Hi all.
A Blaster newbie here. I recently found a good deal on a Blaster and my cousin went and picked it up for his son. It ran okay and everything was in check (besides the front bar being bent and plastic fractures). But the engine noise was described by my cousin as a pinging noise but when I heard it, it sounded more like piston slap.
Nonetheless, I pulled the exhaust off and shone a torch into the cylinder and right there was a chipped piston. Then I took the head off and surprisingly it was in not too bad shape. Just a very small nick but otherwise in good shape. Then I took the cylinder off and revealed a piston ring had snapped (about 1/4 of it was missing) and the other one was stuck in the piston. There is also some knicks around the exhaust port where the ring must have hit before breaking off. So it's impressive it still ran (although quite poorly). So I need a full top end done and I think my options are:
1. Use current cylinder and get it honed and ported near the exhaust port, and use Yamaha Genuine parts.
2. Use current cylinder (same as work as point 1) and use a aftermarket piston (probably Wiseco but they're not significantly cheaper than Genuine Yamaha)
3. Use an eBay cylinder kit including piston (No idea who makes it but likely to be sourced from China).
I have emailed two local shops (on that specializes in 2 strokes) to get a quote to freshen up the cylinder. But pending their prices I'll have to gauge where to go.
Another option is to overbore but I'd prefer to stay with stock for maximum reliability.
I measured the cylinder with two sets of calipers (digital and normal) and they were 65.58 and 65.6mm respectively, measured just under the 2nd ring. So I'm guessing that's stock bore.
Has anyone on here had experience with those eBay cylinders? Best overbore?
I tried searching the forum but didn't have much luck.
I also have to look at the brakes (they're very very bad) bit I thought I'd get the engine done first.
A Blaster newbie here. I recently found a good deal on a Blaster and my cousin went and picked it up for his son. It ran okay and everything was in check (besides the front bar being bent and plastic fractures). But the engine noise was described by my cousin as a pinging noise but when I heard it, it sounded more like piston slap.
Nonetheless, I pulled the exhaust off and shone a torch into the cylinder and right there was a chipped piston. Then I took the head off and surprisingly it was in not too bad shape. Just a very small nick but otherwise in good shape. Then I took the cylinder off and revealed a piston ring had snapped (about 1/4 of it was missing) and the other one was stuck in the piston. There is also some knicks around the exhaust port where the ring must have hit before breaking off. So it's impressive it still ran (although quite poorly). So I need a full top end done and I think my options are:
1. Use current cylinder and get it honed and ported near the exhaust port, and use Yamaha Genuine parts.
2. Use current cylinder (same as work as point 1) and use a aftermarket piston (probably Wiseco but they're not significantly cheaper than Genuine Yamaha)
3. Use an eBay cylinder kit including piston (No idea who makes it but likely to be sourced from China).
I have emailed two local shops (on that specializes in 2 strokes) to get a quote to freshen up the cylinder. But pending their prices I'll have to gauge where to go.
Another option is to overbore but I'd prefer to stay with stock for maximum reliability.
I measured the cylinder with two sets of calipers (digital and normal) and they were 65.58 and 65.6mm respectively, measured just under the 2nd ring. So I'm guessing that's stock bore.
Has anyone on here had experience with those eBay cylinders? Best overbore?
I tried searching the forum but didn't have much luck.
I also have to look at the brakes (they're very very bad) bit I thought I'd get the engine done first.
