Evan
XS400 Enthusiast
Great work! Can you share some more info and/or pictures on how you're mounting the seat? I just picked mine up at the post office and I'm scratching my head over it.
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Restarted Project
- Thread starter Pork Chop
- Start date
Pork Chop
XS400 Junkie
G'day Evan, I guess that you now know that the seat is a little narrow at the rear to sit on the frame. I thought of putting a cut in the fibreglass to let it flex a bit but did not have a dremmel at the time. I made a bracket out of angle aluminum that bolts onto the fender mount and also acts as a mount for the rear indicators. I did not use locking washers so i lost the bolts to hold the seat on. That didn't really matter as to raise the seat off the frame a little i used some 1/2" rubber stuck to the frame with double sided tape and used concrete velcro to attach the seat to the rubber. Funny thing is that the velcro did a great job of holding it in place and was pretty easy to do.
Here is a pic of the bracket.
Here is a pic of the bracket.
Attachments
Evan
XS400 Enthusiast
Right on. Thanks for the info.
Pork Chop
XS400 Junkie
Hey Pork seats looking great, are you not going to chop the back of the frame and grind off the old seat hings? Your bike will look heaps cleaner with all that removed.
Pork Chop
XS400 Junkie
Ah sweet! Paint job looks great too.
Pork Chop
XS400 Junkie
Update.
I successfully removed the rear wheel bearings using the rawl bolt technique but the front wheel bearings are stuck in tighter than a frogs arse. I welded a piece of steel rod to the inner race so it was poking out the other side of the wheel. Gave it a wack with a hammer and part of the race broke off.
The guy at the bearing shop said if the old bearing is stuck in the wheel then to do a couple of weld beads on the inside of the outer race & when the race cools it should loosen. Just using a dremel to cut out the inner race.
Posted via Mobile
I successfully removed the rear wheel bearings using the rawl bolt technique but the front wheel bearings are stuck in tighter than a frogs arse. I welded a piece of steel rod to the inner race so it was poking out the other side of the wheel. Gave it a wack with a hammer and part of the race broke off.
The guy at the bearing shop said if the old bearing is stuck in the wheel then to do a couple of weld beads on the inside of the outer race & when the race cools it should loosen. Just using a dremel to cut out the inner race.
Posted via Mobile
Pork Chop
XS400 Junkie
I just realised that my new case bolts are 5mm shorter than the old ones. I used the part number code translation to order them but the buggers are a different size. I remember reading somewhere that if you have 2 x the width of the bolt in length threaded into the case then that is enough to hold. Does that sound right of should I start re-ordering.
Cheers.
lhaolpa
XS400 Junkie
I remember reading somewhere that if you have 2 x the width of the bolt in length threaded into the case then that is enough to hold. Does that sound right of should I start re-ordering.
Cheers.
I think that I'd return them and get the right ones. The danger of stripping out the threads is too great,and the results would be bad. lha
shamus
XS400 Addict
I remember reading somewhere that if you have 2 x the width of the bolt in length threaded into the case then that is enough to hold. Does that sound right of should I start re-ordering.
Cheers.
I too have heard as a rule of thumb, case bolts should protrude half the length of the bolt before threading it. I think we're saying the same thing, right pork chop?
shamus
XS400 Addict
Scratch that, I re-read what you said and we are not saying the same thing. However, I would imagine if there isn't a significant difference in the length of the bolts, and the threads are the same, I wouldn't be worried.
Pork Chop
XS400 Junkie
I definately don't want to strip anything so I will measure the old bolts & re-order using those lengths.
Cheers guys
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Cheers guys
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jray
XS400 Enthusiast
hey porky, your build is looking great. How are you going with the 400 uograde? Do you have a 400 head?
Pork Chop
XS400 Junkie
It is going slow. I kept the 250 head, cam, valves & carbs. Cash is a bit short at the moment so I am pretty much going to assemble it without making any more modifications (purchases). I will rejet the carbs but that is about it. I know that I will not be getting the full potential out of the 400cc but I aim for it to be an improvement on the 250cc. I probably should of bit the $180 bullet & got a 400 head but I was kind of keen to just try out the cylinder swap.
Hey mate im also looking forward to see your project progress. I was under the impression that if you wanted to run the 400 barrels you would need the 400 head? Wouldnt the valves be too small on the 250 head? Also assumed you would need the carbies from a 400.
Pork Chop
XS400 Junkie
This is a learn-as-you-build project so some or all of what I am about to say could be wrong 
The '78 xs400 pistons and cylinders bolted straight onto the '81 xs250 crankcase and head. I chose the US '78 as they have square fins like the Aussie '81 model. My original approach to this project was this as a capacity increase for the xs250 and not an xs400 conversion. I know that an xs400 head, cams and carbs would be the better option but all that equals more cash - which I don't have. The smaller valves should help with low rpm torque but will not flow enough for max top end power which is fine with me as this is more of a cafe creeper than a cafe racer. With the right jetting, I am pretty confident that it will run better than an xs250 but not as strong as an xs400.
I wont quit and I will keep plugging away at it but I'm just feeling a bit jaded about how long it is taking.
Cheers.
The '78 xs400 pistons and cylinders bolted straight onto the '81 xs250 crankcase and head. I chose the US '78 as they have square fins like the Aussie '81 model. My original approach to this project was this as a capacity increase for the xs250 and not an xs400 conversion. I know that an xs400 head, cams and carbs would be the better option but all that equals more cash - which I don't have. The smaller valves should help with low rpm torque but will not flow enough for max top end power which is fine with me as this is more of a cafe creeper than a cafe racer. With the right jetting, I am pretty confident that it will run better than an xs250 but not as strong as an xs400.
I wont quit and I will keep plugging away at it but I'm just feeling a bit jaded about how long it is taking.
Cheers.
haga41cat
Xs Nerd
Yeah that's right I was on a model update course at Yamaha uk, and the guys there said this is the case
lhaolpa
XS400 Junkie
I remember reading somewhere that if you have 2 x the width of the bolt in length threaded into the case then that is enough to hold. Does that sound right of should I start re-ordering.
Cheers.
That would be great if you're talking about 1/2",threading in 1",but 1/8" threading in only 1/4",I don't know about that. lha
haga41cat
Xs Nerd
Lol I'm talking about 6, 8, 10 and 12mm bolts
