Results 1 to 14 of 14

Thread: Problems after rebuild

  1. #1
    apriliaforum newb
    Join Date
    Oct 2017
    Location
    Moscow
    Posts
    9

    Problems after rebuild

    Hi guys! I need your help.
    I was rebuilding my rs engine last year. I also cleaned carbs with full reassembling. Nowadays i can't get the correct work of engine.
    When enabled choke during warm up, it suddenly grows up and does not respond to the throttle handle. This happens with any needle settings.
    All jets are standard for mk2 carbs
    What i have already checked:
    - i checked the float height as in manual (about 7.1mm)
    - i replaced the gaskets in carbs
    - i checked the air solenoids (it's ok)
    - i sealed the intake valves and manifolds
    - i also bought a transparent spark plug to see the colour of flash during idling (it is blue, so it means that the mix is poor)

    i'm locating in Russia, and i'm the second owner of my bike here.
    what else i have stupidly done: once i messed up the wires of battery, and the fuse blown. (may be it cause the damade of cdi??? and air jets are not working correctly???)
    What else can be the reason? Thank you!

  2. #2
    apriliaforum expert mattology's Avatar
    Join Date
    Jun 2009
    Location
    Saint Petersburg, Florida
    Posts
    2,932
    step 1: check for air leaks

    step 2: reassemble vacuum hoses on solenoids according to service manual

    step 3: re check and re jet carburetor to correct spec

    Get your confidence back with Aprilia.

    caution: the use of motorcycles may be habit forming. side effects include purchasing multiple examples of the same bike, in different states of tune, different years, or different models altogether. some motorcycles may be not running when purchased. some parts are no longer available. there are rare instances where aprilias are bought over the internet and upon arrival, they are not as were originally disclosed. there is a small group of people who cannot handle two stroke engines and motorcycle maintenance. if this is the case, you may not be a candidate for Aprilia RS250's.

    Aprilia. Ask your doctor if the RS250 is right for you.

  3. #3
    apriliaforum Junkie
    Join Date
    May 2010
    Location
    England.. KENT
    Posts
    315
    As above really it does sound like a carburettor issue.
    Are the throttle cables set correctly like they are not stuck half open or one is alot different to the other.
    Is the choke plunger in good condition is the spring in with the choke plunger.
    Power valves not stuck open

  4. #4
    apriliaforum newb
    Join Date
    Oct 2017
    Location
    Moscow
    Posts
    9
    Thanks! Will try it this weekend. Vacuum hoses as in manual. Jets are also as in original. Throttle cables set as in manual (left one is 0.7 height) and there is no differences between. Choke plungers are also checked. Exhaust valves are clean and move easily. One thing i can't understand: That the fuel level 7.1mm under the point and 8mm float height by manual may contradict each other?

  5. #5
    apriliaforum Junkie
    Join Date
    Nov 2009
    Location
    Michigan
    Posts
    404
    Have you checked the carb filters..?

  6. #6
    apriliaforum newb
    Join Date
    Oct 2017
    Location
    Moscow
    Posts
    9
    of course

  7. #7
    apriliaforum Junkie gangus's Avatar
    Join Date
    Mar 2010
    Location
    australia
    Posts
    466
    have you balanced the engine using the grey wire??
    Your powervalves, carbs and oil pump all have alignment marks that must line up when you do the grey wire test

  8. #8
    apriliaforum newb
    Join Date
    Oct 2017
    Location
    Moscow
    Posts
    9
    if I'm not mistaken, grey wire is only for powervalves. I checked it too. Carbs and oil pump are by marks. I'll read the manual attentively. I also didn't checked intake hoses on manifolds, or may be the gasoline is too old in tank.
    .

  9. #9
    apriliaforum expert mattology's Avatar
    Join Date
    Jun 2009
    Location
    Saint Petersburg, Florida
    Posts
    2,932
    crank seals ?

    Get your confidence back with Aprilia.

    caution: the use of motorcycles may be habit forming. side effects include purchasing multiple examples of the same bike, in different states of tune, different years, or different models altogether. some motorcycles may be not running when purchased. some parts are no longer available. there are rare instances where aprilias are bought over the internet and upon arrival, they are not as were originally disclosed. there is a small group of people who cannot handle two stroke engines and motorcycle maintenance. if this is the case, you may not be a candidate for Aprilia RS250's.

    Aprilia. Ask your doctor if the RS250 is right for you.

  10. #10
    apriliaforum newb
    Join Date
    Oct 2017
    Location
    Moscow
    Posts
    9
    So.. I must check my guesses about the float cameras in carbs. Left seal on crankshaft i also replaced by new one. It is sad, if the seals died in 15k kilometers. Next week i'll take 32mm vj22 carbs from working bike to replace mine and try to locate the problem.

  11. #11
    apriliaforum newb
    Join Date
    Oct 2017
    Location
    Moscow
    Posts
    9
    So.... if someone interested. I again checked carbs. Fuel level in it was 7.1 as in manual, but the float height was about 10mm. I fixed it to 8mm, so now the fuel level is much more as in instruction. But it suddenly works! The problem is solved. As i understood, last time, the fuel level was not enough to feed the pilot jet

  12. #12
    apriliaforum expert mcludd's Avatar
    Join Date
    Oct 2007
    Location
    North Yorks UK
    Posts
    1,346
    Nice to get a happy ending

  13. #13
    apriliaforum newb
    Join Date
    Feb 2018
    Location
    Sydney
    Posts
    27
    Q - how exactly do you measure and set the float height correctly on these carbs ? Sorry I've never done it (yet), but am about to.

    I have the manual and a micrometer, just what do I measure, from where, in what position exactly ? Picture or video pointers most welcome, Thank you

    Thanks

    Robert

  14. #14
    apriliaforum newb
    Join Date
    Oct 2017
    Location
    Moscow
    Posts
    9
    Hey, i use calipers for this. All information you can find in manual. Firstly i fix the fuel level as in manual by bending the tongue of float. I also printed a stand with 30 degree angle. But, as you know, it brought problems and the float level was about 10-11mm. So, now my fuel level is more than recommended. In future i would try to find the compromise between this requirements. I would gladly provide the photos, but I really don’t want to disassemble it again) Maybe later Click image for larger version. 

Name:	Новый точечный &#1.jpg 
Views:	11 
Size:	96.7 KB 
ID:	383797

Similar Threads

  1. Bad problems after rebuild.
    By SXV_BOOM in forum 2006-2011 Aprilia RXV, SXV, MXV 4.5/5.5 V-Twins
    Replies: 6
    Last Post: 11-02-2011, 12:37 AM
  2. problems after rebuild
    By TBW in forum 2006-2011 Aprilia RXV, SXV, MXV 4.5/5.5 V-Twins
    Replies: 9
    Last Post: 09-01-2011, 10:23 AM
  3. Slight problems after rebuild.
    By theoperators in forum RS50 Technical
    Replies: 42
    Last Post: 10-19-2009, 01:06 PM
  4. Need Help: 2 Problems after rebuild
    By RS250 Chester in forum RS250
    Replies: 7
    Last Post: 09-22-2008, 03:23 PM
  5. strange problem after rebuild, but solved it today
    By sherpaT in forum RS125 Euro-archive
    Replies: 2
    Last Post: 05-09-2005, 03:06 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •