Engine Design Help

[desgre90]

After two months of having my engine apart, I guess you could say things are finally moving along. The cases were finish being machined yesterday for the +4 stroker crank, and the cylinder should hopefully be finished up today. I can't say I am exactly thrilled about the machining costs after taking this long to do them... but what can you do... Lesson Learned.

So far the plans are (parts are sitting at my house waiting)

new +4mm stroker crank, all new bearings, all new seals, etc. The jug I got from a friend was already ported for the stroker crank so it is getting cleaned up (to 68mm).

Anyway, here is the deal. I still have a ton of unanswered questions so I guess it is time for me to start getting that taken care of starting today.

1. What piston should I go with? The Wiseco that was in my old engine cracked at the piston skirt so this piston kind of caught my eye (increased skirt thickness and adds 5hp)

PISTONKITS-FORGED...

2. Should I get the above with the gasket set, or use yamaha gaskets I have in my basement? Or should I use the vito high compression gasket set?

3. With this setup, would you recommend a +4 degree timing key or should I stick to stock?

4. I plan to use a 35mm keihin airstriker carb. How it will be connected to airbox is still undetermined (vito's stock box adapter, or I have a boot that is ment to go in the same place but fits on the carb, and connects to a K&N round filter, or I have uni tube style that would connect directly to the carb). The latter kind of has me concerned due to dust. Anyway... what I need to know is what jets I need to have in there for this setup, and possibly need to rebuild it since it is used.

5. Those running a 35mm carb, did you use a reed spacer? I am not sure how well a reed spacer would work with vforce 3 reeds because of the intake design. Putting it before the reeds is my only option but have heard that reduces something / increases something else (can't remember sorry).

6. I posted a good while back about maching the head the extra 2mm vs. spacer plate. The consensus was to have the head machined instead of the spacer plate because you change the port timing. What kind of price am I looking at for this etc, and who can do it. Sponsers? Obviously I need to iron out the above (gasket thickness etc.) before I can do anything so I guess lets get the ball rolling. I also would perfer it to run on 89 octane, as that will play a part too.

Thanks in advance, I'm all ears

Greg

 

[super noober]

ok here it goes lol,

wiseco piston

cometic EST gaskets (my guy used them in my rebuild and they are amazing)

learn as you go as far as a airbox setup.. ive got a custom 2" i made using part of the stock rubber boot and stock airbox

with my 34mm pj it did hit the clutch are but you can twist it a bit but i didnt liek the way that sat so i run a spacer plate.

with those mods, 93 octane man

 

[blasterfreek30]

theres is nothing wrong with using the spacer plate, if it was ported for the longer stroke, the port timings will be fine....i wouldnt machine the head down to accept the longer stroke, cutting into the head will build alot more heat up....imo use the spacer plate and have the head milled down abit for more compression

 

[desgre90]

Thanks for the tips guys. Wiseco piston was ordered by my buddy yesterday aparently. I do have a reed spacer in the basement but I am going to try to stay away from it if possible.

I talked to Ken yesterday and he set me straight for the most part. Hotrods instructs to have the head machined (it does not come with a spacer plate) which is why I was wondering what to do. Aparently most of the sponsers on here do not use a spacer plate when building engines either which is another thing. Yesterday, my plan was to hopefully ship the head to a sponser to get machined, but again after talking to Ken that doesn't seem possible (due to tolerance variances from bearing location, all the way up to the piston, he would need basically my engine to see what needs to happen. I thank him a bunch for taking the time to talk to me yesterday, but I am not sure if shipping my engine back and fourth will be an option. A $60 head machining charge is now complicated by shipping charges both ways plus insurance, $75 mock up charge, and whatever else I am missing. I have some time to think about it... so we will see what happens. You got to do what you got to do.

 

[super noober]

yeah man a +4 can add a whole bunch of assache... thats the main reason i went with a +3. i wouldnt sweat the spacer plate, i have one and my motor makes great power I:I

 

[phragle]

ok... first with the spacer plate you are increasing crankcase volume, A reed spacer does the same thing. The blaster motor doesnt need extra volume, so no need for reed spacer.
9why do you tink vitos puts stuffers in their stroker cranks?) to mount the carb to the airbox, go down to your local muffler shop carb in hand. ask for a piece of scrap tubing that matches the intake diameter, if you really want to go balls out they can neck the piece of scrap tubing to the exact diameter. cut the airboot back a couple of inches and silicon and hose clamp the muffler tubing in and use a piece of rubber tubing to connetc that to the carb.

