#6

[F5 Dave]

yeah the RS125 step has been widely covered. The MB has one, but it is used in production to locate the pipe that seals up into it so there is no step, just a small port, which is fine for its intended porpoise of carrying around a small Asian family & their chickens/goats etc.

[speedpro]

yeah its real easy to get those ex ports to flare out without trying. My last RS125 pipe I tried to bring in as 40mm was waay too big. Std MBs are ~32 so the question is where to run them with the std single port. I've tried my new pipe at 34 to try the small end of the scale.

Just to clarify - I did not alter the "outlet" of the exhaust port. It was just a very poor setup as delivered. The port has been altered by someone so that there is no step. The outlet is the same size as the stock exhaust gasket. At the cylinder wall the port shape is a bit different in an effort to get blowdown T/A without exceeding exhaust T/A reccommendations.

[koba]

yeah the RS125 step has been widely covered.

The very day after I spent hours getting my pipe to line up very closely to the port.

Still, I'm glad I did it by manipulating the pipe rather than the still untouched (Fully!) exhaust port.

I need to start building a proper pipe. Among other things, the inlet was too small on the one I adapted. I got around that by adding a small section that I flared out with a large ball-pein hammer. The matching mentioned above was lots of welding and grinding inside the ring that the clamp bears on.

[TZ350]

yeah its real easy to get those ex ports to flare out without trying. My last RS125 pipe I tried to bring in as 40mm was waay too big. Std MBs are ~32 so the question is where to run them with the std single port. I've tried my new pipe at 34 to try the small end of the scale.

32 might be right ...... There are some graphs and pics from the simulator on my original post.

I have been looking at exhaust port nozzels, now I would have thought the best arrangement was to have the exhaust port gently opening up starting at the port window.

But EngMod2T and Wobbly tell me that a nozzel shape is what I need for top end and over rev.

I have done some tinkering with the simulator and a 34.5 nozzel opening up to 40mm to match the pipe is the optimum setup for my 125.

[F5 Dave]

Been playing with a laptop given to us by the sister-in-law. Fitted a USB-serial cable, loaded the software, and connected it to the Ignitech. I fed 12v to the ignition from a battery and it all connected just fine. I now have the programming that we did on the dyno safely stored away and have done a few changes to reflect the powerjet and TPS. It comes up with a funny looking ignition map by default when "3D" is selected so it'll be interesting to see how that compares with what the dyno tells us is needed.
. . .

Just thought about this the other day. Presumably if you have previously got a setup that does its best to extend over rev by advancing the ignition, - you may have to back this off before playing with turning the PJ off cutting fuel & then re-find the curve later- lest you heat it up a bit too much.

[F5 Dave]

Hey Mike, what stator are you using? had a quick squizzy at CRF250s on Evilbay & they all appear to be inside out jobbies with stator mounting on the outer engine case.

Thinking about how to power my waterpump. Not sure if it would drive my current ign. Does stator set have puls coil & charge coil? (I can see the pulser coil) Or just meant for totally electronic ign as it looks?

[speedpro]

Interesting day at the track. With the waterpump the temperature is staying low. I've taped up the radiator a little which brought the temp up to 55 on my gauge. The motor is staying crisp, possibly a little too crisp on the kart track. I've also got some other tyres fitted and it handles differently now. I was running up curbs at the start and generally wobbling round more than usual. Also after riding the scooter for weeks going to work it is real strange riding the bucket, the bars feel like they are bolted to the axle initially and it takes a bit to change the riding technique to match the riding position. My previously damaged right wrist was near useless after the first session. Anyway, the pump seems to be a good mod but it will be more obvious at somewhere like Taupo.

[Pickle]

so with the water pump do you have to turn it on manually or it comes on when the motor is running, I seem to remember popping pistons on the sidecar when someone forgot to turn the water pump on !!!!

[speedpro]

I've had that discussion with someone else already. Currently there is a switch as I don't want the electrical load when I'm starting the bike as there is no battery, just the alternator, reg/rec, and capacitor.

Subject change: - our old sidecar is coming back to Auckland. Sidecars are making a bit of a resurgence. Evidently the waterpump is now driven off the ignition rotor nut. I'm hoping to be able to bludge a ride, that would be cool.

Another subject: - "world domination of bucket racing with a fleet of MB powered buckets" - Gary got a 3rd and 1st today on his and I don't think he was trying too hard. Only a playday though. Tokoroa should be fun next weekend with both Gaz and Dave M riding, and Rick though he has some pussy Suzuki motor.

