Kykdaar
Grey Hound
- Joined
- Sep 14, 2007
- Messages
- 7,610
- Reaction score
- 3
- Location
- Wingate Park - Pretoria
- Bike
- Zundapp (all models)
Recently my TA started acting funny :
At full throttle she runs like da bomb. Throttle down (e.g. for an obstacle) and throttle up again and she stutters and surges in the mid-range until she is at full throttle again.
Sometimes if you start her up and shift through the gears at low throttle openings she runs fine at any low to mid- throttle position. As soon as you open her to full throttle and then close it down, however, the above symtoms re-appear at low and mid-throttle again.
It is driving me UP THE FRIKKEN WALL :dousing:
This is what I have done so far -
Fuel -
1. Overhauled the carbs - No half measures with me ;D I can guarantee you that the jets / float / float needle / pistons & diaphragms / main needles, ect are bog standard, perfect condition and spotlessly clean.
2. Ran a temporary gravity bottle-fed fuel delivery to observe the carburetor pistons in action. No sticking and no discernable loss of vacuum. Throttle valves were working in unison and carbs appeared balanced as far as I can tell with the naked eye (I never tampered with the balance adjustment in any event).
3. Checked choke cable / plungers. Works and not sticking- If the bike is at operating temp and you engage the choke she dies.
4. Checked the supply of fuel under vacuum from the tank. Works perfectly (rear cylinder supplies the vacuum and connecting pipe is not cracked and is dry inside).
4. Checked petrol delivery to carbs with engine running (drains constantly) through the drain opening so no fuel starvation at the carbs.
Spark
1. Fitted 4 new standard plugs.
2. Checked spark of each with the plug in the lead and held a few millimetres away from the frame. Spark so strong you can weld with it. Removal of any plugcap results in a noticable difference to the running of the engine - so no duds and thus coils (X2) also works as well.
Service
Did 12000km service -
1. New plugs
2. New air filter
3. New oil
4. New oil filter
Heard what sounded like a backfire just behind the rear cylinder and found a small round hole just above the clamp in the mid portion of the exhaust. If you hold your hands a few centimetres away you can feel it blow. I will get that fixed, but surely that can not be the cause of this problem?
Please - oh wise dogs. What have I missed? I have done all your average home mechanic can do, but I can't pin this %@$%%^%$^& fault down.
Some pics below.
At full throttle she runs like da bomb. Throttle down (e.g. for an obstacle) and throttle up again and she stutters and surges in the mid-range until she is at full throttle again. Sometimes if you start her up and shift through the gears at low throttle openings she runs fine at any low to mid- throttle position. As soon as you open her to full throttle and then close it down, however, the above symtoms re-appear at low and mid-throttle again.
It is driving me UP THE FRIKKEN WALL :dousing:
This is what I have done so far -
Fuel -
1. Overhauled the carbs - No half measures with me ;D I can guarantee you that the jets / float / float needle / pistons & diaphragms / main needles, ect are bog standard, perfect condition and spotlessly clean.
2. Ran a temporary gravity bottle-fed fuel delivery to observe the carburetor pistons in action. No sticking and no discernable loss of vacuum. Throttle valves were working in unison and carbs appeared balanced as far as I can tell with the naked eye (I never tampered with the balance adjustment in any event).
3. Checked choke cable / plungers. Works and not sticking- If the bike is at operating temp and you engage the choke she dies.
4. Checked the supply of fuel under vacuum from the tank. Works perfectly (rear cylinder supplies the vacuum and connecting pipe is not cracked and is dry inside).
4. Checked petrol delivery to carbs with engine running (drains constantly) through the drain opening so no fuel starvation at the carbs.
Spark
1. Fitted 4 new standard plugs.
2. Checked spark of each with the plug in the lead and held a few millimetres away from the frame. Spark so strong you can weld with it. Removal of any plugcap results in a noticable difference to the running of the engine - so no duds and thus coils (X2) also works as well.
Service
Did 12000km service -
1. New plugs
2. New air filter
3. New oil
4. New oil filter
Heard what sounded like a backfire just behind the rear cylinder and found a small round hole just above the clamp in the mid portion of the exhaust. If you hold your hands a few centimetres away you can feel it blow. I will get that fixed, but surely that can not be the cause of this problem?
Please - oh wise dogs. What have I missed? I have done all your average home mechanic can do, but I can't pin this %@$%%^%$^& fault down.
Some pics below.
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