Bargain or junk....

[Kipp]

I just purchased an 81 XS400 SE for $200. The bike is in really great shape, came with title too.

Chrome isn't rusted. Original side covers. Electrics work great. Rims in good shape too.

Immediate fixes needed.

- new clutch cable and lever (broken)
- new master cylinder and brake pads front (pads worn, brake stuck)
- new exhausts (both cracked)

Got the wheels in motion on those already.

The bike was sold to me for $200 because they said there was no compression, they'd run it without oil and the engine was shot. (Oil has been added since). I have got it to start pretty easily and it'll idle on full choke for 5 mins before then idling fine without choke. I've taken it around my block and rides well, except for a ticking metal noise coming from the cylinders on open throttle. Maybe I need to get it out for about 20 miles to understand what they mean by lost compression?

I did the old finger on the spark plug hole compression test and it shot my finger out pretty good. (I know I need to get a proper test done, but I just don't think it's compression issues) so my question is what should I test to see if this engine is fixable and not a parts bike? Is my best option to pull the engine out and apart? What should I look for? How will I tell if it's rockers? Valves? Piston noise when I open it up? (I've done work on bikes but haven't had to diagnose engine issues like this before.)

Thanks in advance kind people.

 

[xschris]

The bike looks like an 80 SG model. I would go through the entire bike and clean and inspect every thing. A full oil change and a valve adjustment may be all you need for the motor but I would still do a compression test. If it where me I would replace everything that is broken with oem stuff. The bike will be far better for tuning and performance.

 

[Kipp]

Thanks for the reply! Yes plan on replacing the parts that are broken, making the seat pan and rear loop.

For valve adjustment where do I start? Tighten it then loosen? What should I be looking for?

 

[xschris]

It's all in the manual which can be downloaded for free on the site. So your cutting up the bike then. Sorry to hear that. It seems to be what most people do now a days.

 

[MerlinDudley]

Hi, to diagnose any metalic sounding noises from your engine, I would suggest that you invest in a Mechanic's Stethoscope, failing that you could go "Old School" and use a long series screwdriver, with the tip on the part of the running engine, and the handle pressed tightly to your ear! (Please don't use the screwdriver the other way around, or you will be having a perferated eardrum!) Using either of these methods, saves you a lot of time in diagnostic's, and even more time from stripping the motor when there is no need to!

Merlin

 

[MerlinDudley]

It's a shame that your chopping your frame up! If I were in your position, I'd be looking to restore it to it's factory Spec's. That way they command a much HIGHER selling price! and you would also be keeping alive a machine, most bikers thought was dead!
With the very low buying price, I'd have thought that the restoration would have been the better option, for an S.P.Q.R., (Small payout quick return) and also a bigger profit, for yourself!

Merlin

 

[Kipp]

It's all in the manual which can be downloaded for free on the site. So your cutting up the bike then. Sorry to hear that. It seems to be what most people do now a days.

Just a new seat and pan, not planning on changing much else.

 

[Kipp]

It's a shame that your chopping your frame up! If I were in your position, I'd be looking to restore it to it's factory Spec's. That way they command a much HIGHER selling price! and you would also be keeping alive a machine, most bikers thought was dead!
With the very low buying price, I'd have thought that the restoration would have been the better option, for an S.P.Q.R., (Small payout quick return) and also a bigger profit, for yourself!

Merlin

Thanks for the advice on the screwdriver! Not really interested in selling and getting a profit, more interested in a bike to ride and love. My only major mod plan is to replace the chunky original seat with something lower and shorten the original fender. I've already chopped an xj400 into a cafe racer style, trying to keep this one pretty original apart from the seat.

 

[xschris]

That stock seat would way more comfortable than anything else. Also those stock rear lights makes you much more visible to people behind you.

 

[Kipp]

That stock seat would way more comfortable than anything else. Also those stock rear lights makes you much more visible to people behind you.

Understood. I plan on fitting good oem lights and this bike isn't for long rides, not concerned about maximum comfort. I'm young and foolish

Trust me, having chopped and modified my original xj400 and dealing with the ramifications of that I know that keeping things stock has huge advantages - and that's what I plan on doing here, except the seat and rear.