|
Post by jpohlic on Apr 17, 2018 20:19:31 GMT -5
I have a 2005 Piaggio Typhoon 50 2T, completely stock, with 2277km on it. A year and a half ago in late fall I rode out of my garage, down the alley and turned on to the street where I gave it full throttle and it almost completely died. There was a horrible racket - it sounded like something let go inside the engine - and there was a sudden and significant power loss. It didn't die completely but continued to run roughly although it did not make enough power to move the bike. I shut it off and walked it back to the garage where its been parked ever since. I did try and start it a few times after but it was difficult to start and it ran very roughly. I finally started tearing the top end apart expecting to find evidence of a catastrophic failure but the piston, rings, and connecting rod are intact, and the wrist pin and bearing look good. There is some evidence of blow-by but not too bad, the piston crown is uniformly covered in black deposits, the underside of the piston crown shows some black deposits also, the sides of the piston are smooth to the touch but there are faint marks that may indicate a soft seize. Cylinder walls are smooth to the touch with no visible damage, hone marks are still visible. Exhaust port has some buildup but does not appear significant. I have quickly looked at the bottom end, everything turns smoothly, bearings do not appear to have any excessive play, but I have not taken it apart. I'm fairly new to 2 strokes, having only rebuilt a chainsaw once. Does this sound like it seized? Would a new piston/rings fix it? Do I need to pull the bottom end apart? Anything else I should check?
|
|
|
Post by oldgeek on Apr 17, 2018 20:48:00 GMT -5
Interesting symptoms your scoot is having. One thing to try is to remove the flywheel and check to see that the stator or pickup are not loose or something like that. As you have already found out the cylinder, piston and plug look pretty good.
|
|
|
Post by 'O'Verse on Apr 17, 2018 21:11:16 GMT -5
Since the bottom and top end look good. Look inside the cases at the crank for any metal on metal signs or foreign material. I'd also take your cvt cover off. Look around in there.
|
|
|
Post by stepthrutuner on Apr 18, 2018 2:38:26 GMT -5
Check the reeds too.
|
|
|
Post by jpohlic on Apr 18, 2018 11:21:36 GMT -5
Well, I took the CVT cover off and found some damage to the plastic variator fan and a few bits of plastic inside. Everything seemed tight - the nut was not loose. I pulled the variator out and apart from two scratches on the variator face everything looks ok. Can I sand these down with emery cloth or should I get a new variator? The belt looks ok, the kickstart mechanism looks ok, To check the reeds I'll need to get a torx bit for the intake as mine do not work with the tamper proof bolts. I'll also pull the flywheel and check behind that.
|
|
|
Post by jpohlic on Apr 18, 2018 15:02:23 GMT -5
OK, so I got a different torx bit and pulled the intake off and the reeds are good. Looking down into the case I did not see any evidence of metal shavings or anything out of the ordinary. Unfortunately none of my gear pullers work on this flywheel so if I want to tear it down completely I'll have to order the flywheel puller.
I think I'll put the engine back together and make myself a leak tester and see if there are any leaks, maybe check the compression as well... probably should have done that first.
|
|
|
Post by jbjhillbilly on Apr 19, 2018 12:06:45 GMT -5
Do not reuse the old wrist pin. Use a new wrist pin when you put it back together.
|
|
|
Post by jpohlic on Apr 23, 2018 12:49:10 GMT -5
I ordered a variator fan, gasket set and new C-clips but did not get a new wrist pin.
When I tore it apart there was no head gasket??? Did it come like this from the factory or did a previous owner forget to install one? I can't imagine the engine has been opened before as the scoot only had about 600km when I bought it.
My wife managed to find an old sphygmomanometer at work so I've started building a leak tester
|
|
|
Post by pinkscoot on Apr 23, 2018 13:42:45 GMT -5
|
|
|
Post by jpohlic on May 24, 2018 16:13:27 GMT -5
Could it have been a fuel starvation issue that caused my initial problems???
Engine is back together. I have a good spark, over 70 volts out of the ignition system. Carb was cleaned. Fuel petcock works however there doesn't seem to be enough vacuum from the carb to open it. I put my hand over the air intake and there is plenty of vacuum there. I turned it over for a bit and it sputtered briefly!!!
After finding some tape I covered the air intake about 75% and fired it up again. It started fine and idled ok, so I took the tape off and it ran great...too great though as it seemed like it was going full throttle at idle, so I had to hit the kill switch. I tried starting it a few more times and same thing, racing at idle. I haven't changed any of the carb settings, so why is it racing like this?
Anyway, I'm excited that it's not a basket case and hope I can get a ride in soon.
edit: I should add that I'm running the stock airbox and filter and the brass restrictor plate is in the carb, its a Dellorto 17.5
|
|
|
Post by islandscrub on May 24, 2018 16:40:10 GMT -5
Sounds like not enough fuel.
Put some vacuum on the petcock hose manually, see if the flow is good. Keep the hose under vacuum ( i just suck and stick my finger on it) then try and start it with the tape off the airbox and see if the idle is still high.
|
|
|
Post by pinkscoot on May 24, 2018 19:39:31 GMT -5
You have a lean condition that's why it runs fine with the air cut off. Either an air leak some place or too small of a jet. The brass plate your talking about is it in the float bowl under the jet? Remove it, I hear they just cause trouble. What jets are you running? Does your carb have the 2 stroke atomizer?
|
|
|
Post by jpohlic on May 24, 2018 21:39:11 GMT -5
Sounds like not enough fuel. Put some vacuum on the petcock hose manually, see if the flow is good. Keep the hose under vacuum ( i just suck and stick my finger on it) then try and start it with the tape off the airbox and see if the idle is still high. I tried the petcock manually and it was good. I tested the scoot this way and it still idled high
|
|
|
Post by jpohlic on May 24, 2018 21:41:03 GMT -5
You have a lean condition that's why it runs fine with the air cut off. Either an air leak some place or too small of a jet. The brass plate your talking about is it in the float bowl under the jet? Remove it, I hear they just cause trouble. What jets are you running? Does your carb have the 2 stroke atomizer? The bike is completely stock, I haven't changed anything. The restrictor plate is between the airbox and the carb - I ran without it for a few hundred km when I first got the scoot and noticed no difference in performance so I put it back in.
|
|
|
Post by jpohlic on May 24, 2018 21:49:54 GMT -5
So I left the tape over 75% of the intake and idled the engine. After a minute or two the idle slowed right down, almost stalled, so I pulled the tape off and now it seems to run normally. It starts great, idle seems ok and it revs up pretty good with some throttle and idles back down smoothly. I think tomorrow I'll put the seat back on and do a road test.
This one has me stumped but I'm thinking it was a petcock issue, working intermittently, or possibly a clogged fuel filter. I flushed the tank and the petcock with fresh fuel so hopefully its good to go. If I still have issues I might drill out the petcock and get rid of the vacuum and go with a gravity feed - I never had issues like this with my other motorcycles
|
|