jason24robo Posted November 17, 2015 Share Posted November 17, 2015 Tore my motor down. This is what I found. On the rear right cylinder. Pretty rough to the touch. Anybody ever hone or bore their piston cylinders? Sent from my SAMSUNG-SM-N920A using Tapatalk Link to comment Share on other sites More sharing options...
Baileyrock Posted November 17, 2015 Share Posted November 17, 2015 Bummer Jason, pretty sure these are treated & sleeved cylinders and can't be bored. maybe honed though. What model VFR are you working with? used motors have gotten pretty cheap around here. Link to comment Share on other sites More sharing options...
jason24robo Posted November 17, 2015 Author Share Posted November 17, 2015 03 non abs Sent from my SAMSUNG-SM-N920A using Tapatalk Link to comment Share on other sites More sharing options...
Baileyrock Posted November 17, 2015 Share Posted November 17, 2015 Hell, I think you could by a nice used motor for $300-500 and just slap it in. Link to comment Share on other sites More sharing options...
Member Contributer YoshiHNS Posted November 17, 2015 Member Contributer Share Posted November 17, 2015 What made you tear it apart? Link to comment Share on other sites More sharing options...
Member Contributer Rush2112 Posted November 17, 2015 Member Contributer Share Posted November 17, 2015 03 non abs Sent from my SAMSUNG-SM-N920A using Tapatalk I think BR has the easiest most cost effective solution to get your bike bike on the road... used engine swap. This is from the 5th gen shop manual but they are the same sleeve composition. If the temperature is manged the sleeves can be rebored like a conventional sleeve... Link to comment Share on other sites More sharing options...
jason24robo Posted November 17, 2015 Author Share Posted November 17, 2015 Kept fouling plugs on this cylinder. After doing a lot of research and trying a lot of different things I decided to just tear it apart and get right down to it. Sent from my SAMSUNG-SM-N920A using Tapatalk Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted November 17, 2015 Member Contributer Share Posted November 17, 2015 The 6th gen parts fiche shows oversize pistons available of .25 and .50 (which I interpret to mean 25 thousandths and 50 thousandths over), so I would infer from that that boring is an option. Before deciding that however, I would wonder if whatever caused the scoring (lack of lubrication, debris in the oil, etc) has also affected the bearings / crankshaft journals. I might be inclined to pull a rod and main cap and see what they look like. If they're similar, just the machine work to get it all back in spec is going to be more than a low mile engine. My $.02. Link to comment Share on other sites More sharing options...
jason24robo Posted November 17, 2015 Author Share Posted November 17, 2015 Think you're right might just as well get a good used motor rather than put that much time and money into this motor. Damn shame tho. Love this girl. Sent from my SAMSUNG-SM-N920A using Tapatalk Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted November 17, 2015 Member Contributer Share Posted November 17, 2015 If you do swap engines, you might consider going 5th gen. PainterBob and HighSideNZ did that (though he did a lot of internal engine mods) and has a sweet sounding 6th gen! The coil packs take some doing but it's not insurmountable. http://www.vfrdiscussion.com/forum/index.php/topic/81877-5th-gen-engine-in-a-6th-green/ This one is very long and you'll be pages and pages in before you get to his 5th gen engine build and how it came out in his 6th gen. If nothing else, it's a really interesting read. http://www.vfrdiscussion.com/forum/index.php/topic/75067-anyone-ever-reboredoverbored-a-56th-gen/ Link to comment Share on other sites More sharing options...
jason24robo Posted November 17, 2015 Author Share Posted November 17, 2015 Those are very interesting. Sent from my SAMSUNG-SM-N920A using Tapatalk Link to comment Share on other sites More sharing options...
Member Contributer Rush2112 Posted November 17, 2015 Member Contributer Share Posted November 17, 2015 The 6th gen parts fiche shows oversize pistons available of .25 and .50 (which I interpret to mean 25 thousandths and 50 thousandths over), ... It's metric so that's 0.25 & 0.50 millimeters of piston diameter not thousandths of an inch (0.025 & 0.050) like an American machine shop would measure. Link to comment Share on other sites More sharing options...
jason24robo Posted November 17, 2015 Author Share Posted November 17, 2015 I believe it's .010" and .020". Sent from my SAMSUNG-SM-N920A using Tapatalk Link to comment Share on other sites More sharing options...
Member Contributer HighSideNZ Posted November 17, 2015 Member Contributer Share Posted November 17, 2015 Yep, they are boreable as long as you find a machineshop that knows about MMC sleeves. Mine came out really well but it was a big overbore compared to 0.25mm/0.5mm Dependant upon the distance the bike has travelled, if you were going to bore it you'd want to do bearings etc whilst it is down. Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted November 17, 2015 Member Contributer Share Posted November 17, 2015 The 6th gen parts fiche shows oversize pistons available of .25 and .50 (which I interpret to mean 25 thousandths and 50 thousandths over). Why oh why is the USA so stuck in the past, Honda = Japanese company, they are a Metric country, about the only things you'll find with Imperial measurements are the chain/wheels/tyres, just because that's how those things are commonly known. Everything else will be mm's, the over sizes are .25 & .5mm as in 72mm STD, 72.25mm OS1, 72.5mm OS2. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted November 17, 2015 Share Posted November 17, 2015 I am tempted to suggest over boring due to the slight performance gain, but the cylinder scoring that you encountered is extremely rare and it is a red flag, so I would scrap it and look for a clean low mileage engine. I really don't know what could cause that kind of wear, short of extreme abuse or miles, oil contamination, some sand or grit getting past the air filter or failed rings etc.... Link to comment Share on other sites More sharing options...
Member Contributer HighSideNZ Posted November 17, 2015 Member Contributer Share Posted November 17, 2015 To me the scoring look very much like a partial seize. As in it has been extremely hot/ran out of coolant or similar. Link to comment Share on other sites More sharing options...
Baileyrock Posted November 18, 2015 Share Posted November 18, 2015 The 6th gen parts fiche shows oversize pistons available of .25 and .50 (which I interpret to mean 25 thousandths and 50 thousandths over). Why oh why is the USA so stuck in the past, Honda = Japanese company, they are a Metric country, about the only things you'll find with Imperial measurements are the chain/wheels/tyres, just because that's how those things are commonly known. Everything else will be mm's, the over sizes are .25 & .5mm as in 72mm STD, 72.25mm OS1, 72.5mm OS2. Mostly because too many of us are to stupid to change. We almost thought about it a few decades ago. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted November 18, 2015 Share Posted November 18, 2015 To me the scoring look very much like a partial seize. As in it has been extremely hot/ran out of coolant or similar. Good point, Over heated and the piston/rings expand and p2w clearance goes to zero and we have contact. I always have nightmares where I forget to flip on my manual fan switch and I look down and see +250 degrees and a red light flashing. This isn't going to help lol. Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted November 18, 2015 Member Contributer Share Posted November 18, 2015 Hey CR, why haven't you got the manual switch rigged in parallel with the Fan temp switch ? That way you never forget & it will remind you that you have ! Best of both worlds. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted November 18, 2015 Share Posted November 18, 2015 Because then i cant turn it off on the highway. Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted November 19, 2015 Member Contributer Share Posted November 19, 2015 I have my manual switch set up for normal, forced on, forced off. I have forgotten the position it was in a few times. Over the winter I'm going to rig up some sort of LED indicator light(s) that are dash mounted so I'm reminded. If I stay on top of it it definitely helps keep the temps down. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted November 19, 2015 Share Posted November 19, 2015 I have a volt meter on my bike, so it is pretty easy to tell if it is on or off, but yes, an LED indicator would be ideal. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.