First build.. Trying to do a desert sled-ish bike

[Lasper01]

Hello everybody. Lasse from Denmark here. I have enjoyed alot of all the buildthreads in here and now I will try to make one myself. And at the same time hoping to get some input and help.

This is the first time Im doing a build, so it will probably take a while

The bike is a Standard xs650D from '77. I have owned it for almost three years now and have made some upgrades: Hughs PMA, Pamco w/ e-advance and simple wiring. I have also put new stainless spokes in both wheels. Unipods and rejetted carbs.

Me and the bike:

For some time I have been wanting to try to change to looks a bit. Towards the old desert sleds and scramblers.

But I didnt wanted to tear it down without having another bike to be driving, so I bought a standard 79 really cheap because the crankshaft was broken a little bit at the woodruf slot. I bought a Hughs PMA and it started and run perfect.

The engine on the '77 had low compression, so a rebuild is needed. But that came sooner than expected. One day the bike was really hard to get started and when I finally had it running it pissed out of the breathervents with a mix of oil and gas. I quickly turned it off and opened the sump. The mixture coming out was so thin.
I put a woodenstick in it and tried to set it on fire. It burned easily. So Im guessing alot of gasoline in it.
Im not sure for how long it have been gas and oil instead of clean oil but how much could it have damaged?
Could this be caused of a sticky float? Or so bad rings that the gasoline has been pushed pass the rings and into the sump?

I started the teardown:

Yay! The engine came out easy! A big moment for me

I dont have alot of experience with welding but I made an enginestand by myself

 

[Lasper01]

I hope I only need to do a topend rebuild so I started with.. the top

Any words on the carbon on the pistons? Too rich or is it normal?

Its the original pistons.

It looks like the chain has broken the gasket:

 

[fredintoon]

Hi Lasse,
bad English but good advice on a Desert Sled conversion (long ago notice pinned up in Lockheed Aircraft Co's design office)
Simplificate and add lightness.
Aluminum gas tank, headlight & fenders, solo seat, remove electric starter, fit smaller battery and it will still weigh about 180kg.
Most likely your carb floats sank and let fuel run into the intake ports and then trickle past the pistons and down into the sump.
Fuel will trickle past good pistons and rings too.
The XS650's all roller and ball design gives it a far better chance of surviving this than a plain bearing design would have.

 

[Lasper01]

Yes I apologizes for my bad english.. I hope you all get the point
Its mostly the looks that I will try to go for desert sled but yes I will try to simplicate it. I have removed the starter and will run with sparks capacitor.

 

[Lasper01]

Pulled off the barrels

Are the markings on the sides normal or too much wear?

 

[fredintoon]

Yes I apologizes for my bad english..

Hi Lasse,
your English is OK. The BAD English is in the quote:- simplificate and add lightness which should be simplify and lighten but has been stated in the way it was to make sure that everybody keeps reading it until they understand what it means.
About the piston wear; check the piston to bore clearance, the ring gaps and the ring up-and-down movement in the ring grooves.
If they are all within the recommended tolerances, lightly hone the bores and re-assemble.

 

[Lasper01]

Ahh I see.. Thanks Fredintoon
Ok I Will check the clearance soon.

 

[arcticXS]

Lasper,
I am doing the same to my XS, also a 77 D model. I agree with you that losing weight is priority number one. As my XS had twin brake discs, I ordered a custom disc from ISR, 320 mm dia, and a used Brembo caliper. This reduced the unsprung weight from around 15 to 10 kilos. I also got an alloy front fender from The Tank Shop in Scotland, saving more weight. In the rear, I had a custom wheel built, using a Talon MX hub and an ISR brake disc, with a Brembo 2-pot caliper. I haven't checked the weight difference yet, but it will be substantial. Going to a 520 chain and sprockets will also save weight, at least 1 kilo if using an alloy rear sprocket. Then more weight can be saved by replacing the exhaust system with single wall headers and lighter mufflers.

I am considering getting a "Special" tank, since it is slimmer and lighter. I bought a "Classic" seat from Motolanna, and it is nicely made, but looks a bit small with the Standard tank. And I have done a lot more changes, but my project is still far from finished...... But one day!

 

[oldbmw1]

My friend and I built two desert sleds for the 2012 Barstow to Vegas dual sport.

 

[oldbmw1]

Here are some pics

 

[oldbmw1]

More pics

 

[oldbmw1]

More.....

 

[oldbmw1]

Oil seepage.....

 

[oldbmw1]

Friends on the trail
We freaked out KTM riders when we passed them.

 

[Lasper01]

Not to be rude but you are hijacking my thread with your holiday pictures.. Now back to the process:

I found an old honda tank at a swapmeet:

Tried it on

And made a seatpan

I hoping to make the seat so it will follow the lines of the fender.

On to the detabbing the frame

 

[Lasper01]

Pulled the swingarm and the triple trees. They both had the old bearings and bushings

So they will be upgraded to brass bushings and tappered roller bearings.

 

[oldbmw1]

I posted those pics for inspiration in building a desert sled actually participating and finishing the biggest desert race in the nation....."Barstow to Vegas." I was trying to inspire your build titled "desert sled."

 

[Lasper01]

Ok.. thanks.. But it would have been more inspiration if you post pictures of the bikes.. thats all

 

[CDNTX650]

Yeah, more pics of the bikes and info.

 

[Lasper01]

Yesterday I got to work a little bit on the head and valves. I think it got a lot of carbon buildup and the exhaust manifolds are hard to clean up. Does anybody have tips and tricks to clean them up easy?

I used a dremel with a little wirebrush and it work OK

But Im worried about these scratches near the intake valve. Shall I grind it out or let it be?

And is these grindings in the intake normal?