Member Contributer Skids Posted December 5, 2023 Member Contributer Share Posted December 5, 2023 I've ridden over 300000 miles on various VFRs, completed my own valve shim checks on my early 98 model VFR which did 130000 miles so I have a lot of history of valve shim services. With the VTEC engine, I decided to get my engine serviced by Honda and it has been very noticeable that over the years and with new models (98 > 2008 > 2015 >2018) the valve shims needed changing less often so I decided that unless my current 2018 model showed any signs of engine issues, I would not do the valve shim service (add to that Honda moved the check from 16k miles to 24k miles with the 17/18 model). However, I confess I gave in and just had the first shim check completed by my local Honda main dealer and to my surprise (not), there were no shim changes required, all within spec. The bike has done 35,981 miles from new. Now I'm not suggesting anyone else does this, you get your services done when you believe they need doing, but for me that's an interesting, if expensive way of proving what I thought. 5 2 Quote Link to comment Share on other sites More sharing options...
Member Contributer VFR78 Posted December 5, 2023 Member Contributer Share Posted December 5, 2023 Three valve clearance checks in the first 75,000km on my 2014. All within spec. Now over 100,000km and the bike is still running perfectly. I don’t cane it and rarely go into 4 valve mode, although I did one track day a couple of years ago and it was rarely in 2 valve mode. A pretty good motor. 2 Quote Link to comment Share on other sites More sharing options...
gropula Posted December 6, 2023 Share Posted December 6, 2023 I may have bought an abused specimen, but mine wasn't running right since I bought it at 57k km. I was trusting this kind of advice and I wasn't prepared to shell out for the valve service as per advice it would be a waste of money. I didn't yet have the experience or skills to do it myself. So I rode the damn thing for like 20k km and tried to circumvent the problem with a fuel tuner - it masked the problem successfully. The problem was manifesting as low vacuum, thus enrichening the fuel mixture in the 0-40% throttle, where MAP sensor is the load sensor. The autotuner had to take away a lot of fuel to get the right mixture in that part of the fuel map. After 2 years of fiddling with the bike I got enough experience to dig into the valves. In the picture are the valve clearances at around 75k km. All in all, I adjusted 7 regular valves and 5 VTEC valves to adjust clearances so the clearance is bigger than specified or close to specified. Bought 3 VTEC buckets and switched around 2 of them. Vacuum was obviously restored but I didn't measure it yet. The autotuner doesn't take away that much fuel anymore and the old map had to be erased because the bike wasn't getting enough fuel, from that I assume that vacuum is back to normal. I assume that some compression was restored as well because the response is improved. Bike pulls better at lower throttle openings. Also, the engine runs a bit smoother, with less vibrations in the 4-6 RPM range. I used to upshift to 6th often because I felt the vibrations, now I often leave it in 4th or 5th because the vibrations are lower and I don't notice it's time/possible to upshift. Before adjustment: After adjustment: 2 Quote Link to comment Share on other sites More sharing options...
Member Contributer Skids Posted December 6, 2023 Author Member Contributer Share Posted December 6, 2023 Sounds like the early VTEC (6 Gen) models were not much better than the older Fi (5 Gen) models. Glad you got it sorted. Quote Link to comment Share on other sites More sharing options...
Member Contributer VFR78 Posted December 6, 2023 Member Contributer Share Posted December 6, 2023 I guess that means that there is another valve check looming! Quote Link to comment Share on other sites More sharing options...
Member Contributer bmart Posted December 6, 2023 Member Contributer Share Posted December 6, 2023 Glad that you sorted it out. Love the charts. I use the same! I always set my exhaust on the larger side and intake on the smaller side, as they seem to wear in opposite directions. 🙂 Quote Link to comment Share on other sites More sharing options...
RC79NC001 Posted December 17, 2023 Share Posted December 17, 2023 I thought I might weigh in on this discussion. I’ve had the valves adjusted twice. Once at 60k mi ( I was very pleased with the result...a private garage that did stellar work ) and again at 92k mi ( Not pleased at all, never ( ever ) going back to that dealer for service ). I’m currently showing 117300 on the odometer and this is what my VFR sounds like. V1 Cold start....ambient air temperature about 50F V2 Idling after the cold start...ominous knocking sounds from the valve train. V3 Idling after riding 150 mi through the country side. My VFR still runs strong, uses no oil, and delivers about 50 mpg. This is not a “RTF” experiment, been referred to a good private mechanic who hopefully Can Do justice to the VTEC. You guys who claim 100k ( mi ? kilometers ) with no valve adjustments are lucky ducks ! V1.MP4 V2.MP4 V3.MP4 Quote Link to comment Share on other sites More sharing options...
