Power issue // monster 620

[nine_inch_rear]

There are timing parks on counter belt sprocket and cam sprockets. Take a look at youtube- CA cycleworks. Chris does a great tutorial on belt replacement and what marks to look for,etc. I didnt look at all the posts, but air filter in good shape? Also make sure your actually getting full throttle. Im not sure on your year, but mine has push/pull dual cable set up. Here ya go....

[youtube]9vzPZ84ZRjU[/youtube]

 

[Dark_620]

For sure the air filter is brand new.
Here's my process : listing possible issues from the least expensive parts to the highest (pretty logic, I bet we all do the same right ?)

I already checked all of this before :
- fuses (just in case)
- air filter (replaced by Desmoto 1-2K miles mile ago, and I checked, perfectly clean)
- spark plugs and wires
- coils
- clutch (apparently my clutch was dead anyway, so I replaced it two days ago)
- oil & filter (I replaced it since my clutch was very worn and I found some friction material pieces in the engine. The oil filter was less than 2K miles though, but I did it as precaution)
- belts are brand new (replaced at Desmoto 1-2K miles ago)


Here are photos of the belts.
Tell me if you see anything strange from your more experienced eyes guys !!

 

[Dark_620]

MY BAD / oil level

Concerning oil level, let's put this one aside, I just did it wrong.

Since I've been kicked out of my private parking lot because of a stupid building neighbor, I do all my work outside in the street. Truth is my street is a slight down hill (on the opposite of the building's parking), ultimately the level was wrong. I'm so stupid on that one...

However, the power issue was there way before, and we can't loose 80% of horsepower for a bad oil level I suppose

 

[augustiron]

If those reference marks are in the right places in you photos, you are one tooth off on the horizontal belt, double check, find out how/why it is that way and fix it.

 

[Dark_620]

Nobody touched the belts since Desmoto installed it, so if it's wrong, the reason for this can only be a bad installation.

 

[nine_inch_rear]

Those marks have to be dead on. The vert cylinder seems off to me but that might be because of camera angle. Do you have a hole on the back cover to line up for the horiz. cylinder? Both cam marks just dont look right.

 

[nine_inch_rear]

I looked at the video and compared that horiz cylinder (front). That mark is off a tooth. Once you reset the timing, turn the engine over by hand 2 full revolutions. Recheck belt tension and marks. Go ride and have fun

 

[Dark_620]

Hey guys !

I checked on the phone with Desmoto today and they confirmed me that they also did the VALVES ADJUSTMENT during the last service, 1K miles ago. They didn't discover anything weird on the bike, that the previous owner could have hide to me. This was reassuring !!
They confirmed that the guy asked them to do everything that has to be done, so Desmoto's guy on the phone even said that "the bike should be in a pretty good condition".

Then I explained him the story about the loss of power that I've been noticing more and more through the last weeks and noticed that the horizontal cylinder belt was (obviously installed) one tooth off. So I'll bring them the bike on Saturday so that they can check this out and look for other possible issues...

I will keep you informed guys, thanks again !

 

[augustiron]

Good luck, hope desmoto gets you sorted for not much $$$$

 

[nine_inch_rear]

Thanks for keeping us up to date.

 

[Lex Talionis]

If the belt is a tooth off, could that result in burned exhaust valves by the cam not allowing the valves to close all the way when combustion occurs?

I'm guessing the engine design is an interference fit between valves and piston; how many teeth off on belt installation before valve/piston contact?

OP, please provide better pics of the belt position before/after Desmoto looks at it.

Lex

 

[El Feo]

If the belt is a tooth off, could that result in burned exhaust valves by the cam not allowing the valves to close all the way when combustion occurs?

It's advanced 20 degrees (40 degrees on the crank). So, the exhaust valve has long since closed before TDC, albeit open way early.

I'm guessing the engine design is an interference fit between valves and piston; how many teeth off on belt installation before valve/piston contact?

