My windshield killed my bike.....

Story time: I just equipped my XJ700N with a Memphis Shades Road Master windshield.

Without the windshield it will go up to about 110 and red line out. With the windshield it will get up to 55 and sputter and have troubles getting any faster. I guessing I need to re-jet to allow more power for the increased air resistance.

How do i go about the math re-jetting to get more power? It has the stock air box and stock 4 into 2 pipes.

 

what did you do? grind up the windshield and chunk the shavings into the gas tank? :lol:

something else is amiss... drag from the windshield could cause buffeting and instability, but it won't affect your engine performance (unless it's a riot shield). top end gone bye bye could mean a few things, like fuel starvation, poor spark or otherwise missing cylinders.

check the simple things first... got fuel? no kinks in the fuel lines? got spark on all four? plugs look ok? they should have some color to them...

 

Agreed. Your problem is elsewhere.

Did you have the fuel tank off for the install? Check for kinked fuel line or a rise in it that is capturing an air bubble.

 

I didn't need to take the tank off for the install.

The thing is though when I take the shield off, it runs just fine. That's why I think it's the shield. I've checked all the cables and lines and the shield isn't running into anything. I'm very confused...

 

Perhaps you've got a loose connection somewhere. With the shield on, air is being directed onto that connection which is causing you trouble.

 

lose the shield and keep doin 110!

 

I'm in agreement that the shield itself can't be producing enough drag to slow a healthy XJ700 that drastically. SOME performance decrease, yes, but there has to more to this than just the aero resistance of the shield.

 

I'm not a big fan of shield. So, yes lose the shield. Don't just stop there though. There is obviously something else wrong that would require some trouble shooting. Figure out what that is to keep the bike safe so you have piece of mind while going 110.

 

Okay, I think I may have found out the problem.

A week ago I put Restore brand Engine Restorer in my engine. It's meant for car engines but I figured since it's formulated for 4-cylinder engines it would be fine. After riding for a bit the problem started to creep into my lower gears as well. It fell into 1st and wouldn't go 20, then kicked over and went fine for a bit, then shuttered and my 3rd gear was the problem, then it flipped over back into my 5th gear going 55 again.

I'm assuming the problem is my clutch slipping, maybe from the extra lube from the Restore. Does that sound like a clutch problem and would taking the plates out and cleaning them really well fix this?

Another thing, I put new bars on to fit the windshield. The clutch lever now has considerably less play in it than it did. I'm going to adjust it tomorrow and see if it helps. If not I might need to see if someone has a new clutch basket. :cry:

 

OK, there you go. But you're WAAYY jumping to conclusions on the clutch. If what you're describing IS in fact the clutch slipping, which is a good possibility based on the fact you dumped that stuff in your motor, I recommend the following:

Check your owners or service manual and adjust the clutch mechanism correctly, if it's too tight it could be not releasing the clutch all the way.

Change your oil and filter. Use Castrol 4T (motorcycle oil) 20W50. Ride the bike (without the fairing) for a couple of days and see if the clutch issue clears up.

If there WAS any "permanent" damage to the clutch, you wouldn't need a basket; most likely just friction plates if they couldn't be cleaned enough.

 

I usually use the Rotella 15W-40, heavy duty. The bike runs smooth and the shifter is crisp. Would you suggest using the Castrol still or would it be okay to use the Rotella. (I have 2 gallons of it in my garage, just want to know if I need to buy Castrol)

 

I lot of us like the castrol and have had good results. Key here is to get rid of the additive....

 

when it tops out at 55 what rpms are you turning could it be possible that with the wind sheild you are interfering with the throttle cable

my 650 has no performance change with or without my sheild

 

Fair enough. I'll pick up some Castrol and change the filter. Hope this works!

 

My bike is not trying any harder than normal. At 55 I'm running 4k in 5th, no matter how much I open the throttle. When I took my shield off the same thing is beginning to happen.

 

Sorry should have been more clear. I and others love the castrol. Key for you is to get rid of the additive. If you have 2 gal left and have not had issues with your oil I personally would not switch until it was gone - if I wanted to switch. But I'm cheap. Just make sure the oil you have does not contain the friction modifiers.

I would also recommend changing you oil again after a bit to be sure you have flushed the additive but that would be the over cautious method.

 

i dont know if this is much help but my 650 was doing the same thing toped out at 60 at 6000 rpm i found i later found out that the floats in my carbs were upside down leaving the fuel level low i didnt notice a performance issue until about 5000 rpm it still could be fuel starvation or an issue with the throttle

 

So I took some time today and changed my oil and my filter and just for good measure I took my carbs off and cleaned those out, too. After that I took it out for about a 20 mile ride and seeing no problems I put the shield back on and took it out again. This time I did a 40 mile round trip. I'm not sure if one or all of those things helped but my XJ is purring like a kitten and pulling like an ox again!

I managed to hit 105 with my shield on, with some room to spare in the throttle.

I and my bike thank all of you for the help!

 

Also, that Castrol stuff is working smooth than my Rotella. I do believe I will stick with it.

 

OH MY ! ! !

Restore has Mirco bits of copper in it and when it get s hot it sticks to hot metal. chances are your clutchs have been coppered . that would be my best educated guess.