#6

[speedpro]

Damned brakes.

I ended up replacing the rear brake master cylinder and caliper as nothing I tried would get the old one to work.

I decided to swap the front wheel from the MB/FZR as the slick is reasonably new. That wheel has the smaller disc on it and was using a 4-pot calliper with different size pistons. All good, swap the whole lot. The damned thing dragged real bad. I tried the caliper, but without the adaptor for the bigger disc, that was fitted originally but it turns out that the 2 discs have different offset. I thought back and sure enough the adaptor has about a 2mm offset to centre the caliper on the big disc. Another reason for swapping the wheel is that the adaptor is fabricated by bolting bits of aluminium together. I've been using it for years and there is absolutely no way it can fail in normal use. I just wanted to avoid even a hint of doubt at scrutineering by using the other caliper without any adaptor. I tried pumping the pistons out a fair way and cleaning them with a toothbrush and brakeclean. I could push the pistons back smoothly by hand but once assembled back on the bike and pumped up it still drags. The disc was already clean as I have previously scoured it with parts cleaner. On the MB/FZR it was normal with very minimal drag. What I'm thinking now is that there is some slight difference between the front ends and like the old CB150, when you change wheels the brakes drag a bit but free up after a bit of use. Fingers crossed. All up the brakes absorbed another day of messing around.

[F5 Dave]

Damned brakes.

I ended up replacing the rear brake master cylinder and caliper as nothing I tried would get the old one to work.

I decided to swap the front wheel from the MB/FZR as the slick is reasonably new. That wheel has the smaller disc on it and was using a 4-pot calliper with different size pistons. All good, swap the whole lot. The damned thing dragged real bad. I tried the caliper, but without the adaptor for the bigger disc, that was fitted originally but it turns out that the 2 discs have different offset. I thought back and sure enough the adaptor has about a 2mm offset to centre the caliper on the big disc. Another reason for swapping the wheel is that the adaptor is fabricated by bolting bits of aluminium together. I've been using it for years and there is absolutely no way it can fail in normal use. I just wanted to avoid even a hint of doubt at scrutineering by using the other caliper without any adaptor. I tried pumping the pistons out a fair way and cleaning them with a toothbrush and brakeclean. I could push the pistons back smoothly by hand but once assembled back on the bike and pumped up it still drags. The disc was already clean as I have previously scoured it with parts cleaner. On the MB/FZR it was normal with very minimal drag. What I'm thinking now is that there is some slight difference between the front ends and like the old CB150, when you change wheels the brakes drag a bit but free up after a bit of use. Fingers crossed. All up the brakes absorbed another day of messing around.
I often find the white oxidisation behind the seals needs to be carefully scraped out as it pushes on the seals. Or dross that sinks to the bottom of the system.

Twisted seals can cause issues too.
Basically dont try save time. Pop the pistons out.

Oh. Remove the front brake lever. That will tell you if it is closing off the return port in master cylinder. Aftermarket levers can do odd things.

I once had a brake line clog. That brought hours of confusion. Never seen that before.

[speedpro]

I sorted out a Nissin 2-pot caliper off an RS125. I needed to drill out the pin that locates the pads as it was frozen in. I then made a new stainless pin that is held in place with split pins. Took the seals out, cleaned everything, put it back together and connected a nice Brembo master cylinder I have lying around. I've used this setup on my FZR a while ago but swapped it out due to issues with the caliper which should be sorted out now. It seems to have bled out OK. I've left it hanging off the vice to let any air bubbles rise to the top, if any remain.

[speedpro]

Hampton Downs, what a mission. The motor was very lazy building boost. It got there but was slow which i put down to the setup of the boost control which ran off the throttle position. It did get there but typically at about 16,000rpm before it really got going. The rev limiter cut the engine dead at 18,000rpm which made it interesting at times. I had it overgeared as well and was only getting to max revs in 5th. It also was mid-gear exiting corners which was a combination of lack of boost and the hard rev limit. More boost earlier would have enabled a higher gear and a much better exit. The track is also a bit much for a bucket although if I get it all sorted how I would like, it won't be too bad. Looking at the logs the inlet temp was up around 100°C at times which is way too hot and would have resulted in timing being pulled out for safety, losing power.

So, I'm now on the lookout for an intercooler. I may have found a good example from the guy I have bought my scooter hot bits from. He does a turbo kit which includes an intercooler. He may be able to get me all the bits before they are welded together, and hopefully a box of tubing and hose as well.

The guy that tuned the bike for me sent a new setup after looking at the logs. The rev limit setup is completely different. I've loaded it, set the limit to 10,000rpm, and tried it in the garage. It's not a great test but did sound a lot softer on the limit at full throttle. The new setup also changes how the boost control is done. We know what duty cycle works to limit the boost where we want it at the moment, 180 kPa, and simply spanned the boost control table with MAP & RPM with cell duty cycle values to keep the wastegate closed until close to the desired boost. It should spool up heaps quicker. I know from my big bike that keeping the wastegate closed at lower boost levels results in quicker turbo spooling by less wastegate creep.

I also ride like shit. My other rides at home are my scooter and my son's DRZ400SM. Both have a riding position which suits my creaky body, unlike the FZR. The track is a lot faster than my first impression and I'm a slow learner so even by the last session I still wasn't up to speed. Coming into corners I sometimes needed to be in a lower gear, due to the sluggish boost, but this meant being pretty harsh with the downshifts entering the corner. The bike was making loud "bangs" on the upshifts, almost like a quickshifter. The tyres seemed pretty good. I swapped the good front off the MB/FZR and Gary gave me a good rear to use. All up I consider it a success despite the problems. Nearly everything has already been fixed. All that's needed is an intercooler and somewhere to put it, and a new neck for me.

[speedpro]

I dropped the kart starter back to Kev's place this morning. He gave me another one to use as long as I want. I just need to get a battery for it. In conversation I mentioned that I've been playing with brakes and was about to look at another caliper for the rear. After a bit of fossicking around he comes back with the caliper in the photo and says I can have it. It's one of the cutest calipers I've seen. The good thing is that it is solid mount due to having pistons each side which will make fabrication of the mounting a lot easier. The caliper I was going to use slides on pins. I will refurbish that one but will put it back on the RS.

This caliper can be mounted up either way on either side by switching the hydraulic fittings around. Nice and simple. I'll replace the manky bolt with a nice stainless pin with split pins each side. You have to wonder what they were thinking after making such a nice caliper

[speedpro]

The log showed that the inlet air temp was getting to around 100°C so I started looking for a suitable size intercooler. I remembered that the guy I got my scooter engine bits from sold a whole turbo kit for the scooters including a small intercooler. After a bit of back and forth his fabricator guy is going to put together a package including a yet to be assembled intercooler and a bunch of tubing and hose. I've sent a few photos of where everything will go, maybe, and they're going to make a few guesses about what I might need and send it. I'm also going to relocate the air filter from behind the engine to somewhere out front. I probably should relocate the turbo but that is more work than I can be bothered with which would also include replacing a few existing parts like the radiator. Not doing it will probably come back and bite me.

