125-200cc More power in WR125 without changing to CR ignition?

[JB9]

Hi guys. I have a 2006 (EUDM) WR125 with a FMF exhaust, stock TMX carb. Carb in "full power" setting. Final gearing changed to 14/45. I will be using the bike for street, gravel and light enduro/trail riding.

Getting a lot of splooge(?) and poor running on idle and low revs though, despite idle jet being at 30 (down from "stock" 35), thinking maybe the needle jet(?) is bad?

I just feel like its embarrasingly slow for a 125 and according to workshop manual, has 0deg timing from 10Krpm-on? Jeez...

Will adjusting the stator give me any gains? I was thinking perhaps that could offset the whole ignition timing curve a bit? Or is CR ignition the only way to go? I still want lights etc so thats sadly no option. I did see some kind of aftermarket ignition kit on Ebay though, would that benefit me?

I don't expect the bike to perform like a motocross bike, but this just feels sad.

 

[rockdancer]

Poor running could be many things . Whats the compression like ? Could try a new piston - possibly a thinner base gasket . Whats the main jet ? 380 ? I would try a smaller idle jet if you can get one . Top end the CR and WR are similar . I do have a CR ignition set up I may sell but it will not be a cheap upgrade . The newer cylinders are slightly better . I do have a spare one of those also.
Have you checked the silencer - could be gummed up.

 

[rancher1]

The gearing you are using is really high even a 250 would suffer a little with it. That gearing is tall even for desert use. I would try a 13T front sprocket. I think 13/50 would be more common in the US.

 

[Dirtdame]

The gearing you are using is really high even a 250 would suffer a little with it. That gearing is tall even for desert use. I would try a 13T front sprocket. I think 13/50 would be more common in the US.

13/50 is what my WR125 came with off the showroom floor. I do a lot of single track though, so I am running a 52 for those steep, sandy inclines, and sudden rock faces. Can't say that the machine likes to run much higher than 45 mph comfortably, but it is a great trail bike geared that way.

 

[JB9]

Thanks guys. I will be using the bike mostly for street riding, to work and whatnot. Might do some gravel etc. It runs way better like this than with stock gearing, for what I use the bike for. Before, It would barely pass 90km/h and rev like crazy when doing it.. Now I can at least pass 100km/h at somewhat calm rpms. Acceleration still "decent".

Compression feels great, haven't measured it though. I bought the bike with a refreshed engine; New bearings, restored cylinder, new piston, new gaskets, etc. Can't remember which main jet I pút in last, but probably 390 or so.

In the workshop manual they have a page which shows the ignition curve for CR and WR, and the difference is MASSIVE, and should explain why the WR feels pretty much completely powerless at high rpms:

 

[Dirtdame]

Can't remember which main jet I pút in last, but probably 390 or so.

Wow! U.S. offroad version comes with a 460 main jet stock. There is definitely a difference in the way the models are tuned for performance.

 

[rockdancer]

Wow! U.S. offroad version comes with a 460 main jet stock. There is definitely a difference in the way the models are tuned for performance.

Different Carb . Its the old flat side carb . 380 was stock

 

[rockdancer]

Thanks guys. I will be using the bike mostly for street riding, to work and whatnot. Might do some gravel etc. It runs way better like this than with stock gearing, for what I use the bike for. Before, It would barely pass 90km/h and rev like crazy when doing it.. Now I can at least pass 100km/h at somewhat calm rpms. Acceleration still "decent".

Compression feels great, haven't measured it though. I bought the bike with a refreshed engine; New bearings, restored cylinder, new piston, new gaskets, etc. Can't remember which main jet I pút in last, but probably 390 or so.

In the workshop manual they have a page which shows the ignition curve for CR and WR, and the difference is MASSIVE, and should explain why the WR feels pretty much completely powerless at high rpms:

View attachment 105136

WRs actually feel like they have more top end overrev than Crs. Crs has more of an aggressive hit

 

[rancher1]

It is easy and cheap to switch the counter shaft sprocket so if you really need to get dirty on some tight trails it is an option.

 

[Sonnie Mee]

Check the reed petals
Check the crank seal gearbox side it might be sucking gear oil
Check the tiny gasket under the slide seat in the carb the two screws that hold it in are in the float chamber torxs heads sometimes that fails
You can get a little kit for it
Sometimes the oring goes brittle round the float plunger housing so fuel keeps coming in even when the float is closed
Air screw might be out of adjustment

Amongst a few things

 

[Picklito]

If that's a european street model... does it have any restrictors in the exhaust?

 

[Jara]

WRs actually feel like they have more top end overrev than Crs. Crs has more of an aggressive hit

How can you make the WR have more HIT?

 

[rockdancer]

How can you make the WR have more HIT?

Not easy to get much as they are more of a good lugger with a weak mid but good top end .
Options would be
Play with jetting - leaner pilot may help snap but not torque. Good jetting is key. You can try a smaller 36mm Keihen carb for low end response.
Lower cylinder with thinner base gasket - or get head modified (doesnt help much )
Different pipe - Fatty or pro circuit
CR silencer for more hit - not my preference for trails
Make sure power valve is fuctioning correctly . You can also play with power valve springs. I think its best to keep power valve closed longer and keep low down power. When it does open you want to Make sure its opening fully
Make sure the silencer is freshly packed - not choked up - this can make a huge differnce to how it feels
Keep the top end fresh