Post by snaphappyalex on Mar 19, 2013 8:10:38 GMT -5
Hey there guys, I used to roam the Scootdawg forums about 2 years ago 
Currently got one of these BT49QT-9 sorta scoots, ANYWAY it's the engine im gunna be talking about so I suppose the shape and brand is irrelevant as the 50's share the same 4stroke gy6 clone motor usually.
So, I'll walk you through the issues im having from the start...
I'll start my bike up from cold and it'll fire right up and idle fine, rev up fine, and act normal. I'll ride her around for about 15 minutes and for the first 5 minutes, she's sluggish as anything until the variator runs out of gearing at about 28mph, then the revs audiably pick up and the bike gains a bit of power (I know the rollers are too heavy) and she'll be quite content to sit at about 32mph on the flat, Go 40odd on a very slight downhill, and 24mph on a very slight uphill...
So say we've now been out on the bike 15 minutes, and I have a long straight ahead of me. I'll stay pinned at full throttle for about a minute and build up to about 35mph on the flat, after about another minute, she'll begin to hezitate and bog every few revs bringing it down to 25mph, if I let off the throttle at all then revs drop instantly and bog if you try to bring them back up, After teasing the throttle in the first 1/4 turn for a few seconds, she'll spring back to life as if nothing ever happened...
Now to me this would seem like a 'Rich issue' (She's just had a new plug too) yet the plug contradicts me, The plug I removed was white/grey with ash deposits, But it's all stock standard. Exhaust hasnt corroded through anywhere but the EGR system is leaking slightly as the rubber piping has perished, however I wouldnt have imagined this to mess up the mixture massively.
I must admit, these motors are pretty revvy! if I get on a nice downhill bit, she'll do 48-50 and bounce off the clocks once the revs have built up, But if I hold it, I'll still get the bogging.
Any ideas here guys? she's all standard and only 3 years old
Currently got one of these BT49QT-9 sorta scoots, ANYWAY it's the engine im gunna be talking about so I suppose the shape and brand is irrelevant as the 50's share the same 4stroke gy6 clone motor usually.
So, I'll walk you through the issues im having from the start...
I'll start my bike up from cold and it'll fire right up and idle fine, rev up fine, and act normal. I'll ride her around for about 15 minutes and for the first 5 minutes, she's sluggish as anything until the variator runs out of gearing at about 28mph, then the revs audiably pick up and the bike gains a bit of power (I know the rollers are too heavy) and she'll be quite content to sit at about 32mph on the flat, Go 40odd on a very slight downhill, and 24mph on a very slight uphill...
So say we've now been out on the bike 15 minutes, and I have a long straight ahead of me. I'll stay pinned at full throttle for about a minute and build up to about 35mph on the flat, after about another minute, she'll begin to hezitate and bog every few revs bringing it down to 25mph, if I let off the throttle at all then revs drop instantly and bog if you try to bring them back up, After teasing the throttle in the first 1/4 turn for a few seconds, she'll spring back to life as if nothing ever happened...
Now to me this would seem like a 'Rich issue' (She's just had a new plug too) yet the plug contradicts me, The plug I removed was white/grey with ash deposits, But it's all stock standard. Exhaust hasnt corroded through anywhere but the EGR system is leaking slightly as the rubber piping has perished, however I wouldnt have imagined this to mess up the mixture massively.
I must admit, these motors are pretty revvy! if I get on a nice downhill bit, she'll do 48-50 and bounce off the clocks once the revs have built up, But if I hold it, I'll still get the bogging.
Any ideas here guys? she's all standard and only 3 years old