[husaberg]

Ford Courier/Mazda bounty 2.5 diesel 98-2006 is as cute as a button.

https://tbap.com.au/wp-content/uploads/2018/08/TIC-FOR-009-AAT-e1533767597813.jpg

[speedpro]

I looked at those but they seemed a bit big.

The Turbosmart rising rate fuel pressure regulator arrived today. It's made a bit more solidly than my current regulator going by the weight.

[husaberg]

I looked at those but they seemed a bit big.

The Turbosmart rising rate fuel pressure regulator arrived today. It's made a bit more solidly than my current regulator going by the weight.
Size is relative, They sure look tiny compared to a 25DET.
The Daihatsu mira which was one of the engines that had your ihi rhb31 turbo as std had a even smalller one but not as easy to find in NZ :)
353803
https://www.autospeed.com/cms/a_2627/article

[speedpro]

Been machining a caliper mounting bracket. Cleaned up the disc as well as someone had worn the pads to the backing plates and garked it up pretty good. It's taking ages to do but I'm claiming it's because I don't have digital readouts on the mill. There's a little bit of weight loss to do yet but it's already lighter than the original. Weight loss is a bit of a joke given the all-up weight of the bike. It's really obvious the difference between the FZR and the MB/FZR when I'm moving them around in the garage.

353811353812353813353814

[speedpro]

Weight comparison of old and new. A nice reduction in weight plus a shot of the finished setup on the bike. Still need to make a new stay arm.

[speedpro]

I machined up a couple of fancy end pieces, welded them to a bit of tube, and fitted it to the bike. After having a look at it I've decided that the arm is about 50mm too short which is a bit annoying. Fixing it isn't too hard. I'll machine down where the ends and tube are welded together and fit a longer bit of tube to the ends. I just want to get the geometry between the axle, arm, and swingarm mount correct. At the moment with the axle well forward in the swingarm it isn't too bad but if I move the axle back due to fitting different sprockets the geometry will be bad.

[speedpro]

The brakes as far as I'm concerned are finished. As expected it was simple to turn down the weld and the piece of pipe that fits over the endpiece extension. The welding, although still not flash, was markedly better than the first attempt. The geometry is way better and the axle can be moved back and it'll still be OK.

Also looks like a new rear tyre may be turning up. The one on the bike at the moment is of unknown age but it's only got two good features - it's round and it's black.

I have other gearing I want to try at Tokoroa so will be fitting those sprockets. Pretty sure I'll need another new chain but I can get DID chain at Westgate so not a problem.

[F5 Dave]

Always good to get brakes sorted and ideally easy wheel changes with captive spacers like RS have. Spent way too much frantic pit time juggling spacers and discs that needed swapping out to make a change to Wets work.

[Grumph]

These days, if a change to wets is needed, it's beer o'clock.

Can recommend the relaxed approach.

[F5 Dave]

To be fair I was at that stage. Younger me was all keen.

[speedpro]

Ready to go I reckon.

[speedpro]

Got the new Turbosmart fuel pressure regulator today at about 10:00. I ordered it at about midday yesterday so quite impressed. Tried it out and found that in comparison to the other cheapy one, that this one is very smooth to adjust. I also fed 1BAR of compressed air to it and the fuel pressure increased 1BAR. This is exactly what should happen and will allow the 4d fuel trim table to be deleted probably. It might even be time to up the boost. I'm kidding, it's always time to up the boost.

[speedpro]

Off topic, just trying to get an idea.

Just wondering if there is anyone interested in an old RS125 chassis and fairing. I had plans but you know how it goes. I think it's a '93. The suspension will need to be "tuned" and I have modified the front engine mount for the MB100 I planned to fit. No front caliper or master cylinder.

[speedpro]

Monday dyno session to dial in the fuel has been postponed. Hopefully it can be fitted in some time soon.

[F5 Dave]

Bet the plans didn't involve you trying to shoehorn yourself onto it!

Sigh. Great starting point.

[speedpro]

There was a lot more interest than I expected. Good news is that the RS125 has a new home.

[speedpro]

Dyno session is planned for Friday. All that should be needed is a reduction, or elimination, of the compensation for the old fuel regulator which did not increase fuel pressure at the same rate that manifold pressure increased. The ECU expects the fuel pressure to increase on a 1:1 ratio and calculates boosted fuel quantity based on it happening. We'll get a reliable horsepower reading as well.

There is no real plan to bump the boost up. The plan is to stick with what the current target, which from memory was 180kPa(absolute) or 11.6psi of boost. On the dyno doing short runs will yield a better result than on the track. At HD the intake air was hitting 100°C and the ECU backed timing off for safety. Intake air temp should be a lot less of a problem on the dyno. The temptation will be if we get ?8.9hp in which case a small tweak might happen.

Watch this space for the number

[speedpro]

I'm calling it 30hp which is a bit disappointing. There was a few things going on which don't show in the dyno graph with the AFR jumping up & down but not all the time. It looked like a bad wire but could also have been bubbles getting in the fuel to the injectors. Despite having a good fuel pressure regulator which increased the fuel pressure properly it wasn't looking a lot richer like I expected. The injector duty cycle was going over 92% if it pulled decent boost at high revs so, as setup, there isn't much left in the fuel system.
Through the gears if I didn't tap the rev limit it seemed really nice. I need to investigate getting boost sooner. I made adjustments to the boost control table but I think I will set it so the wastegate is never opened and see what happens. If there is no difference then it's a limitation of the little engine and this turbo.

It's strange but this engine does not sound like it's revving as hard as it is. It is only going to 17,000rpm where I really want 18,000rpm but it doesn't sound like it. something else to figure out.

Graphs are:
blue - from 4 years ago just before the previous engine stopped
green - through the gears today
red - 6th gear only

[speedpro]

I've had exhaust wrap for ages, maybe 20 years, just sitting in a bin of "stuff". I have always thought that the exhaust with the plenum chamber was not as efficient as it should be as it would lose a lot of heat from the gas before it got to the turbo. The reduction in gas temperature would reduce the gas volume and therefore the gas velocity through the turbine. It could very easily be contributing to the lazy way it comes on boost. I dragged it out and wrapped the exhaust as good as I could be bothered. The headers were wrapped as one. It's probably not the absolute best but it'll be better than before. Due to the odd angle the pipes enter the plenum and the tapered and turned plenum outlet, the wrapping is more a case of doing it in a way that shouldn't simply come loose. The end result is that most areas have at least 2 layers and there are more layers in a few places. Each end was left mostly uncovered simply due to the difficulty of wrapping it effectively and having it stay in place. Not shown in the photo is a shield that goes over the wrap on the plenum, which is held in place with a couple of hoseclips.

