LIVE FROM LAS VEGAS! Honda CRF250L big Bore?

K

Kustom Kraft

Junior Member
Joined
Sep 17, 2014
Location
Las Vegas
Bikes
KLX330, YZ80-112
Hello There Fender Monkeys.

Kustom Kraft here were looking into a big bore kit for the Honda CRF250L. What are your thoughts? Were looking at making it a true 350cc bike.
 
Welcome aboard Ride Asia :shake: a 350cc kit for the CRF-250 oh yes please !!!!!!!!!!
 
ye , what-s the story, can u be more clear ?
thanx
 
PS in Thailand we don-t have CRF450 so..here we are, just waiting to make the 250cc spicyer!
:jumper:
 
Were in piston design now and have the cylinder done! So soon there will be upgrade for them. We do a big bore kit for the KLX250sf and have shipped into your neck of the world so were hoping this will be a big splash.
 
sounds great!exiting!!big splash on this side of the planet for sure... when is going to be ready for testing ,and price is going to be +- ?

Kustom Kraft said:
Were in piston design now and have the cylinder done! So soon there will be upgrade for them. We do a big bore kit for the KLX250sf and have shipped into your neck of the world so were hoping this will be a big splash.
Click to expand...
 
That is a good question KTMphil. We live in the sand box here in Las Vegas but haven't gotten all the parts in yet. It would be a good idea to betta test one there also I would think. I would like to have that done by Christmas and have the kit ready for spring here next year. Do you work on your bike there or use a shop?
 
excellent question ,although Vegas isn't any cooler...actually warmer/dryier

KTMphil said:
Off-road, the existing cooling system will be able to handle it in the heat we have here?
Click to expand...
 
I use a workshop here





Kustom Kraft said:
That is a good question KTMphil. We live in the sand box here in Las Vegas but haven't gotten all the parts in yet. It would be a good idea to betta test one there also I would think. I would like to have that done by Christmas and have the kit ready for spring here next year. Do you work on your bike there or use a shop?
Click to expand...
 
to put it in wouldn't be a problem.a few shops can also do.u should send a couple test kits for us (at a special test price) I could be one of the guinea pig candidates ;)

Kustom Kraft said:
That is a good question KTMphil. We live in the sand box here in Las Vegas but haven't gotten all the parts in yet. It would be a good idea to betta test one there also I would think. I would like to have that done by Christmas and have the kit ready for spring here next year. Do you work on your bike there or use a shop?
Click to expand...
 
We would do this in 2 stages.

1. Just an over bore to 305cc

2. We have to stroke the motor for the next phase for the 350cc. So we need someone that would be able to work and ride it for the best results. How many klms do you ride the one you have now?
 
is about 12000 km (done in 6-7 months)

Kustom Kraft said:
We would do this in 2 stages.

1. Just an over bore to 305cc

2. We have to stroke the motor for the next phase for the 350cc. So we need someone that would be able to work and ride it for the best results. How many klms do you ride the one you have now?
Click to expand...
 
to stroke the motor have u looked into using parts for the new cbr300.. i actually posted a while ago about this ,wondering, since the 2 bikes (crf/cbr250) share lots of parts as you know.that is what Honda did ,used the same (246cc ?) piston ,stroked the motor to 286cc (?) and called it new cbr300 ;)
 
Yes looking at the cranks we think there the same only stroke makes the motors different. If you put a crank in I would like to try the over bored cylinder on it. Pistons are different between the two as far as we can see. I have just ordered up the pistons from Honda and going into that work now. I would like to know if there is an interest in high compression from 10:7 to 11:1 ?? Or is the fuel there not able for that?

Thanks
 
Kustom Kraft said:
Yes looking at the cranks we think there the same only stroke makes the motors different. If you put a crank in I would like to try the over bored cylinder on it.


Pistons are different between the two as far as we can see. I have just ordered up the pistons from Honda and going into that work now. I would like to know if there is an interest in high compression from 10:7 to 11:1 ??



Or is the fuel there not able for that?

Thanks
Click to expand...




1)is the crankcase big enough to host the new crank? (adapt the ones for CBR300?)

2)sorry i did not see the pistons yet,I was reading an article about it (?), and had a chat with a shop wondering ...

3)we have gasohol 91 (suggested by honda for crf), and gasoline 95 (which also works well)
 
OK we could then go to higher compression. I think the crankcase is the same case. We were looking at the part #'s and we do have cases here. The next thing would be to put a 300 crank in and see what it looks like. I think the pin height is different on 250 vs 300 that's how they compensate for the stroke. So if they use a 250 crank and we take it to 305 that will do but will have to change crank for the 350 with different piston.

Mark
 
so..what do u suggest? i could order a cbr300 crank tomorrow if u garantee it will fit the case ,... then?
let's come up with a proper plan

Kustom Kraft said:
OK we could then go to higher compression. I think the crankcase is the same case. We were looking at the part #'s and we do have cases here. The next thing would be to put a 300 crank in and see what it looks like. I think the pin height is different on 250 vs 300 that's how they compensate for the stroke. So if they use a 250 crank and we take it to 305 that will do but will have to change crank for the 350 with different piston.

Mark
Click to expand...
 
