Good day all
[Sorry for the essay: Just want to make sure you've got adequate backstory... Skip to MY ISSUE: if you don't care to read.]
I've got a 2006 Blaster that I bought a couple months ago; first quad of my own after years of wanting one! I'm what you would call a "sub-amatuer" rider, and obviously didn't know the first or second thing about 2-strokes when I bought it... Didn't own my own gloves, that's my skill-level: Lower than sh*te on a dung-beetle's boots, as it were. I'm not unfamiliar with machines, just with the specifics of all that 2-stroke witchcraft.
I did check it out and the quad looked like it was in decent nick; completely stock, which is how I wanted it. I checked the basics: transmission oil, 2-stroke oil, brakes; anything I could get to and push on or kick basically. It never entered my mind that I'd have to do anything with the engine, because the previous owner said that it had just been serviced... Hahaha - riiiight. Being a bit cautious, I replaced all the fluids and did all the basic maintenance before riding it. At this point I didn't know that 2-strokes needed internal maintenance, so I never touched the engine, just cleaned the carb and changed brake pads - that sort of thing.
It ran great! But it did have a problem with an increasing idle when it heated up (which I now know was the start of the end, but I didn't know enough to diagnose an airleak at the time). Unfortunately, after a few rides it developed a catastrophic case of "previous-owner-was-a-lying-arsehole", and the piston seized. I could restart it and limped it home, but by that time the cylinder and piston were gone... After downloading the manual and inspecting everything properly, I realised that the quad has never had any proper maintenance done. Oh, except the reed valves: These were replaced with Boyesen performance reeds... and then the valve seat bolts over-tightened, which is where the air leaked in
The valve seat was literally warped enough that I could see it without a straightedge... probably 0.2mm or more (8/1000" ? - Sorry I'm all metric).
Anyway, now I'm rebuilding the top-end: Cleaned, rebored, honed, lapped, cussed-at; all of it done to Yamaha spec (except the cussing - I made that up as I went and let me assure you that no mothers got off lightly). I replaced the piston/rings/pin/bearing with stock (oversize +0.50mm) parts since that's all I can afford (prices for parts are ridiculous where I live).
I don't want to just put it together and have something else go, so I'm checking the bottom end too. I don't have the experience to make a call myself, so I'm relying on the Blaster manual's dimensions as much as possible. This is where I need some help, if one of you fine gents can assist.
MY ISSUE:
The free-play for the conrod is given as measurements I can work with: 0.8 - 1.0mm etc., and luckily my blaster appears to be in spec on the big-end (just). However, concerning the piston wrist-pin, the manual just says "No noticeable play"... Well my dial gauge doesn't have Asian units like that, so I thought I'd ask: What kind of play on the end of the wrist-pin would one of you pros be willing to accept?
The reason I ask is that I DO notice free-play, but my friend doesn't... He's suggested that a quick-fix to get me up and running would be for me to just stop noticing
[Sorry for the essay: Just want to make sure you've got adequate backstory... Skip to MY ISSUE: if you don't care to read.]
I've got a 2006 Blaster that I bought a couple months ago; first quad of my own after years of wanting one! I'm what you would call a "sub-amatuer" rider, and obviously didn't know the first or second thing about 2-strokes when I bought it... Didn't own my own gloves, that's my skill-level: Lower than sh*te on a dung-beetle's boots, as it were. I'm not unfamiliar with machines, just with the specifics of all that 2-stroke witchcraft.
I did check it out and the quad looked like it was in decent nick; completely stock, which is how I wanted it. I checked the basics: transmission oil, 2-stroke oil, brakes; anything I could get to and push on or kick basically. It never entered my mind that I'd have to do anything with the engine, because the previous owner said that it had just been serviced... Hahaha - riiiight. Being a bit cautious, I replaced all the fluids and did all the basic maintenance before riding it. At this point I didn't know that 2-strokes needed internal maintenance, so I never touched the engine, just cleaned the carb and changed brake pads - that sort of thing.
It ran great! But it did have a problem with an increasing idle when it heated up (which I now know was the start of the end, but I didn't know enough to diagnose an airleak at the time). Unfortunately, after a few rides it developed a catastrophic case of "previous-owner-was-a-lying-arsehole", and the piston seized. I could restart it and limped it home, but by that time the cylinder and piston were gone... After downloading the manual and inspecting everything properly, I realised that the quad has never had any proper maintenance done. Oh, except the reed valves: These were replaced with Boyesen performance reeds... and then the valve seat bolts over-tightened, which is where the air leaked in
The valve seat was literally warped enough that I could see it without a straightedge... probably 0.2mm or more (8/1000" ? - Sorry I'm all metric).Anyway, now I'm rebuilding the top-end: Cleaned, rebored, honed, lapped, cussed-at; all of it done to Yamaha spec (except the cussing - I made that up as I went and let me assure you that no mothers got off lightly). I replaced the piston/rings/pin/bearing with stock (oversize +0.50mm) parts since that's all I can afford (prices for parts are ridiculous where I live).
I don't want to just put it together and have something else go, so I'm checking the bottom end too. I don't have the experience to make a call myself, so I'm relying on the Blaster manual's dimensions as much as possible. This is where I need some help, if one of you fine gents can assist.
MY ISSUE:
The free-play for the conrod is given as measurements I can work with: 0.8 - 1.0mm etc., and luckily my blaster appears to be in spec on the big-end (just). However, concerning the piston wrist-pin, the manual just says "No noticeable play"... Well my dial gauge doesn't have Asian units like that, so I thought I'd ask: What kind of play on the end of the wrist-pin would one of you pros be willing to accept?
The reason I ask is that I DO notice free-play, but my friend doesn't... He's suggested that a quick-fix to get me up and running would be for me to just stop noticing
