how can i gets more RPM in my yamaha

[pr-550yamahadriver]

i have a yami 30 3 cylinders.....

my question is

if i gets more advance the ignition coil the engine gets more rpm??


sorry for my english....:D

[Roy Hodges]

i have a yami 30 3 cylinders.....

my question is

if i gets more advance the ignition coil the engine gets more rpm??


sorry for my english....:D..................................... ............................................
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It all depends. Most stock fishin ' motors are a little on the rich side , from the factory. If you're already revving it above factory advertised rpm , you might advance the timing 1 or 2 degrees and get a gain. Or you may burn (&stick ) a piston. When we raced SPORT E , back in the late 1970's , on our 1975 year model 75 johnny -rudes , we were advised by Tom Ireland, that the hot setup ,for that particular motor was 1 step leaner jet, (main)
and 2 degrees MORE advance on timing. He only learned that by burning many pistons .

[looseunit225]

the first thing i would be doing is trying to increase the compression ration on the engine!

stock out boards run a very low compression ratio so you can almost get away with running any fuel!
i would advise you to rip the heads off and start shaving some meat off them and than i would do plug chops and see how they look!

[pr-550yamahadriver]

guys thanks for your opinions i try get moer power....jajaja:D:D

[Fast Fred]

no. more timin does Not mean more RPMs. thare is apoint ware too much timin and high RPMs will clash and she will burn down. more comp from the head would help max rpm, could try jackin it up on the transom as well.:cool:

[Miss BK]

When we raced these motors, one of the first mods (of many) we did was put 50hp Yamaha carbeurators on them. This meant a whole new adapter plate for the intake manifold had to be built as well. And you would also need to make some room for these bigger parts by modifying (holing) the bottom pan.

Shaving the heads, like Looseunit described, was also among the first mods.

Handmade dry tuners added more boost. Large exhaust holes at the base of the tower made them VERY LOUD! :D

Later, the motor builders did more radical things like installing special pistons. I don't recall exactly what pistons they were (this was top secret at the time!!), but I seem to remember they came from race motorcycles.

Not sure how radical you are allowed to go - but those are some things done here that enabled them to set kilo records of nearly 90mph.

Val

[OUTBOARDER]

What are the rules?

We had a drag skiff and found that the Yamaha 30HP 3CYL could be modified to use the 40 HP sleeves and pistons.

[pr-550yamahadriver]

val you have any images of this carburators on the 30 and this special part...:)

[John (Taylor) Gabrowski]

From what I learned from Modified enthusiasts because my backgound is stock outboard its more complex than any one thing but being conservative one change at a time is the way to go even though you may end up doing more than one thing.

Being that the engine may be slightly rich on the fixed jets one of the most obvious changes would be to put in 1 or 2 numbers more a cooler set of sparkplugs without altering the ignition timing.

Then go one larger a size mainjet to feed the colder running sparkplugs. There should be an increase in power right there without risking lean out and overheating the engine.

Once that route is established get a portable digital meter that has a under the sparkplug temperature sensor and with that increase and or yes decrease BTDC timing with the objective of keeping the at sparkplug and head water jacket temperature no higher than about 205 degrees Farenheight or it equivilent in Centigrade by also juggling the high speed jets to get optimum air fuel. Power should be optimized.

Assumptions and extras for good tunning also included:

*That you are using a tachometer.
*Remove factory water jackets coolant thermostats.
*That your using a good high load test wheel.
*That your fuel's octane and quality is the same for consistency.
*That your lube is the same and of high quality a for 2 stroke product be it petroleum or synthetic and mixing rations are always the same.
*That you are using a good bright and accurate timing light with well painted indicators the beam stops and can be seen. Even an apparently properly retimed engine can be fighting itself, its own ease of rotation due to overtiming even though it won't be overheating leaving ignition un-optimized.
*That your using good, reliable ignition products (sparkplugs etc.)
*That you have and can use an ignition discharge reader per sparkplug wire. (a properly firing cylinder uses less voltage to get good ignition where one not at optimum can require markedly more) (also weeds out ignition problems like poor coils and bad secondary wiring)
*Install a thin phenolic spacer under each carb gasketted base to kill any possible heat transfer from crankcase to carb therefor air/fuel to keep it all cool as possible.

Anyone want to take their kick in the cat on this subject as I might have gone too far or not enough?

[quty06]

Handmade dry tuners added more boost.


can u show us with pict(s).:)

my experienced with saw engine(single piston) which i put it on R/c boat like @ my avatar, by advancing the timing will give extra top end. But in multiple piston outboard, i guess it'll different & way to do it.

