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Project Fuel Injected Turbo FZR250, half

Discussion in 'Your 250cc Projects' started by Mike Green, May 9, 2020.

  1. gregt

    gregt Well-Known Member Premium Member

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    The usual thing is 20 gauge - .8mm from memory - stainless wire standing about .005in proud of the liner tops.
    Best used with a shim gasket.
    My EX500 racebike has used this since it was built in '87. Only downside is you must use a new gasket each time the head comes off as it stretches the shim.
    We used this setup on the blown 500 too., The head didn't leak at 18lb boost - but the barrel and head moved around on the cases.
     
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  2. Mike Green

    Mike Green Active Member

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    The wire o-ring is definitely a consideration thanks. I have wire o-rings on my other turbo so am familiar with the idea. Previously the FZR was fine, prior to the blowup. I think that the sleeve may have moved a tiny little bit again. I'll find out tomorrow hopefully.

    One other thing I have discovered is that later FZR250s do have 18 pole stators versus the 12 pole stator of the earlier 2KR models. 18 poles seems pretty standard. Ideally I need to score an 18-pole stator to match the rotor.
     
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  3. Mike Green

    Mike Green Active Member

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    I took the cylinder block to Kevin's and tested it with flat steel. One sleeve is still proud of the top of the block and the other has dropped a very small amount and is probably flush. We didn't run any gauges over it but it is definite. The plan is to skim the tiniest amount off it like last time to make the whole thing flat including the sleeves and then take .001" off the alloy of the block. I may start putting it back together late tomorrow afternoon but I'll probably still be cleaning things tomorrow.
    With the top end apart there are no obvious problems. The cam bearings look good and there was lots of oil in the head so the restrictor looks to be about right.
    I just need to find an 18-pole stator and it will be all good.
     
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  4. Mike Green

    Mike Green Active Member

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    I've buttoned up the motor, again. There's just a couple of cover plates and the like to go. It's so easy once all the parts have been sorted.
    I have been looking at how to sort out the alternator. Overnight I thought about rewinding an old stator I have here in such a way that it would work with the new rotor. I had a careful look at how everything fitted and found that the new rotor is about 5mm larger ID than the old which will result in a larger gap than I'd want. This leaves me 2 choices - 1 install a late model stator or, 2 transfer the old rotor onto the newer hub. I'd prefer a new stator and have found one on AliExpress supposedly for a TTR250 which looks very close. It has a diagram with measurements which is useful. I've also found that despite what the wiring diagram shows, the stators I have for the engine are all delta configuration, not star.
     
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  5. Mike Green

    Mike Green Active Member

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    A new stator has been ordered and I ordered a set of valve guide seals as well. I don't have a problem with the seals but they are supposedly for a TTR250, the same as the stator, however the seals are a set of 16 so obviously NOT for a TTR. It'll be interesting to see if they fit on the valve guides when they arrive as I suspect new seals for NZ16.90 including freight might be of interest to others.
     
  6. Mike Green

    Mike Green Active Member

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    As Greg suspected. The seals are the wrong size. The ad is very clear that they are 3.5mm seals. The seals that arrived today, 10 days after ordering, are 4mm seals. They fit very nicely on the older 2KR valves. I've sent a bit of feedback.
    The stator is due to leave China.
     
  7. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    I baulked at buying a set of 3LN seals for specifically that reason - I did order two, 2KR, valves as samples and they were very substandard with the face width varying ~50% because the heads weren't even close to being concentric with the stems

    They get many of their product descriptions 'confused', and clearly they don't bother to check at the warehouse
     
  8. Mike Green

    Mike Green Active Member

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    This lockdown is frustrating. I have been looking at wastegate control. I was hoping to use the ECU in closed loop mode which would have been complex to configure but would have meant precise control. Unfortunately it seems the base model ECU I have can't do closed loop but is limited to open loop. In the configuration help file it seems to control the wastegate on a throttle position versus rpm basis with no account of the actual boost value. I emailed David from Tune Technic who I bought the ECU from and he came back with a suggestion to put Manifold Gauge Pressure(MGP) on one table axis and RPM on the other. The table values are the amount the wastegate is opened effectively. To me this makes it more or less closed loop. Values are entered in the table below the desired boost that result in the wastegate remaining closed. As boost approaches the desired value the table entries result in the wastegate progressively opening. The boost control solenoid has a pulse width modulated(PWM) signal applied which opens a bypass valve an amount depending on the pulse width. Failsafe mode is fully open which will pass manifold pressure to the wastegate without restriction. I can see this working really well with the wastegate closed until boost closely approaches the desired value. This will assist with spool up. I know with my big bike that this can really help. With boost on the big bike set to 12lb the turbo spooled up a bit slower from about 8lb. With the wastegate set for 19lbs boost the turbo spooled up to 14-15lbs really quickly as the wastegate was completely closed until then.
     
