Spooph's 250 build thread

[spooph]

So, Racer X convinced me to post this up here. This is a migration form newninja.com, since the project was started almost 3 years ago!

Re-build dyno, 40K heavy miles on the engine:


Steps towards an empowered engine:
It's kinda funny really... I started out wanting to install steel braided brake lines and just kept running with the "Well, while I'm here, I might as well do this...."

Phase 1: Getting the 250 in shape:
Optomizing stock parts:
1.) Return to stock setup, have it dyno tuned and get a base line figure of HP and A/F
2.) Install data logger from Innovate to match A/F from baseline for future mods.
LM-2 Wideband O2 Digital Air/fuel Ratio Meter
3.) Install modified airbox, run dyno
4.) Install modified exhaust, run dyno
5.) Install flowed head, possibly deck head, Have it dyno tuned.
6.) Install 13:1 pistons, run dyno.
7.) Futz with ignition timing/cam timing, dyno.

[Racer x]

Awesome.

[Racer x]

To address an earlier question. It took just the pressure of my finder nail to push the bearings into the rod.

[subxero]

sounds cool, so where are you at in the process?

you said you started 3yrs ago, are you done?

Did you do all those dyno runs? if so lets see the paper work, i think lots of people would like to see what those mods did on paper.

cool stuff

[spooph]

Thanks for the photo X!

This project is being resumed, so I'm still at step one. I will post some updates tonight concerning the bottom end, and it will be slow-going....

[choneofakind]

Sub'd.

My $0.02: Racer X and I have both found that this engine likes fuel. I've got my EFI setup supplying 12.5:1 AFR at the top end and WOT, and it really responds well. My shop typically tunes for 12.8-13.2, but FWIW richer feels better on the 'ol butt-dyno.

[mgentz]

Interested to see how yours comes along. What are you all doing?

[spooph]

Update: So, this little project isn't nearly as cool as some of the other engine/bike builds around here....

However, I believe mine is the only one with a nearly stock engine without a counter-balancer... Got it all put back together and went for a test ride the other night. Aside the fact that I lost my front sprocket nut (forgot to torque it down in all the excitement) on the high way, I'm happy to report the vibes aren't much more than with the counter-balancer.

So, balanced crank, went from 1,700lbs @ 12K out of balance to 55lbs @ 12K. Scott Jensen at Moto Garage did the work, and tapped a bolt into the counter-balancer to keep it in place and keep oil pressure up. Some of the counter balalncer's weight was cut off to clear the rods and such, and I totally failed and forgot to take pictures....

Next step is to adjust jetting and then get some time on the dyno to see what a balanced crank w/o counter balancer gives, and then see what the subsequent changes (air box, exhaust, etc) does...

Side note: I had no idea there was so much to building an engine. If I have learned anything through this process, it's that I'm not an engineer, and I never will be, and it's much less of a headache to pay a reputable shop to do this, than trying to do it on your own...

[mgentz]

Cool. But seriously pics?

[cuong-nutz]

That's very interesting! How does the motor feel reving? Smoother/faster?

[Somchai]

@spooph it's interesting to read about your plan and why should an engine without a counter-balancer not run smooth? For sure it will rev better...
I remember in earlier times no engine had one and the only engine I know for which it is a must have is the 5 cylinder (engineer is the great Ferdinand Piëch) and the sound from this engine also is much better then the older american muscle-V8 (just not to say that I've been having many fun with one of those old Audi Quattro)
Good luck for you

[spooph]

@cuong-nutz - the engine revs a little bit faster, however I don't think it's going to show it's true benefits until some more modifications are made... Trying to get a dyno run scheduled to figure out if by itself it has provided any gain... Feel-wise, the motor vibrates a little bit more, but not much more than stock. Like, not nearly enough to make your hands go numb, or to make the bodywork rattle, etc.
@mgentz - yea, I know, I'm kicking myself for that now....

[spooph]

Finally got the jetting done and another Dyno in, 2hp gain by removing the balance shaft...

[sonny4472]

What happened to your torque curve? Is that the intention of your design?

[subxero]

^ looks like A/F plot not torque

but regardless your A/F looks like it needs some work.

what is your jetting?

I'm surprised by how much your HP curve drops after 10K especially being rich. I feel like the higher revs run a good bit richer than range.

[mgentz]

2 HP just by getting rid of the balance shaft or did you change your jetting? By and large, slightly lean = more HP. Due to this I would wonder about the true effects of the balance shaft on HP.

[sonny4472]

I always wondered how much a balance shaft affected performance. I wonder how the motor feels without out it or if there are any adverse affects.

[spooph]

@subxero - yes, jetting definitely needs some work! Stock jets, idle and main, 2 shims under the needles to get rid of a pesky low spot around 7K RPM's.
@mgentz - I thought all 250 power curves drop off around 10K RPM with stock exhaust system, as it restricts air flow and starts working against itself?

Next step would be to install either the modified airbox or exhaust, jet appropriately, and get another dyno.

