/ Register

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Project FZR250RR 3LN1

Discussion in 'Your 250cc Projects' started by PhillipFZR, Feb 29, 2020.

  1. PhillipFZR

    PhillipFZR Member Contributing Member

    Messages:
    22
    Likes Received:
    7
    Trophy Points:
    13
    Joined:
    Feb 27, 2020
    Gender:
    Male
    Location:
    South Africa
    My Bike:
    Fzr250r 3ln
    Hi everyone, so I finally got me a nice project, a 3LN1. So straight into it, the bikes starter swings slow even with a fresh battery, And also I found some concerning areas on the wiring of which I will post some pics, I don’t even know how the bike is mechanically, the previous owner has a collection of bikes and never got around this one, So he also doesn’t really know much on the bike, so I figured i’ll try and sort out the slow swinging starter first, any suggestions would be appreciated

    28E6A29E-1B56-4797-8666-06331B9DA59E.jpeg E43F4A8E-F7CE-4E3B-BF14-08ADC95902FE.jpeg 24F608ED-C106-4916-80AA-A74BC15AA6AB.jpeg
     
    Last edited by a moderator: Feb 29, 2020
    PhillipFZR, Feb 29, 2020
    #1
  2. Murdo

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

    Messages:
    6,404
    Likes Received:
    4,792
    Trophy Points:
    1,148
    Joined:
    May 4, 2013
    Gender:
    Male
    Occupation:
    Retired
    Location:
    Tamworth, NSW
    My Bike:
    1937 Royal Enfield 250, CF Moto 250 V5, Honda's XL250, CBR250, FT500 plus a few others.
    Welcome to the party. :party:
    Definately some wiring 'bodgery' there. Do you have a good reliable multi meter, your gonna need one.
    I suggest checking all the wires and terminals from the battery to solenoid to starter. If ok the the earth from battery to frame to wiring harness to engine case. Also check that the bolts holding the starter motor are tight and giving a good earth. Short the terminals on the solenoid to eliminate any problems there, and if still no good the put the jumper cable direct to the terminal on starter. Have you taken the spark plugs out and checked the cylinders are clear?
     
    • Like Like x 1
    Murdo, Feb 29, 2020
    #2
  3. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

    Messages:
    4,741
    Likes Received:
    2,884
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    FZR250R 3LN6
    Check for voltage drop... One meter probe on batt positive, the other on starter motor lead, crank and check the reading. Check each positive point back from the starter motor. As a general rule, anything more than 0.5v in drop across the whole system is a problem, and 0.2v on any individual section.
     
    • Like Like x 1
    Linkin, Feb 29, 2020
    #3
  4. PhillipFZR

    PhillipFZR Member Contributing Member

    Messages:
    22
    Likes Received:
    7
    Trophy Points:
    13
    Joined:
    Feb 27, 2020
    Gender:
    Male
    Location:
    South Africa
    My Bike:
    Fzr250r 3ln
    Ok so I took off the starter and gave it a good clean, brushes and stator looks good, its defnitly turning more free by hand now, but when I put it back it was still the same, i’ll bypass the solenoid later today to see if there is mabye a problem, if so then ill get out the multi meter...ok but that aside, I tracked down the original owners, he said he put other cams in there and thats why the motor is turning hard, so mabye it isn’t wiring at all, how would I know if he put the original cams in there? And if it is the right ones id probably have to replace caps and check if they torqued it correctly?
     
    PhillipFZR, Feb 29, 2020
    #4
  5. Murdo

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

    Messages:
    6,404
    Likes Received:
    4,792
    Trophy Points:
    1,148
    Joined:
    May 4, 2013
    Gender:
    Male
    Occupation:
    Retired
    Location:
    Tamworth, NSW
    My Bike:
    1937 Royal Enfield 250, CF Moto 250 V5, Honda's XL250, CBR250, FT500 plus a few others.
    The reasons the engine would be 'turning hard' with different cams if the valves were hitting the pistons, the cam bearings were tight and 'binding' or wrongly timed. Need to get the top off and check.
     
    • Like Like x 1
    Murdo, Feb 29, 2020
    #5
  6. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

    Messages:
    4,741
    Likes Received:
    2,884
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    FZR250R 3LN6
    Take the plugs out, take the alternator cover off and wind it over by hand. The only real resistance should be the valve springs. If it comes to a hard stop, valve/piston contact would be the first suspect. Unless they're all bent already. If you're lucky the timing will just be out enough for it to not run. It's common when putting cams back in to have one or both out by a tooth.

    Timing marks on the FZR's are easy, under the alternator there is an arrow built into the casting and a T marked on the flywheel. The camshafts and caps are marked with dots on the left hand side of the engine. The hard part is the chain. Simple way to get it right the first time is to keep all chain slack on the inlet side with the tensioner out. Install and bolt down exhaust cam. Fit inlet cam and run the chain over it tight as possible, keeping the slack towards the tensioner. Bolt the inlet cam down, adjust chain position and inlet cam as necessary. When it all looks good, fit the tensioner body and use flat punch to manually extend the tensioner as much as possible. Fit spring and bolt.

    Now the important part for keeping the timing right. Gently rock the crank slightly forward first, and then back, slightly forward again etc in rotation until the tensioner stops ratcheting. Carefully do a full rotation and check the timing marks again. If al goes well it will be timed correctly the first time. If you just do a rotation after fitting the tensioner, the slack is removed as the crank turns and the inlet cam will be out of time.
     
    • Like Like x 1
    • Informative Informative x 1
    Linkin, Feb 29, 2020
    #6
  7. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,115
    Likes Received:
    3,481
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    Ouch, I would be expecting the worse if I heard those words.
     
