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Rebuilt wr300 still lacking power

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Hi guys i picked up a bike a little while ago that had issues. The bike didnt have the power that people say 300s have. i stripped it down as it was due for a top end and found a hairline crack in the piston which was quite worn. I just finished the rebuild, i replaced- Piston and rings (pro-x), carbon fibre reed petals, gaskets, orings, new clutch plates, cleaned powervalve, cylinder diamond honed. The bike now has better compression than before, starts easier and runs better and obviously has more power, but struggles to reach over 85 kph  which seems ridiculous and still doesnt have that power that they are supposed to. im stuck with what to do next. Ive allready played with the air screw etc. The gearing im running is 47t 13t.

 

I wish this bike had a 6th gear!!!!

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Sounds like either the power valve isn't lifting or maybe a crank seal.

Is it smoking more than normal?

take the side cover off the power valve and rev the bike to see if it lifts as normal 

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I bought one of these new in 2013. 52 miles per hour seems a bit slow BUT they are not a wide ratio transmission despite the WR term. This is simply their old Cagiva WMX 250 from 1987 that got a big bore kit in 2009. Ever wonder why it's right side drive? It's because the engine is pretty much original Cagiva from 1987. As I recall it wasn't any faster or harder hitting than my 2007 YZ250 but it did have more grunt/torque comparatively. Also in 2011 they added a Ducati electronic ignition which IMO was soft on spark and made starting MORE difficult. 

If you want more top speed then install a 14T CS sprocket or a smaller rear sprocket. I have both for sale if you'd like. :)

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7 hours ago, sandking11 said:

Sounds like either the power valve isn't lifting or maybe a crank seal.

Is it smoking more than normal?

take the side cover off the power valve and rev the bike to see if it lifts as normal 

This is my first ever 2 stroke so im not sure if it smokes more than it should. It smokes a fair bit until its warm and than it doesnt smoke much.

Ill take the pv cover off and have a look, thanks mate.

3 hours ago, motodr441 said:

+1 bat allso could be jetting 

Yeah i was thinking it could be, what jetting should i be running or do i need a jetting kit and fiddle around?

 

3 hours ago, shrubitup said:

I bought one of these new in 2013. 52 miles per hour seems a bit slow BUT they are not a wide ratio transmission despite the WR term. This is simply their old Cagiva WMX 250 from 1987 that got a big bore kit in 2009. Ever wonder why it's right side drive? It's because the engine is pretty much original Cagiva from 1987. As I recall it wasn't any faster or harder hitting than my 2007 YZ250 but it did have more grunt/torque comparatively. Also in 2011 they added a Ducati electronic ignition which IMO was soft on spark and made starting MORE difficult. 

If you want more top speed then install a 14T CS sprocket or a smaller rear sprocket. I have both for sale if you'd like. :)

Yeah im going to buy a 14t or maybe even 15t, thanks for your offer but i live in Au

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I don't know the wr300 but I wold do the jetting by feel wold start by checking the float if their is play whit the slide check if the carb is clean log the jet sizes and needle  and if you have access to the manual tray to use wat thay suggest for you area 

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3 hours ago, shrubitup said:

I bought one of these new in 2013. 52 miles per hour seems a bit slow BUT they are not a wide ratio transmission despite the WR term. This is simply their old Cagiva WMX 250 from 1987 that got a big bore kit in 2009. Ever wonder why it's right side drive? It's because the engine is pretty much original Cagiva from 1987. As I recall it wasn't any faster or harder hitting than my 2007 YZ250 but it did have more grunt/torque comparatively. Also in 2011 they added a Ducati electronic ignition which IMO was soft on spark and made starting MORE difficult. 

If you want more top speed then install a 14T CS sprocket or a smaller rear sprocket. I have both for sale if you'd like. :)

What was the top speed on your 2013?

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27 minutes ago, JDBKTM350exc said:

What was the top speed on your 2013?

Never got there. Always rode it slow following a trials bike around in thick, tight woods. 

22 minutes ago, motodr441 said:

I don't know what it should be but my 2016 te300 do 85 at 7.5k rpm so it wold make sense it will fill like struggling you could just be to used to a 4t 

No need to compare these. Way different products. The TE300 actually has a wide ratio transmission and the motor (and everything else) is made by KTM. 

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im realy hoping that its not a shot crank seal :(, yesterday when i rode it for the first time after rebuild i put 800cc oil in than after 2 hours of riding 710cc came out :facepalm:. I put 800cc back in and today 750cc came out :banghead: so it seems to be losing a slight amount of oil somehow. How will i know if its a crank seal?? And if i keep topping the oil up is it safe to ride it like that for a few weeks until i have enough money to strip her down again? How will i know if its the left side seal or right side seal? Thanks guys.

Oh and today i changed the air screw from 2 turns out to 1.5 turns out and it seems to be quicker, than changed to 1 turn and felt equal to 2 turns so its now set back at 1.5

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5 minutes ago, JDBKTM350exc said:

im realy hoping that its not a shot crank seal :(, yesterday when i rode it for the first time after rebuild i put 800cc oil in than after 2 hours of riding 710cc came out :facepalm:. I put 800cc back in and today 750cc came out :banghead: so it seems to be losing a slight amount of oil somehow. How will i know if its a crank seal?? And if i keep topping the oil up is it safe to ride it like that for a few weeks until i have enough money to strip her down again? How will i know if its the left side seal or right side seal? Thanks guys.

Oh and today i changed the air screw from 2 turns out to 1.5 turns out and it seems to be quicker, than changed to 1 turn and felt equal to 2 turns so its now set back at 1.5

How to pressure test your two stroke:

If you're losing transmission oil then it's the right side crank seal. To test if the left one is bad, remove ignition cover, start engine, spray carb cleaner or starter fluid behind flywheel. If revs increase then you have a left crank seal that also went bad. 

However! :prof: on your motor it's the reverse. Clutch on left and ignition on right side. Same tests tho. If you're losing transmission fluid then it's the left side crank seal. Test behind ignition cover on your right side of motor for a right side crank seal. 

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1 hour ago, shrubitup said:

How to pressure test your two stroke:

If you're losing transmission oil then it's the right side crank seal. To test if the left one is bad, remove ignition cover , start engine, spray carb cleaner or starter fluid behind flywheel. If revs increase then you have a left crank seal that also went bad. 

However! :prof: on your motor it's the reverse. Clutch on left and ignition on right side. Same tests tho. If you're losing transmission fluid then it's the left side crank seal. Test behind ignition cover on your right side of motor for a right side crank seal. 

Thanks for your help mate im just thinking of selling the bike as is and buying something reliable

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On 5/13/2017 at 3:55 PM, shrubitup said:

Never got there. Always rode it slow following a trials bike around in thick, tight woods. 

No need to compare these. Way different products. The TE300 actually has a wide ratio transmission and the motor (and everything else) is made by KTM. 

My TX with stock gearing goes over 60 mph without WOT, plenty for the woods and single track.  

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Just now, shrubitup said:


Yours is a white KTM not the Italian husky we were discussing.

My bad, didn't read that carefully, just trying to be helpful...

 

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Crank seals are easy to replace and do not require case splitting like other bikes.

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