Engine Porting

[Livinstrong]

I was thinking about getting my engine ported, but I'm unsure of the parts that I need. Until I get it done, what's a good main jet size to start with for my power pros exhaust, stock carb, and mods in my sig?
Here is what I was thinking:
Trail Port
Cut Cylinder Head
Vito's 3mm stroker crank
30mm OKO Carb

Edit: I decided that I'm gonna run with my Power Pros exhaust until I get enough funds for both a new bore and 3mm crank. Working on the jetting now, 35 pilot, 290 main and 4th clip down on needle. It idles really low and the air screw is at 1 turn out so I'm gonna give it a pilot jet one size up, 37.5. Also, it just bogs after like 20% throttle so it probably needs bigger main.

 

[blasterdude14]

well usually when you get a port job you bore over to the next size, otherwise all the damage from the previous piston is still there, you may be able to just hone it.

Also you don't want the head cut what is better to do is get it redesigned by one of the builders on here it works so much better that way and more power

if you eventually want a +3 stroker then save up money til you can do it all at once, because when you get a +3 crank the ports need to be moved up to match the added stroke, if you port before you really dont leave much for the builder to work with. and a 34mm keihin or OKO would be way better for that type of work

 

[Livinstrong]

well usually when you get a port job you bore over to the next size, otherwise all the damage from the previous piston is still there, you may be able to just hone it.

Also you don't want the head cut what is better to do is get it redesigned by one of the builders on here it works so much better that way and more power

if you eventually want a +3 stroker then save up money til you can do it all at once, because when you get a +3 crank the ports need to be moved up to match the added stroke, if you port before you really dont leave much for the builder to work with. and a 34mm keihin or OKO would be way better for that type of work

Thanks for the info, otherwise I would have screwed myself over. I'm gonna wait to do these mods, and install my Power Pros exhaust now. What size main jet should I get?

 

[slickerthanyou]

I was thinking about getting my engine ported, but I'm unsure of the parts that I need. Until I get it done, what's a good main jet size to start with for my power pros exhaust, stock carb, and mods in my sig?
Here is what I was thinking:
Trail Port
Cut Cylinder Head
Vito's 3mm stroker crank
30mm OKO Carb

Would I have to get my cylinder bored out if I do these modifications? If so, then it would replace the 3mm stroker because of lack of funds for both.

This is what I just got. Ya I needed a bore and hone, most do. I'm running a 30mm carb 150 MAIN and 45 pilot clip in the middle, haven't fired it up yet but was told this is a good starting place.

 

[blasterdude14]

Thanks for the info, otherwise I would have screwed myself over. I'm gonna wait to do these mods, and install my Power Pros exhaust now. What size main jet should I get?

well if you are still running the stock carb, i think a 270 would be a good starting point

 

[super noober]

with my power pros, boyesen reeds and modified airbox lid i was running a 300 in the stock carb

 

[brandoz28]

yup, i'd start close to 300 and work down. better to be rich than to be lean

 

[Livinstrong]

I asked for a 300 at the place I went to but was only able to get a 290 main. Yet, I haven't modified my airbox so I should be fine, right? I'm finishing installation now.

 

[Livinstrong]

Just went out and tested it, it idles really low and the air screw is at 1 turn out so I'm gonna give it a pilot jet one size up, 37.5. Also, it just bogs after like 20% throttle so it probably needs bigger main.

 

[yb200]

first of all 1.5 turns out on the air screw then adjust your idle under the seat, with a stock air box and lid on my guess is your running rich,

you need to do a proper plug chop to see if your jetting is correct

check out these links:

2-Stroke Plug Chop How-to

Spark Plugs

 

[blasterfreek30]

if u have to go more than 1 and a half turns out on the airscrew, then go with a smaller pilot

 

[yb200]

it would be ok to run 2 turns out, but i bet its just the main is to big

 

[blasterfreek30]

^right, and also seems like its a giant pilot....isnt stock 32.5 (cant remember lol) and u are running a 37.5

 

[blasterfreek30]

oh i didnt realize u where running a 30mm carb....yea then prolly a 40 pilot would be good start

 

[Livinstrong]

oh i didnt realize u where running a 30mm carb....yea then prolly a 40 pilot would be good start

No, I haven't done those modifications yet.

Right now I only have boyseen reeds and a power pros exhaust. Before my exhaust, I had a 32 pilot in my carb, I had huge problems with throttle response and fixed it by putting in a 35 pilot. When I put my exhaust on today, I started with the 35 and set the air screw so where it ran highest with the throttle slightly pushed in. But with the 35, any throttle above like 25% would make the engine bog and then die. I thought the fix would be a 37.5 pilot but it didn't make a difference. I'm gonna get a 300 main and then another spark plug for a plug chop test before I do anymore testing.

 

[Awk08]

i ran the same motor in both my bikes with power pros/f7 on both my bikes,

in my bike with cfm airbox, stock carb = stock pilot, needle 4th down and 320 main

then put it in my sons bike with stock airbox and carb = stock pilot, needle 3rd down, and 300 main

runs like a raped ape with those settings

 

[Livinstrong]

i ran the same motor in both my bikes with power pros/f7 on both my bikes,

in my bike with cfm airbox, stock carb = stock pilot, needle 4th down and 320 main

then put it in my sons bike with stock airbox and carb = stock pilot, needle 3rd down, and 300 main

runs like a raped ape with those settings

Sweet, I definitely try these settings out once I get my 300 main

 

[blasterfreek30]

yea bro keep that pilot stock for the time being