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Project GFS250P Slingshot rework...

Discussion in 'Your 250cc Projects' started by Bab, Oct 13, 2017.

  1. Bab

    Bab Member Premium Member Contributing Member

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    The judge won't hand down a sentence until he studies all the evidence. At this point the investigation is still underway.
     
  2. Joker

    Joker CLUB250 Staff Member Premium Member Ride and Events Crew Contributing Member

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    Mine were similar and bike wouldn't run without a significant rolling start. That was with new rings. I hope it runs, best of luck.
     
  3. Bab

    Bab Member Premium Member Contributing Member

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    I mentioned I received my ignition module elsewhere on the forum, and Linkin asked me to let him know the results of my purchase from Lixanda. At this point all I can say is they delivered 2 days short of their promised deadline, and when I plugged it in I had a strong blue spark at the plug immediately. I believe fuel issues are the next problem. I seem to recall reading some where this unit is equivalent to the original, meaning it is restricted. I'll do my best to find the source of that description.
    My67xr pointed out my terminology in describing the igniter as a CDI was incorrect, and I confess I am a slouch when it comes to accurate definitions. This goes beyond the Aus vs. Canuck parlance. I do thank him for the correction, and particularly for the lesson on the TCI's. The pics and explanations were a big help in shedding more light on a topic that was somewhat dim previously.
    I was able to dismantle the original unit, and examined it closely, using a loupe to magnify all soldered connections. I looked for physical damage, loose parts, corrosion, and evidence of heat anywhere on the board and found none. The inside looked pristine.
    IMG_20171125_125944.jpg IMG_20171125_130004.jpg
    There will be a day when I investigate this further.
    Meanwhile I'll proceed with getting fuel to the cylinders in a fuel / air ratio that works. At present we have had partial ignition, but it would not hold. I suspect the oil I introduced into the cylinders doing compression tests has complicated issues. I have no clear history of the bike, but I suspect it was abandoned because of the ignition module failing, and with that follows the issue of fuel left to gum, and plug everything up. I am attempting to eliminate the potential of the petcock being the cause of the fuel starvation by using a bottle cobbled into place. The "Threebond" route is out of the question in Canada as there are no distributors, however a distant cousin "Seafoam" will be introduced to the exercise tomorrow.
     
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  4. Wozza

    Wozza Active Member Premium Member Contributing Member

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    Hmmm looks fine in there, if me id prob replace T4 and T5 transistors as these tend to go due to heat stress...also how rusty are the pins in the sockets? they look pretty bad but could just be the pic's
     
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  5. GreyImport

    GreyImport Administrator Staff Member The Big Cheese Contributing Member

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  6. my67xr

    my67xr Well-Known Member Premium Member

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    I agree with replacing the 2x transistor's, while you're at it also replace the 4x capacitor's.
    And get some silicon heat transfer compound to go between the transistors' back and the alloy heatsink's.
    Computer shop's have some good quality stuff available really cheap, i picked up a couple of 15g pot's of silver thermal paste for $2ea at MSY Computer's down the road.

    When you look for replacement Darlington Transistor's for it, the part number's printed on them will need a 2S put in front of it eg D1071 will become 2SD1071

    The bottom brown capacitor in your pic look's like it may be bulging ? is it the same part number as the brown one above it ?

    With the capacitor's try and find some replacement's that are a Low ESR Electrolytic Capacitor, they are better quality than standard capacitor's so will last a lot longer than the standard type.
    You could also upgrade the voltage on them if you wanted too, if one is say 47 Ohm's and 16v, it would be best to replace it with a 47 Ohm 25v, this way it give's them a bit of a chance if there is ever any power spike's for whatever reason and they should help extend the life of the cap too.


    One way to test a circuit board for dry soldered joint's is to heat it up with a hot air gun, run the hot air across all the soldered joint's for a minute or so and then try it out in your bike, if you start getting spark at you spark plug then it's most likely a dry soldered/fractured joint.
     
