keny Posted June 23, 2015 Share Posted June 23, 2015 So I know many VF ovners have done them in different versions, and there are kits awable also to buy. As i looked at my VF500F and its tiny outer 5mm oil tube for the top, that is split into lines, I seriusly started to think of doing a convension, but....as I came to Dave Dodges site (sorry copy-paste do not work on job Computers at VFRD for some reason) he is not recomending the kit for the VF500....Why? Site: http://www.honda-v4.com/sabmag/v4honda/oilmod-dd.html Also he clames the low end pressure will rise 3-5psi whit the kit, and increse the top end flow By 3 times and dubble top end feed pressure. Kit is a adapter at oil filter whit new oil lines from that to the top and pluging the orginal feed. I would belive the pressure will stay the same or drop slightly as part of the oil will go to the top? Link to comment Share on other sites More sharing options...
jeremyr62 Posted June 23, 2015 Share Posted June 23, 2015 Because oiling hasn't really been seen to be a big problem on the 500. Valves dropping into the cylinders is a the major cause of premature failure and this probably is not related to oiling. Link to comment Share on other sites More sharing options...
Member Contributer Dutchy Posted June 23, 2015 Member Contributer Share Posted June 23, 2015 So what can you do to prevent valve from dropping? Saw the pictures of Yoshi so revving it to 11,500rpm becomes a bit daunting.... Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted June 23, 2015 Member Contributer Share Posted June 23, 2015 Better springs . Roll On .. Link to comment Share on other sites More sharing options...
keny Posted June 23, 2015 Author Share Posted June 23, 2015 Is it the intake or exhaust valves that first drop? And normal milage? I did read somewhere that its one of the springs that brake and then the valves drop. Did look at CMSNL site, and it has listed 2 different intake valves for the 1986 VF500F, one upgraded. For the valve springs they are out of stock of the outer valve springs. Link to comment Share on other sites More sharing options...
jeremyr62 Posted June 23, 2015 Share Posted June 23, 2015 It's always an exhaust valve that fails. Not all bikes are affected. There are plenty of high mileage bikes out there. The belt drive conversion sometimes mentioned on here has about 100K miles and I regularly see 40-50K examples on Ebay UK. However I also have a collection of pictures of blown engines. Neglect the valve clearances at your peril. Some recommend keeping the revs below 9K, but where's the fun in that and there's no evidence this has a beneficial effect. New valves and spring are unobtainable despite what CMSNL say they have. I have two spare engines if mine lets go. Link to comment Share on other sites More sharing options...
keny Posted June 23, 2015 Author Share Posted June 23, 2015 A thing that have crossed my mind, IF, and only IF my engine brakes , in a way or a other, I wounder how mutch wider is a VFR750F engine...... Link to comment Share on other sites More sharing options...
jeremyr62 Posted June 23, 2015 Share Posted June 23, 2015 I think a VFR750 is a much better bike than a VF500. I really like my 500 but I'd still prefer a similar condition 750. Link to comment Share on other sites More sharing options...
Member Contributer Dutchy Posted June 23, 2015 Member Contributer Share Posted June 23, 2015 or a VF500 AND a 3rd gen AND a 4th gen? After almost 18 years 4th gen, I know oww a VF500 as well (with 44,000km) Am I mad? Link to comment Share on other sites More sharing options...
Member Contributer YoshiHNS Posted June 23, 2015 Member Contributer Share Posted June 23, 2015 I think it's an exhaust valve that goes. I'll have to look at my junk heads to see which valves are missing, but I do remember it being the same one on all of mine. When I was rebuilding the heads on mine, there was noticeable difference between resting spring length. I had enough extra parts to pick the longest set. Might have a pic of that in my build thread. You can get better springs and valves and everything, but it would be custom from http://www.kpmivalvetrain.com/ When I did the math, it would have been somewhere around $800 USD + for a full rebuild (springs, retainers, valves, guides). It would be nice if existing springs could fit in, but how do you even begin to check? Link to comment Share on other sites More sharing options...
Member Contributer Dutchy Posted June 23, 2015 Member Contributer Share Posted June 23, 2015 Yeah the picture of the different length springs is in a post I just read..... Are the failures linked to 1984/85 (the F) engines or also to the F2's 1985? This table suggests the F2's were not sold in the USA?? Model '86 was USA only (i've seen a few imported here in NL). Carbs on Keny;s F2 are VD41B (Swiss bike) mine VD41A. Since it was 1st registered in NL; we reckon EU direct sales... $800 for valves etc.... eeeuuh no. So *if* a valve drops while you are bombing it, what will happen (other than a lot of noise and smoke)? Will the drive train lock up as well and you crash? My front garden (the black concrete slabs are on order) with Keny's VF Link to comment Share on other sites More sharing options...
jeremyr62 Posted June 23, 2015 Share Posted June 23, 2015 The end of the valve bounces around the cylinder holing the piston. Lots of noise and smoke. I think the momentum of the crank/flywheel is sufficient to overcome a lock up but don't quote me on that. I haven't read of a lock up happening. It's a pretty terminal type of failure though. Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted June 23, 2015 Member Contributer Share Posted June 23, 2015 The end of the motor !! Roll On .. or if the valve drops Roll Not ! Link to comment Share on other sites More sharing options...
