Upgrades for CRF250

[thaiguzzi]

You SHOULD NOT be riding that bike (a 24 hp 250 single) two up until the bike is FULLY RUN IN.

Put the bloody 13T front sprocket on.

And give it some Beanz. Solo.

Last post on this topic from me.

I'm outta here.

[taninthai]

Welcome to the world off low power single cylinder 

 

i have ave been trying to resist posting as I don’t think any more words can be said 

i was gonna ask how many km you put on bike

is there not anyone here that lives near poor Allan so they can go test bike and put this to rest????

[jb525]

I have ridden many crf250l bike ranging from stock, to 305cc big bore kits with cams and api injection. 

The best thing you can do is, tear up your warranty. Head over to Chiang mai. See Nat at it_shop#5.  He will put a cbr300 crank in. New camshafts which have had the timing changed on them.  Heavy duty clutch springs and take out the anti judder system.  And fit a fuel injection controller.  

They can also fit a longer 6th gear.

i rented one of his bikes and rode with some of his Thai mates.  The bike had more torque and lower down.  

Standard crfs have no power till you rev them over 7000 rpm.

[AllanB]

13t fitted and "seems" to be more torquey, smoother too, so maybe a slight chain misalignment, didn't check beforehand.

 

We have a trip to Loei province planned soon, we have each lost a couple of kilos over the summer and the bike has done a few more kms, so anyway... 

[taninthai]

going back to the sprockets .....turns out I made mistake and bought 45 t rear instead of a 42t.

obviously realised when I couldn’t get the back wheel back on due to chain to short,only option at the time was to switch back to the 13 t on the front instead of standard 14t,wheel just  about fitted on had to remove chain guide and wind adjusters all the way in.

dont like the 13t/45t combo at all ,feels horrible on the road have to go through gears quicker and just revving the arse of it all the time.

speedo reads super high 130 km/r when going what feels more like 70km/r

[AllanB]

 

going back to the sprockets .....turns out I made mistake and bought 45 t rear instead of a 42t.

obviously realised when I couldn’t get the back wheel back on due to chain to short,only option at the time was to switch back to the 13 t on the front instead of standard 14t,wheel just  about fitted on had to remove chain guide and wind adjusters all the way in.

dont like the 13t/45t combo at all ,feels horrible on the road have to go through gears quicker and just revving the arse of it all the time.

speedo reads super high 130 km/r when going what feels more like 70km/r

Yes, you will need a longer chain, the reason I changed the front sprocket. The 13t gives 7% 45/14t gives 12.5% and better power transmission, so may switch to that when the time comes.

 

By then the engine may have improved, as it is still surprisingly harsh.

 

I read that holding high revs for a couple of minutes when running in a Enfield engine can rid the bike of vibration. This is done as phase II of the running in process. There are a couple of Youtube vids on this.

 

With regards to the speedo reading, you have to do the maths and then keep it in your head. If I want to cruise at 80kph, I need around 85/86 on the clock.

[Kwasaki]

 

going back to the sprockets .....turns out I made mistake and bought 45 t rear instead of a 42t.

obviously realised when I couldn’t get the back wheel back on due to chain to short,only option at the time was to switch back to the 13 t on the front instead of standard 14t,wheel just  about fitted on had to remove chain guide and wind adjusters all the way in.

dont like the 13t/45t combo at all ,feels horrible on the road have to go through gears quicker and just revving the arse of it all the time.

speedo reads super high 130 km/r when going what feels more like 70km/r

What did you expect the OEM 14 / 40 is what the Honda bike is designed for, understand if guys do a lot of off-road stuff but other than that don't see the point.  

[taninthai]

 

What did you expect the OEM 14 / 40 is what the Honda bike is designed for, understand if guys do a lot of off-road stuff but other than that don't see the point.  

Yep as said I made mistake and for some reason ordered wrong sprocket...had been running,14/42 for road which I find fine ,did experiment with 13/42 for road and wasn’t keen on that,the 45t sprocket is on my off road wheels anyway .....will be ordering a new 42t for my road wheels as old 42t has worn out also put 14t front back on when fitting road wheels????????

[thaiguzzi]

5 hours ago, AllanB said:

I read that holding high revs for a couple of minutes when running in a Enfield engine can rid the bike of vibration. This is done as phase II of the running in process.

????

That might work on an extreme short stroke water cooled DOHC motor like a CRF250L, (but very much doubt it ) but i would not even think of doing that on an all roller bearing big end long stroke air cooled single, like a 500cc OHV Enfield.

Just cos you see something on YouTube does not make it true.

There is a lot of utter garbage out there.

Buyer beware!

Bit like the Google internet health experts. Instead of actually going to see a real doctor, they google a bunch of "net experts" for their ails and believe it as gospel.

Like my mum.......

