3ma problems

[louis]

Hi Edd,
I do have the same explanation as Warwickb,
If i ride a couple of Km low in rpm's and then fully accelerate, yes mine is smoking to. It is quite normall I had it also with other 3ma engine's (As Warwickb says, it can be reduced by carbs setting, but i don't think you can get it fully away) (don't forget it's a twostroke )
But I have no problem with that, a bit off fog around the 3ma

[rz350]

+ it smelllzz nizze 

[Edd]

Hi Guys;

Thanks for the feedback, I am hoping this is the case I am monitoring my gearbox oil level. The reason I am suspecting gearbox oil is because the bike is not smelling nice. At start up you can smell a twostroke it is nice, but once you have accelerated hard and kept her there now that's when a twostroke smells at its best. That's why I have become addicted. (say no more)

Cheers

[deonillovo]

Hi Louis; thanks for the help i have fitted a new connecting shaft and the bike is going like a bomb i am very impressed by the power difference,but i still need to sort out and fine tune it i have a slight problem,could you tell me why the bike boggs down a litte in lower revs under 4000 rpm and i still cannot get it to rev to 11,500 rpm the max i get is about 10,000 rpm but when i ride it and the power band kicks in it goes quite a lot over 11,500 rpm and no smoke but my problem is below 4000 rpm it smokes a bit but not a lot as well it has a slight hesitation when ridding and below 4500 rpm could this be a pv adjustment ?
The other thing is what it the little round electrical unit on the side of the carb is it the throttle power sensor?? and could you explain to me what is its function and give me some for of settings or how do i go about it,the final thing is when the bike idles it seems to that the rpm drops to such an extent that the bike almost dies has this got something to do with the electric switch on the side of the carb.

Sorry to be a pain in the but,but i have no one else to turn to for assistance with this bike in SA and i value your technical notes and knowledge this has proven invaluable to me and has made my life a pleasure as all the things you have told me to do have made such a huge difference to the bike that is is going to be hard to sell this bike.

Many Thanks;Deon SA

[louis]

Hi Deon,

I do not understand you completely, but if you mean can't rev more than 10,000rpm when the bike is standing still. that's good.
All 3ma's have a rev limiter and it kicks in when the bike is standing still ore when you hit the 180kmh (the rev limiter signal is coming out off your speedometer and is going to your cdi)
So when you are driving and you can hit more as 11.500 its good

And below the 4000 rpm is a place where the 3ma is not feeling right they start to doggs/clutter it is not there strongest point.
Don't forget that your standard barrels are havely tuned (with race pipes and a good carb setup they go over 60 ps rear wheel)
That is a lot.
You have standard exhausts a standard carb setup you should have about 45ps.
Did you check you airjets sensenoids do they click when on throttle, they can help a bit on low rpm's
below 4000rpm the pv is already standing close you cant adjust it more.

That electrical unit is in portend, it is your throttle position sensor. You have 4 ignition curves stored in your cdi unit
The position of throttle the cdi chooses the ignition curve. pleas do check if it is connected
If the tps sensor in never been taking off the carbs (you can see withe paint dots) leaf it there.
If it is been taking off the carbs try to mound it in middle position. You can check it if it is working by only setting you bike on contact an gif some throttle 25% 50% 75% 100% you should here the airjets sensenoids clicking.
If they do the tps is working.

Cheers Louis

[rz350]

They way I checked if it is working or not is by disconecting the sensor, the bike wouldnt keep the RPM at idle speed and would switch off. Is the sound of airjet solenoids is loud enought to hear? Thinking to check it as well...

[louis]

rz350,

The engine does not run, only powered on. then play with throttle, you can hear them click.

[Warwick]

If in any doubt you can take the solenoid unit apart easily enough. You should then see the solenoids move too when you twist the throttle with the ignition switched on. Some owners have reported them gumming up a bit over time, so it can be useful to clean them up and lubricate them. It allows you to check and clean the jets too. Personally though I think it better to junk the whole system and simply run a single fixed air jet - either in the hose or in the (suitably modified) carb bellmouth.

