APS/G 250

[AuotonomousRX]

Thanks for the feedback

A few little things to tidy up seeing I got time.

The AFR bungs on a 2 Stroke need to be a little longer to keep so that the O2 sensor is just in the pipe (Innovate sell them).
I made my own up and seem to work OK with my sensor.

Dave,the funny thing is, it is still registered and I have ridden it around the block without the body work (put the silencers on it).

It is surprisingly easy to ride at 40ks, so I must have at least got the Pilot Jets right.

Off to Willowbank Drags a week or two after the Winternationals for a test run.

I took the bike there when it was standard and it consistently (8 passes) ran 100mph - 101mph depending on the start and gear changes. 250 2strokes are not real good on a drag strip

It's a base line, so I will put the same gearing on it and compare the MPH. Can also log AFRs/RPM with my Innovate Meter. I can at least see if I'm in the ball park.

I'm running larger Main and Power Jets - 2 sizes up on the Suzuki Race Kit size, so it should be rich.

I'll know soon enough

Pete
#866

[AuotonomousRX]

Still trying to get Jetting right the RGV Carbs are not the easiest to get right as they have a number of different Air Feeds.

Got 57hp at 9800 rpm, and 29.8 ft/lbs at 9500 which is looking good but it should rev to 12500 with current set up.

Will rejet and try again on Monday test ride and then Dyno in a couple of weeks.

Pete
Smokin#866

[AuotonomousRX]

Changed Jets (It has 2x34mm Mikuni carbs) from 390L/400R to 360/370 which is the Suzuki Stage 1 Race Kit Jetting.

Different Jetting on each cylinder is because a 2 stroke V twin is like having two separate single cylinder engines at 90 degrees.

Test ride was successful and now revs out to 13000 that is a surprise.

Back to Dyno soon.

Pete
Smokin#866

[AuotonomousRX]

Because I have removed the Std Airfilter/Aibox, I have been chasing the Jetting a bit with this engine, I can see why a lot of RGV owners keep the Box on , but I think I got it pretty close .

I think I have now learnt a bit more about the influence the Main Jet has on the Jet Needle/Needle Jet (emulsion tube) on the Midrange.

One of the base line tuneups recommended using the Std Jet Needle/Needle Jet with much richer Mains 400/410.

The Stage 1 Suzuki Race Kit specs use richer Jet Needle/Needle Jet and leaner Mains 360/370.

After using both and many combinations my Bike will only run smoothly on the Suzi set up except for one thing.

Both tune ups have the Needle Clip in the middle slot on the Needle, my bike is not happy there.

I raised the clip one slot (leaner) and bingo the mid range ran a lot cleaner, but I still had left cylinder EGT reading dropping out.

Well I then found the Carb Balance is much much more sensitive than when I had the Airbox, once I tweeked that a bit then I got the EGTs reading within 10 degF of each other.

Pete
#866

[RGV]

Hey Pete,

Good to hear ya getting ya head round the jetting. Mines still a bit off on part throttle, need another T&T day to get it sorted.

[AuotonomousRX]

I finally got around to weighing the individual pieces of the Fairing

Front Fairing is 8.1kgs
Rear Fairing/Tail is 8.3kgs
Belly Pan is 5kgs

The Bike naked and wet is 128kgs
Suzuki claimed Stock Fully Dressed Dry Weight is 139kg

So I am up around 6kgs wet.
I tried to get 60F/40R weight % distribution, I got 58F/42R.

Thanks
Pete
Smokin#866

[Stayt`ie]

Pete, that weight bias looks to me as being "bike only" ,, imho, should be within the 60/40 parameters with you fully dressed (as on course) and in a comfortable tuck position (feet on pegs),,

[AuotonomousRX]

Just did a Plug Chop and



the EGTs read 1064F left plug #360 MainJet and 986F right plug #370 MainJet. I am aiming for something between the two due to the WOT running.

The RGV usually has this staggered jetting but mine seems to want 370s each side maybe even Jets swapped over.

more to come.

Pete
#866

[gennyshovel]

Good luck with the tuning Pete, I'm still fighting mine
Tiny

[AuotonomousRX]

I know what you mean Tiny, good luck with yours to.

You change one thing and it throws another thing out.

This is the closest I've got lost count on how many jetting changes

got everything crossed

Pete
#866

[Stayt`ie]

id suggest that you fellas get yourselves a Air Density Gague, there a several brands out there (google it),, "Longacre" is the one i use,, makes tuning so much easier, but, remember to keep notes,,
also, while ya at it, get a Spark Plug Reader (little magnifieing glass/tourch) brmotorsports.com make a good cheap one,, allows you to get a good look at the plug and read whats going on in there,,
with these two gadgets you can get a "real" handle where the tuning for a particular motor is at,,

Target EGT's,,, Gasoline - 1550*
Alcohol - 1300*
Nitro - 1700*, but you dont want to go there,, ,,,,,,,,,

[AuotonomousRX]

Thanks for that Ron, I am having to go back and relearn a lot of things, those tools sort of dropped off the radar for me.

Trying to get that baseline when you have made a number of mods to the engine got me going around in circles, then,

I found I had a carb that is blocked in one of the many passages these carbs have, even after cleaning and blowing it out. I replaced it. All seems good now.

I also stuffed up when I was programming the ignition curve, it returned to default settings, I probably forgot to save it .

I have checked and rechecked and it's holding the curve I put in there, it's a bit crisper now lol!

Pete
#866

[AuotonomousRX]

I've had a very neglected Honda NSR 250 sitting around for a while. I dragged it out and it had spark so, I put fresh fuel and new plugs in it, started 3rd kick

So what can a man do but get it ready for Feb. I am going to set it up for MG 250 class. No engine changes, I'll build a Seat/Tail section and do the Safety mods.



Yep it's a Rat that smokes!

Pete
#866

[gennyshovel]

I know the feeling Pete.
I'm confident the next jet up I have planned should be the last I need to be in the "safety zone", and if that combo passes the test, I'll have a slightly leaner main to use if I manage to get down the GPS and short courses , all the moving parts are still in the right location & there's no new holes in anything,,,,,I might hit my target speed and finally get a 125 MPH license.
Then there's the unopened can of "whoop-ass" I have, just in case.

[AuotonomousRX]

Tiny, yours has a lot more revs than my smokers, it will sound I can't wait to see and hear it.

Keep at it
Pete
#866