If you think this might be a waste of time, a simple experiment will illustrate the difference in gas volume with barely a 100°C change in temp. Get a 2L plastic milk bottle. Pour in a cup of boiling water and slosh it around to heat the air in the bottle. Quickly tip the water out and put the top on. Cool the bottle under the cold tap. The bottle doesn't just crinkle up a bit but completely collapses.

[speedpro]

Had a good session on the ESE dyno. I was only checking how the boost was building in certain scenarios.
Tried 3 setups
1 - Wastegate actuated as standard.
2 - Wastegate controlled by a solenoid, closed up to 160kPa, opening around 180kPa
3 - Wastegate held closed manually.
1 resulted in 140kPa boost with a gradual increase from 8,500-10,000rpm then ramping up to 140kPa at about 14,000rpm.
2 resulted in 180kPa boost with a gradual increase from about 7,000rpm, then from 10,000rpm ramping up to 180kPa at about 14,000rpm.
3 resulted in plenty of boost if I let it. It was making minor boost from about 9,000rpm and pulled through the 10,000rpm flat spot reasonably cleanly. By 13,000rpm it was making 130kPa and after that it was on a mission. I closed the throttle at 14,500rpm at which point it was making 190kPa and climbing.
3 resulted in 1-2hp more in the lower rpm which is worth having.
I'm going to add a spring to the wastegate actuator to hold the wastegate closed until about 180kPa or a bit less. This should make the boost ramp up quicker, the same as holding the wastegate closed manually. If it turns out that I can run lots more boost I'll add springs to achieve 90% of the boost and use the solenoid and ECU to limit/control the boost. It will remove control in lower revs and lower boost but that doesn't concern me.
1 = Green.
2 = Blue.
3 = Red.

[F5 Dave]

My 50 would nail it from about 6000 to 11000rpm.

Lot of revs, but doing the business. Can you keep it above say 10 all the time out of the pits? Presumably pulls cleanly without loading up from there?

Must be low gearing.
.

[speedpro]

It has a great gearbox. Once under way it's not difficult to keep it over 14,000rpm. The trick is changing down what seems like enough gears going into a corner only to find you need to drop another gear on the exit. With the boost control solenoid setup how it was it really liked being over 16,000rpm as it took until those revs for all the boost to be made. I changed it for these tests so that when it was connected, run 2 above, it was making 180kPa, max boost, by 14,000rpm. Nett result of doing just that was a 4,000rpm powerband where max boost was available. I limit max revs to 18,000rpm although I have been getting "noise" on the ignition recently which has made anything over 17,000rpm worth avoiding.

I measured the force needed to start opening the wastegate. I used a luggage scale, as suggested by Rob, to pull on the arm. It took about 4.5kg to move the actuator arm about 1mm. I've lockwired a spring between the actuator and the lever. Now it needs about 9+kg pull to open. The difference between the tests showed that the wastegate was creeping open even with no manifold pressure to the wastegate. The exhaust pressure alone was pushing the wastegate open. This will cause the boost to build slower than possible. Holding the wastegate closed proved this as it made more power from about 10,000rpm up.

[Grumph]

That exhaust pressure opening the wastegate is something to be wary of. Some time back on probably another thread I mentioned being told of probs on a turbo'd Subaru where exhaust pressure spikes were opening the exhaust valves. With dire consequences. Blowing them open to where they were hit by pistons.
I know just how soft the valve springs are in the little FZR - so it may become a real possibility.
Even the 1200 Kawasaki turbo I rebuilt had witness marks on pistons where exhaust valves had touched. Putting the cams on wider lobe centers at least averted the worst.
The Subaru was eventually cured by redesigning the exhaust layout.

[speedpro]

Must be low gearing..

As tested it was geared for 90-95mph. Previous dyno chart has x axis set to "mph".

[speedpro]

Recent tests have recorded trigger errors and rpm noise. I racked my brain about the cause and the guy who tuned the Link suggested maybe some sort of backlash due to it happening if I backed off at high revs or after it hit the limiter. The thinking was that the crank and cam triggers were getting just that little bit too close for the ECU to process both signals at the same time. Yanked the alternator cover as part of the process of checking cam chain tension and found the wires had been rubbed by the alternator rotor. My little theory is that originally the wires were good as gold but tension has been applied and pulled the wires over a little boss making them stick up just enough to get rubbed. One of the 2 wires from the stator was disconnected where it rubbed. I've soldered it back together and put a bit of tape on it, reassembled it, making sure the wires were out of harm's way.
A good look at the logs after the dyno session showed the actual Lambda to be above the "desired lambda" across most revs. Both the old and new regulators looked to be set to the same pressure but obviously the new gauge reads different. I've wound it up .5BAR which will get more fuel into it and move the Lambda closer to the desired. I'll check it at the next dyno session. Either that or go for a ride and check the log, and adjust as required.
I've also adjusted the rev limit up 300rpm as the ECU limiting starts early and has a hard limit before or maybe just on 18,000rpm. I'd rather it revved to 18,000, and then started limiting. It'll be limiting at less revs than the standard redline. Standard of course it ran a bit less boost.

[speedpro]

I rode the turbo twin on the Saturday of the 2hr meeting at Tokoroa. Apart from me being abysmally slow, the bike ran reasonably well. The engine pulled through the gears nicely and generally behaved. It was a touch lean in a few places but no real concern and easily rectified. The injector duty cycle was going over 90%, even close to 100%, so something needs to be done there. I've ordered bigger injectors. Once fitted it will be a simple matter to reduce the main fuel map values until the "desired" and "actual" Lambda match again. Very easy to do by highlighting the whole map and reducing values by, say, 25%. This would be done with the wastegate open so there is little chance of boost. Once that's sorted the wastegate is reconnected and a further test to confirm that the Lambda values match once on boost. Then I can start adding boost. I reckon it will be good right up until the head lifts and the coolant is blown out.
The front brake was absolute shit so I've taken the RS125 caliper off and fitted a big heavy standard front caliper. Piston size goes from 25mm to 32mm so the ratio of master cylinder to caliper should be much better.

[speedpro]

I have other FZR250 chassis project bikes. I'm looking at possible plans and want to know what others have done to improve the handling. I already have emulators in my turbo twin forks but have received "feedback" about the front end. That bike has a stock rear shock which to me seems reasonable but I'm not a good judge. The chassis with the MB100 engine has a standard looking rear shock but it does have an adjuster on the base of the shock. I have not played with it so don't know the effect it has. My son seems to like how the bike handles. The front forks have a few washers each side on top of the springs. Apart from that I don't know what's been done. The turbo feels quite firm, the MB/FZR feels softer front and back, and Gregs twin is softer again. Greg's bike has a shock with a reservoir and adjustment. At a guess I think it might be off a 600 maybe but with a different spring. I'm considering emulators for the front of the MB/FZR from Sports Valve, https://sportsvalve.com/sports-valve. A friend has fitted them and is singing their praises. If someone knows of a good replacement shock I'll check them out.