[deonillovo]

Hi Louis Deon here sorry for taking time to reply but i am doing things slow here as i still have some problems with the bike boggin down under 4500 rpm i have checked all settings all okay PV working well TPS also working well i really think my problem lies with the carb settings as i said i have standard jets in it but what i have found is that the snorkell in the air box is missing just leaving 2 large open ends on both sides of the air box ?could this be the problem that the bike is sucking large amounts of air and that the air/fuel ratio is out not sure of this,i was wondering if you could tell me which way to move the needle clip to lean the carbs as i still get some oil/fuel mixture coming out of the exhaust this i think is over fueling or what not sure ?
If i drop the needle will this lean it up or should i raise the needle to lean it up
I forgot to mention that the 2 stroke mixer is not working on the bike so i am pre mixing it what is the correct mixing ratio,at present i am using 250ml oil - 10 lt of fuel please advise me
I need one more favour how do i know the carbs are balanced as i see the small sight glass on the side but not convinced if i can make out what the hell is happening there.

Many Thanks;Deon

NOTE;How do i upload pics i would like to upload some so that the guys can see what i have and doing to this bike

[TZR-V4]

Hi,

To add photos use the Additional Options under the text edit at the left : Attach

Olivier.

[louis]

Hello Deon,

Dropping down the needle will make your bike leaner on 1/8 till +/- 1/2 trothel. So if you drop down your needles you can have less cluttering/bogging under 4500 rpm. (do not expect miracles, under 4500rpm, it is not the strongest point off a 3ma)
Be cear full, you have 180 mains that is pretty lean without the snorkels. (if you have, try 220's main)

I do not know your driving stile, If you are just mainly cruising and some times rev the engine up.
Do consider that on long straights on low rpm's the 3ma choke it self a bit, and after a period on low rpm's you di side to ref the engine up
It will smoke, and burns the remaining oil that is left behind.

If you are mainly reving high rpm's and ride it like a racer, you have to buy a lot off main jets from 190 to 300 i think.
And try, try and try the best setup fore you engine (Sample: I have 260 mains now (still a bit to lean) with almost same setup as your, (with a change too the original exhausts) but wat works on my bike does not main it will do the same on your bike!

I do not have experience with premix but 250ml on 10 Liter is 1 : 40. With modern twostoke oil it will be good I think.
But a bit more for save, will be not harming the engine. With 180 mains you are on the lean site. So a bit more oil will be better i Think.

Checking if you carbs are sinchrome will be easier if the airbox pipes are removed. You can see what is happening than.
Looking trou the Little glasses is not easy and is difficult.

Cheers
 

[deonillovo]

Hi Louis i have balanced the carbs as well as re adjusted the tps slightly and found the bike has responded to this in a small way,i will be dropping the needle position over the weekend as i have some other work on the bike to do.
What i have noticed is 2 pipes at the bottom of the engine,these pipes go to the carb housing but they go from right to left carb and left to right carb do you know why this is or what is there function.

Many Thanks Deon (South Africa)

[Edd]

Hi Deon;

I have the same question. I am not 100% sure what there function is,  but I know the ones closest to the intake is called a checkvalve and is one way only from the reeds to the crank. The one below the crank is called a nipple and it is two way. From this I figured their purpose is to use the unburnt oil in the crank to lubricate the bottom bearing of the conrod? Lets see what the other guys say?

Cheers

[Warwick]

The crank action effectively acts as a pump to suck out some of the unburned fuel and oil that tends to accumulate in the intake tracts on the 3MA motor (refer to my response to your geabox oil post, Edd). Never seen such a set-up on any other motor so I suspect that the reverse cylinder layout/design is more prone to this issue than conventionally orientated motors? So long as the checkvalves work so that the crank can only 'suck' from the opposite cylinders' intake all should be well though...

   

[louis]

I have the same explanation as Warwickb (again, sorry) but can let you see that yamaha made some small changes between the 3ma1 and the 3ma3 regarding this problem.

As you can see this is a 3ma1 engine and reeds


Her you have the 3ma3 engine and reeds.


With the 3ma3 they moved it to the right and made a kind off gutter to guide the oil/fuel to the valve.
They also add a small reed on the lowest point (think to help, Wash away the remaining oil/fuel)