I'd bet one more tooth would make the piston crash right into the intake. arty

 

[Dark_620]

Desmoto's feedback :

My fuel tank is filled with mud, like REAL DARK CRAZY MUD !
(probably the reason why my spark plugs were so dark)
- Weird... 4 months/1K miles ago they cleaned the tank with anti-rust stuff... and I only use the best gas. I don't understand -

(and my fuel tank cap is the original one, requiring the key to open it, so nobody could have drop shit inside the bike)

They put another fuel tank and fuel filter on it but nothing changed.
So they're planning to change the fuel pump tomorrow and see how it goes...

Injectors might need a serious cleaning, like opening the engine clean the inside for real

 

[El Feo]

Desmoto's feedback :

My fuel tank is filled with mud, like REAL DARK CRAZY MUD !
(probably the reason why my spark plugs were so dark)
- Weird... 4 months/1K miles ago they cleaned the tank with anti-rust stuff... and I only use the best gas. I don't understand -

(and my fuel tank cap is the original one, requiring the key to open it, so nobody could have drop shit inside the bike)

They put another fuel tank and fuel filter on it but nothing changed.
So they're planning to change the fuel pump tomorrow and see how it goes...

Injectors might need a serious cleaning, like opening the engine clean the inside for real

Mud, you say?

You've got feces throwing monkeys working on your bike. The fuel pump, filter, etc are all in the tank. So, if they swapped the tank already...

And all that stuff is super easy to test (flow rate, pressure, injector spray pattern, etc.)

 

[nine_inch_rear]

Did they address cam timing issue?

 

[El Feo]

Did they address cam timing issue?

Was wondering the same thing.

 

[Dark_620]

Today's feedback from Desmoto : "THE BIKE RIDES VERY GOOD !" :boobies

The problem is cleared now it has :
- another fuel tank
- another fuel pump
- new fuel filter

Concerning the belts : the man told me it was all right when he rode it today so he said it shouldn't be a tooth off, but they'll remove the covers and check this out tomorrow.

Talking about the tank... Do some of you guys experienced that with your bikes??
Apparently the problem comes from the tank which is too old...
It's a 14YO 33K miles bike. And Desmoto cleaned this tank 4 months/1K miles ago. Plus... if the tank was loosing some material in the inside, this would be rusty colored right ? not BLACK ?!! I really don't know what to think about this story guys...

 

[bpw]

Today's feedback from Desmoto : "THE BIKE RIDES VERY GOOD !" :boobies

The problem is cleared now it has :
- another fuel tank
- another fuel pump
- new fuel filter

Concerning the belts : the man told me it was all right when he rode it today so he said it shouldn't be a tooth off, but they'll remove the covers and check this out tomorrow.

Talking about the tank... Do some of you guys experienced that with your bikes??
Apparently the problem comes from the tank which is too old...
It's a 14YO 33K miles bike. And Desmoto cleaned this tank 4 months/1K miles ago. Plus... if the tank was loosing some material in the inside, this would be rusty colored right ? not BLACK ?!! I really don't know what to think about this story guys...

Almost sounds like someone coated the tank at some point and didn't do it right or used the wrong stuff. A regular steel tank shouldn't have any issues beyond a little surface rust unless it sat for a very long time.

Maybe the cleaning agent they used reacted poorly to a tank coating and now it is flaking off?

Not sure why someone would coat a steel tank on such a new bike though.

 

[Dark_620]

Yes, that hypothesis makes sense.

I'll normally get the bike back tomorrow. I'll let you know some more details !

Damn... That was all just a stupid basic problem, not even spark plugs or air filter ! I learned some stuff with that clutch though!

So THANK YOU ALL guys for your feedbacks and your help!
See you on the road ! arty



... Let's hope I'd never get smoked by a Bonneville again !

 

[ScottRNelson]

Talking about the tank... Do some of you guys experienced that with your bikes??
Apparently the problem comes from the tank which is too old...
It's a 14YO 33K miles bike. And Desmoto cleaned this tank 4 months/1K miles ago. Plus... if the tank was losing some material in the inside, this would be rusty colored right ? not BLACK ?!! I really don't know what to think about this story guys...

My 1993 Ducati 888 SPO Superbike had rust in the tank when it was about 15 years old. It would clog the fuel filter making it cut out right after getting on the throttle a bit. It definitely was rust colored. I spent hours cleaning it out of the tank. It didn't come back.

It makes a difference if the bike is stored in a garage or if it sits out, especially in a place like San Francisco.