[Grumph]

Rob can probably confirm but I think my one was set up for/by Avalon. Hence the soft spring.

[F5 Dave]

I ran 11mm master cylinders on my RS125 based bikes and they were pretty demonically vicious:devil2: on the picks. Which is how I like them. Check what mc size was?

That said my 100 was about 70kg and the 50 was 60kg. Both of which puts me to shame, but all helps trying to be nearer to stationary in the least possible time.

[husaberg]

https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130222905&highlight=shock#post1130222905

the rear shock is from a 2007 GSXR600 with compression and rebound adjustment fitted with the original spring from my FZR 3LN frame.

[Grumph]

Thanks for finding that link Husa. There you go Mike, I never touched the suspension so that should be what's still in it.

Emulators to copy even...

[speedpro]

Sweet. I had already discovered where the shock came from by looking up numbers on it. Nice to know about the spring. I've moved the shock to the other bike(MB/FZR). The shock is 25mm longer which raises the rear by quite a bit and also messes with the link geometry. I used the standard dogbones at 140mm c-c rather than the slightly shorter, 137mm, original ones on the bike which would have raised the rear even more.

After a bit of feedback on another forum I've decided I need a 2006 or 2007 Yamaha YZF-R6 shock, maybe 2008. They are a straight bolt in and supposedly work OK with the adjustments backed off a bit. They are only a few mm shorter so may need slightly shorter dogbones to maintain ride height.

This is the shock. This earlier one has 2 separate compression adjustments while the slightly later has them combined.

If anybody has one or knows where to get one, let me know. I see them on ebay but holeeee shit, $$$$$. Maybe I'll talk Cricket into buying an Ohlins for it.

[speedpro]

It's looking more and more likely that it's gonna get a pricey shock from ebay. No promises have been made yet.

I have put the standardish shock that it came with back in the chassis. I've played with the rebound damping adjustment and can detect no difference between either end of the adjustment. I left the standard dog bones in place.

I made an alloy strut to replace the shock in Greg's bike. Whatever happens I'll need a different shock for that bike as the Suzuki shock is too long to work.

I also drained the oil out of one fork and after pulling the spring and the many washers and spacer found there was an emulator in it. It looks a bit different to how I remember the Racetech gold valves I have in my twin but look to work in a similar manner. The oil needs to be changed as well as it's dirty. I'll probably dismantle the forks to check them out.

I weighed the bike as well using our bathroom scales. 39.9Kg on the front and between 46.3Kg and 44.4Kg on the rear. I made a number of measurements and for some reason got different numbers on the rear. Either way the bike weight with no fuel is between 86.2Kg and 84.3Kg so it isn't as bad as it looks. It still has the big steel tank and the rear disc could easily lose more weight, if I could be bothered.

[husaberg]

https://www.mikesxs.net/yamaha-xs650-damper-valve-pr-front-forks-77-84-oem-1t3-23170-00-00.html
there was another lot the klr guys were using
https://hyperpro.com.au/store/pd-fork-valve

Then the YSS versions

[Grumph]

I'd be curious to see the weight of my old one. The rear subframe alone i reckon saved about 5kg

[F5 Dave]

It's looking more and more likely that it's gonna get a pricey shock from ebay. No promises have been made yet.

I have put the standardish shock that it came with back in the chassis. I've played with the rebound damping adjustment and can detect no difference between either end of the adjustment. I left the standard dog bones in place.

I made an alloy strut to replace the shock in Greg's bike. Whatever happens I'll need a different shock for that bike as the Suzuki shock is too long to work.

I also drained the oil out of one fork and after pulling the spring and the many washers and spacer found there was an emulator in it. It looks a bit different to how I remember the Racetech gold valves I have in my twin but look to work in a similar manner. The oil needs to be changed as well as it's dirty. I'll probably dismantle the forks to check them out.

I weighed the bike as well using our bathroom scales. 39.9Kg on the front and between 46.3Kg and 44.4Kg on the rear. I made a number of measurements and for some reason got different numbers on the rear. Either way the bike weight with no fuel is between 86.2Kg and 84.3Kg so it isn't as bad as it looks. It still has the big steel tank and the rear disc could easily lose more weight, if I could be bothered.
That does sound suspiciously light. Just the wheels would be much heavier than the RS yet only 14kg heavier despite tiny alĺy tank, tiny frame forks, no linkage?

[speedpro]

Double checked with a better way of getting the bike on and off the scale. 40.1kg front, 44.5kg rear. Total of 84.6kg. I have a baggage scale which I’ll do a measurement with as well

[speedpro]

Bit the bullet. Two R6 shocks are on their way from the USA. One is an 06-07 model so should go straight in and the other is an 08-16 model which hopefully will also slip in without too much agro.
I bought 4L of kerosene this arvo to use to test the flow of the new injectors which have arrived, I'm not 100% what size the injectors are in the bike at the moment so will need to test them as well. I've borrowed an injector test setup from Rob.
I'll drain the forks and use some of the kero to flush them out before filling with fresh oil. The plan is to try 5W first and go from there. I have 5-10-15-20W in stock and it's easy enough to drain and refill the forks.

[speedpro]

Thought I'd have a chat to my mate Kev about how to measure the springs and then modify them to reduce the rate. As usual it went well off track and things got complicated fast. Also as usual, Kev had stuff lying around to make the proposed jig including a solid steel frame already welded up. He also pulled a couple of struts out of the neighbour's bin which have useful long threaded portions for adjusting the jig for different length springs. On top of that there are also a couple of springs with the same 62mm ID which are possibly a bit softer than the current FZR spring fitted to the GSXR shock. The lengths seem close or slightly shorter so I'm gonna give them a go at the start anyway. Be a fluke if the springs out of the bin are good to use. They are Blitz brand. Not sure of the relevence of the numbers.

[speedpro]

Shit just happens sometimes. I read somewhere that the stock FZR spring rate is something like 8.1Kg/mm and the 600 spring is 8.3-4Kg/mm. Given the light weight of the MB/FZR I thought I might try something like 7kg/mm. One of the springs I have out of the bin has the numbers 62.200.007 on it. The .007 at the end stands for 7kg/mm.

[speedpro]

Correction. FZR spring rate is supposedly 9.2kg/mm and R6 spring rate 9.8kg/mm

[speedpro]

I had an idea of fitting a 200mm 5kg/mm spring to the FZR(?) shock in the MB/FZR. It can be done but it got harder and harder the more I looked at it. In the end it wasn't worth doing with the R6 shocks on their way. The original spring on the shock is about 275mm long.