What I'm really trying to do is to see which single factor has the biggest impact on the engine, and how much of a multiplier the counter balancer removal... Unfortunately I don't have oodles of time/money to dump into a purely scientific approach (changing 1 factor at a time), but I've never seen a systematic look at each factor....

usually it's intake + exhaust, jet appropriately and more power, but does anybody know how much each part is worth?

any ideas on how to do this better would be appreciated!

[subxero]

Originally Posted by mgentz

2 HP just by getting rid of the balance shaft or did you change your jetting? By and large, slightly lean = more HP. Due to this I would wonder about the true effects of the balance shaft on HP.

from the graph he would be rich though right?

A/F higher being lean, lower being rich?

[sonny4472]

This could turn out to be an awesome thread.

[subxero]

Originally Posted by spooph

@subxero - yes, jetting definitely needs some work! Stock jets, idle and main, 2 shims under the needles to get rid of a pesky low spot around 7K RPM's.
@mgentz - I thought all 250 power curves drop off around 10K RPM with stock exhaust system, as it restricts air flow and starts working against itself?

Next step would be to install either the modified airbox or exhaust, jet appropriately, and get another dyno.

What I'm really trying to do is to see which single factor has the biggest impact on the engine, and how much of a multiplier the counter balancer removal... Unfortunately I don't have oodles of time/money to dump into a purely scientific approach (changing 1 factor at a time), but I've never seen a systematic look at each factor....

usually it's intake + exhaust, jet appropriately and more power, but does anybody know how much each part is worth?

any ideas on how to do this better would be appreciated!

Oh you are still running stock, I was under the impression that you had some other things done. My mistake

[jkv45]

Originally Posted by spooph

I thought all 250 power curves drop off around 10K RPM ..

Isn't that because of the New Gen tuning changes for more midrange?

[spooph]

@jkv45 - Yes, I believe so, somebody correct me if I'm wrong!

[subxero]

I really like what you are trying to do but you probably already know that it is going to be tough to really get individual affects narrowed down because you will have cumulative affects with some things.

I might have done this

Tested stock
I would have probably jetted the bike first - test 2
Remove snorkel, rejet - test 3
Full exhaust, snorkel in rejet - test 4
Full exhaust, snorkel out, rejet- test 5
Full exhaust, pods, rejet, - test 6
Return to stock everything, balanced shaft, - test 7
Balanced shaft, full exhaust, snorkel out, rejet - test 8
......................................, pods, rejet - Test 9
ect...

^ the idea being to try and get readings for all the more easily swapped on and off parts first before doing things that can not be easily un done... if at all. Since you balanced the shaft already you have kind of created a new baseline in which your other readings will have to be measured from unless you put an unbalanced shaft back in, ya dig?

Again impossible to get around in some instances but it is what it is.

Regardless it will be cool to see everything and a boat load of work

[spooph]

@subxero - yup yup, I totally agree, but here's my thinking.. I don't have that kind of cash - that's $486 in just dyno pulls (I haven't been able to find anybody willing to do it for less than $54)... This is also a great discussion to point out what we don't know.

I thought with the variances in dyno results I would be getting trends anyway, not hard numbers, since it takes me forever to do anything. If I could, for instance, do this all within a week in a temperature/pressure controlled dyno it would most certainly be worth it!

I can't remember all the threads and discussion, but from before my internetz hiatus these were the trends (2011):

pods + full exhaust would usually get ~33rwhp.
high comp pistons, worked head ~37rwhp.
ignition timing 38rwhp+

@RacerX I believe was the first to push a new-gen 250 beyond the limits of the stock clutch around ~40bhp (~38rwhp).

So, I was hoping to interpolate from those numbers, so I wouldn't have to redo all of that work. So, anyway, you and I are tracking. I guess I just wanted to put these number down so that other people could follow along...

I guess what I really want to know, and through using other's results (I know, not terribly consistent and scientific) I'm hoping to figure if the counterbalancer is a multiplier, or if it's worth a finite amount of power on it's own. So, as long as the question is a "yes" or "no" and not that of a value amount, methinks this process will be accurate enough. It won't produce hard numbers, but it will give us an idea, so somebody else can do something better with their resources...

[mgentz]

Originally Posted by subxero

from the graph he would be rich though right?

A/F higher being lean, lower being rich?

yes, he is rich now. Leaning up the main will get him more HP (in theory).

I am still shocked about the 2 HP.

[mgentz]

Originally Posted by spooph

@subxero - yup yup, I totally agree, but here's my thinking.. I don't have that kind of cash - that's $486 in just dyno pulls (I haven't been able to find anybody willing to do it for less than $54)... This is also a great discussion to point out what we don't know.

I thought with the variances in dyno results I would be getting trends anyway, not hard numbers, since it takes me forever to do anything. If I could, for instance, do this all within a week in a temperature/pressure controlled dyno it would most certainly be worth it!

