#6

[speedpro]

Making a bit of progress. The engine has always run OK and it was easy enough to make changes to sort out issues at lower revs and loads. I've now had a couple of days on the ESE dyno and have been doing full throttle runs to whatever revs it will do.
I had a configuration programmed that I thought was not going to work after the first day. We gave it another shot today and it is good enough that I'm not bothering to change it. One difficulty today was a fueling issue just as it is coming up on boost. We never really got it sorted. It was actually better at half throttle. A pleasant surprise is how easily it pulls boost. If the revs drop to 6K you can give it full throttle and by 10K it has boost and would probably have more if the fueling was better. If you have had revs high and let it run down to 10K and open the throttle full it pulls 140kPa straight away. i'm pretty sure the turbo wastegate is opening at 140kPa so that's all I've seen. A real problem is that it isn't happy revving over 16K or so. the AFR moves about a bit and as it approaches 16K it suddenly goes very rich. We were thinking it was an ignition issue but I think not. Lambda meters measure the oxygen in the exhaust and if ignition failed there would be more oxygen and a lean indication. something to check some other day.
The motor might be making a bit of noise, a sort of top end rattle. I'll be taking the camcover off to have a look and will check tappets and cam chain.
Anyway, the end result is a pretty impressive torque curve and an OK horsepower figure. There's more to go if I haven't broken the motor. There's 2K rpm to go for instance. The turbo will hold the torque up which with revs will make more horsepower.
One thing I like with this setup is how the throttle can be moved how you like at any revs and the motor smoothly goes about it's business.
Must sort out a generator for the bike. The small battery charger wasn't keeping up with the supply and the little battery ended up dropping to 9V or so. The bigger battery and charger sorted it out today.
It's a thirsty little beast as well.

[Grumph]

Check valve springs too. Your over-rich top end could be an inlet floating.

[speedpro]

I knew there was a reason I was putting off top end maintenance, what a bitch getting it all apart. The problem is all the modifications that have been made.
Anyway, got the top off and measured tappet clearances. Inlets were all .05mm or slightly less, when they should be .1-.2mm. The exhausts were all at .2mm with the range they should be being .2-.3mm. The head was reconditioned before I assembled the engine and all the shims were in a tight range of sizes. I've ordered a collection of shims from an Aussie crowd - Precision Shims. Really fast reply to my email enquiry and getting shipped this afternoon.
The cam chain seemed a bit loose when I checked. I had a look at the tensioner which was only out about 1/4-1/3 of it's travel so I put it back together and pushed the rod out one more click on the ratchet which seemed to be about right.

I just hope the cams go back in and can be lined up with the marks I've made. The standard marks are no good as the bit of each cam I'm using is the bit that was over #1&2. I've flipped the cams over so the locating disc on the end of each cam is retained when I cut the cams in half. Luckily the cams have symmetrical lobes so can be rotated in either direction. Also luckily, Yamaha had small recesses at the other end of the head where the locating discs fit into above #4. A small shim was made to get the cam sprockets to line up with the crank sprocket.

I'll probably give it a run with the 2:1 exhaust just to check things are good. The plugs came out with a slight wet oily look. It might be something to do with the turbo, maybe. On the dyno we had the exhaust going straight into a vent to the outside so had no view of smoke if any. It's only 4 more bolts so why not.

[speedpro]

All shimmed up. Luckily I bought a wider range of shims then I thought I needed as basically I went one smaller shim on nearly every valve. Got it back together without too much drama, and no bits left over. I've gone with the 2:1 exhaust to sort out the revving with a simpler setup. 2:1 is not ideal with this firing order but it really is just 2 headers into a common muffler. I had it on the stand, powered up, in 3rd gear and was turning the back wheel slowly just to get a feel for the compression when it popped on one cylinder. It took little effort with the throttle held at about 10% to get it fired up. I'd sort of forgotten just how good a 180' twin sounds at a few revs though it's possibly a bit loud. Long weekend coming up in Auckland.