I've had a thought about testing the springs. All I need is a platform, either a bit of wood or steel/alloy with a hole through the middle. Sit the spring on the platform with something on top to tie a bit of string to. Put a baggage scale on the end of the string and add weight until the spring is compressed a set amount as measured with a DTI. Weight/mm compressed is the value I'm looking for. So easy.

I used an old trick to compress the spring enough to get it off the shock. I turned preload to maximum and put hoseclips around 3 coils of spring, spaced out around the spring, then tightened each hoseclip in turn until the spring was compressed enough to remove the collets. I left the spring on the shock while I released the hoseclips in the reverse of doing them up. I also looped a tiedown around the spring and the vice so if it did decide to jump up it wasn't going anywhere.

[speedpro]

Spring rate testing jig made and used. Very simple and worked perfectly. I used one of the Blitz threaded collars with a bit of alloy on top. A loop of lockwire went around a 6mm bolt, down through the alloy bit, through the spring and a hole in the bit of wood, to the baggage scale, which had a 20kg bucket of concrete hanging off it.
Without the bucket of concrete I setup the dti for 5mm of compression. I then hung the bucket on the scale which resulted in the spring being compressed an amount which I read off the dti. Simple math gives the spring rate.

[speedpro]

DTI reading with a 5kg/mm spring. In a perfect world it would read 4mm less than the start of 5mm. Actual measurement change is 4.3mm.

[speedpro]

Measurement of the 7kg/mm spring and the spring off the 600 shock. The DTI has moved more or less 3mm for both springs which is correct for a 7kg/mm spring with a 20kg load

[F5 Dave]

All good garage math. I just put a scale on the press and compressed the spring. 20mm made it more accurate I seem to recall.

[TZ350]

.
Team ESE sat their springs on a set of bathroom scales. Then used the press to compress the spring. Recording the scale reading and compressed length as we went.

[F5 Dave]

Yeah better explanation of what I did.

[speedpro]

I've been checking weights, spring rates, and linkage ratio. I'm not sure what it all means yet but it is quite interesting how the linkage ratio ramps up quickly from fully extended over the first 5mm of wheel travel and then increases a small amount over the rest of the travel, see the attached image. The final ratio measured at 90mm of wheel travel was 2.46:1. The first column, turns, is the turns of a nut on a piece of 8X1.25 threaded rod used to lift the wheel. I also made a tool to bolt in to replace the shock which I attached my digital calipers to which measured the amount the shock would be compressed as the wheel was lifted. The results tie up with what I feel. The initial travel is very soft but firms up quickly. In my opinion the R6 spring is way too hard. The stock FZR spring may also be too hard. I think a spring rate needs to be chosen for the middle area of the stroke where the ratio is approx. 2.60:1. I'm sure there's more to it, but with my son on the MB100 powered bike the weight on the rear wheel is 80kg. 80X2.6=208kg on the shock spring. With an 8kg/mm spring it would compress only 26mm. With a 7kg/mm spring it would compress 29.7mm. With a 6kg/mm spring it would compress 34.66mm, and with a 5kg/mm spring it will compress 41.6mm which is getting close to mid travel. If installed with say 5mm of preload the 5kg/mm spring would be compressed as if by 25kg and the travel would be decreased by a similar amount for any particular load, theoretically. I have 5kg/mm and 7kg/mm springs which could be used. They both need to be shortened and adaptors made so I'll give them a try. Probably the 7kg spring first.

[speedpro]

These arrived which has prompted the fascination with spring rates and stuff. R6 shocks with damping adjustments that actually work. They are just slightly shorter than the stock shock. Compared to the similar vintage GSXR shock they are in another league. The shock with seperate compression adjusters is an '06-'07 model and the other is a 2012 model.
After placing the order in the USA I had 2 replies to an enquiry here in NZ. One shock was $100 plus freight which I think is a bargain.

[F5 Dave]

If you are lucky there will be enough thread on that clevis for a spacer to make up the difference. Then a bit more to race it up a bit from conservative Road setting. My YZF750SP got +5mm as per YEC handbook.

[speedpro]

I've been working away on fitting new springs to the R6 shocks. The first bit was checking the rate of standard shock compression versus wheel travel. I've measured a few springs. I also dragged a couple of springs out of a bin and have been cutting bits off and shortening them using heat and compression. I think I have figured a way to shorten springs in a controlled manner and will test the method next time at my mate Kev's place. If it works I'm going to cut down one of the Blitz 220mm long 7kg/mm springs to fit the R6 shock. Over the last couple of days I've made an adaptor for the top of the shock for the Blitz springs and a whole new piece for the bottom.

All this work and measuring has led me to believe that if nothing else I need to reduce the preload on the stock shocks. Currently the shocks can be compressed initially but as soon as the rate gets to the working range of the linkage it hardens up excessively. A lower preload will let it move into the working range before the spring compression gets too much. The standard shocks have about 10mm preload and being 8kg/mm springs the shocks have 80kg preload. This would require 30kg on the rear of the bike just to overcome the preload. The bike alone only has 40kg on the rear and with Cricket it's a total of 80kg. Minus the 30kg need to just overcome preload we have 50kg to compress the shock. This equates to 130kg on the shock which should compress it about 16mm. It'll be less as the spring rate will be increasing. I really need to measure the spring rate through the full stroke but the rear should sag about 40mm. It actually moves less than that so the math is wrong or the spring rate increases more.

[Grumph]

The team of production car racers from Timaru who were very successful over many years used to lower a car by leaving it full of sandbags while the engine was blueprinted. As much as 1 1/2 in lower with no marks or cuts on the springs.
Sit a concrete block on a spring for a week and see how much it shortens it.

[speedpro]

I'll try that, but probably with end caps and a threaded rod through the middle to clamp it up.

[Grumph]

I'll try that, but probably with end caps and a threaded rod through the middle to clamp it up.

It's got to be loaded past it's yield point. IE collapsed with a weight on it.

[speedpro]

New spring on shock, shock in bike, new short dog ones fitted. It feels ok just bouncing on it. Still need to map progression and if there’s nothing too horrible happening I’ll finish the dog bones

[F5 Dave]

Needs slotting and GreenLinKTM on the side:msn-wink:

[speedpro]

Both excellent suggestions. I'm going to rough out another pair of links to use with the other R6 shock and then finish all 4 at the same time.

[speedpro]

Not too bad a difference. Good enough to give it a go.

[speedpro]

I have 2 pairs of dogbones and have made a start on taking off a bit of weight. No science involved, just cutting a bit off using the mill. I made a jig to allow each dogbone to be bolted down in exactly the same position each time. If, once I've finished, I decide I could take a bit more off it'll be a simple matter of bolting each one back on the jig and mowing a bit more off.

[speedpro]

The 8mm cutter I'm using is supposedly 70HRC. It mows through mild steel of course and when I milled a flat in a piece of round tool steel it just made nice chips and didn't seem to notice.

