My XS400 build/restoration thread

Update on strange sound issue:
Its not starter motor. I removed starter motor chain and the weird sound is still there. But there is one more thing: the sound is there ONLY when there is a resistance on rear wheel when in gear. So when i sit on it and ride. When in centerstand and go to 1st gear roll the wheel withou any resistance from the ground or weight. There is not that sound. Even when i hold the rear wheel when in gear the sound is back. So? I am clueless really.
 
What about the oil? If the oil were thin (wrong viscosity) or thinned (such as with fuel), then it may not provide enough film strength between the gears and cause noise. Or a thrust bearing (if there is one) is failing.

Just thinking out loud, in the hopes it helps...
 
Oil pump. hmm. I still cannot understand why the noise is there only when there is a load, oilpump would make noise with engine revs, even in netrual? or not?

Oil is mineral 20w50, I was wondering the same, so i am going to make some tests with 10w40 mineral oil.
My thought is also that maybe there is some clutch slip, because of too thick oil, this i will test also.
 
So.. just a small update. All investigation was unsuccesfull, so engine is splitted, and all ball and needle bearings on tranny will be replaced, because that noise has to come from one of that bearings, there is no other choice left :) Inspection of all parts will be included, when the engine is open already :) wish me luck

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Question:

Crankshaft bearing, there are 3 of them, color coded, they are in shape of letter C, on the bottom half of the case - sorry I dont know the correct english name for them (shell bearing probably). Should I replace them, if there was no problem before? I am not sure from reading haynes manual, its says thats its inexpensive change so they recommend it, but i dont see any wear on them, also crankshaft has no side to side play or knocking sound.
nr.10 in the diagram.
crankshaft.PNG
OEM parts are obsolete from what I see, so only aftermarket are available, but if this is not necessary, i would like to avoid this change.
What are your thoughts?
 
Aaand another question: today I was inspection transmission and shifter. I checked all gears, they look ok, there si very minimal chipped corner on one gear, I will probably change it, but still its the 3rd speed gear, and there is no problem with enganging 3rd gear. but I have problem engaging 5th and 6th gear. from 4 to 5 selector drum moves forks but the gears will not engage properly, and transmission is slipping. After several really hard attempts, it can go to 5th and then again problem with 6th.
My first thought is bent shifter forks. I do not see nothing on them, but I suppose they can be bent really just a bit, which i will not see and cause this king of issues. Wheat are your thoughts? thanks
 
Well I was quiet for a while guys, so here is a small big update. Engine is done after complete rebuild. All bearings are new, all rubber parts are new. cylinders honed, valves gapped, pistons cleaned and with new rings. During rebuild I sodablasted engine parts to clean them up, great way to remove old gasket material and all that old gunk, then water pressure, then air pressure and they are clean as new.

I have to proudly say, that after rebuild, and fresh oil. she started after only few seconds of hesitation, and now she starts like a new bike. I have to play with carbs a bit, because with choke she dies. but luckily its not necessary to use choke to start it up even when cold :)

Funny thing : that whining sound is still there, but everything is new and working like a new. so i just realised, it will be specific sound of this motorcycle, so she received new nickname: Cricket :))

First kick is the best one ;)

more updates soon and during the winter (customization is planned)
 
Great work. Love the sound of an easy start. Where did you get your shell bearings for the crankshaft mains? I debated replacing mine too but could not find any OEM.
 
Great work. Love the sound of an easy start. Where did you get your shell bearings for the crankshaft mains? I debated replacing mine too but could not find any OEM.

Thanks, actually i did not replace crank shell bearing, they are in very good shape by visual reference, no wobble, no ripping. so i reused them. But yes, they are not easy to buy, and OEM are obsolete.
 
Quick question guys: my bike is running well and i can start it without choke(enricher) anytime, DURING SUMMER TIME. Choke will actually kill the engine, cold or warm. Because there was no issue with starting it without, i leave it as i was.

But now, during winter, i have big issues to start the engine when cold. I have to warm the engine externally with heater, and use startgas spray to help it to start.
Soo, i want to play with carbs a bit more, to set up it correctly. I will study, but maybe you will know what to check first. Am I running rich? and because of that with enrichener fully open, mixture is so rich that it actually kills engine/cannot start?

I ran the bike only cca 100kilometers after full rebuild, so i am not able to check plugs for mixture.

thanks
 
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