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

Project Another VT250F-2

Discussion in 'Your 250cc Projects' started by Murdo, Apr 8, 2020.

  1. Murdo

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

    Messages:
    6,397
    Likes Received:
    4,786
    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.
    Got this bike in a swap deal. 5/85 build MC-08.
    VT250 x2 003.jpg VT250 x2 004.jpg
    Engine in a tub and more bits to come. Gave it a clean down and off with the heads.
    VT250 heads 015.jpg VT250 heads 026.jpg VT250 heads 028.jpg Heads are both cracked and valves missing, the bores are a problem with wear and marks from foreign objects. I gave the bores a light hone to clean up the surfaces and was even worse.
    VT250 x2 014.jpg
    They will have to be rebored but finding new O/S piston kits have so far eluded me. Have read about using standard Kawasaki ZZR250 pistons and I compared to one I took from one of my ZZR's. Honda piston on rod.
    VT250 x2 006.jpg VT250 x2 008.jpg VT250 x2 010.jpg
    Pin dia, length and pin height are the same, but whether the Honda bore can take the 2mm overbore is yet to be determined. The front cylinder rod bearing wasn't too healthy (knock, knock, anybody home) and would have made a horrible noise. The crank pin has a couple of marks but cleaned up with some 800grit linishing paper and is still at std size. Mains are good.
    VT250 x2 012.jpg
    So far need to get piston kits, crank bearings, cam chains, valves and gaskets. Feel this could be a long project.
     
    • Informative Informative x 1
    Last edited: Jul 6, 2021
  2. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,102
    Likes Received:
    3,472
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    That is grim about the parts. They made the 250 V-Twin for a long time. You would think that os pistons would be available.
     
    • Agree Agree x 2
  3. Murdo

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

    Messages:
    6,397
    Likes Received:
    4,786
    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.
    Plenty of STD stuff. Have found one .50mm O/S piston, but no rings to suit. Kawasaki has plenty of std pistons/rings.
    Edit; have found .50mm VF500 pistons but have yet to decide which kidney to sell.
     
    • Informative Informative x 1
    Last edited: Apr 8, 2020
  4. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

    Messages:
    4,313
    Likes Received:
    2,383
    Trophy Points:
    898
    Joined:
    Jun 18, 2016
    Gender:
    Male
    Occupation:
    Panel Beater, Spray Painter, Custom Fabricator
    Location:
    Adelaide, South Australia
    My Bike:
    Yamaha's , 1990 FZR250R 3LN3 , 1986 XT250TS 57R , 1984 IT200L 43G, 1976 IT400C 510
    • Thanks! Thanks! x 1
  5. Murdo

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

    Messages:
    6,397
    Likes Received:
    4,786
    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.
    Thanks for that but CMS were slightly cheaper and am getting their 'gold plated' pistons so added to the pile. Gasket set from UK and bearings (China) on way too. Got two cam chains for Yamaha SR/XT500 or XS650 (same chains and length as VT which are 219FTS x 106 links) coming from Norway.
    Spending Scomo's bonus to stimulate the economy. :lolsign:
     
    • Winner Winner x 3
  6. jmw76

    jmw76 Well-Known Member

    Messages:
    1,151
    Likes Received:
    585
    Trophy Points:
    498
    Joined:
    Mar 12, 2017
    Gender:
    Male
    Location:
    Melbourne, Australia
    My Bike:
    Honda cbr250rr mc22 road + 1 track, Honda RC 162 tribute bike, Honda Spada Vt250, Honda CBR900RR
    Where in China did you end up getting the bearings. I have rings and bearings that are still in transit. Ordered early feb. Complained Aliba and got my money back . Now looking for somewhere else to by. Thinking AHL.
     