[speedpro]

One R6 shock fitted to the FZR/MB bike and this kit ready for my turbo twin bike.

The dogbones are slightly thinner than standard dogbones so 1.4mm washers are needed on each bolt to make sure that the dogbones are clamped tight to the bearing bushes. The top shock mount is only 30mm wide versus the original FZR shock being 40mm wide, so I made 5mm tapered washers to fit against the shock top mount(16mm OD) out to 25mm OD to spread the load on the inside of the chassis mount.

I'm going to try the stock R6 spring but I'll make an effort to reduce the preload by hopefully compressing the spring a bit. Using the spring compressors wasn't giving me any confidence so I'm going to have to come up with something really solid to do it.

[pete376403]

One R6 shock fitted to the FZR/MB bike and this kit ready for my turbo twin bike.

The dogbones are slightly thinner than standard dogbones so 1.4mm washers are needed on each bolt to make sure that the dogbones are clamped tight to the bearing bushes. The top shock mount is only 30mm wide versus the original FZR shock being 40mm wide, so I made 5mm tapered washers to fit against the shock top mount(16mm OD) out to 25mm OD to spread the load on the inside of the chassis mount.

I'm going to try the stock R6 spring but I'll make an effort to reduce the preload by hopefully compressing the spring a bit. Using the spring compressors wasn't giving me any confidence so I'm going to have to come up with something really solid to do it.

What spring compressor are you using? I got a set of DRC compressors from bits4bikes. $36. While made for twin shocks, the springs I was compressing are off a GS1100G (ie heavy) and they handled that with no problems

[speedpro]

The spring compressor is a cheap one from TM. I had to modify it a bit to fit the R6 shock. I can compress the spring more than enough to fit & remove it but compressing it to the yield point is another matter. I compressed the spring about 30mm. Being a 9kg/mm spring that's at least 270kg. I've discussed it with mate Kevin. We agree that the spring needs to be captive when compressing this much. It can be done by fitting the spring inside a tube and then compressing the spring with a piston in the tube, pushed by a hydraulic press. All very time consuming for doubtful results. Not wanting to spend the time fabricating all the bits I've decided to simply heat one end coil and compress it a bit using the same process I used when I shortened the 7kg/mm spring after I cut it. I only want to shorten the spring about 8mm so it's only a slight adjustment.

[pete376403]

Thinking about this - I've just done a valve grind on a 40 year old bike (GS1100G) and as far as I can tell its the first time the head has been off. Last time the engne was run was in 2009. So thats 14-15 years that the valve springs have been compressed without change, some more than others. All of the springs measured within a millimetre or two of specified length. Same goes for clutch springs. Maybe suspensions springs are lower grade steel?

[speedpro]

Possibly lower grade steel, given the operational requirements. Compressing a spring to the yield point will be well beyond normal operational limits. It might even coil bind before it gives. I'm going to heat it. I know that works although I'm still to actually use the spring I shortened to see if it packs down in use.

[speedpro]

I went out looking for Threebond sealant. The local Repco were helpful but didn't have any "1215", which is the typical sealant I think. I drove up the road to Partmaster and a guy working there used to work for ThreeBond in Australia. After a bit of a chat he told me that "1215" is not rated for use in contact with gasoline. Obviously a problem for 2-strokes and possibly the cause of the air leak which caused the latest siezure as I used it to attach the reed cage and adaptor to the cylinder. The stuff to use instead is ThreeBond "1104 NEO PLUS" which is rated for use in contact with gasoline. The data sheet says it can be used on the flange surfaces of fuel pumps which is pretty definite. The good thing is that it's lots cheaper than "1215".

[speedpro]

I've finished getting the MB/FZR rebuilt after it nipped up at Edgecumbe. I fired it up and it is super crisp with throttle. A little dyno time is scheduled to make sure it's all good.

I've also shortened a stock R6 spring to reduce the preload when it's fitted to the shock. Standard it's compressed about 10mm when fitted. This spring results in only about 1mm preload. It'll be interesting to see how these shocks work and what the difference is with the 7kg/mm cutdown spring on the shock in the MB/FZR. I'll fit the shock to my turbo twin tomorrow. The MB/FZR suspension feels pretty good. There seems to be a nice balance between front and back.

[speedpro]

It hasn't been working out how I hoped. The engine did a soft seize on the dyno, barely any throttle and lowish revs. I ran it again afterwards as I wasn't sure what happened. It seemed OK afterwards but I pulled it down anyway to have a look and found rub marks both sides of the boost port. I fixed the piston with a sheet of 1200 W&D on a piece of glass. The cylinder was fixed by running a reasonably coarse hone down it. With other maintenance I found water in the tank. This was probably from being left outside in the pouring rain for a few days. I suspect water got through the keyhole in the fuel cap. The gearbox oil was also looking suspect so the gearbox has been flushed with kerosene and has full synthetic 4T motorcycle engine oil in it. The chain rubbed on the R6 shock absorber remote reservoir. I moved the engine to the left about 3mm which was not too hard to do with how I have it mounted in the chassis, and to be honest this probably resulted in better sprocket alignment. I have machined 6 washers 2.5mm thick which I will weld to the inside of the rear sprocket to space the sprocket out a bit as well. I've thought about the washers a bit more after making them and will probably make larger diameter ones, weld them on, and then machine where they protrude on the inner diameter. Unusual for me but I'm not feeling confident about the engine. The rear end feels much better with the R6 shock and the modified 7kg/mm spring

[F5 Dave]

Up one on the pilot to be safer starting point.

Diesel is great for water put of gearbox.

[speedpro]

The bike ended up running reasonably well. 1st qualifying was a cautious affair and 2nd qual was getting after it a bit. Cricket qualified in 10th which was reasonable. The bike was actually running pretty good. The suspension was working well enough that we didn't make any adjustments. Cricket was getting his knee down here and there where previously he hasn't, plus, where he had been standing on the pegs to let the bike move around he didn't have to now. Not being an expert but to me the tyres were looking OK as well. He got a good start and ran at a reasonable pace for the whole race. The bike ran great from start to finish. Placed 6th at the end. Due to a previous problem we were very cautious with the amount of fuel. VERY very cautious with 4L or so remaining at the end.

Short video from the start of the race for about 5 minutes, looking back, making reasonable 2-stroke sounds. It highlights just how tractable this engine is with Cricket short-shifting through the double lefts at the back of the track and then pulling clean to the right up the hill - https://youtu.be/0woduTFN90A?si=0WZZK8Sxkr3fCd7t

[speedpro]

Blast from the past with a much younger Jato and his brother Peter. Both those bikes I suspect would be competitive even today. Both certainly fast enough to keep everyone honest.

[speedpro]

Getting the air bubbles out was a problem. A three man job.

