skullarms Posted July 14, 2008 Posted July 14, 2008 Hi all, finally got my TR1 back together but it wont start, turns over and blows back through the carbs, these have been taken apart and cleaned etc and look fine, any ideas?? Thanks in advance for any help. Andy
yoda Posted July 14, 2008 Posted July 14, 2008 Hi all, finally got my TR1 back together but it wont start, turns over and blows back through the carbs, these have been taken apart and cleaned etc and look fine, any ideas?? Thanks in advance for any help. Andy I think your ignition timing is way out.
Moderator drewpy Posted July 14, 2008 Moderator Posted July 14, 2008 I think your ignition timing is way out. or you mixed up the coils if there are two single ones
Moderator Airhead Posted August 19, 2008 Moderator Posted August 19, 2008 Hi all, finally got my TR1 back together but it wont start, turns over and blows back through the carbs, these have been taken apart and cleaned etc and look fine, any ideas?? Thanks in advance for any help. Andy What blows back through the carbs, is it smoke, is it firing, Have you checked is it sparking?
skullarms Posted August 19, 2008 Author Posted August 19, 2008 What blows back through the carbs, is it smoke, is it firing, Have you checked is it sparking? It is sparking fine, but not firing, and as it turns over it blows the carb off its mounting rubber!!! I cannot see any smoke, or smell anything, maybe a little petrol but thats all, I am using unleaded will that make a difference??
Moderator Airhead Posted August 19, 2008 Moderator Posted August 19, 2008 It is sparking fine, but not firing, and as it turns over it blows the carb off its mounting rubber!!! I cannot see any smoke, or smell anything, maybe a little petrol but thats all, I am using unleaded will that make a difference?? Sound like youve got a serious leak through an inlet valve, i dont know the bike or how many cylinders it has, but does it only do it on one cyl? Obviously its that one thats leaking, as the compressed gasses hit the closed slide on the carb in question it blows the carb off its mount
skullarms Posted August 20, 2008 Author Posted August 20, 2008 It is sparking fine, but not firing, and as it turns over it blows the carb off its mounting rubber!!! I cannot see any smoke, or smell anything, maybe a little petrol but thats all, I am using unleaded will that make a difference?? It's a v twin and its the rear cylinder thats blowing the carb off, twin carbs, one for each cylinder, I have checked and re-checked the valve timing and the rocker gaps, these seem fine!!
Moderator Airhead Posted August 20, 2008 Moderator Posted August 20, 2008 It's a v twin and its the rear cylinder thats blowing the carb off, twin carbs, one for each cylinder, I have checked and re-checked the valve timing and the rocker gaps, these seem fine!! Well the valves may well be closed but something's getting past it to blow the carb off its mount so it must be passing very badl. Can you spin the motor with the killswitch on, if it blows off it must be the compressed gasses that are doing this. From TDC on the problem cylinder with both valves closed if you turn the engine in its normal direction then the first valve to open should be exhaust, can you confirm this.
fosdyke Posted August 20, 2008 Posted August 20, 2008 Well the valves may well be closed but something's getting past it to blow the carb off its mount so it must be passing very badl. Can you spin the motor with the killswitch on, if it blows off it must be the compressed gasses that are doing this. From TDC on the problem cylinder with both valves closed if you turn the engine in its normal direction then the first valve to open should be exhaust, can you confirm this. Only a couple of things this could be - 1. Either you have your timing out 180 degrees either by having the timing marks set up wrong or the ignition wired incorrectly. 2. You have blowback because the inlet valve is not closing completely on the compression stroke. A leak down test will pinpoint exactly - but you probably don't have the equipment - but if you have a compression tester use that and see what the compressions are on these cylinders - they should be at least 100 psi. You say you have 'got it back together' so I am assuming that you did a major rebuild - check everything you did when you reassembled - and check it again - make sure you put the cams back on in the right order, double check the ignition timing, check the valve clearances, check the wiring. It has to be one of these, took me a couple of weeks to diagnose a blowback problem on my kwak to a shim problem - runs fine now. Good luck.
skullarms Posted August 25, 2008 Author Posted August 25, 2008 Only a couple of things this could be - Hi all thanks for your time! OK have checked the wiring and thats fine, the coils are connected to the correct cylinders and the valves appear to be closing completely, valve clearances checked OK, have not checked whether the exhaust valve is the first to open after TDC will be checking that today In the manual (Haynes) for setting this up it tells me to get the piston to TDC but doesnt specify this has to be on compression stroke, could that be my problem? that would make it 180 degrees out right? Will be checking all this today and will let you all know Again, thanks for all your help guys! 1. Either you have your timing out 180 degrees either by having the timing marks set up wrong or the ignition wired incorrectly. 2. You have blowback because the inlet valve is not closing completely on the compression stroke. A leak down test will pinpoint exactly - but you probably don't have the equipment - but if you have a compression tester use that and see what the compressions are on these cylinders - they should be at least 100 psi. You say you have 'got it back together' so I am assuming that you did a major rebuild - check everything you did when you reassembled - and check it again - make sure you put the cams back on in the right order, double check the ignition timing, check the valve clearances, check the wiring. It has to be one of these, took me a couple of weeks to diagnose a blowback problem on my kwak to a shim problem - runs fine now. Good luck.
skullarms Posted August 27, 2008 Author Posted August 27, 2008 Hi all, Finally got my TR1 to fire and run, for a little while, she was idling ok (no exhausts on so flames shooting out!!) i turned her off, but when i tried to re-start the starter motor didnt seem to turn the engine, just made a whiny noise, then turned a little, then whiny noise again! Any ideas guys??
Moderator Airhead Posted August 27, 2008 Moderator Posted August 27, 2008 Hi all, Finally got my TR1 to fire and run, for a little while, she was idling ok (no exhausts on so flames shooting out!!) i turned her off, but when i tried to re-start the starter motor didnt seem to turn the engine, just made a whiny noise, then turned a little, then whiny noise again! Any ideas guys?? Hey come on, share the secret...What was wrong with the blowback problem? As for starter, take it off and mahe sure the gear is free on the shaft (Thats if its anything like a car one)
skullarms Posted August 28, 2008 Author Posted August 28, 2008 Hey come on, share the secret...What was wrong with the blowback problem? As for starter, take it off and mahe sure the gear is free on the shaft (Thats if its anything like a car one) Ah the mysterious blowback problem, well I would love to tell you that with all my technical knowledge and mechanical skills I fixed it, but the truth is I just did what you said, checked, and re-checked, I took the carbs off again and cleaned them, again, I cleaned every single bloody connector on the wiring loom I could find, I swapped the coils over, no difference, so it wasn't that one, and I re-set the cam timing, although it was fine anyway, so the truth is I don't know!!!
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