    • Bummer Bummer x 1
  7. Murdo

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

    Messages:
    6,397
    Likes Received:
    4,786
    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.
    Last edited: Apr 10, 2020
  8. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    3,225
    Likes Received:
    1,416
    Trophy Points:
    918
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    Looks like you may already have gold plated pistons en route

    If that's not the case - here's two potential candidates for you

    http://hispeedpiston.com/ThaiProduct/RacingPiston/RX/RX145461/
    There's lots more pistons on this site, however they've re-arranged it, yet again, it is possible to navigate the Thai language menus by hovering and watching the status bar in the web browser which gives the menu items on English

    Or there is this one...
    https://www.daytonaindonesia.com/product-detail/ninja-250-62-hi-comp-/30
     
    • Informative Informative x 1
  9. Frankster

    Frankster Grey Pride...Adventure before Dementia Staff Member Premium Member Ride and Events Crew

    Messages:
    3,980
    Likes Received:
    2,208
    Trophy Points:
    923
    Joined:
    Nov 19, 2013
    Gender:
    Male
    Occupation:
    Gardener
    Location:
    Tasmania
    Home Page:
    My Bike:
    Spada, VT250F & ZX2R
    Happy Easter everyone. @Murdo that link is to your order, which none of us will be able to see. Can you repost with the link to the bearings please? Thanks Frank
     
    • Agree Agree x 2
  10. Murdo

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

    Messages:
    6,397
    Likes Received:
    4,786
    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.
    Edited post for bearings.
    Thanks @ruckusman but I could not find any of those with the right size gudgeon pin.
    Today whilst 'twiddling my thumbs' not being able to go anywhere I started on some small bits to rebuild/check.
    I filed down the runner ridge of the cam chain guides so the rollers were not touching.
    VT250 x 3 002.jpg
    The front sprocket seal was still soft and with good 'lips' to the seal so I shortened the inner spring about 4mm and refitted to give a bit more 'grip' onto the shaft.
    VT250 x 3 004.jpg VT250 x 3 006.jpg
    Checked the gear 'dog teeth' and some wear marks on second but consider them to have a lot of life left yet.
    VT250 x 3 008.jpg
    Blasted the thermostat housing and joint pipe. Checked the thermostat, working ok too.
    VT250 x 3 010.jpg VT250 x 3 014.jpg
    Stripped and cleaned the carbs, replaced some dodgy screws and a couple of missing O rings.
    VT250 x 3 016.jpg
    With no new parts its now back to 'thumb twiddling'.
     
    • Like Like x 1
    Last edited: Apr 20, 2020
  11. Frankster

    Frankster Grey Pride...Adventure before Dementia Staff Member Premium Member Ride and Events Crew

    Messages:
    3,980
    Likes Received:
    2,208
    Trophy Points:
    923
    Joined:
    Nov 19, 2013
    Gender:
    Male
    Occupation:
    Gardener
    Location:
    Tasmania
    Home Page:
    My Bike:
    Spada, VT250F & ZX2R
    Stripped and cleaned the carbs, replaced some dodgy screws and a couple of missing O rings.

    What O-rings were missing? What main jets were in their?
     
  12. Murdo

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

    Messages:
    6,397
    Likes Received:
    4,786
    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.
    Two rings off the drain screws and one of the idle mixture. Mains are 100 in both and 38 pilots.
     
  13. jmw76

    jmw76 Well-Known Member

    Messages:
    1,151
    Likes Received:
    585
    Trophy Points:
    498
    Joined:
    Mar 12, 2017
    Gender:
    Male
    Location:
    Melbourne, Australia
    My Bike:
    Honda cbr250rr mc22 road + 1 track, Honda RC 162 tribute bike, Honda Spada Vt250, Honda CBR900RR
    Just a question about that front rod bearing. Any idea why it was cactus and other rod bearing ok? I have a very similar issue with my little Spada. Crank also ok on mine. Wondering if there is some inherent design issue or just crap bearings. No idea whether they are original or not, but all std size. My cylinder bores appear to be in good shape.
     
  14. jmw76

    jmw76 Well-Known Member

    Messages:
    1,151
    Likes Received:
    585
    Trophy Points:
    498
    Joined:
    Mar 12, 2017
    Gender:
    Male
    Location:
    Melbourne, Australia
    My Bike:
    Honda cbr250rr mc22 road + 1 track, Honda RC 162 tribute bike, Honda Spada Vt250, Honda CBR900RR
    Why did you file down the cam chain guide?
     
