172 setup too loud

[172racer]

Hello all!

I was wondering how can i lower the engine noise by removing some malossi parts?I noticed that my scoot is noiser now with malossi parts then when it was stock.When it was stock,it was quiet and nicer...

I have this on my scoot:
172 ccm malossi ported
25mm carb
MHR reed valve vl13 (the one without carbon petals limiters,45 degrees)
MHR intake manifold (45degrees) modified (bigger hole)
the rest is original
original airbox
original exhaust
original variator
original belt
etc...
I was wondering what part(s) increases noise the most?

I don't think that malossi cylinder does that because it revs almost as stock,but i don't know if porting affected the noise?
Maybe i should blame bigger carb,MHR reed valve and short intake manifold?

What do you guys(and girls) think?

 

[Rydah1]

your carb is making the noise. if you can get a airbox on it then it then the noise will be cut in half.

 

[172racer]

what do you mean to get airbox on it?

I already have original airbox not open filter if that's what you mean.
I have dellorto phbl bd 25mm carb.I use it because it is easy to jet.
Why is that carb different than standard 20.5mm mikuni in producing noise?Is it because it's bigger or it has different chambers inside?

So what is the solution?I don't want to go back to original 20.5mm carb but if that's the price i have to pay to reduce the noise....:'(

 

[Rydah1]

maybe you need a bigger airbox, some kind of kart airbox or if you cannot take the noise of a modded scooter then you should go back to the stock carb. a modded scooter will never be as quiet as a stocker. i cannot imagine your bike being that loud with a carb only and not a pipe.

 

[172racer]

well,it is loud...much louder than stock...When i first put 172ccm kit on it and took a drive around neighbourhood at the evening,next day i heard from my parents that a lot of neighbours asked who was driving so loud motorcycle the other day :# O-)

I will remove malossi manifold and 25mm carb and put 20mm mikuni vm,that was original.
I read in malossi manual that in original carb i only have to raise needle to fifth,but i don't buy that.I think original carb must be completely rejetted,different slider,needle,main jet etc..
Do you know by any chance how to setup that original carb on 172ccm?

 

[Rydah1]

i dont have any idea of how to set up your 172. but when i do i am going to run everything pipe, carb, and everything else to make noise, just as long as its fast. good luck with your set up.

 

[Steven#36]

I don't think your scoot will be more quiet removing any of the parts. The main producers of noise are open airboxes and non-stock (race) exhausts.

You are using the stock parts for both of them so your scoot does not have to sound a lot louder then before when it was totally original.

I think you should look for a leaking exaust gasket (did you put a new one in after mounting the malossi 172?) or a leaking exhaust (maybe rust-holes or something like that).

It can also be a leak in the intake system, maybe the airbox isn't mounted correct?

 

[Spank]

exactly, what steven already said, i think your exhaust is the main problem, maybe there's a leak in it? or make a video (with good sound) so we can help you further
and you sure need to check your airbox

 

[172racer]

sorry for delay,i have so much work to do(school),so only thing that relaxes me is riding scoot.But it really bugs me beacuse it's so loud.Everybody asks me why my scoot is so loud.Even friend who drives stock Runner 180 2T didn't want to drive my scoot beacuse he said it's to loud.When i drove his Runner,it was so quiet that i thought it was turned off


So you guys don't think that bigger carb,shorter manifold and malossi valve don't have anything to do with increased noise?

 

[Rydah1]

like the other guy in this forum check your header bolts. your header might be loose and you have a exhaust leak, that will make your bike way too loud.

 

[172racer]

i bought new gaskets but i will check again.

Now i remebered when i had 50ccm scooter and had 70ccm malossi and leovince zx and it wasn't nosier than stock,but when i put 19mm carb instead of 12mm stock,then it was much louder,i instantly noticed difference...Yes,that's it!
First,i put zx on scoot and it wasn't nosier,only different noise.Then i put malossi cylinder 70ccm and the same.Than i purchased 19mm dellorto carb,malossi valve,multivar and secondary gears and with that stuff it was much louder.

Is that make any sense that bigger carb produces more noise?Or maybe dellorto carbs are very loud?

 

[Lodewijk]

Use a different air-intake-thing (airbox?) and make sure everything is connected properly, no loose bolts or anything. It really shouldn't make THAT much more noise.. noticable yeah definately, but farrrrr les than for example a leak exhaust

 

[Bandana]

hi Guys

I reading your quotes, and yes when you change the carb from the stock 19mm to a 25mm most probably it is a delhorto right, the scooter makes a higher noise that is because of the higher air flow going in.

I have a 180 sp used in scooter racing modified block, 25mm carb , carbon fibre leafs (pm tuning ) short intake, and also Pm tuning high flow air filter. Also to let you know i have modified the inlet of the standard exhaust making more like a straight pipe combined with the modified block. Any way makes a bit of a noise to tell you the truth but when putting the normal air box with a high air flow filter the noise reduces, then what the hell if you want to go faster was not worthed to put a malossi 172 kit if you are then struggle the power to achieve the result after spending money and time to do it .

regards jo