[speedpro]

Been playing on the ESE dyno today. Turbo has been removed and a simple 2:1 pipe installed. The fuel map is a simple TPS/RPM map with a limited number of variables.
It was running lean at the start despite the warmup enrichment so I added more fuel and also increased the amount of enrichment. Once warm and over a number of runs it was obvious that more fuel was required everywhere. Just going by the Lambda meter I was increasing fuel run after run until it was reading about what it should. The end result was about 16hp. It was still limiting around 15-16,000rpm and would go very rich very quickly. I did notice that the engine rpm reading in a display turned yellow once it got near 15,000rpm. Considering that I have disabled all the engine protection features in the software I didn't expect it to be limiting.
The first runs were done with the intake plenum fitted.
I was trying to eliminate reasons for the rev limiting so another set of runs was done with the plenum removed. Unexpectedly a lot more fuel was required, about 50% more in a few areas. It revved a bit harder but was still limiting at about the same rpm. These tests ended with a bit less than 18hp. Not too bad for a 125cc normally aspirated motor.
Currently the throttle response is flawless and the torque curve is very handy. Looking at the power curves it would be a very nice bike to ride.
The attached screen shot shows 3 runs. RED is with the intake plenum fitted, BLUE is with the plenum removed, and GREEN is an older one with the turbo in place on the 100cc engine(cough cough). The fuel map has low values in areas that aren't used, for instance 0% throttle over 7,000rpm. You can see this on the overrun as it goes super lean and as the revs drop down closer to 4,000rpm it comes back to a normal reading. Just touching the throttle brings it back instantly.
I didn't really achieve anything today apart from coming to the conclusion that something in the software is causing the rev limiting. Also the intake plenum is restrictive but works fine with the turbo.
An interesting observation with the plenum off was that there was no fuel standoff outside the throttle bodies. With the open carburetors there was fuel standoff about 100-200mm at certain revs so I figure all the injected fuel must end up going in the engine.

[speedpro]

Went down to the garage and plugged the laptop in to the ECU. In the Engine Protection part of the screen it was showing a RPM limit of 12,000rpm. Bit odd as all engine protection is turned off. I went looking for where this might be configured and actually turned on rpm limiting and had a look at the associated table. Sure enough there is an entry for 20' ECT with 12,000rpm. Looking a bit further along there is also an entry for 100' ECT with 16,00rpm in it. This is more or less the rpm at more or less the head temp where I'm having the problem. I turned off rpm limiting and the table became unavailable. The rpm limit remained. I turned rpm limiting back on and set the rpm at 20' to 18,000rpm and then disabled rpm limiting. The rpm limit was now 18,000rpm so that table is still active despite me disabling rpm limiting. It seems obvious that it is also active at 100' and is causing the limiting problem. I've asked about it on the Link forum so will be interesting to see what answer I get.
I had configured this table when initially playing with the software. I had thought that the engine would run a bit cooler so had it configured to reduce the max revs as the temp hit 100'. When I disabled it I didn't think about it any more.

[husaberg]

Went down to the garage and plugged the laptop in to the ECU. In the Engine Protection part of the screen it was showing a RPM limit of 12,000rpm. Bit odd as all engine protection is turned off. I went looking for where this might be configured and actually turned on rpm limiting and had a look at the associated table. Sure enough there is an entry for 20' ECT with 12,000rpm. Looking a bit further along there is also an entry for 100' ECT with 16,00rpm in it. This is more or less the rpm at more or less the head temp where I'm having the problem. I turned off rpm limiting and the table became unavailable. The rpm limit remained. I turned rpm limiting back on and set the rpm at 20' to 18,000rpm and then disabled rpm limiting. The rpm limit was now 18,000rpm so that table is still active despite me disabling rpm limiting. It seems obvious that it is also active at 100' and is causing the limiting problem. I've asked about it on the Link forum so will be interesting to see what answer I get.
I had configured this table when initially playing with the software. I had thought that the engine would run a bit cooler so had it configured to reduce the max revs as the temp hit 100'. When I disabled it I didn't think about it any more.

Be interested to see what they really rev to i always thought the CBR were a bit optimistic atindicating they were revving to M which was 20K.
I never rode a FZR250 but i dont imagine there were much different.
So the rich mixture at 16K was the ignition signing off an raw fuel being dumped into the exhaust

[speedpro]

Anything, ignition or injection, signing off will result in more oxygen being in the exhaust giving a lean indication. There may be unburnt fuel in the exhaust but Lambda probes don't measure that, just oxygen. The richness is more likely caused by a reduction in VE, possibly valve float has been suggested. I have read that max power is at 14,000 which it may be.
Feedback from Link is that the flashing RPM indicator is just that. It isn't an indicator of rpm limiting. It changes colour with revs because it has been programmed to do that. We'll see. I'm going to programme in real low revs, say 8,000rpm, and see what happens with the rpm limiter turned off.

