XJ550 Owners in LA?

Hi Rooster. I had never used a torque wrench before. Everything I was doing was by feel. My only experience to mechanics prior to my XJ were on BMX bikes back in the eighties. So I got a torque wrench and after experimenting with it it does seem that the bolts to the cam caps were over torqued. According to the manual the torque specs are 7.2foot pounds. I messed around with that torque specification on some other things and when I compared that to the bolts that were still in place I could tell that they were tightened WAAAAY more then that. I figured they needed to be extra tight but I'm learning that heat expands and all that other stuff. With bicycles you don't have to deal with heat and engines and all that fun stuff.

 

Normally you need at least two torque wrenches when working on an engine. The reason is the bottom 20% of a torque wrench is not very accurate, so using a torque wrench that starts at 5 ft-lbs would not be advisable to torque the cam caps at 7.2 ft-lbs. In that case, an inch pound torque wrench should be used preferably with a range that puts the required torque near the middle of the range of the particular wrench being used.

 

You are right. I only purchased a torque wrench that starts at 5 ft-lbs. I'll get another one. Thanks again for your help.

 

It was recommended to me that I post some pics of my cam caps, cams, and motor head for inspection. I have included two sets. The set with only four cam caps are from the original engine. The picture with the complete set of 6 cam caps are from the head that I bought off ebay. All of them seem to be smooth to the touch inside with the exception of one which I singled out. You'll notice that there is a mark possibly from the cam getting wobbly inside. This cam cap is from the original engine head. I also included

 

Here are the rest. As far as I can tell the cams look fine but what do I know. Also, both places where the cam bearings rest on are also smooth to the touch I didn't notice any severe marks, scrapes, or dings. My question is, do I stick with the original head and try to make that work or should I use the head I found on ebay with it's original cam bearing caps. Does it really matter?

 

you get some plasti guage strips to measure clearances. if you trans plant the caps or cams

 

It turns out something got caught between the tach and cam sprockets thus damaging the cam and bending the tach sprocket which may be the reason why my cams went crazy and busted the bearing cam bolts loose. If you look at the picture I attached you'll notice one of the teeth on the cam have been damaged. Is this cam still usable? I have acquired cams from a Maxim 550. I know that the cams can be interchangeable but would mean I would have to rejet the carbs if I went ahead and used the Maxim cam. Does anybody know what the main and needle jet sizes would be if I changed them? Can I use the Seca cam on the exhaust and the Maxim cam on the intake? What's the worse that can happen if I change to the Maxim cams and keeps the carbs with the stock jetting?

 

https://losangeles.craigslist.org/sfv/mcy/d/northridge-yamaha-xj550-engine/6818941245.html

 

Saw that. Thanks

 

Hoping you go for it. Just about all the pictures you posted earlier shows scoring on the cam caps on both heads. Add to that all the charging system issues you are having, the busted cam caps earlier that likely filled the engine with debri, and just the general condition of all the parts the complete engine might be cheaper in the long run.

 

Thanks for the advice. I can't put any more significant money into this thing.

 

Doesn't hurt to offer 100-200$. Whats the worse that could happen he says no? The ad is 22 days old.

If the engine is still available.

 

not a lot of difference in the jetting http://xjbikes.wikidot.com/carb-specs
main needle jet is the expensive parts then pilot air jets
Years & Models: 1981-83 XJ550 Maxim North American models
Carb Manufacturer: Mikuni
Carb Series: BS28
Carb Model ID: 5K500
Main FUEL Jet Size: #112.5
Pilot FUEL Jet Size: #35
Main AIR Jet Size: #70 (non-removable, in carb throat)
Pilot AIR Jet Size: #165
AIR COMPENSATOR Jet Size: not used.
Starter FUEL Jet Size: #35 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #4GN
Main needle JET Size: #O-8 (the main needle JET is also known as the "power valve" or "emulsion tube").
Fuel Level in float bowls: 2mm +/- 1mm (.08" +/- .039")
Idle RPM's: 1,200 rpms

Years & Models: 1981-83 XJ550 Seca North American models
Carb Manufacturer: Mikuni
Carb Series: BS28
Carb Model ID: 4U800
Main FUEL Jet Size: #112.5
Pilot FUEL Jet Size: #35
Main AIR Jet Size: #70 (non-removable, in carb throat)
Pilot AIR Jet Size: #170
AIR COMPENSATOR Jet Size: not used.
Starter FUEL Jet Size: #35 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #4GZ11
Main needle JET Size: #O-8 (the main needle JET is also known as the "power valve" or "emulsion tube").
Fuel Level in float bowls: 2mm +/- 1mm (.08" +/- .039")
Idle RPM's: 1,200 rpms

 

Hi everybody. Just wondering if there's a method to finding an oil leak on the underbelly of the engine. My Seca 550 always leaks about a few drops after every ride and when I look down below there's oil and dirt and sutt all on the bottom part of my engine. Any advice would be great.

 

clean and powder with talc.

your oil leak could be as simple as the crush washer om the drain bolt, replace it.
oil filter housing the o ring that comes with filter is not the correct size you can get the correct one from xj4ever or you can seal the housing with rtv .
thin smear on the surface tighten it up let sit then torque to spec.
next under side leak could be the o ring seal on the oil level sensor.

another common leak is the tach housing seals

 

Thank you very much. I hope it's really simple.