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  7. Bab

    Bab Member Premium Member Contributing Member

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    Early on in my effort to diagnose the ignition I made a point of cleaning and inspecting all the pins and sockets in the wiring harness that was related to the circuit, and I am confident all was good. Now that the case is off I'll plug the board back in and try the heat gun on it. I have used that method to illustrate a problem I had with my Ultraglide years ago, and had forgot about the potential problems of expansion and contraction.
    I have minimal skills regarding electronics, but have no fear with the removal, and replacement of the individual components now that they are pointed out to me. Every day is an adventure, some more intense than others, but this will lead to another.
    I am learning volumes from you guys, everything from electronics to retrieving parcels from Canada Post. Thank you, volumes ...Bab
     
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  8. Bab

    Bab Member Premium Member Contributing Member

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    I've been doing a lot of reading here, and got sidetracked with the topic of carb cleaners. The timing was good because the carbs were plugged up solid. Suggestions were made by you, and followed by me. The book "Zen And The Art Of Motorcycle Maintenance" come to mind last week. There is something about sitting at the bench scrubbing and poking at a bank of carbs to cause a person to look inward and ask some interesting questions. For example, in mapping our DNA have they discovered the motorcycle gene? Think back to when we drew bikes on the cave walls with a piece of charcoal, and how much more fun were having with bikes today...
    Any how, I began the exploration of the carbs by cleaning my bench up, and covering it with a flattened cardboard box. This serves many purposes. I soaks up oil etc., it is soft and things don't slide around, if you drop small parts they don't bounce as far, and is easier to find, and if you want you can jab things into it so they don't roll away.
    I pulled the carbs off and in doing so determined someone else had a go at them or they had a limp wrist because the clamps were hardly done up on the collars. once I got them on the bench and did some cleaning of the outside I found one new screw that although JIS was stainless and did not match the originals. Inside I found some of the screw slots abused.
    IMG_20171127_113118.jpg IMG_20171129_113016.jpg IMG_20171130_151600.jpg IMG_20171130_151617.jpg IMG_20171130_151734.jpg IMG_20171130_163621.jpg IMG_20171130_163631.jpg IMG_20171129_113637.jpg
    The first mystery the carbs revealed to me was what happened to the breather box (foam?) filter? I was sure there should have been something in the breather / vent box and found what was left of it on top of the diaphragms.
    I still haven't figured how to rotate the photos, but the first is the carbs on a cookie tray I use to catch spills, and I knew what awaited me in the fuel bowels. The 2nd shot shows the difference between my effort of cleaning and as I found them. The other photos are various stages of cleaning. The lower photo is an assortment of weaponry used in the assault.
    I don't have the access to sonic cleaners, and soda blasters, but I do have a small chip fryer that I fill half full of water, then in a tin can I put my nasty degreaser, and set it in the fryer. Now I can heat up the degreaser, and use it as a miniature dip tank. With the help of the tooth brush I end up with a clean parts (fuel bowl first photo). The jets were a different story. They were soaked in the heated solution, and then transferred to a more volatile carb cleaner, then with the fine wire probe, and air gun this was repeated until with the aid of my loupe I could see the holes were all clean.
    I mentioned earlier the action of the choke had serious stiction at the beginning of the travel when it was engaged. I took the rail and broke the sharp edges with some draw filing thinking they were hanging up. Further inspection showed wear in the bore of the nylon slide. The wear on the leading edge on the top of the bore had trapped dirt and was scoring the shaft it travelled on. The same applied to the opposite end only it showed on the lower side. I took a fine file and worked the dirt out of the nylon, and softened the leading edge and the trailing edge to ease the rotational force the action of the cable creates when attempting to pull the choke bar out.
    The aluminum tube / shaft the actuator slides on showed galling and wear, so I cleaned the opposite one that is used as a spacer and exchanged them. I gave it a shot of WD40 to help lube it and with my hands activated it to find it worked fine on the bench.
    With the carbs all together, I had a close inspection of the boots, and reinstalled the rack. With my not so limp wrist and these arthritic fingers, I tightened everything up. After hooking up the choke cable I was pleased to find it works with no hesitation.
    I decided at this time to dismantle the petcock and eliminate the chance it might be malfunctioning, and proved its integrity.
    Instead of dicking around with bottles of fuel, I strapped the tank to a short step ladder ( same height as the bike, don't want too much head) and hooked it up with a length of fuel hose, and vacuum hose. The prime function works, and with the valve in the "on" position the absence of vacuum works to keep fuel from flooding the bowels.
    I've cleaned the plugs again and cranked the bike over, it wants to, but it hasn't caught yet. I think the plugs are struggling with the contamination the oil I used for the compression test is creating. I don't have a great feeling about the shape of the spark I'm getting either. It is not a sharp arch as you'd expect, but is rather dispersed. Canada Post will correct that next week as new plugs are on the way.
    Thanks to all...Bab
     