[F5 Dave]

Blast from the past with a much younger Jato and his brother Peter. Both those bikes I suspect would be competitive even today. Both certainly fast enough to keep everyone honest.
Gyro (Gary) pictured to the right in those hideousbut long served white and green leathers. .

I borrowed Peter's bike at Tauramanui and found it was very rideable, but a bit lowslung on 17s. Actually the bars were flighty. I did some reversible mods like ace bars and RS muffler when I took it to the BOB in chch. . . and fell off.
But it did promote the sale to a local who rode it there for quite a while. Lost touch with Bren, once a poster here.

[Kickaha]

I took it to the BOB in chch. . . and fell off.
But it did promote the sale to a local who rode it there for quite a while. Lost touch with Bren, once a poster here.

Didn't you fall off everything at every BOB ?

I think Bren still has it, that's the bike called Joe ?

[F5 Dave]

I stayed on my 50 every visit.

. . . Well, except that time it snowed. In 27 years, never raced on a snowy track till then.

Yeah Joe he called it for some reason.

[speedpro]

The Sunday racing at Tokoroa was close to perfect. I rode the MB/FZR which went really well. It was hard work tooling around in B grade. Nothing like a bit of bucket racing to remind you how old you are. I'm still a bit sore. Without really knowing what I was doing I dropped the high speed compression damping 2 clicks after the first ride. The bike was really harsh. I dropped it 2 more and it seemed a bit better. I dropped the low speed 2 clicks as well but figure that could be reduced a bit more as well. Cricket rode it how it was originally in the GP and had no complaints. The suspension wasn't playing up, it simply wasn't all that compliant. I have a reasonably soft spring fitted and very little preload so I figure the harshness is due to the damping, which is no surprise to me as it's an R6 shock. I want to organise a day playing at the track and really play with the damping so I can understand it better.

Anyway, a big thank you to the organizers for an excellent day.

[speedpro]

Had a very interesting and long conversation about turbos and other important things. While discussing compressor maps and how even the tiny turbo I have can't be operating efficiently, a silly comment was made about bleeding off intake air to allow the compressor to run up into it's efficient zone. The compressor might get more efficient but overall system efficiency would probably remain about the same. The idea would be to disable the wastegate in the closed position and control manifold pressure by bleeding it off. I doubt the turbo would overspeed. Possibly, with the turbocharger operating closer to it's efficient range, the charge temp might drop. Something like an external wastegate(blow off valve) on the intake would be worth trying. One benefit might also be that the turbo would spool up faster given that all the exhaust gas would be going through the turbine all the time with no bleed from a creeping wastegate, although I currently have that more or less sorted out with the increased wastegate base pressure and the ECU controlled valve to the actuator.

[speedpro]

I've been making a bit of progress with the intercooler. The top tank is fully welded in place and the plenum between the core and the throttle bodies is tacked on. I'm going to hold off fully welding it until I sort out how I'm going to make the connection from the turbo on the other side. I'm reasonably happy with how it's coming out although I would like the welds to be a bit more presentable.

[F5 Dave]

So, explain the core please?

[speedpro]

The core is going to be positioned above the throttle bodies and goes the full width of the chassis. The outlet of the turbo goes up and feeds into the bottom on the left half. It travels up to the top tank, across the top, and down the right side into the throttle bodies. I'm going to make ducts that feed air from the front of the bike to the intercooler. I'll also make a fuel tank that fits between the seat and the intercooler leaving a space for the cooling air to pass through the core. There may be louvres involved.

[speedpro]

Very nearly finished with the flanges. Just need to drill the 2 holes in the flange to bolt to the turbo, left one. The other one will probably have a bit more machined off once I figure out how it's going to fit to the bottom of the intercooler core. Inside the turbo flange is 2.5° from about 5mm in through to the start of the other flange. Then the angle changes in 5° steps to 25°(per side) where it will open to the core. I'm not holding them together very well in the photo. When I do I can't see where they join. The OD where the connecting hose will be is 36mmOD

[Grumph]

Can you do a tank like mine but smaller ? Mine was intended for BoB race length.

What about a tank cover/engine cover done in mesh over a light frame.
Feed air in via the OE fairing ducts through the frame.

[speedpro]

I'm thinking of starting to mock up a tank tomorrow. The main mount will be the standard rear tank mount. The forward mount(s) will probably end up being the top bolts for the sub-frame. I suspect it will be about 5L when finished.

The bits of tube I have made aren't going to work. I'll be able to retain the turbo bit after a change but I'll make a new 2nd part to weld to the first. A 45° elbow from Mikunioz will fit and connect to the plenum. The elbow is 34mm ID so the alloy will have a reasonable taper.

[speedpro]

Progress with duct for cooling air to the intercooler. Luckily the worst of the welding is on the inside. I'm still thinking about how to secure it at the front. There's a few options but I might leave it for a bit.

A 45° elbow arrived from Mikunioz today so I can get back to making the connection from the turbo to the intercooler. I already have the tapered pipe designed and just need to spin it up using the lathe. As usual the plenum on that side will be mocked up using old cereal boxes.

[speedpro]

Intercooler finished. Hopefully it won't be too difficult to install now that everything is welded together. I'll find out tomorrow.

[speedpro]

Intercooler fitted with the ducting, and enough room for the little pit bike tank

[speedpro]

The pit bike tank was a bit manky so I've started work on a nice alloy one. The rear curve is similar to a stock tank and it will slope forward at a similar angle. I have nearly finished the base, although I'm debating whether to mill ribs into the bottom. It'll look cool, not that you can see it, and will save a bit more weight. Kinda funny considering how heavy the bike is compared to other bikes in the class. I've made a rear mount which will bolt into the stock mount and 2 front supports from 5mm plate which will bolt into the 2 sub-frame bolts which I'll machine a flat into and then drill and tap. There was a couple of rubber grommet things which are perfect for the job.

[speedpro]

The tank base is finished apart from welding the mounts to it. I will attach the front mounts to the subframe bolts which I have shortened, drilled through with 5mm, tapped 6x1, and machined the hex off. I made new inserts for the front mounts with a 6mm centre hole plus a 20mm washer on the end. The rear mount fits in the standard tank mount on the subframe. I have the majority of the tank mocked up using cereal boxes and have a flip-up fuel filler cap which needs an alloy piece designed and machined for it to bolt to. I've figured it out but want a drawing so it's clear. I'm not going to be able to make it all in one hit.

[Grumph]

I have the majority of the tank mocked up using cereal boxes and have a flip-up fuel filler cap which needs an alloy piece designed and machined for it to bolt to. I've figured it out but want a drawing so it's clear. I'm not going to be able to make it all in one hit.

Oooh flash. Mine uses a screw cap and matching thread from a cheap cam cover at Pick-a-Part.

[speedpro]

I looked at something like that but wanted the tank vent inside the cap. Getting it from pick-a-part was a good idea. I'll have to remember that.