Member Contributer Grum Posted December 17, 2023 Member Contributer Share Posted December 17, 2023 Great effort achieving 117,000 mile! Video 2 definetly sounds like a CCT issue, not valves, also the fact that its More noticeable on the Right side of the bike where the timing chains travel. Listen closely to determine if it's the front or rear cylinder pair that's chattering then replace the appropriate CCT. Wouldn't be surprised given your mileage for a CCT to be the problem. Hopefully an easy and not too expensive fix. Good luck, let's know how you get on. Cheers. Quote Link to comment Share on other sites More sharing options...
RC79NC001 Posted December 17, 2023 Share Posted December 17, 2023 Both CCTs were replaced at the 60k service...wouldn't be suprised if the valve check ( at 92k ) wasn't even done....but I was surely paid a lot of $$$ for the service ! Quote Link to comment Share on other sites More sharing options...
Member Contributer Grum Posted December 17, 2023 Member Contributer Share Posted December 17, 2023 12 minutes ago, RC79NC001 said: Both CCTs were replaced at the 60k service...wouldn't be suprised if the valve check ( at 92k ) wasn't even done....but I was surely paid a lot of $$$ for the service ! I'll still put my money on a dud CCT. And surely worth eliminating first. Just establish whether it's the front or rear causing the issue, hopefully it's the rear, an easy one to replace. I'm surprised they decided to simply replace both at the 60k Service! CCT's are generally replaced when noisey Not on a distance spec or service interval.. Quote Link to comment Share on other sites More sharing options...
RC79NC001 Posted December 17, 2023 Share Posted December 17, 2023 Thanks Grum. Always appreciate your technical expertise and insights. Quote Link to comment Share on other sites More sharing options...
Member Contributer Grum Posted December 17, 2023 Member Contributer Share Posted December 17, 2023 7 minutes ago, RC79NC001 said: Thanks Grum. Always appreciate your technical expertise and insights. No worries RC79. Good luck and see how you get on with the CCT replacement. I'm sure she'll be good for another 200,000miles!! P.s Nice clean looking 8gen considering its mileage, well cared for, I like that. Quote Link to comment Share on other sites More sharing options...
Member Contributer Grum Posted December 17, 2023 Member Contributer Share Posted December 17, 2023 Another thing, If your valves were so badly out of adjustment to be making that amount of noise I'm guessing your bike would run like a chaff cutter and possibly difficult to start!! However a CCT issue has no effect on performance appart from the noise, generally speaking. Quote Link to comment Share on other sites More sharing options...
gropula Posted December 17, 2023 Share Posted December 17, 2023 Another touch on the subject of valves. Yesterday I did the valve clearance check on friends bike. These are his valves at 66k km on a 2006 (refresh) 6th gen. He had the bike for the last 20k km, rarely uses VTEC. All VTEC are in spec, but two are closing in on the tolerance so we think they should be adjusted. Thing is, when I ordered the VTEC buckets they took almost 3 months to arrive. Dealer said there weren't any in Europe and they ordered from Japan. Haven't called the dealer yet because it's Sunday to check for these two buckets, but we were thinking about machining the VTEC bucket. What do you guys think? Taking off a few hundredths of a mm from the bottom of the bucket, off the raised part? I don't think machining the top would be a good idea. Are the buckets all the same thickness? Just the raised part in the middle varies the overall thickness right? Is it maybe too hard and brittle to machine? Quote Link to comment Share on other sites More sharing options...
Member Contributer Skids Posted December 17, 2023 Author Member Contributer Share Posted December 17, 2023 David Silver Spares are showing 6th gen shims available, albeit they're not in Europe any more. Quote Link to comment Share on other sites More sharing options...
gropula Posted February 1 Share Posted February 1 On 12/6/2023 at 7:47 AM, gropula said: Vacuum was obviously restored but I didn't measure it yet. I got to synchronizing the starter valves again. Luckily I took pictures of the gauges when I first did the sync. Here are the results. It looks like cyl 4. was loosing quite a bit of vacuum. The MAP sensor was reading lower than expected vacuum and ECU was over fueling. Maybe it being the datum for syncing made the overall situation even worse after others were synced to match. This might be a crude way to test if the valves need adjustment. Cyl 4. was way out on the exhaust valve. 0.25 measured, 0.35 spec. The intake was close to the limit at 0.18 measured, 0.20 spec. This one is the best cylinder to draw conclusions from because it's vacuum was never adjusted, as it cannot be adjusted, it's the datum. Other cylinders have restored a significant amount of vacuum, their clearances were all over the place. 1 Quote Link to comment Share on other sites More sharing options...
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