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  9. kiffsta

    kiffsta Administrator Staff Member Dirty Wheel Club Contributing Member

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    Ahhhh , so close
     
  10. Murdo

    Murdo The Good Doctor Staff Member Premium Member Ride and Events Crew Contributing Member

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    Go for it Babs, your doing good work there.
     
  11. Bab

    Bab Member Premium Member Contributing Member

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    I'm at the stage where I have to wait for the battery to charge between sessions. My trickle charger takes forever, and my other one I fear will boil the heart out of the battery. So while I wait, I spend my time reading on the forum...
     
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  12. risky

    risky Megelli King Premium Member Contributing Member

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    try a second battery -plus to plus and minus to minus.just use battery jumpers and see if 12 volts with greater amperage does.
     
  13. Bab

    Bab Member Premium Member Contributing Member

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    I discussed that option last night with my son, but we only have the one battery at the present. I do have a start function on my large charger, but again I fear I'll fry a $100 dollar battery. I might be going out today to buy that 2nd battery as we'll need it eventually. I'll see what is on the shelf locally, as well as price, and compare it to what can be bought on line close by so I don't have to wait 3 weeks for the boat to run aground somewhere on Lake Ontario.
     
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  14. Bab

    Bab Member Premium Member Contributing Member

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    Today I would like to thank my lucky stars and golden garters, for I got the Slingshot to run!!
    I nursed the battery to life, and when the bike was cranking, I gave it a light shot of quick start (ether). It fired and the revs climbed and started to settle down as I tried to get down to a reasonable idle with the adjusting knob. I targeted the 1600's, and succeeded relatively easy.

    IMG_20171203_104549.jpg

    If I blipped the throttle it would rev up immediately, and was what I considered slow to idle down. I let it idle for some time (10 minutes) and walked around with the poor man's stethoscope listening for anything weird, but I think all is well that way. I'm not sure but I think I hear an occasional slight flutter in the exhaust note, I don't know how else to describe it. It is not reflected on the tach and at this time isn't serious enough to anticipate a full on miss or tendency to stall out. I let it idle because I was waiting for the thermostat to open, and have the fan kick in, because I didn't think to jumper the fan prior to see if it worked, however it kicked in as it should. Life is grand...
    All was good until I ran out of fuel. I put more in, and primed the carbs, and started the bike again without the ether.

    IMG_20171203_104512.jpg IMG_20171203_104523.jpg

    However this time I couldn't get it to settle down as it seemed to hunt, reving up, then slowing down. I could idle it down so I could almost count the revs, then it would go off to2500 - 3000.

    IMG_20171203_111615.jpg IMG_20171203_111648.jpg

    I did notice the fuel line had a pronounced pulse to it, so I switched over to reserve and that settled down some what. While checking the fuel line to see if there was fuel running I did notice air in the line at the carbs.

    IMG_20171203_112737_panorama.jpg

    I bled the air out by lifting the line allowing the air to escape up to the tank. Now when I blip the throttle, I discover air in the line. Is this a result of leaking gaskets on the bowels, or just the residual air leaving the bowels, and my impatience?
     