[wildman]

I've had that discussion with someone else already. Currently there is a switch as I don't want the electrical load when I'm starting the bike as there is no battery, just the alternator, reg/rec, and capacitor.

Subject change: - our old sidecar is coming back to Auckland. Sidecars are making a bit of a resurgence. Evidently the waterpump is now driven off the ignition rotor nut. I'm hoping to be able to bludge a ride, that would be cool.

Another subject: - "world domination of bucket racing with a fleet of MB powered buckets" - Gary got a 3rd and 1st today on his and I don't think he was trying too hard. Only a playday though. Tokoroa should be fun next weekend with both Gaz and Dave M riding, and Rick though he has some pussy Suzuki motor.

If it works out sidecar should be in Auckland for April meeting at Mt Welly

With your elec water pump you could set the earth lead up through an air con thermo switch, they're fairly small and can be adjusted to switch on at different temperatures. We've used them for switching on cooling fans on vehicles, only hassle is getting water hose to seal with capillary tube in it

[F5 Dave]

That water pump looks like a gallery tap water delivery pump.


oh yeah I worked out the X model is the enduro one the R is MX.

[husaberg]

That water pump looks like a gallery tap water delivery pump.


oh yeah I worked out the X model is the enduro one the R is MX.

Now how pray tell, did you figure that one out Dave?

Someone telling you it was a X model must have been a good start?

[F5 Dave]

yeah thanks for that, but Honda still has a silly name for the CRF250 with the suffix determining if it is the enduro model or MX.

How hard would it have been to call it a CRX250? or CXR, or CXX? or XRF ar any other range of letters.

Mind you Yam had confusion when they introduced their 4 stroke YZ range as they had already used YZF for thier road bikes.

[husaberg]

yeah thanks for that, but Honda still has a silly name for the CRF250 with the suffix determining if it is the enduro model or MX.

How hard would it have been to call it a CRX250? or CXR, or CXX? or XRF ar any other range of letters.

Mind you Yam had confusion when they introduced their 4 stroke YZ range as they had already used YZF for thier road bikes.

WR as well are a bit confusing different motors depending on last letter. not to mention 2 and 4 stroke

Speedpro
Did you move the Powerjet on the KX shorty carb?
Wob mentioned something about that?

[speedpro]

What fun Tokoroa was. That track is nothing like what it looks like on Google or the Youtube vid. My bike was hauling arse well enough that it wasn't worth checking the jetting even though it was surely a bit rich. In the end it came to a reasonably sudden stop(plug chop) so I have checked the plug and it was rich so possibly should have been a bit faster. Didn't matter as it went as fast as it was going to go with me on it. The temp stayed at about 55-60deg with the pump running and with 2 strips of duct tape across the bottom of the radiator so there's about 25% cooling capacity in reserve. It definitely likes being a bit cooler than previous. It was nice and crisp all over and shot between corners with only a little dab at the clutch sometimes

The other two MB/H100 engined bikes went OK though they looked a whole lot better because of Dave and Gary riding them. Gary's bike has no plug gap now so it'll be interesting to have a look inside. Both engines are what I consider to be baseline considering what had already been done to them and I really only intended to get them going reliably before proceeding with a proper tuneup. Only 1 out of 2 so far. I kept telling Gary to thrash his bike as hard as he liked as he wouldn't be able to blow it up, I may have to revise that advice. Honestly though I don't know why it stopped. When I got the engine I did use Draino on the cylinder to get the smeared aluminium off the bore followed by emery tape for the bore and piston to remove the worst of the scores but it shouldn't have stopped, maybe just been a bit slower. On the dyno it only revved to about 11-12,000rpm so plenty safe for one of these engines.

I'm having a few days off work. Seems I might have tweaked my neck/ribs a bit and there may also be a bit of nerve tickling going on. There's funny crunching noises I can hear in my head when I move my neck and the odd pop from my shoulder/rib area though no broken bones. I stopped into the Emergency department at the local hospital to be greeted by my name. Turns out the nurse on the counter used to be the AMCC medical advisor/organiser when I was on the road race committee. Rather than a 4 hour wait to be seen we had a good chat in an adjoining room and she checked me out to confirm I'd survive till the next day and to go see my own doctor. Thanks very much to Annemarie - very much appreciated.