I have had another look at my motor but still can not find anything obviously wrong.
I did forget to mention that occasionally after about 10/15mins of riding, when de-accelerating and coming to an intersection it would sometimes make the same rattly noise. It doesn’t make the noise when accelerating or under load, only sometimes when slowing down and intermittently at idle/lov revs. It seems sensitive to revs because I can blip the throttle a bit and it will settle down for a few minutes and then all of a sudden the noise appears by itself when its in neutral and then as soon as the clutch is pulled in it stops, then let the clutch out and its back and I can pull the clutch lever in and out and turn the noise on or off as if it was a switch.
The last time I rode the bike before the rebuild was in September 03 and it had a noisy top end but im pretty sure it didn’t have this new noise I cant suss out. It may be possible it was there but I couldn’t hear it because of the rattly piston but I doubt it. Back then I was using Penrite 2 stroke gear oil for jap bikes. Back 3 weeks ago when I had it rebuilt I just had some Mobil 2 stroke gear oil in it until I was going to order some good Belray gear oil. I know the recommended gear oil is ment to be an engine oil but I don’t think it would make too much difference.
The next thing ive looked at is if the left hand side needle roller bearing for the lay shaft was inserted to far. I cant remember if I re-newed it but anyway I found out that it doesn’t affect the layshaft end float anyway as there is a thrust washer against the 2nd gear cog that rests against the cases and the bearing end is not closed off. The reason im thinking it could be layshaft endfloat is because when after bolting the cluch basket on and doing up the clutch center drum nut I could still grab hold of the clutch center hub and could get it to move in and out and make a noise.
The right hand layshaft bearing was a SKF and is driffted in all the way and ive got the kickstart gear pressed into it all the way like original. I cant imagine the SKF bearing is totally out of wack and not as good as a genuine bearing which would be a Koyo probably.
I measured my laysaft cluster from the surface of 2nd gear to the surface of the 1st gear which is actually machined onto the layshaft. My specs say 78mm +/- a little bit and right on about 78mm was what I have, which it should have been because I haven’t removed and refitted the 2nd gear which is pressed on.
Up against the fist gear pinion which is part of the layshaft there is a combination of thrust washers and thrust needle roller bearing. This is where im not sure. I have several manuals inc a factory manual and they don’t all agree which each other on the order and don’t match up the same with the parts book on alpha-sports. There are 2 washers the same size and one larger OD one. According to the parts book for 1980 they show 2 washers the same part number with the thrust needle roller bearing in between and no larger third washer. My Haynes and factory manuals show 3 washers. I don’t know if the parts book is right and maybe they have used the diagram for the B/C 185 which in my B/C factory manual only shows 2 washers. I 2 smaller washers and one larger one and I know the history of the bike and know its had them since new. I also don’t know if the way ive been putting the washers on is correct.
Does the one large one go on first then a small one, then the bearing then the other small one? Or do the 2 small ones go on first then the bearing then the larger washer? Which is what one manual says.
So that is one area I am not sure on, but when I first put it together I thought it was right.
After these washers and thrust bearing there is a needle roller bearing split in 2 halfs and that goes inside the kickstart gear. There is a right and wrong way for this bearing to go on and im aware of this.
Ive got all new clutch plates and new heavy duty springs but once again I can see these causing a problem.
At the moment I don’t know what to do. Im searching for answers. I think my first option is to replace the left side thrust washer against 2nd gear, the 3 thrust washers and needle thrust bearing against 1st gear and also replace the split 2 halves needle roller bearing. And then reasseamble it once I know what is the right way to put those 3 thrust washers back on. I cant see any evidence of a big end or main bearing seizure so I don’t think my motor had seized. I was getting worried though and fitted a bigger main jet. I have used the OEM left side main bearing with shield but used a SKF main bearing on the right side. Its just a normal 6205 or something. Should the right side main bearing only be OEM? Does the OEM right side main bearing have a C3 tolerance and should I only use a OEM bearing here? I cant see its casing any problems but if it’s a definite no no then I will change it now while its apart. I know for an Adler motor I just did it was recommended to put C3 main bearings in that but that was a twin with a bolt together crank shaft in 2 pieces. Has anyone else just used off the shelf non OEM main bearings in jap 2 stokes with no issues?
How far off are you from getting your 185 motor together Doc? I would really like to be able to compare mine with yours and know how your layshaft assembly and clutch goes together. Maybe I can wait for a bit until you can pull a 185 engine apart or get one back together.
If I still have the noise once fitting these few minor bits and maybe trying a heavier oil I think my next step is to replace the whole clutch basket with a new one which I think is about $80-$100 because mine has got some internal movement in the rubbers. After that I don’t know, throw the bike in the bin?, I hope not because ive spent a lot on it and just want a simple noise that I believe is not normal and not ment to be there to go away.
Any suggestions are welcome especially in regard to the correct order of fitting the washers/thrust bearing on the right side of the layshaft against first gear as I now do not know what manual/parts diagram to believe.
Thanks