Premium Member upshift Posted July 12, 2018 Premium Member Share Posted July 12, 2018 Just got back from a 9-day, 4,000 km ride and the bike was running a bit rough - some minor surging on steady throttle and not having quite its usual pop for acceleration. It was also nearing the 42,000 km mark where valve clearances need inspecting so I took it to my usual mechanic and he informed me today that cam lobes appeared worn and were out of spec (ie. "The exhaust cam lobe minimum measurement is 1.4060" with 1.4063"-1.4102" required. The intake cam lobe minimum measurement is 1.4250" with 1.4287"-1.4327" required"). Has anyone experienced this issue on the FJ previously? (I searched the forum but couldn't find anything related) Could I really need new cams at 40,000 km? (seems bizarre...) Thanks, in advance, for anything you might suggest. Link to comment Share on other sites More sharing options...
pattonme Posted July 12, 2018 Share Posted July 12, 2018 how is the mechanic measuring? calipers or dial indicator with cam on a jig? is there cracking or other surface damage? How tight were the clearances? Wasn't there a thread like this on that sister forum? Link to comment Share on other sites More sharing options...
Tusk Posted July 12, 2018 Share Posted July 12, 2018 Could the cams have been adjusted previously incorrectly? Too much torque on something? Link to comment Share on other sites More sharing options...
koth442 Posted July 12, 2018 Share Posted July 12, 2018 This is the first time I've heard anything about worn cam lobes. Pictures and the answer's to Matt's questions above will be greatly helpful. '15 FJ09 Link to comment Share on other sites More sharing options...
partypat Posted July 12, 2018 Share Posted July 12, 2018 What oil do you run? Have you owned this bike since new? I work for a motorcycle cylinder head machine shop and we sell cams as well. When we see cam and tappet wear (the buckets the cam lobe rides against) it's normally due to the oil used in the motor. Use the right oil = no wear. Use the wrong oil = severe wear, fast. Just curious. I'm not trying to say you knowingly did anything wrong..... I'm not meaning to offend.... Regards, Pat Link to comment Share on other sites More sharing options...
pattonme Posted July 12, 2018 Share Posted July 12, 2018 @partypat, can you elaborate/define "wrong" oil? I assume you're referring to sheer/viscosity/additive characteristics and not mineral vs synth. Link to comment Share on other sites More sharing options...
Premium Member upshift Posted July 12, 2018 Author Premium Member Share Posted July 12, 2018 Thanks for the quick responses, folks. To answer your questions: 1. I believe the mechanic is using callipers to measure but will confirm when I meet him later today. He's pretty meticulous and even double-checked his micrometer's calibration to be sure it's not reading inaccurately. 2. He didn't mention cracking or other surface damage to the cams, other than that he can feel some ridges with the fingernail test. Images attached for your review. 3. The Intake clearances were apparently okay (0.15-0.15mm, 0.15-0.14, 0.15-0.13) but the exhaust valves were pretty off (0.16-0.20mm, 0.20-0.23, 0.18-0.23). 4. I'm the second owner of this bike (bought it at ~8,000km) and have always used fully synthetic oil (Motul 7100). I was under the impression that this would constitute "right oil", but am no expert in this area. The previous owner seemed like a reasonable guy and said he'd followed all of the specified break-in procedures and also used only fully synthetic. If it helps, I'm not an engine thrasher with my riding style (no wheelies, burnouts, or snappy right hand). I ride smooth and generally have the revs in the 4-7,000 RPM range (I've literally only bounced off the rev limiter twice in the 2.5 years I've owned the bike). Going to look at the cams this afternoon and chat with the mechanic. Really hoping a set of new camshafts isn't in my future (read: budget). Open to any further thoughts and advice you may have. Thanks. Link to comment Share on other sites More sharing options...
duhs10 Posted July 12, 2018 Share Posted July 12, 2018 @skippert any input? '15 FJ-09 w/ lots of extras... Fayetteville, GA, USA Link to comment Share on other sites More sharing options...
nsmiller Posted July 12, 2018 Share Posted July 12, 2018 You are talking about 3 ten-thousandths of an inch out of spec, or 7.5 microns. First, I'm not sure a caliper can measure that small. Second, if it was my bike I would make sure the clearances were good and not worry about it. Edit: Other things that are between 5 and 10 microns - Length of a typical human male spermatozoon's head- Width of strand of spider web silk Edit2: Your intake cam is a little bit more out of spec than what I discuss above regarding the exhaust cam. Link to comment Share on other sites More sharing options...
partypat Posted July 12, 2018 Share Posted July 12, 2018 @partypat , can you elaborate/define "wrong" oil? I assume you're referring to sheer/viscosity/additive characteristics and not mineral vs synth.I am just referring to using Motorcycle specific 4 stroke oil. Commonly shown with the 4T on the label. These oils contain zinc which is required to protect the valve train from wear. The damage we've seen is normally when automotive oils are used. They don't have the correct additives. Pat Link to comment Share on other sites More sharing options...
nsmiller Posted July 12, 2018 Share Posted July 12, 2018 Just got back from a 9-day, 4,000 km ride and the bike was running a bit rough - some minor surging on steady throttle and not having quite its usual pop for acceleration. It was also nearing the 42,000 km mark where valve clearances need inspecting so I took it to my usual mechanic and he informed me today that cam lobes appeared worn and were out of spec (ie. "The exhaust cam lobe minimum measurement is 1.4060" with 1.4063"-1.4102" required. The intake cam lobe minimum measurement is 1.4250" with 1.4287"-1.4327" required"). Has anyone experienced this issue on the FJ previously? (I searched the forum but couldn't find anything related) Could I really need new cams at 40,000 km? (seems bizarre...) Thanks, in advance, for anything you might suggest. They are not outside the wear limit. See photo from service manual. Link to comment Share on other sites More sharing options...
Premium Member upshift Posted July 12, 2018 Author Premium Member Share Posted July 12, 2018 Thanks much for this @nsmiller - super helpful! (I don't have a service manual so was relying on my mechanic's range numbers) I'm curious as to why the "Limit" numbers are different than the lowest numbers in the "Base circle diameter" range...isn't the point of a range to indicate the acceptable max and min? I also spoke with a local shop today to inquire how much new camshafts would cost and they were stupefied, as they'd never had a request for new cams (and never installed any new ones, themselves, apparently). That's another vote for keeping my current set, methinks. Link to comment Share on other sites More sharing options...
nsmiller Posted July 12, 2018 Share Posted July 12, 2018 I could be wrong, but I think the lobe height min/max are for new cams. The limit is the wear limit, since they will only ever get smaller with wear, not larger. Link to comment Share on other sites More sharing options...
Supporting Member betoney Posted July 13, 2018 Supporting Member Share Posted July 13, 2018 I also spoke with a local shop today to inquire how much new camshafts would cost and they were stupefied Tell the local shop to try google, they are $110.00 each @ Partzilla ***2015 Candy Red FJ-09*** Link to comment Share on other sites More sharing options...
skipperT Posted July 13, 2018 Share Posted July 13, 2018 @skippert any input? Sure. I’m not sure what Yamaha means about the “base circle measurement”, generally when I measure cams, the max lobe height and the smallest OD of the shaft where it rides in the head are the specs I am most concerned with (besides clearance and out-of-round). The service manual may give specific instructions under “measuring cams check/inspect “ in the head disassembly area. Running clearance would be the next spec - whether the cams are so loose in the head journals that the oil clearance is too great. either calculate that one or use plastiguage. The gent who chimed in from the machine shop (Pat) would know better than I. The wear marks are consistent with a bike with some miles. Sometimes cams wear a bit more in one particular area of the circumference of the journal due to load place on them as they rotate in the head and depress the valve lifters. Polaris 900 and 1000 DOHC engines typically show those kinds of marks. I never measure cams with vernier calipers - only with a good, calibrated micrometer. -Skip. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.