[F5 Dave]

Think 250s redlined at 17 but as later found out the new at the time R6 was super optimistic on the Tachometer so the revs they were boasting about in press releases was later debunked..

My RZ runs an R1 clockset. The Dyno reading 10,000 was 11,000 on the clocks. Think it got worse as the revs got higher but ok at 5000.

[Grumph]

Little story about a CBR250RR....Guy came to me with one he'd had for about a month. Gray import bought from a largish dealer in ChCh. They didn't want to do a service - so I did oil, valve clearances, balance carbs...Shall we say, they were more used to Harleys...

Anyway a couple of weeks later I got a ring from them - "what did you do to it ?" Told them - and asked what had happened. Leg out of bed.

Next time I was in there I asked what the outcome was. Got told that the owner had delighted in it's ability to show 18,000 rpm - and used them all frequently.
Post blowup, they'd had the tacho checked - it was reading 2000 rpm LOW....

Someone in Japan must have swapped in an ignitor box with no limiter.

[husaberg]

Little story about a CBR250RR....Guy came to me with one he'd had for about a month. Gray import bought from a largish dealer in ChCh. They didn't want to do a service - so I did oil, valve clearances, balance carbs...Shall we say, they were more used to Harleys...

Anyway a couple of weeks later I got a ring from them - "what did you do to it ?" Told them - and asked what had happened. Leg out of bed.

Next time I was in there I asked what the outcome was. Got told that the owner had delighted in it's ability to show 18,000 rpm - and used them all frequently.
Post blowup, they'd had the tacho checked - it was reading 2000 rpm LOW....

Someone in Japan must have swapped in an ignitor box with no limiter.

Revving that high std was fun for a laugh but really rather pointless the gave up the ghost around 14-15, but once we discover the Hondas went to the indicated 20k everyone in the shop used to do it to the poor things anyway.
I never tried a Kawa one either ,but on paper they are in the highest state of tune,comp, bore, valves carbs etc The couple of Suzi ones i tried were never as quick as the Hondas.
I think Mike said he reverese the cams pretty sure you can do the inlet to ex cam swap and used do for the biker models That way you only need one new cam for the Normally aspirated hotted twin.
AS i have said to Mike before there is 2 different cam profiles on the yams if not more the first 3ln i think has the hottest one.
It actually says a lot for their engineering that any of them are still alive considering they were learners bikes. and the number of ham fisted hands they would have passed through

[Grumph]

My 150 twin has the ex cam reversed - and a bigger profile put on the inlet which of course is also reversed compared to std.
And yes, I did some measuring and checking, all the 3LN's I have here have the early, bigger cams.

[speedpro]

Definitely not the Link ECU. Set the rpm limiter table to 6000 everywhere and turned off limiting. Main screen indicated 6000rpm limit but quite happily revved over that. Turned on limiting and I could hold full throttle and it just sat there at 6000.
I'm going to pull all the valve springs I have out and check them. If they are consistent I can reasonably assume that the springs I have in the bike are the same. Failing that maybe the cam profiles aren't exactly symmetrical and I'll have to get a grind that is around the right way now they are being rotated in the direction they are. Grumph have you measured profiles of the cams for symmetry?

[speedpro]

My cams are still in their original locations, exhaust in exhaust etc. But they have been flipped over. The left end is now the right end and as a consequence the cams are rotating backwards

[Grumph]

No I haven't measured them - but all my previous experience with bucket and shim cams says they will be symmetrical.

Springs - I checked how far from the seals the retainers came - miles away. And how far from coil bind they were - again miles away. I shimmed the seats up from memory about 1mm. Without putting them on a spring checker, I'd pick that puts seat pressure up about 10lb.
They are after all, bloody small springs....I have a heap here if you can't assemble a good set.

Sadly, mine has not yet run. It will be a while too as the priority is now to earn some $$ to buy a new ignitor ex China. This appears to be the simplest way of putting an ignition on mine.

Edit afterthought - what lobe centers have you put them in on ?