[John (Taylor) Gabrowski]

Doing all this is a steep learning curve that is no small feat. I learned because others took the time to mentor me, teach me. I made it a point of being their good student and a good listener. I was not afraid to get down to what I learned and did it so carefully knowing I would be observed by my teachers. Money was not plentiful being a student when it came to making mistakes myself that could potentially ruin things. From all that I managed to cook only one engine, only one piston in it, being a little overzealous with the top carb's high speed jet needle tunning it on a Merc 55H stock racer back in the middle 1970s.

First thing you need to become is a good student and then find your mentor amongst others who will guide you because you are there to listen, learn and be helpful and thankfull for the privilege being taken on by that mentor. :)

Listen to old TV shows like Kung Fu? That was the only TV show I can recall that taught some common sense with a fictional story line.

[Roy Hodges]

Listen to old TV shows like Kung Fu? That was the only TV show I can recall that taught some common sense with a fictional story line.
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That's right, grasshopper !

[pr-550yamahadriver]

Are you think I 'm a NEWBIE but i am double galician champio PR-550 AND 4 OF THE WORLD IN 2007 MY FATHER IS 2nd OF EUROPE AND THE CATEGORY OF OUR TEAM IS CONSIDERED ONE OF THE BEST PERFORMANCE IN THE NORTH OF SPAIN

BUT THE PROBLEM IS WE DON´T KNOW OF PERFORMANCE ELECTRONIC PART....

BUT THANKS EVERYBODY :D

[John (Taylor) Gabrowski]

The last time I saw anything from Vigo was its part as a location a U-Boat was going in the movie I have in my library called "Das Boot".

When it comes to electronics on these engines there are just so many good ignition systems out there. Some very simple that carry every manner of flywheel weight. I am prone by background to getting rid of excess weight to get quicker spin up. On these older technology Mercury 4s you can get rid of everything to just a low ounce weight core, belt drive it with battery CD ignition with next to no drag and very problem free so you tend to stick to it or in the alternative a belt drive, very low drag high output mechanical magneto at some 20+KV. Keeping things simple and plentiful renders reliable ignitions.

The only thing I don't ever see is the "open" pipes systems of there in Europe we are use to around here for deflector/crossflow engines. It gives them an Indy or Formula One racecar sound all their own as 2 strokes that make for racing excitiment you just don't get out of expansion chamber exhausts. Kind of makes the particpant deaf on the long run though! :)

[pr-550yamahadriver]

A Really Nice Shot

[Miss BK]

[QUOTE=quty06;64557]can u show us with pict(s).:) QUOTE]


I wish I had pictures of all of this, but I don't. That one photo in my avatar is one of the few I have of the boat at all.

During my last year of racing, one person was doing the majority of the "radical" work on my Yamaha (Jimmy Johnson) - but there were 2 or 3 others that were experimenting with these 30hp motors too. Glenn Schaid and Rick Hoffman to name a few.

They all were pretty tight lipped about what they were doing.

One time when going to our usual "test" lake, I accidentally came upon several of these guys hammering on the lower pan of one of the Mod C racers. As soon as they saw me walking up they swarmed me, saying, "YOU WILL NOT TELL A SOUL WHAT YOU JUST SAW!!!!"

I laughed, because all I saw was someone with a hammer, smacking the lower pan. What did they think I'd do?...run off and tell our competition; "They are making new modifications - he's hitting his cowling with a hammer!" LOL :eek::D

But it did make me feel good that they had assumed I was that mechanically savvy! ;)

Only later did I learn they were actually adapting the motor with 50hp carbs and they needed to break a hole into the lower pan to make these bigger carbs fit. (I didn't even notice the big carbs at all!!!)

I only saw that special tuner one or two times - I saw four flat pieces of metal, hand welded together into a box, tapered at the end. :confused:

One time, the weld on the tuner didn't hold, the tuner slipped down without anyone knowing what happened. I ended up having a VERY miserable 5 hours at the Parker mini enduro and the following Havasu mini race, running 65mph instead of the usual 75-80mph. I didn't find out what was wrong until after getting run over a week later at Havasu.

A friend looked inside the tower and saw the broken weld. :(

That was the last time I saw that motor. My injuries meant I'd be out for at least a year. I sold the motor to the builder, mostly because he didn't want his engine secrets being sold (and discovered) by his competitors.

I think my old builder may be a member here on BRF --- Ron may know how to get in touch with him....

Sorry I couldn't help more....

[quty06]

Thanks Miss BK,
here a pic, guys same moda with u

[pr-550yamahadriver]

thanks for the info but i can´t use all of then because the UIM rules are very strics but grace mille XD :D

[tsrt]

I bought that last super mod c from ron, its run 78mph on my gps before i melt the piston. This motor really amazing, it is an art of engineering

[tsrt]

Miss BK ,

I need help on timing setting, my mechanic wrongly set the timing thinking same timing with stock and melt the piston