Results 1 to 10 of 10

Thread: Scabby 200 Head gasket change Looking for TDC & Cam lobes

  1. #1
    apriliaforum Member
    Join Date
    Aug 2017
    Location
    Napa CA
    Posts
    133

    Scabby 200 Head gasket change Looking for TDC & Cam lobes

    I am doing a head gasket on a Scabby 200. I pulled cam gears out and got them mixed up I assume the A is for Intake and S is for exhaust (English to italian translation of intake and exhaust)

    Now for the second part, my service manual shows where there is notches in the flywheel for lining up TDC but my flywheel doesn't look the same. Obviously mine is the DOHC whereas i think the service manual shows the SOHC. Also where do you line up cams as well? Anyone have a picture? I know I can rotate the piston via flywheel to the top but how do I know which stroke its on?
    Here is mine
    Click image for larger version. 

Name:	IMG_0433.jpg 
Views:	48 
Size:	91.8 KB 
ID:	384012
    Here is service manual
    Click image for larger version. 

Name:	Flywheel.jpg 
Views:	45 
Size:	41.0 KB 
ID:	384013
    2016 Piaggio BV 350
    2008 Yamaha WR 250

  2. #2
    apriliaforum Member
    Join Date
    Aug 2017
    Location
    Napa CA
    Posts
    133
    Really could use some guidance here gang. Can anyone point me in a direction? I really want to get this scooter up and running ASAP


    Sent from my iPhone using Tapatalk
    2016 Piaggio BV 350
    2008 Yamaha WR 250

  3. #3
    apriliaforum expert
    Join Date
    Apr 2011
    Location
    Clearwater, Fl
    Posts
    8,225
    That engine has no balance shafts so there technically is no difference on the crank synchronization as far as the TDC of the Compression stroke or TDC of the Exhaust stroke is concerned. Its all dependent on the cam timing alone so you set the piston at TDC and then there should be lines or holes on the cam gear that align with some flat feature on the head such as the cam bearing cap joint.

    The mark on the flywheel may not be that distinct. Many times with my old eyes I can't really see them very well and can only find them after putting the piston at TDC and then checking for the mark. Many times the line might be a punch mark nearer to the rim of the flywheel. If I have the head off I will make my own more distinct mark if I can't find the one from the factory. On the 250 there is a timing port plug that screws out so you can see the mark without taking the side cover off the engine.

    The newer DOHC 4 Valve 200 is a different beast compared to the more traditional SOHC 4 Valve Piaggio built engines so I can only make general observations not having taken one apart personally.

  4. #4
    apriliaforum Member
    Join Date
    Aug 2017
    Location
    Napa CA
    Posts
    133
    Thanks Rocky!
    2016 Piaggio BV 350
    2008 Yamaha WR 250

  5. #5
    apriliaforum Member
    Join Date
    Aug 2017
    Location
    Napa CA
    Posts
    133
    Well I found TDC, and the mark on the flywheel, although it does not line up with the picture. The pictuire look like around 5:30, whereas mine is at about 1:30. So that that.

    Re: the cam gears, yes I agree there is usually some type of mark where you line things up. I cannot find any kind of mark. I have a light and magnifying glass and I dont see anything. I called local shop and they said the cam gears don't have any mark and I have to do some kind of punch thing? This was translated from service tech to guy on the phone and i think lots got lost in translation. So I dismissed that info. I fidn it hard to believe aprilia wouldnt have put some kind of mark on it. That makes no sense that they didnt
    I called a guy out here in NorCal, and he said to start intake valve at 2:00 and then set exhaust 11 pm, and fidget with that. That seems dangerous to me.

    Click image for larger version. 

Name:	IMG_0472.jpg 
Views:	9 
Size:	98.6 KB 
ID:	384219Click image for larger version. 

Name:	IMG_0475.jpg 
Views:	8 
Size:	102.0 KB 
ID:	384220Click image for larger version. 

Name:	IMG_0476.jpg 
Views:	8 
Size:	95.2 KB 
ID:	384221
    So pic one is what I am looking at, pic 2 is both cams facing out , and pic 3 is some kind of mark. but nothing specific about it
    2016 Piaggio BV 350
    2008 Yamaha WR 250

  6. #6
    apriliaforum Member
    Join Date
    Aug 2017
    Location
    Napa CA
    Posts
    133
    The gold marks I made prior to removal in attempts to maintain timing, but it didnt work
    2016 Piaggio BV 350
    2008 Yamaha WR 250

  7. #7
    apriliaforum Member
    Join Date
    Aug 2017
    Location
    Napa CA
    Posts
    133
    OK. I finally figured this out. THERE ARE timing marks, but the timing marks are on top not front or back. Here is what I am going to go with as it makes the most sense. There are 2 holes in the top of the head. Take one of the bolts that hold down the cam gears and insert it through the hole and turn cam gear until the bolt slots down in place. Do this on both sides. This seems to me to make sense as to where the cam gears are supposed to be. There seems to be a small bit of play but very little so I would think it should line up pretty well once I install it. Here goes!
    Click image for larger version. 

