Yamaha 130 V4 Project Build.

[Mr. Demeanor]

I have a set of carbs from a v6 special minus the jets that I will part with if you are interested.............benji

I have some. My understanding is you actually need two sets of V6 carbs to make a set for the V4.

[mackeral5]

It only takes 2/3 of a set of v6 carbs to make a set of v4 carbs....

[Ray Neudecker]

Takes a set of 3 V-6 carbs to have enough of the right parts to end up with the two needed for the v-4.

[Mr. Demeanor]

Well...I knew it was something like that....

Math...numbers...




Ray, have you ever seen a set of all 4 rods "out of round"? Thought it was odd.

[Mr. Demeanor]

Not much to report. Still waiting on the crank and have just been busy but today I decided to do a little work.
This is probably a good place to show you guys my intake. I have been running Chris Carsons reeds and Chris was kind enough to find me an OMC primer and some nipple to plum my intake. I have been running this with the Yamaha choke plates removed for a year or so. It starts MUCH easier and was a very simple install. Removing the choke plates has to be a good thing for airflow.When I did this mod and had the intake, I had cleaned up some casting imperfections and smoothed some corners in the intake as well.

[Mr. Demeanor]

Today I decided to get a little more aggressive with grinding in the intake tracts. There are some sharp corners that can be removed which will straighten the flow and decrease turbulence.
I have a little experience porting on 4 stroke motorcycle engines but its been a long time....

You can see in this pic, the runner on the left is nearly stock (I had cleaned it up a little). The one on the right got some grinding today removing most of the sharp "ledge" on the bottom.

[Mr. Demeanor]

Another view:



Its rough now. I'll go back in and blend when I have the bulk of it right.

[1FASTLASER]

I know I have asked or talked about the balancing of the rotating assembly before and got mixed answers on this. I understand that it doesnt add horsepower persay but allows what horsepower you have to effevtively spin easier with alot less variances therefore ....imo....allowing the motor to spool up easier,possibly a quicker midrange and certainly live life better at higher rpms. I assume this is your reasoning as well???

[Mr. Demeanor]

I know I have asked or talked about the balancing of the rotating assembly before and got mixed answers on this. I understand that it doesnt add horsepower persay but allows what horsepower you have to effevtively spin easier with alot less variances therefore ....imo....allowing the motor to spool up easier,possibly a quicker midrange and certainly live life better at higher rpms. I assume this is your reasoning as well???

Longevity. A balanced rotating assembly should last longer especially sinning it at higher RPM.

[1FASTLASER]

Yeah I beleive you and I are on the same channel

[Mr. Demeanor]

I am glad I sent the parts out as I wold not have known I needed new connecting rods. Looking at it that way, it already saved me a lot of money.

[powerabout]

are they going to balance it to zero like a 4 stroke?
( sure rods and pistons should all be the same)

[Mr. Demeanor]

are they going to balance it to zero like a 4 stroke?
( sure rods and pistons should all be the same)

Im not sure exactly how they do it with a 2 stroke but I believe so. I weighed the connecting rods on they were VERY close and Gordon balanced the pistons when he ported them for the finger ports. My biggest concern is the flywheel since we cut 5lbs out of it.

[71V153]

Longevity. A balanced rotating assembly should last longer especially sinning it at higher RPM.

Yup I agree! (Btw sinning at any rpm is against gods will ...)

Regardless, I'm in the process of balancing the pistons & rods for my 140 project. Figger it cain't hurt none. Well that & I got this new scale ... Been weighin all kinda stuff.

Interestingly the stock '83 pistons w/rods were within 10 grams of each other. The 020 Wisecos from the '78 were within 15g, and the 020 Wisecos from the '86 were within 20g. And that '86 ran great! It'd still be running today if not for the water jacket erosion? But I digress

Keep up the good work Chris, hope to see you out on Snake soon.


Doug

[Mr. Demeanor]

Did some more work on the intake. Really straightened out the runners and removed almost all the sharp outide corners. Going back in with epoxy today and filling the remaining inside corners. Been a long time since I did this type of grinding and that was on drage bike cylinder heads. Hopefully similar principles apply or Gordons going to hang me. I have another intake if he thinks I screwed this one up though.

Stock vs. modified;



Epoxy in the inside corners and curing:



Hopefully final cleanup and then match up the cages and gaskets. I have two sets of reeds here. Chris Carsons single stage and Boysen dual stage. Thinking just maybe the dual stage will help the low end and this little motor may need that to get up and going. I will try them both thoughl