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  9. Mike Green

    Mike Green Active Member

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    I finally got my little scales and have weighed the valves. Very obvious how much better the later ones are. I made it into a small video -

     
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  10. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Mike - I've just been doing some affiliated research for alternative conrod big end and main journal shells from the CBR250rr, GSF250 and ZXR250 for use in the 3LN - I know that's not something that you need, but nice discovery, the CBR250RR MC22 L model uses valves with a ~3.5mm stem and the valve springs use ovate wire also - here's the two relevant pages from the service manuals - I am yet to cross reference the springs -v- the FZR250

    Good thing is that the CBR250RR manuals are in English and give good details
    From these two manuals:
    https://www.2fiftycc.com/index.php?resources/honda-cbr250-mc22-service-manual-base.267/ - page 7

    https://www.2fiftycc.com/index.php?resources/honda-cbr250-mc22-l-service-manual-supplement-2018.266/ - page 11

    I do seem to recall reading valve spring seat and nose pressures somewhere also, but I've literally speed read hundreds of pages in the last few days - I will see if I can find that specification again also

    Here's the specs for the FZR250 and GSX250F springs
    pages 3-4 from the 3LN7 specs

    For the Suzuki - extracted from
    https://www.2fiftycc.com/index.php?...-1991-service-manual.211/download&version=212 - page 51

    Similar free length, for the GSX250F longer installed length with a slightly higher installed pressure - might work to keep those exhaust valves in check
     

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    Last edited: Oct 7, 2021
  11. Mike Green

    Mike Green Active Member

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    Despite a lack of Track&Trace information the stator arrived earlier this week. It wasn't a direct drop in but needed only minor mods. I removed the crank trigger and wiring, replaced the alternator output connector, and drilled the mounting holes from 5mm to 6mm. It fits perfectly but I haven't fired it up to check output yet. Since I had the stator I went ahead and balanced the rotor which turned out to be further out of balance than I initially thought. This afternoon I have been looking at what is required to replace the watepump with the electric one. There's a few little bits to be machined. Luckily we put a bit of thought into it as originally I was going to machine a fairly complex piece to cap off where the waterpump was originally mounted. In the end it's going to be a simple cap with a small screw through the end to hold it in place. I already have the flange made to mount the pump to the back of the block.
    IMG_0692.JPG
     
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    Last edited: Oct 7, 2021
  12. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    @maelstrom might have the skinny on an electric water pump - I think he's already sourced one and fitted it to his FZR400
     
  13. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Like everyone else, I am using a Bosch PAD pump. The main issue is that you need an electric controller because it pumps way too much for this application. Because I didn't like any of the commercial versions. I have had a prototype PWM controller made that is managed via bluetooth. My Yamaha has not got to that point yet, so it is on hold at the moment.
     
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    Last edited: Oct 7, 2021
  14. Mike Green

    Mike Green Active Member

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    I already have the pump. I have an electric water pump on my scooter and have another to go on the FZR. It's a Davies Craig EBP15, made by Bosch. The rotor is magnetically coupled to the motor so there are no seals to wear out or leak
     
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  15. Mike Green

    Mike Green Active Member

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    In the Davies Craig information the EBP15 is not manageable by their pump controllers. I presume their pump controllers are PWM devices so I wonder if the EBP is actually compatible with that type of controller. On my scooter the pump runs continuously and does seem to circulate a lot of water but my theory is that this will help with consistent temperature within the engine. The scooter has the radiator under the seat and temperature is controlled by the fan which is controlled by a temp sensor in the water flow.
     
  16. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    I had the same thoughts but thus far with the tests we did there has been no issues, more extensive tests to follow, and the engineer who designed the controller thinks it is not an issue. Ideally the pumps job is to maintain optimum water temperature and that is the advantage of using an EWP. Running it continuously will negate that benefit.
     
  17. Mike Green

    Mike Green Active Member

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    After a bit of fiddling the new stator has been fitted and is generating electricity.
    I made a little video about the stator and balancing the rotor after the long tooth was reduced in length. As per the old 2KR rotor this newer 3LN rotor was out of balance before I modified it and modification made it worse.
    I have also converted the cooling system from the mechanical water pump to an electric pump the same as in my scooter. The whole cooling setup is a lot tidier now and doesn't have the pipe from the pump sticking out the side acting as crash protection. There's also a small video(with sound) about the cooling system. Video is here:



    IMG_0730.JPG Pump9 small.jpg Water2 small.jpg Water3 small.jpg
     
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    Last edited: Oct 10, 2021

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