My RC24 resurrection

Discussion in '1st & 2nd Generation 1983-1989' started by Wheezy, Sep 24, 2021.

  1. Wheezy

    Wheezy New Member

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    I’ve found this YouTube clip, about the same sort of noise I’m getting and it being a fault with the early ‘86 models. Didn’t know about this.



    just seen the cost of a new spark unit. Oh. My. Days! Really hope that this issue with the non-firing cylinder is an easy, or at least cheap, fix.
     
  2. Colddevil

    Colddevil Member

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    I think you two are talking about different things. Wheezy mentioned wanting to adjust the valve clearances, so I believe what he actually meant was a Valve Cover Gasket as opposed to a Head Gasket.
     
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  3. RogueRC24

    RogueRC24 Member

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    valve cover gasket.JPG That sounds like a nasty version on my -86 7Hundie proj bike. The person is claiming that the coil is bad and causing the lack of firing and thus the noise? 83BP from CMSNL. Maybe a used one on Ebay?

    ^^^ valve cover gasket.
     
  4. Wheezy

    Wheezy New Member

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    Yes, my bad. Apologies for the confusion. I meant the valve cover gasket.


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  5. Wheezy

    Wheezy New Member

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    I knew this bike would be frustrating, but it’s really exceeding itself.

    So yesterday I swapped over coils and HT leads to see if that would get cylinder 4 to fire. It didn’t work so I put everything back as before.

    This evening I have spent a good 2 hours re-examining the jets on carb 4 and getting the float height correct. Pretty happy that it’s all correct.

    Carbs back on and fire up and now I’ve lost cylinder 4 as well. Spent 30 minutes checking the connections on the coils, ht leads but no joy. Quite pissed off now. Ran out of daylight so I’ll check for a spark on both cylinders next week. Need to walk away from the bike for a bit and do something else.


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  6. Wheezy

    Wheezy New Member

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    Sorry, I’m tired. I meant I’ve now lost cylinder 2 and 4.


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  7. squirrelman

    squirrelman Member

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    try finding a bloke with the same bike, and try swapping cdi boxes for a test.

    85414571_033_33vfrside.JPG.c3cd3ee3cd79c42f10e76742969b5f36.JPG
     
  8. straycat

    straycat Member

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    Hmmmm.

    Sounds alot like the issues I was having with my GSXR750.

    I chased everything on that and it was fueling all along.

    All the advice here is good, one thing at a time etc.

    All I can say is, when it comes to Carbs and fueling, take your time, check EVERYTHING carefully, clean them properly, check and clean every circuit, remove and clean every jet, check all needle/seats are sealing, be 100% sure your float heights are correct, be sure the pilot air/fuel screws are set properly.

    does it fire on 2/4 if you give it a squirt of fuel or ether down the carb throat ?
    Tried new plugs ?
    have you checked the coils Primary & secondary circuits ? im not familiar with your bike, but is it a wasted spark system ? ie do cylinders 2 & 4 run off the same coil and fire at the same time ? these are things that may help you sleuth out the issue.

    do you have one or 2 full feeds to the carbs? do 2 & 4 feed off the same fuel line ?

    it may be worth searching out my GSXR thread, NorcalBoy had a good checklist there too.
     
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  9. Captain 80s

    Captain 80s Member

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    There's a part of me that thinks the fuel supply is somehow fouling shit up again.

    VFRs that "ran when parked" rarely have ignition problems, unless they have been used as boat anchors or barn door stops.
     
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  10. squirrelman

    squirrelman Member

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    ^^about that video........

    the noise is unusual and alarming, not common. :confused: check valve clearances at least.
     
    Last edited: May 14, 2023
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  11. Wheezy

    Wheezy New Member

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    Right, a good night’s sleep and a bit of perspective. Not going to throw the bike into the nearest hedge, yet!

    Thanks for all the comments above. Will work my way through things and try to eliminate issues.


    Here’s my plan for the next couple of weeks.
    I’m going to get a multimeter and check all the resistances on the coil circuits / pulse generators / HT leads

    Get new spark plugs.

    I was getting a spark in cylinder 4 and as cylinder 2 was running until 24 hours ago, I was getting a spark in cylinder 2, but maybe the spark just isn’t strong enough?

    Open up all the float chambers again and check my work. Hopefully will be ok but clear out all the jets again, just to be sure.

    Can I confirm, I’m using a gravity feed fuel supply in a temporary tank as the pump is not working. Could there be a fuel starvation problem due to this?

    Thanks all.


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  12. squirrelman

    squirrelman Member

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    gravity feed works best the fuller the tank is, not good less than half-full.
     
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  13. straycat

    straycat Member

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    I had issues where cylinders were firing and then went dead. turned out the carbs were dumping too much fuel and flooding cylinders out.

    sometimes I'd pop in a new set of plugs and the bike would come alive again, only to start dropping cylinders soon after.

    after that I fixed the needles and seats, fixed float heights and was still dealing with a starved cylinder due to fuel screw adjustment.