[speedpro]

Been chipping away at making the tank. It's way rougher than I'd like but is quite good when sitting on the bike. Very much like the original tank when cornering or hanging off. It does have a few pin holes which I'll fix tomorrow. Tested by filling with water.

[speedpro]

Only one ittle job to do. I need to reduce the steering lock. Not by a huge amount but it doesn't need all the lock that a typical road bike has which makes them easier to manoeuvre in the carpark or garage. It now has the intercooler in place and the air duct to it, and the small alloy fuel tank which holds more than needed but the size is due to other considerations.
I fired it up with everything in place and it's still sounding fine so it should be fine at HD on Sunday. Not sure about the gearing but it's currently geared for about 130k with a 13T front sprocket, and each tooth on the front adds about 10kmh so the 14 & 15T sprockets will have it covered for sure.
Cricket will be riding the MB100/FZR bucket. Hopefully it lasts a bit better than last time when the ignition failed at the end of the first practice. It's been ridden at Tokoroa a few times and gone great so should be great. As usual it sounded real sharp when I fired it up in the drive.

[Sketchy_Racer]

Nice work, I'm curious to hear the improvements from the intercooler. I suspect if you were at 100deg IAT it will be significant.

Speaking of gearing, what size rear sprocket do you run?

[speedpro]

60T on the back and 13T on the front. Still too high for a kart track. I will give it a go tomorrow on the HD club circuit. I have 14T and 15T sprockets if it's too low on HD

[diesel pig]

60T on the back and 13T on the front. Still too high for a kart track.

I am first to admit I know nothing about the engine you are working on. But that statement about the gearing on a it for a kart track, is doing things to my mind that I thought could only be achieved by vast amounts of illegal drugs

[F5 Dave]

It is 250 based gearbox spinning to silly revs.
We usually run like a 50 rear.

[Grumph]

Get the boost coming in at lower revs and then the question becomes "how many gears do you need for the track'?

Bit like the days of Foggy setting up the WSB Ducati to only use 5 of the 6 gears.

Our blown 500 Kawa could have used a 3speed gearbox. Rider wore out ankle getting to top quick enough.

[speedpro]

The motor wasn't really doing it's thing but the gearing was OKish with most of 6th gear still to go at the end of the straight. I was revving it to most of an indicated 18,000 but the logs showed it only going to about 16,000.
The intercooler made a huge difference. IAT was going to most of 100C when I ran it on the HD big track. Now it barely goes to 20C. Riding it was far easier with it pulling boost much earlier and quicker. When changing gears it still banged more often than not, and the turbo made a clearly audible "chirp". I figure it was flowing more with the much denser, cooler, air.

The problem was that much cooler IAT which resulted in much denser inlet air. Although the ECU should have calculated the required fuel taking account of the low IAT it didn't compensate enough. The engine was running leaner than the desired AF ratio. Lambda was around .9 versus a desired value of .78. The exhaust was so hot that the turbo outlet pipe was a nice blue to the tip and the exhaust collector wrap was making sizzling noises for over 10 minutes after I returned to the pits.

There was an odd cycling thing happening as well. The MAP was cycling at max boost, and at the same time so was the AFR. The AFR cycled between very lean and farkin lean. The MAP cycling might be because of how I have the ECU setup to control the boost. There is absolutely no control until MAP is at the desired boost. This causes a tendency to overshoot then over-correct.

There is big positives. The leanness can only be caused by a greater mass of inlet air due to the air being cooler and therefore denser. With the correct amount of fuel I can feel that it will be much quicker. I'll check the mixture/Lambda off boost but at 100% throttle. Changes to these values will determine the calculated fuel on boost. I think on the old setup even off boost the IAT was higher than 20C. Either way, adjusting the 100% throttle fuel map values will result in the desired changes on boost which is all I'm worried about. I'll finesse the boost control later.

[F5 Dave]

So let's say in the spare area above the empty cylinders, you rig up one of the old carburetors and feed petrol to the bowl. Then run small tubes to the throttle bodies with some brass tube into the airstream?

World first PowerJet into Fuel Injection tm

The innovation never stops.

[speedpro]

Way ahead of you. I had already thought of something similar. The issue is the air pressure at the TBs. I would use fuel from the injector pump through a control valve similar to what I have on my McIntosh. This can be tuned to open at any boost pressure. The initial flow can be tuned to be whatever amount I want, and then the flow varied by tapered needle, and springs, which control the movement, with different rates. On the McIntosh the fuel is delivered to the valve from the tank which is pressurised and the valve delivers the fuel plus leaked air as a froth to the inlet of the carb. The air is required to move the fuel quickly when required.

[speedpro]

The MB/FZR had issues as well unfortunately. It ran well and sounded crisp but every now and then it went off just for a very short moment. At the very end of the first race Cricket pulled in after it went off properly. I pulled the plug and found that it looked sort of OK but had specks on it. I surmised at the time that it was detonating now and again and the specs on the plug were from the centre of the piston. I was 100% correct. I have a box of pistons & rings and have a +.05mm set that should sort it out once honed. The question is why this is happening. There's a few possibilities. Recently I have used 98 octane, versus always using 100 octane Avgas in the past. I tuned it on the dyno but maybe I now have fuel from a dodgy batch. Another possibility is the frankenstein ignition system I put together which might be doing something odd. It's frustrating as I have bought one of those detonation detectors that Wobbly is keen on, and I ordered a new sensor from a guy here in NZ. This ass has my money but won't return calls and I haven't received the sensor. With it we might have seen the issue before it became a show-stopping problem.

[speedpro]

It is 250 based gearbox spinning to silly revs.
We usually run like a 50 rear.
The standard sprockets are 55T on the FZR250

[speedpro]

There are a few issues with the tuning now that I have the intercooler fitted. There are also huge positives. One major change is how easily and quickly it now builds boost, even down around 10,000rpm where previously it had real issues. Now the boost more or less follows throttle position(TP) and boost is held even with the throttle being part closed. There is an issue with oscillation but that is due to how I had the boost control configured in an effort to get it to build boost before I added the intercooler.

The turbo is clearly much happier now. Closing the throttle results in an audible "chirp" from the turbo.

As can be seen from the log the mixture is much leaner than desired. On boost the desired Lambda is .78 which is a nice safe rich mixture for a turbo. The log shows it oscillating between .87 and even as lean as 1.0. That's leaner than even a normally aspirated race engine would be run.

Hopefully I'll be able to get back on Kris's dyno and he'll be able to work his magic. There's different ways of getting more fuel into it. Simply turning up the fuel pressure would do it, but it's already seriously rich at the bottom. With the injector duty cycle only going to about 60% a proper adjustment of the fuel maps is the way to go, maybe even just a change to the 4D fuel map as it seems reasonably good off boost.