Air sensor mounting

[Stephan1992]

Does the placement of your air sensor reflect on the output of your power ?
I took my bike to the shop because it wasn't performing how it should.. I paid $200 (hours for labor) for them to tell me that my air sensor was just dangling about the area around my headlight. The previous owner who I purchased it from removed the headlight mounting which has the mounting unit for my air sensor. So I have already order my headlight mounting so I can properly mount my air sensor . The mechanic at the shop tied my air sensor to the side of my fork because he had no where else to place it. He said my problem was fix and I was happy to take my bike home . The reason I'm worried and posting this question is because I didn't have the chance to take my bike past 60 mph do to the fact that I live within streets from the shop and it was raining at the time so I preferred not to ride on the freeway. So when the whether cleared up I took my bike straight on the freeway to see how much power I can get out of it . And it's sad to say but I couldn't take my 2003 monster 620 ie past 80mph!!!! seriously I don't know what's going on! Cause the did a compression test on both cylinders and the read 170 even. Both evenly in sync ! And they gave my all my paper work indicating everything is in working condition . My bike only has 5k miles. It's not beaten in at all. As for the mechanic who said my bike is up and running , I'm thinking he didn't test ride the bike properly before giving my back my keys . Is it possible that my air sensor being mounting improperly is the problem I'm having with my bike lacking power??? Let me know so I can call the mechanic and tell him a solution so he doesn't MILK me out more money for all those pre tests in order to find out one simple thing. All I know it's nothing dealing with my engine . It's something simple . Simple as my air sensor not being mounted?

[skurvy]

Did the previous owner do any other mods to the bike? Did he change the sprockets and gearing? Different exhaust?

[Stephan1992]

The sprockets and gearing are stock. He didn't change them to my knowledge. They appear unchanged. However it has a full arrow exhaust system which is high mounted . Thats all that appears change, with the exception of rizoma covers and handlebars. Also the headlights are swapped with dual rizoma headlights. That's why he changed the headlights mounting unit. And contributed to my air sensor problem . So to answer your question just a full arrow exhaust system has been installed . No pc.

[Howie]

That sensor ain't your problem.  I suspect fuel starvation.  Fuel filter?  Pinched line?  Any other symptoms?  Air box opened up?

[Duck-Stew]

That sensor ain't your problem.  I suspect fuel starvation.  Fuel filter?  Pinched line?  Any other symptoms?  Air box opened up?

All these are valid questions and to them I add:

Fuel filter gone bad due to sediment in the tank (9 yo bike w/5K miles).
Has anything been added to the computer to add fuel to the motor due to the Arrow exhaust?  (Typically, you can get away with just an exhaust swap on non-O2 sensor bikes so long as the airbox hasn't been modified.)
Does the exhaust 'pop' on deceleration through about 4000 rpm?  If it does and it's bad, you may not be getting the fuel you need due to the computer.

But, I agree: Your 620 should be faster (good for at least 110mph) and it also sounds to me like fuel starvation & NOT your air temp sensor.

[Stephan1992]

The air box has not been modified at all. It's completely stock. But seriously I think it's fuel starvation! I've never came across it
Until HOWIE , and DUCK-STEW mentioned it!! How would I fix my problem And idea , where do I start And DUCK-STEW my bike doesn't pop on Deceleration anymore. It pops when trying to surpass 5000rpm in 5th gear. And that's what makes me stay at about 85mpr. Cause me revving isnt doing any good . Just feeling popping and it gives out its power. But also I doubt they hooked my bike up to a computer to sync it with my exhaust . Would that be my solution for fuel starvation

[Stephan1992]

There are no other symptoms with my bike. Just the ones I mentioned . I'm taking a look at the Fuel filter And seeing if any pinched lines come about. Thanks guys. I just really want to fix my own problem as much as possible before I take it to a shop again. I understand I'm going to have to have a running expert sync my exhaust on a computer. But that's all I want to do . Not have them charge me hours for something I can find. Also is it ok to be riding the bike as is ??

[Howie]

I can't say for sure about riding the bike.  If the bike is only running seriously lean a high RPMs you might be OK for a while.  You might want to pull the spark plugs and take a look.  If they are tan limited use may be OK if you avoid speeds where the bike misbehaves..  If they are white and blistery the risk is higher. 

Changing the fuel filter is a maintenance item anyway, so go ahead.  If you change in tank fuel lines they must meet SAE 30R10 spec.  While looking for pinched fuel lines also check the vent lines and if the carbon canister is still in the bike make sure it is not clogged. 

You might want to post up on your local board and see if they can recommend a good shop.  My guess is you wouldn't be upset about the $200 if your bike was fixed.

A computer is not needed to synch the carbs.  Mercury sticks, matched vacuum gauges, Twinmax and a variety of other tools will work.  TPS should be checked on your bike too.  This can be done with a good multimeter.  Brad Black on this forum has done some excellent write ups on this.  Check out  http://www.bikeboy.org/