    • Like Like x 1
    • Agree Agree x 1
    maelstrom, Feb 29, 2020
    #7
  8. PhillipFZR

    PhillipFZR Member Contributing Member

    Messages:
    22
    Likes Received:
    7
    Trophy Points:
    13
    Joined:
    Feb 27, 2020
    Gender:
    Male
    Location:
    South Africa
    My Bike:
    Fzr250r 3ln
    Ok so I checked the timing and its spot on, I then decided to remove tension on the bearing caps and the motor freed up, I traced the problem to the I1 cap, looked like the bearing picked up, so im guessing my best bet would be to take it to engineering shop to do a line bore on all 4 caps

    3192A9D8-C737-4500-80CE-1B985B47D3CA.jpeg 5BDF06C5-BED7-4956-A7C0-FC214047EB09.jpeg
     
    • Bummer Bummer x 2
    PhillipFZR, Mar 1, 2020
    #8
  9. Murdo

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

    Messages:
    6,404
    Likes Received:
    4,792
    Trophy Points:
    1,148
    Joined:
    May 4, 2013
    Gender:
    Male
    Occupation:
    Retired
    Location:
    Tamworth, NSW
    My Bike:
    1937 Royal Enfield 250, CF Moto 250 V5, Honda's XL250, CBR250, FT500 plus a few others.
    Yes, that will need some attention. First two questions, why did it do that and are the oil ways clean? Could the cam cap be on the wrong way around?
     
    • Like Like x 1
    Murdo, Mar 1, 2020
    #9
  10. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

    Messages:
    4,300
    Likes Received:
    2,514
    Trophy Points:
    918
    Joined:
    Oct 6, 2016
    Gender:
    Male
    Location:
    Albury 2641
    My Bike:
    1987 Yamaha SRX250, Honda 1974 SL125 K1, 2022 Triumph Tiger Sport 660
    Line boring wont help you as the caps and head dont run seperate bearings and I doubt you can get oversized camshafts... at least not cheap (you could have them built up and ground).
    As @Murdo says.. you will need to check the oiling system as a minimum. It could well be that the cam cap was from a different motor.. Yamaha were known to line bore their heads and cam caps as matched pairs.. so interchanging them is fraught with danger... looking at that Cam cap I would say the head is toast too.. time for an engine strip and a new 2nd hand cylinder head with cams and cam caps.
     
    • Agree Agree x 1
    Andych, Mar 1, 2020
    #10
  11. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

    Messages:
    4,741
    Likes Received:
    2,884
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    FZR250R 3LN6
    I have seen car engine blocks with main bearing caps jones on special equipment, I can't see any reason it can't be done on a cylinder head, it's just a matter of having the right equipment.
     
    • Like Like x 1
    Linkin, Mar 1, 2020
    #11
  12. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

    Messages:
    4,300
    Likes Received:
    2,514
    Trophy Points:
    918
    Joined:
    Oct 6, 2016
    Gender:
    Male
    Location:
    Albury 2641
    My Bike:
    1987 Yamaha SRX250, Honda 1974 SL125 K1, 2022 Triumph Tiger Sport 660
    Line boring on car engines is fairly standard practice... it is done for main bearings (caps) and cam shafts (block) (OHV not often in OHC). Generally it is done when blueprinting an engine to ensure everything is smack on, parallel to one face etc.
    It has been done on some OHC bike engines known to shed camshafts and needle roller bearings fitted but it is a very big engineering exercise.
    The FZR does not run bearing shells on the camshafts so once you machine out (line bore) the bearing caps to ensure they are all round and parallel with no scoring the camshaft will have too much clearance... much like the proverbial D#ck in a sock.
    You could have the bearing journals on the cam built up and re-ground but I doubt that an FZR engine is worth that expense.
     
    • Like Like x 1
    • Informative Informative x 1
    Andych, Mar 1, 2020
    #12
  13. Murdo

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

    Messages:
    6,404
    Likes Received:
    4,792
    Trophy Points:
    1,148
    Joined:
    May 4, 2013
    Gender:
    Male
    Occupation:
    Retired
    Location:
    Tamworth, NSW
    My Bike:
    1937 Royal Enfield 250, CF Moto 250 V5, Honda's XL250, CBR250, FT500 plus a few others.
    Seeing as how it is the cam cap that takes all the load of the valve springs I would suggest trying to find another cap and CAREFULLY fit it to your head. It may need to have some bearing blue (machinist blue) put on and the cap lightly fitted and engine turned once, then removed and checked for clearance and lightly sand any high spots.
     
    • Like Like x 1
    Murdo, Mar 1, 2020
    #13
  14. PhillipFZR

    PhillipFZR Member Contributing Member

    Messages:
    22
    Likes Received:
    7
    Trophy Points:
    13
    Joined:
    Feb 27, 2020
    Gender:
    Male
    Location:
    South Africa
    My Bike:
    Fzr250r 3ln
    So I took off the head and the sleeves, and the oil ways looked gummed up with rtv, they tried to make a base gasket and also smeared it with rtv, I cleaned off all the rtv and also checked the sleeves and rings, the sleeves looks perfect but the rings looked to be seated in the pistons, so far I managed to free up the rings on 1 cylinder, going to take the head to a engineering shop this week, hopefully they’ll be able to help me with a decent head jobs

    18E8581E-5349-42A4-A625-AE36FC842BC1.jpeg
     
    • Nice Work Nice Work x 1
    PhillipFZR, Mar 2, 2020
    #14
Tags:

Share This Page