[canthai55]

5 minutes ago, thaiguzzi said:

but i would not even think of doing that on an all roller bearing big end long stroke air cooled single, like a 500cc OHV Enfield.

https://www.change.org/p/suffering-major-problems-with-royal-enfield-himalayan

[Kwasaki]

1 hour ago, canthai55 said:

https://www.change.org/p/suffering-major-problems-with-royal-enfield-himalayan

Glutens for punishment comes to mind. 

[thaiguzzi]

9 hours ago, canthai55 said:

https://www.change.org/p/suffering-major-problems-with-royal-enfield-himalayan

Lemon?

Or Lime?

Or Royal Enfield dunno how to cope with OHC? ????

Either way, no way Hose.

Again, Luddite TG here, the last proper Enfield was the last of the Pre Units in 09..........

 

[Kwasaki]

12 hours ago, thaiguzzi said:

Lemon?

Or Lime?

Or Royal Enfield dunno how to cope with OHC? ????

Either way, no way Hose.

Again, Luddite TG here, the last proper Enfield was the last of the Pre Units in 09..........

 

As was said the old cast-iron engine which was heavy with a separate gearbox and a carburettor ( not carburetor), ???? was more space consuming and wasn’t very efficient either but it seemed to me what Enfield owners liked.

It's not really a Royal Enfield anymore just another poor attempted copy.

A bit like Ducati doing the same as a Harley twin.

[AllanB]

On 12/4/2018 at 3:10 AM, Kwasaki said:

What did you expect the OEM 14 / 40 is what the Honda bike is designed for, understand if guys do a lot of off-road stuff but other than that don't see the point.  

My original posting was about increasing the torque at the wheels which this cheap change in gearing will do. Possibly not sufficiently, but it's a start. I don't need a top end much over 80 klicks, so no real losses and it takes the load off the engine when there is a 140/150kg payload on board. 

 

My guess is that this bike/engine/gearing is designed for one rider mainly on-road, so mods are helpful for other applications.

[Kwasaki]

16 hours ago, AllanB said:

My guess is that this bike/engine/gearing is designed for one rider mainly on-road, so mods are helpful for other applications.

I don't see it like that 1st gear is low enough to pull weight I guess  Honda expects you to use the gearbox.

[canthai55]

4 hours ago, Kwasaki said:

I don't see it like that 1st gear is low enough to pull weight I guess  Honda expects you to use the gearbox.

Changing the gearing will not increase torque or horsepower.

The engine has a torque and horsepower curve, this remains the same whatever gear you are in. Lines cross at 5252 RPM.

What it will do is change the road speed where the maximum of either is reached.

Gear the bike down and you achieve max torque at a lower speed.

Want more torque - burn more fuel, all other things being equal. To burn more fuel, you must pump more air. Increase displacement or forced induction Changing the camshaft lift, duration, and overlap also work, but normally aspirated engines can only go so far with this, and it brings a whole lot of issues with it, chiefly raising the RPM where the engine can take advantage of the increases in breathing the cam change allows.

My GPZ1100 would not idle below 5000 RPM due to the 'lumpy' cams installed.

No such thing as a free lunch.

[AllanB]

On 12/6/2018 at 4:45 PM, canthai55 said:

Changing the gearing will not increase torque or horsepower.

The engine has a torque and horsepower curve, this remains the same whatever gear you are in. Lines cross at 5252 RPM.

What it will do is change the road speed where the maximum of either is reached.

Gear the bike down and you achieve max torque at a lower speed.

Want more torque - burn more fuel, all other things being equal. To burn more fuel, you must pump more air. Increase displacement or forced induction Changing the camshaft lift, duration, and overlap also work, but normally aspirated engines can only go so far with this, and it brings a whole lot of issues with it, chiefly raising the RPM where the engine can take advantage of the increases in breathing the cam change allows.

My GPZ1100 would not idle below 5000 RPM due to the 'lumpy' cams installed.

No such thing as a free lunch.

Obviously changing the final drive won't have any effect on the engine torque/bhp, but it will increase torque at the rear wheel. You will also be using a higher rpm for a given road speed in all gears and since this bike needs rpm to perform, so changing the front sprocket is an advantage. The level of advantage is the question, but since the mod is cheap, easy and reversable, it is worth a try and the only downside is a possible loss in top end speed performance which is not important to me. My guess is that the revised gearing will increase maximum road speed when the bike is heavily loaded.

 

Who is looking for a free lunch, just simple street food, in any case I have had many free lunches, so I don't know why people use that saying? Expectation and delivery are two different things.

[papa al]

...so wise !

[Kwasaki]

On 12/6/2018 at 4:45 PM, canthai55 said:

Changing the gearing

My GPZ1100 would not idle below 5000 RPM due to the 'lumpy' cams installed.

No such thing as a free lunch.

Yep the CRF250L comes already for the road IMO.

GPZ1100 now we are talking 2 up full luggagt and still plenty of torque. ???? ????