On the 4 mill stroker Im building I am going to be using a 5 mm longer rod as the stock stroke is already rod angle challanged. Plus this extra 5mm will give me lots of room to decide how far toraise the cylinder and cut into the head to get my porting degreed in to where I want it. Remember when just using a spacer plate, if you add a 4 mm stroker crank that breaks down to 2 mm up and 2 mm down. if with the stock stroke your piston stops at the bottom of the transfers and you go to a 4 mm stroke your piston now stops 2 mm BELOW the transfers add a 2mm spacer plate and your piston now stops 4 mm BELOW the ports, you are GIVING the potential for a lot of power away. Sure as mentioned earlier, just cutting into the head can cause heat problems, if you have a hack with no clue doing it. If you have someone good doing the head work the chamber and squish band can be significantly altered to accept the stroke, add power and RUN COOLER as trhe stock head dsign is basically garbage.

You dont need to think 'whats going to make it work" going +4 in stroke and a 115mm rod you now have the flexibilty to decide exactly how you want your motor to run and build it accordingly. Forget fancy timing adjustments and reed spacers etc... design the motor the way you want it port timing and compression wise, get it going and tuned, then think about the other stuff. reed spacers and timing changes arent power building items, they are tuning refinements

 

[desgre90]

ok... first with the spacer plate you are increasing crankcase volume, A reed spacer does the same thing. The blaster motor doesnt need extra volume, so no need for reed spacer.

It wasn't about increasing crankcase volume, it was about whether the 35mm keihin air striker carb will clear the clutch cable or not. Not about any performance gain / loss. The other question was about spacer plate vs. head machining for the stroker crank.

9why do you tink vitos puts stuffers in their stroker cranks?) to mount the carb to the airbox, go down to your local muffler shop carb in hand. ask for a piece of scrap tubing that matches the intake diameter, if you really want to go balls out they can neck the piece of scrap tubing to the exact diameter. cut the airboot back a couple of inches and silicon and hose clamp the muffler tubing in and use a piece of rubber tubing to connetc that to the carb.

Yeah, they would use the stuffers to decrease volume, but was asking about the reed spacer to clear the clutch cable. As far as the carb mounting, I already have an intake boot for the carb, it is more about which of the four different airbox setups I can run.. of which I want to choose.

On the 4 mill stroker Im building I am going to be using a 5 mm longer rod as the stock stroke is already rod angle challanged. Plus this extra 5mm will give me lots of room to decide how far toraise the cylinder and cut into the head to get my porting degreed in to where I want it. Remember when just using a spacer plate, if you add a 4 mm stroker crank that breaks down to 2 mm up and 2 mm down. if with the stock stroke your piston stops at the bottom of the transfers and you go to a 4 mm stroke your piston now stops 2 mm BELOW the transfers add a 2mm spacer plate and your piston now stops 4 mm BELOW the ports, you are GIVING the potential for a lot of power away. Sure as mentioned earlier, just cutting into the head can cause heat problems, if you have a hack with no clue doing it. If you have someone good doing the head work the chamber and squish band can be significantly altered to accept the stroke, add power and RUN COOLER as trhe stock head dsign is basically garbage.

Good luck with your build. Yeah I'll have to piece it together and see if I need a spacer I guess.

You dont need to think 'whats going to make it work" going +4 in stroke and a 115mm rod you now have the flexibilty to decide exactly how you want your motor to run and build it accordingly. Forget fancy timing adjustments and reed spacers etc... design the motor the way you want it port timing and compression wise, get it going and tuned, then think about the other stuff. reed spacers and timing changes arent power building items, they are tuning refinements

The "fancy timing adjustment" was just something I was curious about while looking at the project as a whole. I figured while the engine was already apart, moding my stator would be no problem, but rather more of a pain after everything is hooked back up.

 

[phragle]

adding stroke already advanced ignition timing.