80 XS G engine knock

[turbodave_98]

I was on an extended ride with my 80 G standard and it was running great and at high speeds. Had done about 150 miles of hard riding. Pulled into get some fuel and heard a knock in the engine that I had never heard ever before. Engine is stock with 30K miles. The oil light never came on but I checked and it needed about 1.5 quarts. I had been running Royal Purple synthetic and had noticed that it seemed to use more oil than with the Castrol GTX that I had used almost exclusively.
The knock seems to have a relationship to engine rpms as it increases but is more difficult to hear at higher rpms.
The sounds seems to be coming from the lower aft area of the engine and middle gear area.
Does anyone have a suggestion of what may be the noise and a suggested action to correct it without opening up the engine for trouble shooting. I have thought about adjusting again the cam chain tension and also changing back to dino oil vs. synthetic.
Any help greatly appreciated. I bought the bike new in 80 and want to keep it forever. Please advise.

[Doyle]

TurboDave, I don't want to be the bearer of this experience but it is so similar to yours, I must reply.......I'm riding long and fast with a bunch of guys to our annual pilgrimage to the AMA Superbike races at Laguna Seca. My 80 Standard (pipes, carbs, cams, Wiseco pistons, etc. begins this small but constant vibration, above 4000rpm not at steady speed but when going up through the gears. On the way home it worsened and finally froze at freeway speed. I trucked it home thinking rod or piston,etc. Upon teardown all the above mentioned parts were fine...it was the center bearing on the crankshaft! The bearing support tower(grows from the bottom of the lower case) had fragged and the motor was running(at the end) with shavings and no center support! Let's call this a serious scenerio, not the worse though if you get it early. I hope that is not it though...let us know! Good Luck. Doyle

[turbodave_98]

Doyle, thanks for the info. Did you have the motor repaired and how costly was it?? Just want to evaluate the cost of repair for planning purposes. Thanks again.

[Doyle]

What I did was buy a thrashed XS motor and take the bottom end (lower case) and crankshaft from it for a replacement onto my engine. I had to replace the CS bearings (oem Yamaha) as part of the reassembly. I did not do the lower end wrenching myself, I talked to a Yamaha dealer mechanic who did it at home in his spare time, alot of those guys are willing to do that for 1/3 the labor cost (talk to them privately of course). Buy the way, XS cranks letting go are very much a rarity, modified engine or not. The thrashed motor (50000 miles without carbs) cost me $100 and the mechanic charged me $450...parts as I remember were about $200(buy them from classified section of M/C magazines that advertise OEM Discount Yamaha parts). The enging is now bulletproof, I even ran a nitros system for awhile! Later, Doyle

[turbodave_98]

Thanks for the repair details. I think I may have come upon the problem, I think it is possibly a broken gear tooth. The sound is focused in aft lower middle gear area. I changed the oil to dino and it seems to be much less loud but it is still knocking. I will keep you informed. I have no vibration in the motor or bike at all, like you described.

[turbodave_98]

Doyle, looks like I have possibly a failed piston ring. Will know next week. Thanks for the help.

[Doyle]

Hey TurboDave, let us know what you find! Are you going to tear it down or have someone else wrench on it? What makes you think ring failure? Anyway, I hope that's it...way better than bottom end. Good luck Doyle

[turbodave_98]

XS 80 G Engine Knock

Took it to my 20 year association dealer, Owner used to mechanic on this bike. He think is a bad ring. Should know tomorrow or Wednesday. Hope it is the top end also.
Will keep you informed

[turbodave_98]

XS 1100G engine noise

Engine in the shop heads off and the #2 piston seized, no damage to the lower case or crankshaft. Looks like I will have a new piston and rings on all four(other 3 pistons ok) and valves replaced.
Anyone know a company to get some new pistons, valve springs and rings?? Appreciate the help. Do not want to part with this bike as I bought it new in 1980 and it has lots of fond memories for me with summer touring with my grown son.

[ratbyk]

Motor Repairs

I would suggest your best way to go for satisfaction, ease of parts availability, another 15-20 tears of life would be a Wiesco big bore kit. Have not had to do on my bike yet but if and when I need a top end overhaul it will be that route. Several of our members have gone this route. Possibly some of them will speak up and give you some encouragement. Do not believe that stock pistons or rings are available from Yamaha anymore.
Ken/Sooke

[TopCatGr58]

Hey there TurboDave98,

I agree with Ken/RatByk. I had my 81 since 83 when it had 15 miles on it!!! The Odometer broke at 980, never got it fixed, drove it for 9 years, 2 were 365 to work, guestimated I had over 40K on engine when I parked it, sat 8 years from 92-2000, not sealed or protected properly, my fault and ignorance , tore into it and found tons of rust, got the big bore kit, didn't have to touch the bottom end, just bored cylinders, put new pistons, wristpins, rings and did a valve job myself, been running 3 years now, 4 rallies, many thousands of miles, no problems!!! I pulled the engine to work on mine, had to do the 1st/2nd gear fix anyways, was easier that way!

Took a while to get my kit, tried going thru local bike racing machine shop, Wiseco only makes them a short time per year. Company in Fla., Pro-Flo IIRC, sells them and seemed to have a decent supply of stock and great prices! I don't have their exact web url handy, a simple search here should let you find the link!
Good Luck!

[turbodave_98]

Thanks guys, I have bought a Big Bore Kit going to 1179cc. Purchased thru Pro-Flo, $365 includes, rings, clips, etc. Will let you know when it is back on the road.
I think I might have caused this failure by using Royal Purple synthetic 15W40 oil. I have it used in my 96 Royal Star and 99 Venture. The XS never seemed to like it, it didn't drip or have detected smoke but it used it. After this repair going back to dino oil for it.

[Geezer]

Originally posted by turbodave_98
Thanks guys, I have bought a Big Bore Kit going to 1179cc. Purchased thru Pro-Flo, $365 includes, rings, clips, etc. Will let you know when it is back on the road.
I think I might have caused this failure by using Royal Purple synthetic 15W40 oil. I have it used in my 96 Royal Star and 99 Venture. The XS never seemed to like it, it didn't drip or have detected smoke but it used it. After this repair going back to dino oil for it.

I wouldn't use synthitic oil in anything. Regardless of the hype it's just not as good as the regular mineral based oil.

Geezer

[John]

TurboDave, I would recommend getting an oil cooler, because it will run hotter. I also have the 1179 cc Big Bore, and a Lockhart cooler. They are available still. Do a search here, as I posted the URL for Lockhart a while ago, but I don't have it saved.

[turbodave_98]

XS 1100G engine knock

John, thanks for the tip. I have been told it will run hotter with the Wiseco Big Bore Kit. I probably will get an oil cooler. Thanks again.