Here goes nothing

pwizl · Mar 12, 2014

Picked up this '81 XS from a buddy at work, he had it running for a while, but could never get it going quite right. I've been talking about building something for years and he has too many projects, so I bought it off of him and brought it home.

Tore it down and started working on some design ideas. RD400 tank and 21" front wheel.

Have some unique ideas for the rear suspension, hopefully I can get them to work.

Frame pretty much as it sits now..

Plans so far, keep stock front end with 21" wheel, rebuild carbs and motor, very leaky and had been around a lot of moisture at some point, design and fabricate a rear subframe for seat and mounting of rear suspension, monoshock. So, like the title says...Here goes nothing!

Paulrxs650 · Mar 12, 2014

Sounds interesting, keep it up with plenty of pics

Bellingham eh? I live a couple of miles from Bellingham in England

pwizl · Mar 12, 2014

We're practically neighbors Paul :laugh:

Over the past several months I've been acquiring parts and getting design ideas and doing a LOT of reading and research on this and other forums. This is my first motorcycle, I have some decent mechanical abilities, and have worked on cars before, but never bikes, so this is all very new to me. But I will say, the work I've done so far has been a lot of fun. I enjoy the mechanical aspect and the satisfaction of taking something that is not looking or working the best and bringing it to where it looks and works good again.

This forum has been a wealth of information and I've learned a lot already! I'm looking forward to getting all of your feedback and suggestions as this build goes on

bowietwin · Mar 12, 2014

Give it hell. I will be following. Good luck.

Fndirtygreaser · Mar 12, 2014

Tank and 21" front wheel is already looking good.

pwizl · Mar 12, 2014

Started with the motor, doing a complete tear down and rebuild. The motor has just over 20k on it and is leaking from just about every seal and gasket so I figured I might as well take it all apart and start fresh. From rebuilding a 350 Chevy, and helping friends on their stuff, I've learned it's better to just do it all the way and right the first time, then try to polish a turd.

First evidence of a moisture problem, going with a PMA so I'm not sweating trying to save anything

Once I got into the motor I was pleasantly surprised with the top end..
Cam lobes and bearings looked great, cam chain will be replaced so I don't have to worry about stretch

Tappets looked good, no gouges or weird wear marks

Signs of running rich? Possibly some oil getting in the combustion chamber? Top of valves and valve springs looked real good, I'll clean up head, disassemble and take it to my mechanic to see what can be saved and get a valve job done.

TwoManyXS1Bs · Mar 12, 2014

Looks pretty good for a 20k+ engine. Sound thinking on the 'do it all, right first time'.
Might just be reflections, but cam followers look to have flat spots?
Have mech lightly dress the valve stem tips, to remove any 'doughnut' wear grooves...

pwizl · Mar 12, 2014

TwoManyXS1Bs said:
Looks pretty good for a 20k+ engine. Sound thinking on the 'do it all, right first time'.
Might just be reflections, but cam followers look to have flat spots?
Have mech lightly dress the valve stem tips, to remove any 'doughnut' wear grooves...

The followers looked really good to me, no flats that I could tell. I'll post a picture, first time with these, so I may not see things right. Thanks for tips..keep em coming!

alfredo · Mar 12, 2014

I agree. That looks like a runable and pretty clean setup. Welcome to the site and good luck!

Airwolfie · Mar 12, 2014

Wow,nice and clean inside! Do the lapping yourself! So much more satisfying than someone else doing it!

pwizl · Mar 12, 2014

Airwolfie said:
Wow,nice and clean inside! Do the lapping yourself! So much more satisfying than someone else doing it!

I just want to make sure all the tolerances and dimensions are within spec. Want him to check valve guides and re-cut the valve seats to match the angle on the valves in particular, then I may lap in the valves. But I hear you Airwolfie, I will be doing as much I can myself, that's what makes this fun!

pwizl · Mar 12, 2014

Tore into the motor a little bit more. Got into the cylinders and found a bizarre line etched into the walls of each cylinder in a perfect circle. At first I couldn't figure out how in the world that could happen, the only wear I've ever seen to a cylinder has always been vertical. I was stumped and curious so worked my google foo and came up with a cause....water in the cylinders! At some point water got into the cylinders and the bike just sat causing the water to sit in one spot and cause the corrosion. I'll post pictures of the etched cylinder walls when I can find my decent camera.

pwizl · Mar 14, 2014

Picked up a nice set of used cylinders on the cheap, old ones would have to be bored out and the cost of that plus new oversized pistons and rings just didn't make sense. The original pistons are in great shape, so new rings and the new cylinders were much cheaper.

Took the carbs apart and soda blasted the bodies and bowls, put the jets, needles and such through the ultrasound. Everything cleaned up real nice.

pwizl · Mar 15, 2014

This is the exhaust I'm going to run. Designed with collaboration from Gordon Scott Engineering and built by him. It's 2 into 1 that runs down the right side of the frame still allowing for access to the drain plugs. I'm still not sure how and where it's going to end, it'll depend on the rear suspension.

ANLAF · Mar 15, 2014

PWIZ, that strange perfect circle in the cylinders says it has been stood for a while and will need a rebore. Airwolfie and I are on the same wavelength - do as much yourself as possible. The valve lapping is very satisfying, but if you have someone who wants to check out stuff for you then that is good too.

I like those pipes.

ANLAF

pwizl · Mar 16, 2014

Blasted the head and took it apart with my ghetto spring compressor tool. Taking it in for a rebuild Monday.

Also blasted the replacement cylinders and got some color on them.

ANLAF · Mar 17, 2014

PWIZL - that's a lot of good work there. Just one thing - if you do have any imperfections in the cylinders (circular ridge or rust pitting) you might want to consider a rebore to the next oversize and stick new piston rings in there. Just a thought.

Great work, looks good.

ANLAF

pwizl · Mar 17, 2014

ANLAF said:
PWIZL - that's a lot of good work there. Just one thing - if you do have any imperfections in the cylinders (circular ridge or rust pitting) you might want to consider a rebore to the next oversize and stick new piston rings in there. Just a thought.

Great work, looks good.

ANLAF

Replaced original cylinders with the ones pictured in previous post

CDNTX650 · Mar 17, 2014

Did you get the new set checked with a bore guage? Who says the new cyls arent out of round too..

Posted via Mobile

pwizl · Mar 17, 2014

CDNTX650 said:
Did you get the new set checked with a bore guage? Who says the new cyls arent out of round too..

Posted via Mobile

Bought them on faith that they would be good, pictures I saw looked real good and the seller said they were good, but you're right, with used parts you never know. Fortunately the cylinders were perfect and the bores checked good.

Head dropped off for rebuild. Cases being cleaned and blasted today, head cover, sump cover, breather and tappet covers dropped off for powder coat. More to come.

Here goes nothing

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