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  15. Murdo

    Murdo The Good Doctor Staff Member Premium Member Ride and Events Crew Contributing Member

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    I would think it is just the air bleeding out.
    Good work getting it running. :thumb_ups:
     
  16. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club

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    Good work. I suspect your hunting idle/slow dropping to idle may be an air leak. Spray starting fluid / brake cleaner at your air box and carb manifolds and check for a change in RPM. If there are vacuum lines, replace them all.
     
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  17. Bab

    Bab Member Premium Member Contributing Member

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    Thanks Linkin, your idea of using the starting fluid to find if it is sucking air (at the boots) has reinforced the same train of thought I had. At this time I don't have the air box on the carbs, nor are their any vacuum lines except to the fuel tank. The only lines not present are the breather / vents to the diaphragms, and the two vents off the top of the carbs. Would that make a difference? I suppose it wouldn't be too much effort to intsall them to find out. That'll happen with the morning coffee.
    While on the subject of vents, the two 1/4" (7mm) lines coming off the air side of the carbs are open to atmosphere. I suspect they are to allow the venting of the fuel bowels so the fluids will displace the air and allow the smooth introduction of fuel as demands require. Now I am curious as to why there are no filters on the end of these lines to eliminate the introduction of dirt, spiders, small children, etc.
    Would the resistance created by a filter be too restricting to allow the efficient changes in volume of fuel? If that is the case, why not apply a larger filter?...Anyone?, Anyone?...
     
  18. GreyImport

    GreyImport Administrator Staff Member The Big Cheese Contributing Member

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    Heres the Bandit carbs and airbox
    Looks like some sort of small filter above the airbox in the diagram or possibly they vent into the airbox

    bandit carbs.png bandit airbox.png
     
  19. my67xr

    my67xr Well-Known Member Premium Member

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    The 3LN FZR250's have the same style carby's BDST28's, your's has BDST30's i'm pretty sure,
    the vent line's for the fuel bowl's have no filter's on the FZR carb's.


    Running it with no airbox it'll be a bit leaner than normal as the filter will restrict the amount of air that goes into the carby's a little and help smooth out the air flow.

    I don't think you'd get any insect's wanting to explore where there are fuel vapour's

    When you cleaned out the carby's did you remove the mixture screw's and reset them to where they previously were ?
    Did you check the port's at the bottom where the tip of the mixture screw sit's through to the main bore of the carby's were all open ?
     
  20. Bab

    Bab Member Premium Member Contributing Member

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    I printed off a copy of the drawings (from our resources!) Greyimport has posted previously as part of my investigation into the missing filter. It would be item 15 in figure 13. My first look inside this small filter box showed no evidence of any filter. I figured the sponge medium had degraded and that is what I found between the diaphragms, and their caps. I bought a filter for a lawnmower, and cut it down to fit the box. That mystery is now solved.
    The topic of not having some sort of filter medium on the end of the vent hoses #12 figure 12 still grates with me. I never thought to look at the drawing to determine if filters were in fact an integral part of the carb system until after I posted my rant last night. Everything I was taught about automotive, and mechanics reinforced the observation that dust and dirt is not our friend, and having the vents open to the atmosphere in that manner grates with me. Anyway I'm not an engineer, but I do know enough to stay off the tracks...
    I did check the mixture screws for cleanliness, counting turns for the positioning prior to removing them. The published benchmark states they should be 1 turn out. Mine are closer to 2, but I'm not stressing about it since it started up and ran so smooth considering the fact others have dicked with it, and it obviously sat for 3-4 years.
    The tube that exits the bottom of the fuel bowels were indeed plugged when I began cleaning the carbs but when I soaked them in my "boiler" the air pressure from my needle gun cleared them right away, so there shouldn't be an issue there.
    I had a real good look at the boots at the intake and they looked mint, so don't expect issues, but I think I'll check the fit.
    I'll check a few more things before I start to put it together to day. I'm hoping I can get it out for a turn before the weather here closes in. Presently temperatures are holding around 3-5 deg. F with rain and possibly snow expected in the near future. Doing 120 kilometers / hour with an open face helmet, and no windshield this time of year can get your attention. That's where the NT shines.
    Once again thanks to all who has taken an interest and have gotten me this far...Bab
     
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