Big Bore rebuild over heating and oil consumption

Hello, 

I was just looking for some advice. I've gone through the forums and I'm still unclear about what to do about my big bore kit. I purchased a used 07 XRL and didn't know it couldn't ride highways at high speeds without constant oil supervision. Eventually I starved my engine. I had it rebuilt and honed out my cylinder to make the bike a 685cc (so they say) big bore engine. The problem with that was it would get really hot (375-400deg) while riding to work. Never at night coming from work, which is a 50 mile round trip 95% highway miles. I also changed the rear sprocket to a 40 tooth and cruised at about 80-85 MPH. The RPMs stayed at about 4-5K. Any recommendations on what to do? I've considered getting an oil cooler put in and possibly going back to a sleeved stock piston. I don't want to lose that power though. Thanks.  

 

K&N air filter

Stock Carb (Had Keihin FCR 41, but wouldn't idle at stops or start when cold)

Fresh Spark Plug

After market header and exhaust

You have the wrong tool for the job of your commute. It is fairly known that the XRL doesn't like high speed, extended running. The XRL is basically a big pump and it uses oil when run hard as your doing with your 80/85 MPH run. Bottom line, buy a different bike for this commute.

 

BTW... I wouldn't be surprised if you haven't already damaged your new piston.

Edited by mcma111

What carb jetting? Have you done a spark plug chop during an 85 mph ride?

Stock carb, K&N, Bigbore and exhaust? You're waaaaaayyyyy too lean. In the least you need to rejet the carb. Even then sustained high speed will take its toll. As mcma said you probably already damaged the new piston, rings and /or cylinder running that hot and it's sucking oil from the premature wear. And it's likely 675cc not 685. Above 675 takes double the money to install as the cylinder, sleeve and maincases all need machine work to fit up the pistons larger than 102.4mm. You might have a 103mm piston in the stock sleeve but that is guaranteed to not last long as the sleeve is far too thin to maintain roundness for any time at all. I don't know any mechanic, engine builder or machinist that would bore an L barrel that thin.

Edited by valvesrule

That sucks. Thanks for all the feedback.

I bought this because it's a "dual" sport. Is there any configuration or speed suggestions to keep this bike for what I need. On my way to work I have transient speeds of 80 MPH but mostly lane split and ride at 75 MPH. At night it's an open freeway, and if need be I'll slow down. Lol. I have 90/10 tires on there now and the 40 tooth sprocket.

I've seen on forums where ppl use this bike on there highway commutes.

I'm sorry, the temp it runs at is 275-300 during the day. 225-250 at night.

That sucks. Thanks for all the feedback.

I bought this because it's a "dual" sport. Is there any configuration or speed suggestions to keep this bike for what I need. On my way to work I have transient speeds of 80 MPH but mostly lane split and ride at 75 MPH. At night it's an open freeway, and if need be I'll slow down. Lol. I have 90/10 tires on there now and the 40 tooth sprocket.

I've seen on forums where ppl use this bike on there highway commutes.

oil cooler for sure, big fin  head would help too. does sound like its running way lean though. extra fuel consumption is cheaper than constantly replacing parts.

Just so we are on the same page, is the countershaft sprocket a 15?

It's stock.

First you need to get the jetting right, if its lean (highly likely with your current setup) it will run HOT, thats a fact. After that you should be able to control temps with the right gearing and an oil cooler, but if you constantly push the engine hard then it will be difficult to control temps. Shortening the back of the front fender to expose the engine to more air may also help some.

It came with a KTM fender and it is short and has air vents.

You have the wrong tool for the job of your commute. It is fairly known that the XRL doesn't like high speed, extended running. The XRL is basically a big pump and it uses oil when run hard as your doing with your 80/85 MPH run. Bottom line, buy a different bike for this commute.

 

BTW... I wouldn't be surprised if you haven't already damaged your new piston.

