Nearly-terminal motor please help.

ChildOf*RGV · 20-07-2008, 05:01 AM

I was riding to work the other day down the highway - doin about a buck eighty when all of a sudden she just died, complete loss of power.. It managed to run on idle and i limped it to a servo, but when i pulled up it stalled completely... Got it home on a trailer, and i CAN start it but it wont rev over idle (idles lower than usual) and the tiniest twist of the throttle makes it stall out completely... I just cleaned the carbs out 3 days prior and its been running sweet! Really hoping its nothing too serious, has anyone encountered a problem like this at all? Its a 1991 RGV with a '94 motor.
Top cylinder has good compression, but i cant feel any in the bottom one.. Cant get the gauge to read at all and putting finger over plug hole i feel nuttin...
Removed the cylinder and piston only has slight burr to top edge, and only slight scuff in the cylinder near the ports.. Otherwise is fine??!!? Can someone tell me what the fuck is wrong, and why no compression? Thanks.

arwon · 20-07-2008, 07:14 AM

might have been running lean and melted the top of the piston, at that speed over distance, it will not be good. 2strokes are good at getting up to speed but not sustaining it. You won'y know until you strip it down and if it is stuffed check the other piston then the oiling system.

Melted does not mean a puddle of metal but deformed and holding rinds in right up to hole in piston.

either way, get the spanners out.

ChildOf*RGV · 20-07-2008, 07:21 AM

Like i said its not too bad, heres a pic... Does this look bad enuf to have caused it?

Jamathi · 20-07-2008, 08:06 AM

Pic is a wee bit blurry, but looks like the piston/rings have nipped up and need to be replaced.
Bore should be inspected.
there are many reasons why it could have happened.
Some of them are;
Lack of oil/lubrication, to lean/hot, fatiguge of piston/rings/topend bearing.
try to have a look at all the tell tales and eliminate them out to come to the cause of it.
If you only have to replace the piston, replace both.
For a excelent supply of Suzuki parts go to;
Mick Hone Motorcycles
715 Whitehorse Road
Box Hill
98900304. Steve Hunter.
Good Luck!

ChildOf*RGV · 20-07-2008, 08:21 AM

Thanks for your thoughts Bert, knew it wouldnt take you long... Yeah i'll continue disassembly and inspection till i hopefully find a reason. BTW, hows the west coast treatin ya? Im disappointed that i bailed before we could grab that beer mate, but theres always a chance that Woodside will bump the payrate up and ill be back to milk 'em!

Jamathi · 20-07-2008, 08:27 AM

Kevin Fn Crudd and his Green paper might come in between a possible meet.
Unbelievable how Australia has gone from a Booming economy to a recession fighting economy! in a period of 7mnds!!!
Some how I remember vaguely something like ;
"I'll look after the fuel prices, the food prices, the morgage rates and keep you people in employ with better pay and contiotions"
AND; The Buck stops with ME!
40 billion of new investments are in jepordy just with 2 of the gas projects about to start construction!

ChildOf*RGV · 20-07-2008, 09:01 AM

Hey Bert, while i got you here - a question.. Got myself a 22D30 sapc to replace my restricted job, im already running 34mm carbs - so whats the procedure? Do i just unplug the old one and plug in the newie and rock on? Or will the carb settings have to be changed etc? Just my luck it arrived in the mail the day I killed my poor bike LOL!

druu · 20-07-2008, 10:14 AM

Just make sure you're running 270 left, 280 right main jets, unplug battery, plug up new SAPC, replug batt and away you go.

From what I've read, the carbs and SAPC are the only differences between restricted and unrestricted, but I could be wrong.

ChildOf*RGV · 20-07-2008, 10:17 AM

i take it 270 and 280 aint the stock jet sizes??

druu · 20-07-2008, 01:21 PM

270 left and 280 right are the stock jet sizes for 34mm carbs. Just be sure you have those.

rgvlee · 21-07-2008, 09:18 AM

hard to tell from pic but that piston looks naff. looks like it's taken out the edge of the crown and seizure marks along the piston walls below the rings.

ChildOf*RGV · 22-07-2008, 08:55 PM

Yeah, think you're right Lee.. I got another cylinder lyin around, ill grab some new pistons n rings n throw that lot in see how that goes..

rgvlee · 23-07-2008, 10:15 AM

I would be interested to know why it has nipped up. I would be checking the oil pump and oil lines, also inspect the head gasket. I have seen water do that kind of damage before.

Doesn't look like it was running lean otherwise we'd see a hole in the piston. What is the head combustion face like? Smooth or lots of small chips? What was the spark plug like?