Acerbis 5.8 installed, Q4 opinion of both

Let me start with the tank. Everything you read below is just my opinion and I am really frustrated right now. Feel like I wasted half a Saturday and 225 dollars.


Harder than hell to get mounted, took 3 hours, all parts were 1/4-1/2 inch off. NOTHING FIT CORRECTLY!

Instructions sucked, tiny picture on 1 page not telling you where to use lock nuts, washers and mount rubber pad. No big deal until nothing lines up.

Had to use dremil to ream holes in the rear bracket to get 2 rear tank bolts/bracket to fit tank holes. Their bracket their holes their tank NO EXCUSE!

After 3 hours of cursing, beating and standing on the tank with all my weight I finally got the damn front brackets to line up with wifes' help.

MY F'ing god it was stupid tight and even with 220lbs weight on the tank the brackets were still 1/4 inch off.

The bracket is hitting the rectifier.

The rectifier is hitting the tank. Not hitting but gouging into the tank.

Rear bracket is NOT centered in the tunnel it is 1/2 inch canted left.

Rear bracket holes were drilled or mounted 1/4 inch too close, and bracket could not be mounted to tank. Either the tank or the bracket was off or both.

The signals hit on both sides. Why? If the stupid engineers had made it 1/4 inch less high on each side the signals would clear and the steering would lock.

The steering cant be locked.

OK so after 3 hours of cursing I get it mounted. I pour in some gas and test for leaks. All looks good.

The test ride........

First off I notice that the tank is vibrating like a pair of band drums. I thought it might be because it was empty. Oh how wrong I was.

I ride down to the gas station, and the tank is vibrating like crazy.

I fill it up thinking it will dampen the vibration. WRONG! It made it worse. Now it vibrates twice as bad. Its so bad you cannot rest your legs against the tank.

Next thing I notice is my bike is near bottomed out in the front. Its hard to come off kickstand as the CG is heavy and on top.

I get to the first freeway onramp and its a sweeping turn I usually can blaze through. Not today! The big top heavy tank makes it feel like I have a rider on back leaning the wrong way. The bike kept wanting to right itself instead of leaning over. Driving down the freeway it felt like a 73 Cadillac not a nimble dirt bike. I get to the offramp and start to take the turn only to find traffic was backed up. I hit the front brakes and holy shit the front slams to the bottom and almost takes me down. Only my 30+ years of riding kept me from crashing. I had to let off the front brake and swerve around in another lane because I wasn't going to stop.

Same thing happened to me when a light changed real quick in front from green to red. I had a hard time getting the bike stopped. The front slammed down and it was a weird feeling. Not good!

Drives like a big fat pig. I hate it!

Oh and the bike is running 25F hotter now.

The pipe (Q4)

The pipe was good at first and it has sense developed an irritating chirping noise as I go through the gears. Almost like a high freq whistle.

Sound like something is loose inside????

I'm going to spend the rest of the day removing the tank and the Q4 pipe with the annoying squeaky chirping rattle of noise coming out the back. Stock tank and stock pipe were much better than these parts.

I could not imagine taking this bike offroad at this point. The first small rock or slight crack would cause big problems.

Edited by problemchild200

Instructions do suck. But the fit is fine if tight. Some folks use boiling water to soften the plastic during the install, I used ratcheting straps to pull the tank down. It forced it just fine. Brackets fit, the rectifier touches (some folks grind the fins down, I didn't. Had it like that for about a year now. :)

OK, almost 6 gallons of fuel up top at around 8.5lbs per gallon one must expect a few changes in the CG. Imagine your surprise when you drop it on the trail and it's a bitch to pick up! :)

I have not noticed any vibrations, probably because I was able to snug the tank down with the factory holes.

In several locations, including the vendor I got the tank from, say the front signals need to be relocated. Guess you missed that.

I did not experience any braking issues either so I suspect it may not be related unless you somehow pinched a line somehow while mounting the tank. That one is a head scratcher.

I wonder if there are different generations to this tank? I had absolutly no issues mounting it(getting it on and off) whatsover, and I had it on and off about 20 times while I was trying to get it to seat right. I remeber suggesting that you read my write up as it would save you a few headaches that I had.

Addressing the weight, there is definitly a difference, but that is to be expected as you are adding basically double the gas supply. That being said the tank is also lighter and you dont have to keep it at capacity, so in a sense you could still have more fuel and it be lighter or the same weight. Just fill it when you know you are going on a long commute.

I have had no issues with braking or handling. But I dont generally ride this bike too agressivly. This bike is really, to use a term from futurama...the scooty puff jr of bikes lol. I have a cr250 that handles the dirt and a 1krr that handles the street.

