A while back I posted about my low compression and "worn out" motor, what Yamaha had told me and what the techs were telling me. With suggestions from the list I did some decarbonizing routines and oil changes, but to no avail, the compression continued to fall at approx. 5 psi per 1k miles. To review, minimum spec is 198 and I was down to 165, now below 150. I have continued to ride the bike. Uneven idle issues have plagued me as well as poor low rpm response and stumbles starting out from a stop or at low rpm parking lot speeds. Once up to speed it rides ok, but is down on power and would bog if you whacked the throttle.
New year's day I did a 280 mile rain ride to the coast for a RTE and during the ride it was brought to my attention that steam was coming out of my exhaust pipes, much like what you would see during cold start up on cold day, but more intense, and that there was a smell to it.
Fearing a head gasket issue, and having a long ride this coming week, I decided it was time to pull the motor and swap in a low mile '05 motor I had in the garage. (that's still in progress, but coming along well).
What I discovered upon pulling the motor was that the boots connecting the TBs to the airbox were all loose. None of the clamps were tight, and one had the ends not even connected by the bolt, which was just hanging there. There was a lot of crud on that side of the TBs, significantly more, darker and heavier and all around the diameter of the TB. The other side was quite clean, I suspect from fuel spray and the decarbonizing efforts.
The only time the bike has been worked on by other than myself was at the three valve check/adjustment intervals. Two of those were done by the same shop with very experienced techs. One was done by the local shop and a Jr. tech that had little experience of this level, (and zero FJR experience), and was following the shop manual to the letter. I was told by the Sr. tech, (who had been on vacation when the work was done), that "they took way more apart than necessary" when I picked the bike up.
You don't have to pull the TBs to do the valve check, but the shop manual has you do it as part of the "remove engine" sequence that leads up to pulling the valve cover. If you just follow the manual, I could see that occurring. I know I never took the TBs off or tore into the bike that far until now.
The steam may have simply been water getting in at the loose boots and entering the air/fuel mix into the engine, or I may have some head gasket issue, (both?), that is unknown at this point. It was raining heavily with 30-50 mph winds during the new year's ride over the entire 6 hours of riding.
What is known is that the service by the Jr. tech was at 60k, so that's likely 30k of riding with loose TB connections and likely some unfiltered air and crud entering the engine during that time. I've ridden gravel roads, desert playa and plenty of rain rides during that 30k. I now suspect this is the root cause of my early low compression, although it is certainly possible that there are other, as yet unknown, contributing factors. I consider the low compression to be early based on the number of FJRs known to me with higher mileage that are fine, and the bikes with comparable mileage that I've personally tested for compression and found to be w/in spec, or only slightly below it.
I'm not going to be tearing the motor down soon, so this is more a sharing post than one seeking advice. No way I could prove who left the TB boots loose at this point, or that it contributed to premature wear, so I'm not going after anyone with attempts for compensation. My talks with Momma Yamaha concluded long ago, so don't even suggest I go there.
Again, I just wanted to share this info with the forum. I'm not seeking advice and that motor is out of the bike. I may rebuild it and keep it for when the '05 motor wears out, but I'm not sure at this point. If I rebuild it, I will share any other info on what is found at that time. Just adding to the collective FJR data base.
Eric V.
New year's day I did a 280 mile rain ride to the coast for a RTE and during the ride it was brought to my attention that steam was coming out of my exhaust pipes, much like what you would see during cold start up on cold day, but more intense, and that there was a smell to it.
Fearing a head gasket issue, and having a long ride this coming week, I decided it was time to pull the motor and swap in a low mile '05 motor I had in the garage. (that's still in progress, but coming along well).
What I discovered upon pulling the motor was that the boots connecting the TBs to the airbox were all loose. None of the clamps were tight, and one had the ends not even connected by the bolt, which was just hanging there. There was a lot of crud on that side of the TBs, significantly more, darker and heavier and all around the diameter of the TB. The other side was quite clean, I suspect from fuel spray and the decarbonizing efforts.
The only time the bike has been worked on by other than myself was at the three valve check/adjustment intervals. Two of those were done by the same shop with very experienced techs. One was done by the local shop and a Jr. tech that had little experience of this level, (and zero FJR experience), and was following the shop manual to the letter. I was told by the Sr. tech, (who had been on vacation when the work was done), that "they took way more apart than necessary" when I picked the bike up.
You don't have to pull the TBs to do the valve check, but the shop manual has you do it as part of the "remove engine" sequence that leads up to pulling the valve cover. If you just follow the manual, I could see that occurring. I know I never took the TBs off or tore into the bike that far until now.
The steam may have simply been water getting in at the loose boots and entering the air/fuel mix into the engine, or I may have some head gasket issue, (both?), that is unknown at this point. It was raining heavily with 30-50 mph winds during the new year's ride over the entire 6 hours of riding.
What is known is that the service by the Jr. tech was at 60k, so that's likely 30k of riding with loose TB connections and likely some unfiltered air and crud entering the engine during that time. I've ridden gravel roads, desert playa and plenty of rain rides during that 30k. I now suspect this is the root cause of my early low compression, although it is certainly possible that there are other, as yet unknown, contributing factors. I consider the low compression to be early based on the number of FJRs known to me with higher mileage that are fine, and the bikes with comparable mileage that I've personally tested for compression and found to be w/in spec, or only slightly below it.
I'm not going to be tearing the motor down soon, so this is more a sharing post than one seeking advice. No way I could prove who left the TB boots loose at this point, or that it contributed to premature wear, so I'm not going after anyone with attempts for compensation. My talks with Momma Yamaha concluded long ago, so don't even suggest I go there.
Again, I just wanted to share this info with the forum. I'm not seeking advice and that motor is out of the bike. I may rebuild it and keep it for when the '05 motor wears out, but I'm not sure at this point. If I rebuild it, I will share any other info on what is found at that time. Just adding to the collective FJR data base.
Eric V.