Name:	IMG_0479.jpg 
Views:	8 
Size:	99.1 KB 
ID:	384228Click image for larger version. 

Name:	IMG_0480.jpg 
Views:	8 
Size:	99.1 KB 
ID:	384229Click image for larger version. 

Name:	IMG_0481.jpg 
Views:	7 
Size:	98.6 KB 
ID:	384230
    2016 Piaggio BV 350
    2008 Yamaha WR 250

  8. #8
    apriliaforum expert
    Join Date
    Apr 2011
    Location
    Clearwater, Fl
    Posts
    8,225
    On page 122 of the service station manual for the Chinese Scarabeo 200 it shows that valve timing is set by placing 0.25 inch steel pins through the hole in each camshaft. If your manual shows a single cam then it may be for the older Piaggio engine and not the newer Chinese version. The Chinese engine has much higher compression DOHC design and eliminates the single cam lobe to two valve stem rocker arms typical of the Master and Legend SOHC engines which makes it so you loose the ease of adjustment that provides giving you a bucket shim between each of the valve stems and the cam as your means of valve gap adjustment instead.

    Did you purchase the manual from AF1? If so you may want to let them know that you appear to have gotten linked to the wrong one. Actually regardless of which dealer you purchased the manual from let them know so they can get you linked to the correct one.

  9. #9
    apriliaforum Member
    Join Date
    Aug 2017
    Location
    Napa CA
    Posts
    133
    Well gang I wish I had a great story to tell you of how I got this engine running, but I cannot. I committed the biggest mistake of all. I went about putting my engine back together and made sure my torque settings were correct and proceeded to crank things down. I set my torque wrench to the proper setting and after a few turns without hearing the click, i went one further waiting for the click. I never heard the click but i heard the snap. The snap was the head bolt snapping in two. And unfortunately I was not able to back out the half in the engine casing. So now I have a 2008 Scabby with lots of parts to sell. See my next thread in the sales section
    2016 Piaggio BV 350
    2008 Yamaha WR 250

  10. #10
    apriliaforum expert
    Join Date
    Apr 2011
    Location
    Clearwater, Fl
    Posts
    8,225
    Fast - That's usually not the end of the world. Yes you likely will have to now drain the coolant and remove the head and possibly the cylinder too which should expose enough of the head bolt to get a "GOOD" pair of Vice Grips on it but that should be do-able. Even if it broke off flush in the engine case you just stuff a rag in the top of the engine around the con rod to catch and metal burs, grind the broken stud flush, center punch it, drill it and take it out with an extractor.

    You are talking about one of the four M8X166 bolts. I really prefer studs to bolts since with the stud the wear and tear when you tighten them is mostly to the threads on the stud and not the threaded hole in the crankcase. If you were closer I'd be more than happy to come by and assist.

    I have multiple click style torque wrenches however after I set them I use my old beam indicator torque wrench to double check the accuracy of the setting. On more than one occasion I have had a clicker bind up and end up at over 100 lbs when the setting ring only showed 10 or 20 lbs. It even happens with the more expensive clickers and is not limited to just the bargain brands so I do not have much faith in the clickers and keep going back to the old fashioned beam and pointer style.

    I prefer the Lisle Extractors
    https://www.amazon.com/Lisle-62900-E...s%2C188&sr=8-1


    My beam style torque wrench is a Craftsman 1/2 inch model that I bought about 50 years ago for around $25 so I would say it would be a $55 to $80 wrench today something equivalent to these:
    https://www.amazon.com/GearWrench-29...%2C186&sr=8-25
    Last edited by Rockynv; 07-14-2019 at 10:19 PM.

Similar Threads

  1. Going rate for head gasket change?
    By Brian_M in forum RST1000 Futura (all years)
    Replies: 13
    Last Post: 09-25-2009, 09:26 PM
  2. Head Gasket Change Questions
    By kingjtthompson in forum RSV1000 Mille, Mille R, and Mille SP (1998-2003)
    Replies: 14
    Last Post: 03-07-2009, 07:03 PM
  3. Looking for a stock head...
    By Cheshire in forum RS250
    Replies: 2
    Last Post: 08-22-2006, 03:51 PM
  4. looking for rs250 head,2004
    By cobra96461 in forum RS250
    Replies: 4
    Last Post: 03-28-2006, 01:12 AM
  5. Help Needed to change Head Gasket
    By bill stevens in forum Pegaso 650 Cube and IE
    Replies: 9
    Last Post: 06-26-2002, 03:11 PM

Posting Permissions

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