I think you should sleep on it and rethink it in the morning, oh the tank does vibrate a bit but I hardly even notice it now.


Your post made me laugh.

I saw that tank mounted on a bike in Nevada, looks too massive.

Even though the stock tank is small on the volume side, its a nice part.

People say the air scoops suck and bla bla bla...

They are there for a reason.... To direct cooling air tword the head and exhaust.

I've read so much complaining about the XR650L.... (tear rolling down cheek)

First, if it aint broke.... Second if you don't like all the things wrong with it...

(too heavy, choked up, next 100 items here _____)

Why buy it?

I've left my L stock with the exeption of: Pro Moto billet rack, RSW upper triple, scotts damper, knobbies

Other than that... bone stock... smog pump, jetting all of it....

Its one of my favorite bikes of all time.

I was really tempted to go with that big tank, or even the Clark 4.7. I went with the Clark 4.0 and certainly don't regret it. Only wish is that it had 2 petcocks. Fit was flawless and zero problems.

Glad I saw this thread as I was starting to think about going the big ole tank again but I think I'll stick with my 4.0.

I put an ims 4 gallon gas tank in my old 93 xr650l. It fit great and took no time to install it. At 5.8 gallons full, your carrying 48 lbs at nearly the highest part of the bike other than the handlebars. It's liquid weight which moves when you hit bumps, brake ect. Check out the ims 4 gallon tank, it's much more reasonably sized.

OK I figured out how to use this tank.

1.)Spend 225 dollars on a big old clunky vibrating gas tank

2.) Cuss, and throw tools for 2+ hours while you install poorly fitting tank.

3.)Drive to gas station and add 2.5 gallons of gas (same as your stock tank).

4.) Drive around with the same amount of gas you had with your stock tank after wasting 225 dollars while your kneecaps vibrate off.

5.) Think of all the steak dinners you could have eaten with the 225 dollars.

6.) Pick which day you will remove tank, install OEM tank and list clunky tank on Fleabay.

Edited by problemchild200

Were you at least in a good mood when you bought these parts, or were you just as miserable as you are now? lol

Wow, I appreciate this experience as I will be sure to go no larger than a Clarke 4.7 when I upgrade my XRR ... ;) ...


I put an ims 4 gallon gas tank in my old 93 xr650l. It fit great and took no time to install it. At 5.8 gallons full, your carrying 48 lbs at nearly the highest part of the bike other than the handlebars. It's liquid weight which moves when you hit bumps, brake ect. Check out the ims 4 gallon tank, it's much more reasonably sized.

Wow! 5.8! You are the refueling carrier! I'll just run stock & buy gas of you on trail. Exxon Valdez!

As for the pipe, any updates. Just out of interest, are you just running the pipe on original headers or new headers?

As for the pipe, any updates. Just out of interest, are you just running the pipe on original headers or new headers?

Stock headers.

Q4 is chirping and squeaking when I grab gears. The stock pipe was fine and I saw NO gain going to the Q4. Another waste of money or a years with of fuel in my bike wasted. I dont like the sound either. Its harsh and not deep sounding like I thought it was going to be. More like fingernails down a chalk board type sound.

Edited by problemchild200

i have the clarke 4.7 on mine, its a little bigger than i prefer but i have gone 250km before reserve so its worth it to me


A+ to the Clarke 4.7, I would've gotten the 4, but the 4.7 came with the bike. Now if you do the mounting bracket mod, allowing the tank to mount to the frame, it is very stout. in fact the Clarke fits so nice, I had to run it when I did my USD fork swap so the forks wouldn't hit. I miss being able to run my stock tank, since I feel it would do better in the rough off road stuff.

Roll that beautiful bean footage....


I wish they would make an XR600 style tank for the XRL.

Edited by bluffskier

I didn't install the Clarke 4.7 on my bike originally, since it was already there when I bought the bike, but it's very easy to take off and put back on.

I just have to remember to not fill it to the top before riding on dirt trails, since the extra weight affects handling.

I prefer the larger tank so that I can ride 150 miles without having to think about refilling. I've only "hit reserve" on it a couple of times in five years.

i had the acerbis tank on my old xr600r back in the day and never had any problems with it,rode around the south island of new zealand a few times and loved it.i did however change my suspension settings,oil height and preload to accomodate the extra weight.

i just wonder if the acerbis xr650l tank fits on as nice?

ive got another 94 xr600r now and am wanting the acerbis 21lt tank to retrace my steps....


i also had the first run of fmf q mufflers for the xr6 (had the bike from 98 till 2003)cant remember exactly when i got it but it was crap,always hitting the rear caliper and denting the can,it was pretty flimsey

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