  15. Murdo

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

    Messages:
    6,397
    Likes Received:
    4,786
    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.
    Haven't really looked at it. It had been hammered pretty well as it fell out of the rod when I took it off the crank, ie bent out of shape and not a spring fit into the rod. The other rod bearing has some wear marks so I am guessing that they have some problem with oil supply as both big end are fed by only the right side main bearing. Will be checking the oil pump carefully when I get to it.
    The chain guides are designed to guide the flats of the chain by using a ridge in the middle. When the guide sides wear down it allows the rollers of the chain to touch and turn as they roll over the guide. Can you imagine how fast those little roller would be turning as they run over the lump in the middle of the guide at redline? This would cause them to wear at a much faster rate then they should and require more frequent chain replacement. By filing the centre down so that the rollers clear (by about 1mm) this will give longer chain life.
     
    • Informative Informative x 1
    Last edited: Apr 10, 2020
  16. jmw76

    jmw76 Well-Known Member

    Messages:
    1,151
    Likes Received:
    585
    Trophy Points:
    498
    Joined:
    Mar 12, 2017
    Gender:
    Male
    Location:
    Melbourne, Australia
    My Bike:
    Honda cbr250rr mc22 road + 1 track, Honda RC 162 tribute bike, Honda Spada Vt250, Honda CBR900RR
    Ok. Makes sense about the chain. I had not really thought about it. Spada uses silent link chain, so not an issue.
    I will check my oil pump also.
     
    • Like Like x 1
  17. Frankster

    Frankster Grey Pride...Adventure before Dementia Staff Member Premium Member Ride and Events Crew

    Messages:
    3,980
    Likes Received:
    2,208
    Trophy Points:
    923
    Joined:
    Nov 19, 2013
    Gender:
    Male
    Occupation:
    Gardener
    Location:
    Tasmania
    Home Page:
    My Bike:
    Spada, VT250F & ZX2R
    I will check my oil pump also.

    Not sure if the Spada has the same issue as the VT250F. I found the following online years ago when I got my first VT250F. I check the PRV on all bikes I buy. I've done this mod on a couple of VT250F's. @Murdo check the thickness of the washer as I don't put 2x washers in there as suggested. I just replace it with a slightly thicker one. Also, @Murdo don't get too attached to those carbs. I'll give you another set with a standard airbox/filter etc. Those and that custom airbox are from my track bike.

    Oil p1.JPG Oil p2.JPG
     
    • Informative Informative x 1
  18. jmw76

    jmw76 Well-Known Member

    Messages:
    1,151
    Likes Received:
    585
    Trophy Points:
    498
    Joined:
    Mar 12, 2017
    Gender:
    Male
    Location:
    Melbourne, Australia
    My Bike:
    Honda cbr250rr mc22 road + 1 track, Honda RC 162 tribute bike, Honda Spada Vt250, Honda CBR900RR
    Excellent tip. I would not be surprised if my bike missed an oil filter change at some point during its life.
     
  19. Murdo

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

    Messages:
    6,397
    Likes Received:
    4,786
    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.
    Agree that the relief valve is in the wrong place, should be after the filter.
    @Frankster, then you will be happy I cleaned them for you. :lolsign:
     
  20. Frankster

    Frankster Grey Pride...Adventure before Dementia Staff Member Premium Member Ride and Events Crew

    Messages:
    3,980
    Likes Received:
    2,208
    Trophy Points:
    923
    Joined:
    Nov 19, 2013
    Gender:
    Male
    Occupation:
    Gardener
    Location:
    Tasmania
    Home Page:
    My Bike:
    Spada, VT250F & ZX2R
    Thanks Murdo. I'm learning some valuable lessons on this build you're doing. That tip about the cam-chain guides makes so much sense when you think about it.
     
    • Agree Agree x 1

Share This Page