B16 cylinder head.