Mark, welcome and happy to see you join. I hope the members of this forum will give you lots of feedback and room for testing/prototyping.
Your proposal for a 350cc conversion for the CRF250L/M makes me reconsider (again :roll:).

Marcel
 
In order for you to ride that you will also need a new piston we think the pin height is different than the 250 or you would hit the top of the cylinder because the difference in stroke. They are the same cylinder we check on that here. So the piston is different. Our lead time for pistons are 8-10 weeks for custom pistons. I would also want to put a cam in for more performance.
 
Thanks Marcel "Anything for the cause" Look forward to talking with you guys. They have passion about this type of bike
 
ok ,here I am .. look forward to your updates mate.. we'll get this going :RO

Sergio


Kustom Kraft said:
In order for you to ride that you will also need a new piston we think the pin height is different than the 250 or you would hit the top of the cylinder because the difference in stroke. They are the same cylinder we check on that here. So the piston is different. Our lead time for pistons are 8-10 weeks for custom pistons. I would also want to put a cam in for more performance.
Click to expand...
 
Well Mark, it look's like you have the attention of many of us on RA, we have all been eagerly awaiting for Honda to give a 350 or 400 variant of the 250 but nothing looming as yet. A reliable 350 platform would be a perfect balance, our riding season is fast approaching so if you can get the beta testing done soon then orders await :dirtbike:
 
What about fuelling? Can the standard EFI cope? Remap required? Or, a piggyback something like JD Jettings Big Bore Fuel Controller? (These are good as can deal more with the varying conditions we have here due to location and season - humidity, temp and altitude differences.)

Re. cooling, maybe you could sort something so you can fit a bigger water pump impeller - dunno the bike so not sure if this is poss'... Or just a high pressure rad cap. Better fan? Only 1 rad though!
 
Thai riders are passing by the KLX these day's in favour of the CRF, lot's of minor mod's around but nothing serious, seen some pictures of two fan's installed on the single radiator which may help, off road riding in this climate has the fan running pretty much all the time.
 
Kustom Kraft said:
I would like to know if there is an interest in high compression from 10:7 to 11:1 ?? Or is the fuel there not able for that?
Click to expand...
Mark, what would be the fuel requirements for the higher compression?

Thailand has ethanol mixed fuel, normally the fuel stations sell E10 in 91 and 95 RON, occasionally pumps sell ethanol free 95 RON. I have also seen pumps with E20 and E85!
I am not sure about Laos but think they get their fuel from Thailand, only recently Lao government announced rules enforcing petrol quality?!
 
Fuel and cooling

Hey there :dirtbike: Sorry for the delay in getting back online but had some other "Stuff" going on. We can make it stock compression if you think the fuel is going to be an issue? As far as fuel mapping we will have to do some experimenting with maybe a Juice Box?? Don't know if the injectors will need to be changed or not?? I just ordered pistons from Honda last week then off to get the custom ones on the drawing board.


brake034 said:
Mark, what would be the fuel requirements for the higher compression?

Thailand has ethanol mixed fuel, normally the fuel stations sell E10 in 91 and 95 RON, occasionally pumps sell ethanol free 95 RON. I have also seen pumps with E20 and E85!
I am not sure about Laos but think they get their fuel from Thailand, only recently Lao government announced rules enforcing petrol quality?!
Click to expand...
 
We make a KLX250sf-330 big bore kit for Kawasaki now. So that motor we did years ago. Big Bore kit | Cylinder Repair | Nikasil | Motorcycle | ATV

http://www.kustom-kraft.com/klx250bb.html




bsacbob said:
Thai riders are passing by the KLX these day's in favour of the CRF, lot's of minor mod's around but nothing serious, seen some pictures of two fan's installed on the single radiator which may help, off road riding in this climate has the fan running pretty much all the time.
Click to expand...
 
Thanks for the update, most of us are aware of your big bore for the KLX, so the CRF should be a walk in the park for you guy's Mark, keep us posted eager riders waiting :jumper:
 
that is gasoline 95 with the highest number of octanes,and able to withstand higher compression.(it also burns hotter then the gasohol mixtures etc)..it's been a while I haven't been there , can-t remember ,but i think in the states the highest was 91(?)
and being nearly 350cc changing EJK is a must.
bring it on guys ..we wait for some Vegas magic!! :MJ

brake034 said:
Mark, what would be the fuel requirements for the higher compression?

Thailand has ethanol mixed fuel, normally the fuel stations sell E10 in 91 and 95 RON, occasionally pumps sell ethanol free 95 RON. I have also seen pumps with E20 and E85!
I am not sure about Laos but think they get their fuel from Thailand, only recently Lao government announced rules enforcing petrol quality?!
Click to expand...
 
yes KustomKraft guys let's do it! any news?cheers
 
Mark mailed me following today: "I will be back in the shop on Sunday and I'll send you more info. :) Pistons are in the works and we have to see how far we can stroke the crank but looks good so far!"
 
You must log in or register to reply here.
Thread starter Similar threads Forum Replies Date
P hello from KALASIN Introductions 2
J solo scootertour of thailand/malasia - hi Introductions 2
Similar threads
hello from KALASIN
solo scootertour of thailand/malasia - hi
Back
Top Bottom