Member Contributer Dutchy Posted June 23, 2015 Member Contributer Share Posted June 23, 2015 That is comforting to know, that if she blows me she will (most likely) not kill me ... Not to worries, yer Irish so I cannot sue you Here's hoping the failures were all on early F's or the US '86 models...... Slainte! . Link to comment Share on other sites More sharing options...
jeremyr62 Posted June 23, 2015 Share Posted June 23, 2015 I just live in Ireland. Not a native. The term is "blow in". There's no pattern to the failures I have seen. Some are the early 84/85 and some are the later modified 86s. Honda just made the valve train a bit fragile. Shame really because other than that the bike is a gem, in sharp contrast to most of the bland (4 stroke) stuff around at the time. Link to comment Share on other sites More sharing options...
keny Posted June 23, 2015 Author Share Posted June 23, 2015 Now let me put in a thing here, can it be that the valves drops becorse of valve springs break and they break becorse of material stress from heat becorse the engine has enough oil flow to live mecanical but not to transfer heat. I know its a water cooled engine, but the oil transfers heat also. Just a theory, and can be the engine would just need more oil volume also, or a oil cooler? Link to comment Share on other sites More sharing options...
jeremyr62 Posted June 23, 2015 Share Posted June 23, 2015 Who knows? The failures I have seen involve the button head of the valve separating from the stem in the radius at the end of the stem. However this could well be a secondary failure with the valve stem failing further up in the collet/keeper radius. Not enough evidence either way to say. I doubt the temperature of the valve has much to do with it. The failure is a fatigue failure. Some claim the valves float when the springs take a permanent set due to overload at high rpm but I have yet to see compelling evidence of this. If the valve clearances are not set correctly then this puts extra loads on the valves, but again this will be marginal. Bottom line is they are just under engineered. It's probably not one thing causing the failure but a sequence of events. So if you keep your engine in tip top condition hopefully you will avoid this type of failure. As I said, there are plenty of high mileage VF500s out there so don't get too worried about it. Link to comment Share on other sites More sharing options...
Member Contributer YoshiHNS Posted June 23, 2015 Member Contributer Share Posted June 23, 2015 The valve springs do not break. Out of my three engines, I have not seen one broken valve spring. I'm in the boat of under spec'd or poorly made valve springs. I think that the spring wears out enough where it doesn't provide enough force to push the valve back up before getting hit by the piston. If you're lucky, the valve breaks at the end, punches a hole in the piston, and the broken valve bit ends up in your oil pan. One of my engine ran with 3 good cylinders and 1 with a hole in the piston. Oil was pissing out the exhaust though. Here's a pic of the difference in valve spring heights for two different engines. They varied across the same head when I measured them. Rest assured, I did not use the same spring set that was on the broken valve. Unless you are going to get a discount somehow, new valves for the VF500 are $40. So 8 x $40 = $640. Add in $200 for a new set of springs. Link to comment Share on other sites More sharing options...
jeremyr62 Posted June 23, 2015 Share Posted June 23, 2015 OK. Very interesting. I assume they were the same year of bike? I think there is a service limit on the springs in the manual. Be interesting if yours were past it. That does lend credence to the suggestion valve float is a factor. I suppose if you want the springs to last longer then keeping the RPM down will aid this. Link to comment Share on other sites More sharing options...
Member Contributer YoshiHNS Posted June 23, 2015 Member Contributer Share Posted June 23, 2015 Oddly enough, I think almost all of them were still in. Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted June 24, 2015 Member Contributer Share Posted June 24, 2015 Who knows? The failures I have seen involve the button head of the valve separating from the stem in the radius at the end of the stem. However this could well be a secondary failure with the valve stem failing further up in the collet/keeper radius. Not enough evidence either way to say. I doubt the temperature of the valve has much to do with it. The failure is a fatigue failure. Some claim the valves float when the springs take a permanent set due to overload at high rpm but I have yet to see compelling evidence of this. If the valve clearances are not set correctly then this puts extra loads on the valves, but again this will be marginal. Bottom line is they are just under engineered. It's probably not one thing causing the failure but a sequence of events. So if you keep your engine in tip top condition hopefully you will avoid this type of failure. As I said, there are plenty of high mileage VF500s out there so don't get too worried about it. The term use to be called "slide hammer"ing in the old days . I think the valve bounce cause metal fatique . Roll On .. Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted June 25, 2015 Member Contributer Share Posted June 25, 2015 Mite help . http://www.holeshot.com/ Looks like Holeshot is making components for the oil mod. Roll On .. Link to comment Share on other sites More sharing options...
keny Posted June 25, 2015 Author Share Posted June 25, 2015 $329! I have to see how mutch it will be if I have the lines made in a local shop, as a adapter to put betwene the oil filter is like 23€ Link to comment Share on other sites More sharing options...
jeremyr62 Posted June 25, 2015 Share Posted June 25, 2015 Don't bother. How many miles are you actually going to do on an ancient VF500? Ride the thing and invest the money in a spare engine if you are worried about valve drop. I ride mine a fair bit and will take it to Grenoble this year but I'd be pushed to do >3K miles a year. I have other bikes so am lucky that way though. Use good oil, change it pretty frequently and make sure valve clearances are in spec and you'll be fine. Link to comment Share on other sites More sharing options...
keny Posted June 25, 2015 Author Share Posted June 25, 2015 One more thing about the valve springs and dropped valves, is it always rear cylinders valves that drop or is it random? Link to comment Share on other sites More sharing options...
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