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RGV250 Power-valves

Discussion in 'Bling and Appearance' started by Slade, Mar 12, 2007.

  1. Well, after all the trouble ive been having it was time to check the power valves, heres what I found in the top cylinder


    as far as I know these are not the original power valves for my bike being a 90 model, but later valves from maybe a 95 model.
    Sadly whoever installed them did not do the top cylinder properly and had the spacer at the wrong end, and the pic you see above is the end result :(

    I managed to get ahold of 2 replacements for the time being, but the top of the piston that munched on one of the valves is dinted along the top edge, thankfully though it seems to of not killed the rings nor scored the side of the piston and hopfully not any more damage has been made. Or nothing to serious.

    Now im on the road to start saving so I can buy a new set of valves, new pistons, rings and probably a bore and replate :| :( . Lets hope the replacements I found hold out for the next 3-4 months :roll:
  2. Damn, thats nasty.
    Cant really trust anyone these days.
    So what exactly dropped in the engine?
    Hope it never happens to me. Touch wood
  3. How much are you looking at $$$$ wise for the rebuild if you get it done by a shop?
  4. thankfully nothing dropped "into" the motor.

    But the two top left circles I made are where the piston kissed the valve when they dropped down to far after the shaft broke on it.

    its the earlier model valves that have the pin that can drop into the motor, which sadly the 2 replacement valves I got are this kind :(

    Here is a pic of the replacements I will be aiming to get. Designed better, made stronger and flow better, so more hp also :grin:

    As for the rebuild im not sure how much it would cost by a shop, but dollar wise for parts im looking approximatly $1000 for the valves, $400 for the pistons and rings, and gaskets for the top end. If the cylinders need boring and replating, i guess that could be upto $1000? but i really am unsure about that 1.
    If you got a bike shop to do it all, I guess your looking at maybe another $1000 on top again? Depends how many hours it takes them, Most bike shops charge about $65 an hour I believe
  5. They are definitely 3 piece valves from a VJ22, "supposedly" better than the 2 piece VJ21s. The collars on the pvs have the locating holes drilled off centre so you can definitely see when you have installed them the wrong way, I'll refrain from commenting about the person that put those calves in ;)

    Are you sure you got all the bits of the pv out? You don't want something floating in the big end.

    You can also change the pv screws with some cap screws, I think they are M5x10mm. This helps you later on when you take the pvs out for a service.

    Did you run your finger along all side edges of the piston just to make sure there was no damage to them?

    Did you also remember to coat everything you put back in (PVs, pistons and rings) in 2 stroke oil before you put it back together? This is to reduce the chances of a seizure.

    Your gaskets in good condition or gasket gooed?

    Sorry for all the questions, try trying to make sure you avoid a big bang.

  6. actually no i did not coat it all in 2stroke.
    Had nothing available.
    Hit them up the best I could with a spray lubricant so I hope this holds out until the 2stroke works its way in.

    As for gaskets, I had 1 replacement gasket off the 91 head, was perfect and the other was gooed...

    Sadly as much as I wanna pull it all down now I cant, havnt got the place nor the money to get it done so if I did the bike would be sitting for months again.
    As for all the bits out, the motor has been running for a good 2000km's or so before i realised what had happened (bit of a worry i know) but im fairly certain its all cleared out. Hopefully....

    As for the pv screws, when i get to replacing them it will most likely be with a hex type screw as getting a screwdriver into these is a pain in the arse with the motor in the bike, especially when i had to break them all with an impact driver :|

    anyhow fingers crossed everything holds out for a few months. I'll just have to keep a close eye on these replacment pv's as 1 of the pins was a bit loose and the centre hole had been ovaled a bit :(
  7. If you remember next time, pull the tube going to the oil pump off and bleed a little out of your oil bottle on the bike into a jar or something and then smear it all over anything that moves.

    best of luck! You'll enjoy the bike once it runs.
  8. hehe oh, the bikes running, hasnt really stopped apart from when I pulled it apart to find the inside jigsaw :LOL:

    Lets just hope it KEEPS running til I can afford to fix it all proper

    till then if any1 has a good set of replacement valves, only need 2, please PM me asap :D
  9. Good work slade. I think you probably know more than a lot of the bike shops now :wink: Maybe you can earn a bit of extra cash for the rebuild by fixing other 2 strokes, as the place you took it last obviously had no idea what they were doing.
  10. When I worked as a mechanic, poor servicing where the powervalves were not cleaned was the #1 reason why RGV motors ate themselves.

    Outside regular "as intended" use, they coked up and eventually started to jam, whereby they started to meet with other parts they shouldnt meet....
    End cost usually deaf powervalves, pistons, rings and most importantly and expensively dead nikasil cylinders.

    If you've been faithfully paying a proper bike shop to maintain it for a long time, I'd be asking them to come to the party.

    If you havent (eg it's only been serviced here and there or you havent had it long enough for them to have a good service history) then you're probably on your own.

    nikasil can be resurfaced much cheaper than you can buy new ones. Even back in the early 90's it was like $1200 a set of cylinders IIRC.
  11. Light damage to pistons like that can be reworked with files, emery paper and some patience without ill effect, particularly in 2 smokers.
    However, if you had to rebore anyway, forget what I said!

    Regards, Andrew.
  12. I actually have the feeling someone has done it before, just from the look oh what I saw when I had a peak, But I really dont know

    Good news is I got my set of 2piece valves yesterday, and they went in the bike today. Yay for much easier tuning and less problems imo

    Bad news is ive been sent the wrong gearbox plate twice in the row haha

    3rd time lucky I hope, also hoping it comes before this long weekend so I can get the bike fixed and running

    2 weeks without my bike going (maybe longer) and im starting to climb the walls :|