    Aside from removing the float bowls, and checking floats, have you removed all jets, needles, slides, pilot screws, choke plungers etc ? in my experience, v4 carbs have alot of parts to remove and check properly. be aware that the pilot screws have springs, tiny washers and tiny O-rings in there too. I highly recommend making sure everything has been removed and cleaned. dont use carb Cleaner on or near the rubber diaphragm it will destroy it. If you dont have access to can ultrasonic cleaner, you may want to clean the outside of the carbs very well and then soak them overnight in Pinesol (if you have that on the UK).

    If it were me, id separate all the carbs off the rack too, and check there is nothing blocking any of the fuel supply tubes.

    If you go this far, id recommend being extremely organized in you disassembly and parts storage, take lots of photos at each step and make notes. The first time is rather daunting and putting it all back together the first time is highly dependant on how well you organized.

    Now, you may not have to go that far, but, what I have learned the hard way is, if you short cut on carb cleaning, you end up taking them on and off more times than you can count on 2 hands and spend way more time in the long run messing with them.

    Lastly, id recommend you connect your remote fuel bottle while the carbs are off the bike. remove the float bowls and hold the bank of carbs over a washing up tub and see how much fuel flow you are getting to the carbs. Then put the bowls back on and turn on your remote fuel bottle, leave the carbs for a day in the DRY wash tub and see if any of them are dumping fuel. This helped me out when I had my issues. thanks to the good advice on this forum
     
    Last edited: Jun 17, 2022
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  14. straycat

    straycat Member

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    There are some excellent youtube videos by a guy " MagnAndy" who takes you step by step on taking them apart, cleaning and re assembly (15 videos in all I think -- I watched them). you can also find his videos in the CarbSpa section of V4msclebikes.com.

    https://v4musclebike.com/forums/showthread.php?t=34135

    Direct linke here :

    http://v4musclebike.com/forums/showthread.php?p=305813#post305813

    Keep at it, try not to get frustrated or discouraged, we have ALL been there (many times), ready to light a bike on fire or dump it off a cliff out of frustration, but...there is always a reason always a solution and as I have learned, often even the smallest of things will muck things up for you, and you'll be so satisfied when you finally sort it.
     
    Last edited: Jun 17, 2022
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  15. Wheezy

    Wheezy New Member

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  16. Wheezy

    Wheezy New Member

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    Thanks both. I have done a full carb strip down and replacement of fuel lines, o-rings, float gaskets etc. followed the instructions closely on v4dreams as I bought all Joe Nelson’s kit. I really took my time, and while I could well have stuffed it up, I made sure that all the jets were clean using carb cleaner and electronic spray etc. There’s no doubt that I might have done something wrong or a valve not closing properly etc. Think I will check all float heights again, but I didn’t alter any of them and the bike was working ok, afaik, for 15 years in those float height settings. I can’t see how they would change simply by being dormant for all this time. Pilot screws were set to factory settings of 2.5 turns out from seated, which was what they were anyway, when I stripped down.

    my problem is, I don’t have the experience to know what I should be looking for. All the needle valves and seats looked fine, no broken bits, scores on the surface etc, but there might have been something that to my untrained eye, I just didn’t see. At the moment, I’ve just got too many variables I’m trying to sort out.
    I’ll give it a couple more weeks, but I might just have to bite the bullet and pack the carbs off to someone who knows what they’re doing.
     
  17. Wheezy

    Wheezy New Member

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    Thanks for this tip. Will do this to see how much fuel is being delivered.
     
  18. Colddevil

    Colddevil Member

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    One thing about float heights I want to mention since it bit me in the ass on another bike recently... If you change float valves and seats to anything non-OEM, you may be chasing a different value for float height. On the Honda Shadow 750 I was messing with recently, the rebuild kit I worked with (K&L) had a new float valve and float valve seat. I verified that the float valve was the same size and shape. One thing I didn't do though was verify that the float valve seat was the same. If that float valve seat has a different shape than OEM (seals higher or lower), it'll throw off readings. The stock float height for that bike was 7mm but I was still way too high of a wet float height when adjusted to 9.5mm. I was basically flooding the cylinders at anything besides 50%+ throttle.

    I don't have the bike in my possession anymore to verify, but I would venture to guess that I would have saved myself many many hours by just re-using the OEM float valve seats and replacing the rubber-tipped float valves and setting to 7mm float height. I bet if I checked the wet float height by hooking up a small tube to the drain and filling with the OEM float valve vs. the replacement K&L at 7mm, I would have gotten two very different readings.

    I've already learned my lesson about changing jets to anything besides original manufacturer. I think I need to add float valve seats to that as well.
     
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  19. Wheezy

    Wheezy New Member

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    AFAIK, it’s all oem. I’ve just asked my brother and he didn’t have any work done on the carbs.

    I took a picture of the float needle when I took it out and it had a rubber end on it. Is this oem, as far as anyone can tell?

    My brother said that it was definitely running on 4 cylinders when it went into storage, so that would suggest it’s more likely something I’ve done during the carb strip down and refurb, or degradation over time, possibly with the electrics.


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  20. Wheezy

    Wheezy New Member

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    [​IMG]
    This is the float needle on carb 4. Looked I damaged. Rubber tipped.


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