thesickness Posted May 29, 2011 Posted May 29, 2011 I bought a basket case tzr50 2007. The bike was used and abused to say the least, no electrics whatsoever, water had got in everywhere..Painstakingly gone through electrics, now I have all electrics (excluding headlights/taillights) but I have a good spark and the starter is spinning well...I have rebuilt top end new piston, rings, and gaskets. had carb to bits all looks good, no blocked jets, bowl fills with fuel. Reed valve appears to be ok. Turns over but refuses to start, seems that no fuel is getting to piston (if I put my finger in exhaust port no petrol, just oil I used on assembly)Thanks in advance if you could offer any advice. Oh I put the piston rings in with concave edge facing up, as no markings or instructions... if I put my hand over air intake on carb it feels like its sucking..
Moderator Airhead Posted May 29, 2011 Moderator Posted May 29, 2011 What about the choke, I dont know the bike or the carb but it wont start without a choke ? Edit you put your hand over intake of carb so is the airbox disconnected?, this may also upset matters greatly
thesickness Posted May 29, 2011 Author Posted May 29, 2011 What about the choke, I dont know the bike or the carb but it wont start without a choke ? Edit you put your hand over intake of carb so is the airbox disconnected?, this may also upset matters greatly tried choke/ no choke. Carb has 2 adjustment screws on side, I guess idle speed and fuel air ratio, tried adjusting these as well, nothing, not a single sign of life. Airbox is disconnected, did try it with airbox connected but not for long, just seems not a drop of fuel to cylinder...
Moderator Airhead Posted May 29, 2011 Moderator Posted May 29, 2011 You should have airbox connected and filter insitu, choke ON and little or no throttle opening, set the mixture about 1 1/2 turns out at a guess...at least the plug should show signs of wetness even if it didnt start I think it's a fuel related issue Where is the reed inlet attached, barrel or direct to case?
thesickness Posted May 29, 2011 Author Posted May 29, 2011 You should have airbox connected and filter insitu, choke ON and little or no throttle opening, set the mixture about 1 1/2 turns out at a guess...at least the plug should show signs of wetness even if it didnt start I think it's a fuel related issue Where is the reed inlet attached, barrel or direct to case? Reed valve direct to case, thanks for your time..
thesickness Posted June 5, 2011 Author Posted June 5, 2011 Ok, I tested compression today, hardly registered until I put a glug of 2 stroke down barrel then I got a reading of 70psi...So I guess I should have bought a new barrel as well....
Moderator Airhead Posted June 5, 2011 Moderator Posted June 5, 2011 Ok, I tested compression today, hardly registered until I put a glug of 2 stroke down barrel then I got a reading of 70psi...So I guess I should have bought a new barrel as well.... might not need a new barrel but you'll have to take it off to see that. Perhaps the rings are gummed up in their grooves, if they are get some new rings of the correct size.
thesickness Posted June 5, 2011 Author Posted June 5, 2011 might not need a new barrel but you'll have to take it off to see that. Perhaps the rings are gummed up in their grooves, if they are get some new rings of the correct size. took it off, piston and rings are new, looks like barrel is as large in places as 40.06mm limit according to book is 40.03, so i'm assuming this is the problem...should of noticed this first before rebuilding...
Tuesday Posted June 5, 2011 Posted June 5, 2011 If it is poor compression, I would expect it to be hard to start but at least show some signs of life. The lack of petrol mixture being pulled through the engine is a big clue though. Crank seals,Bottom Barrel gasket? Unlikely but is it possible the spark timing is wrong (Don't know if it is adjustable on this engine)
Moderator Airhead Posted June 5, 2011 Moderator Posted June 5, 2011 If it is poor compression, I would expect it to be hard to start but at least show some signs of life. The lack of petrol mixture being pulled through the engine is a big clue though. Crank seals,Bottom Barrel gasket? Unlikely but is it possible the spark timing is wrong (Don't know if it is adjustable on this engine) fair point but with hardly any compession suction will also suffer badly?
thesickness Posted June 5, 2011 Author Posted June 5, 2011 I'm sorry I failed to point out a big thing .... after cranking all day without a sniff of petrol or any sign of life I decided to strip down as I noticed a big hole under the exhaust port in the crankcase, the head gasket catered for this but the barrel didnt?? So im thinking "ahh hole/airleak in crankcase" took off the barrel and it appeared the hole only vented to a slot in the bottom of the case, not internally to the case...put back together, refitted reed and carb, a good old glug of oil down the barrel, turned over.....petrol pouring out the exhaust port like a tap, can only assume the oil increased compression enough to draw fuel through....as i said before a 2 stroke novice..
Moderator Airhead Posted June 5, 2011 Moderator Posted June 5, 2011 I'm sorry I failed to point out a big thing .... after cranking all day without a sniff of petrol or any sign of life I decided to strip down as I noticed a big hole under the exhaust port in the crankcase, the head gasket catered for this but the barrel didnt?? So im thinking "ahh hole/airleak in crankcase" took off the barrel and it appeared the hole only vented to a slot in the bottom of the case, not internally to the case...put back together, refitted reed and carb, a good old glug of oil down the barrel, turned over.....petrol pouring out the exhaust port like a tap, can only assume the oil increased compression enough to draw fuel through....as i said before a 2 stroke novice.. Hardly thin petrol would pour through like a tap...this would be the oil slug more likely. still no sign of life then?
thesickness Posted June 5, 2011 Author Posted June 5, 2011 Hardly thin petrol would pour through like a tap...this would be the oil slug more likely. still no sign of life then? the petrol was pouring through so much i had to put a bucket undrneath to catch it, still not a sign of life, not a burp or splutter....
blackhat250 Posted June 5, 2011 Posted June 5, 2011 Get that carb off , its obviously in need of inspection, float valve sticking if as much fuel as that coming thru. your heading for hydraulic lock , if you keep pouring that oil in big quantities like that, along with the crankcases being full of fuel. ,
Moderator Airhead Posted June 5, 2011 Moderator Posted June 5, 2011 sounds to me your crank is full of fuel...or coolant
Recommended Posts