I can't remember all the threads and discussion, but from before my internetz hiatus these were the trends (2011):

pods + full exhaust would usually get ~33rwhp.
high comp pistons, worked head ~37rwhp.
ignition timing 38rwhp+

@RacerX I believe was the first to push a new-gen 250 beyond the limits of the stock clutch around ~40bhp (~38rwhp).

So, I was hoping to interpolate from those numbers, so I wouldn't have to redo all of that work. So, anyway, you and I are tracking. I guess I just wanted to put these number down so that other people could follow along...

I guess what I really want to know, and through using other's results (I know, not terribly consistent and scientific) I'm hoping to figure if the counterbalancer is a multiplier, or if it's worth a finite amount of power on it's own. So, as long as the question is a "yes" or "no" and not that of a value amount, methinks this process will be accurate enough. It won't produce hard numbers, but it will give us an idea, so somebody else can do something better with their resources...

@Racer x exceeded the stock clutch abilities before adding N2O I believe. Then he added N2O and got 60 (+?) HP. Too much for stock, but not for a modified clutch like he and I have.

As for these numbers:

pods + full exhaust would usually get ~33rwhp.
high comp pistons, worked head ~37rwhp.
ignition timing 38rwhp+

They may be in the ballpark, however if I would guess they should be more like 32, 35, 36. Also, you must remember that many other systems will need to be updated along the way.

NOT TUTING MY OWN HORN HERE, but I most likely have one of the most modified NA bikes and I am working to get 40 HP out of just the motor. I will post my dyno results here and in my thread once completed.

[spooph]

@mgentz - thanks for the #'s! Just post your dyno in your thread, we'll keep things organized... BTW, I'm going through you Ultimate build thread with a fine toothed comb, trying to soak up as much as I can...

I was surprised by the 2 HP as well... I thought it was going to be a decimal increase and it would pay dividends later... We'll see how the other mods get on..

[subxero]

same dyno right? Just 1 pull for each time there?

[mgentz]

Originally Posted by spooph

@mgentz - thanks for the #'s! Just post your dyno in your thread, we'll keep things organized... BTW, I'm going through you Ultimate build thread with a fine toothed comb, trying to soak up as much as I can...

I was surprised by the 2 HP as well... I thought it was going to be a decimal increase and it would pay dividends later... We'll see how the other mods get on..

careful in that thread. There is a lot of information buried in a lot of problem solving, mixed with a lot.

[mgentz]

you should get a package deal from the dyno place. Agree to or pay for 10+ pulls for a time period, then ask for a discount.

^ this works as I have done it before

[subxero]

Originally Posted by mgentz

you should get a package deal from the dyno place. Agree to or pay for 10+ pulls for a time period, then ask for a discount.

^ this works as I have done it before

+1

Was thinking along same lines, you should be able to do some quick changes between pulls. All plastic and non essentials off the bike and you should be able to change jetting, remove snorkel, re install snorkel and even, put on a full exhaust system between pulls. Probably wouldn't be able to remove airbox and install pods between pulls though

[Racer x]

Unfortunately most shops cant let you work on the bike in the shop. The insurance will not cover a giant fire from spilled gasoline and a spark from the starter lead touching a fuel bowl. Just for instance.
And you probably can't push it outside and do it in the parking lot either.

[mgentz]

Originally Posted by Racer x

Unfortunately most shops cant let you work on the bike in the shop. The insurance will not cover a giant fire from spilled gasoline and a spark from the starter lead touching a fuel bowl. Just for instance.
And you probably can't push it outside and do it in the parking lot either.

this sounds like you have some experience with this?

[Racer x]

I have been on fire. But not from that one. But I am aware of the danger.

[cuong-nutz]

Would you want the counter balancer oiling holes to face perpendicular to the oiling galleys on the crankcase to keep oil pressure up?

So to make this work you remove the gear off the counter balancer and clearance the counter weights on the balancer.

[Racer x]

Ya that seems to be what he did. A brilliant way of doing it. I wish I was that smart.

[mgentz]

Originally Posted by cuong-nutz

Would you want the counter balancer oiling holes to face perpendicular to the oiling galleys on the crankcase to keep oil pressure up?

So to make this work you remove the gear off the counter balancer and clearance the counter weights on the balancer.

@spooph do you have pics of this? From what I've seen you would need to turn the balance shafts weights almost completely off as they will hit the crank. the shaft will turn.

[Racer x]

The normal way to remove a balance shaft is to make pieces that replace the shaft but allow oil flow. Using the original shaft and just removing the weight is a better solution in my opinion.

[mgentz]

Originally Posted by Racer x

The normal way to remove a balance shaft is to make pieces that replace the shaft but allow oil flow. Using the original shaft and just removing the weight is a better solution in my opinion.

I think that's a good idea too. I would like to see pics I like it so much.

The only thing to note is that the shaft will turn no matter how you initially orientate it. However, using the original shaft with the oiling holes and proper clearances would be best.