What he said, just because it's a dual sport bike does not mean you can ride it on the street like a GSXR then ride it like a KTM in the dirt.  It is a "compromise" bike.  It does neither of those roles really well but rather good enough. 

What he said, just because it's a dual sport bike does not mean you can ride it on the street like a GSXR then ride it like a KTM in the dirt. It is a "compromise" bike. It does neither of those roles really well but rather good enough.

I just ordered an oil cooler from SRC and the shop is going back to stock with my piston. I'll try to watch my temps and slow down. Hopefully I don't have to sell it.

I have a 2001 XRL with a JE 101mm high Compression piston with some other minor motor mods including an oil cooler.  I built mine as an "adventure" bike to take to Central America in June.  Loaded up with all my gear it weighs right around 500 pounds.  It cruises all day at 70 mph with minimum oil burn and it runs fantastic, the gearing is stock.  When I try and push it to 80 and 85 mph I can tell by the engine I am pushing it hard and oil temps start coming up and oil consumption goes up.  The big bore has nothing to do with your problem, it's how you are riding it.

You just have to accept it for what it is and not try to ask it to do something it was not designed to do. 

DSC00029_zps93b1a44d.jpg

 

When I want to ride fast I simply break this one out.

 

100_0227_zps3d83419b.jpg

Edited by baldy110

I have a 2001 XRL with a JE 101mm high Compression piston with some other minor motor mods including an oil cooler. I built mine as an "adventure" bike to take to Central America in June. Loaded up with all my gear it weighs right around 500 pounds. It cruises all day at 70 mph with minimum oil burn and it runs fantastic, the gearing is stock. When I try and push it to 80 and 85 mph I can tell by the engine I am pushing it hard and oil temps start coming up and oil consumption goes up. The big bore has nothing to do with your problem, it's how you are riding it.

You just have to accept it for what it is and not try to ask it to do something it was not designed to do.

DSC00029_zps93b1a44d.jpg

When I want to ride fast I simply break this one our.

100_0227_zps3d83419b.jpg

That's some great advice. I guess I just got excited when I bought it. I'll try to keep the speed down. I actually got a dual sport to help limit my need for speed. Lol.

I just ordered an oil cooler from SRC and the shop is going back to stock with my piston. I'll try to watch my temps and slow down. Hopefully I don't have to sell it.

[cough] Jetting [cough]

[cough] Jetting [cough]

Noted. Thanks!

people seem to think ..since these are big bikes.....can cruise like a sport bike all day long..never did understand it myself..

 

These are only a 650 SINGLE CYLINDER  dirtbike......although large bore for a dirtbike,it`s seriously small and under powered for a road bike.....it can be riden up to 65-70 for hours.....but anything over that and you are at full throttle,,pinned....

 

You gotta ask yourself this......would you drive your car full throttle and expect it to last any real length of time???..not likely..

 

These are a great bike,,tons of torque ..decent enopugh suspension..and can do moderate road duty..if not over stressed..and it pays back in durability and not needing constant maintenance..

 

B

What oil are you running? I usually run a Motul,with little consumption, except recently I had to resort to a Castrol, which  simply dissapeared.

  Wont be using that again!

people seem to think ..since these are big bikes.....can cruise like a sport bike all day long..never did understand it myself..

These are only a 650 SINGLE CYLINDER dirtbike......although large bore for a dirtbike,it`s seriously small and under powered for a road bike.....it can be riden up to 65-70 for hours.....but anything over that and you are at full throttle,,pinned....

You gotta ask yourself this......would you drive your car full throttle and expect it to last any real length of time???..not likely..

These are a great bike,,tons of torque ..decent enopugh suspension..and can do moderate road duty..if not over stressed..and it pays back in durability and not needing constant maintenance..

B

Changing the rear sprocket should make it easier on the engine though, right? Or rarely saw over 5K RPMs on the highway.

What oil are you running? I usually run a Motul,with little consumption, except recently I had to resort to a Castrol, which simply dissapeared.

Wont be using that again!

We ran motul also. No dice.

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