270° 953cc Sidecarcross engine build

[270YAM]

That cam & sprocket is some piece of work! Do you mind sharing some specs on the cam?

Hi Okie
I have the specs written down somewhere, when I find it I'll let you know
Pretty sure it is Shell #1 or very similar. The 101° lobe separation could be a giveaway...

 

[Paulrxs650]

Hi 270yam, nice work on the Pattern and the mould. They turned out well! Yes, time served Pattern Maker and Mechanical Engineer. I served my time for Rolls Royce. We made patterns for items like the ones you've done up to around 150 tonne. Yes, plenty of experience casting, from cast iron, through to aluminium and stainless and exotics like titanium. Happy to help

 

[mick71b]

Heating the metal in a propane fired furnace that I made from a beer keg.

Now I'm really impressed.

 

[bergoff]

All I have to say is WOW. You are talented nice work.

 

[JohnGoodenough]

You're a genius Matt!

 

[XSGLENN]

My God! You are a BEAST. Great job man.

 

[xs650dreamer]

Kick start shaft has also been modified to allow 100% engagement of kick gear onto the dummy 1st gear. Standard XS650 only engages about half way across which is fine for a stock motor, but can lead to problems with big cube engines. It causes first gear (countershaft gear) to wear unevenly, and even lead to cracks between teeth.

Quaife 1st gear damaged by kick starter- has a small crack at base of gear tooth

Because the dummy first gear in this setup is sitting further to the right side than standard, I only had to make the kick gear slide across a little further to achieve 100% engagement.

Kick start shaft with the flange faced back to allow the gear to engage further:

what exactly did you do here man ? bacuase my kickstarter works but sometimes slips because, the gear inside the tranny has a couple of chipped teeth. guesing po kicked it over when it was already on haha. im guessing if i can get 100% instead of the 50% or so stock contact it would always engage

 

[270YAM]

It finally lives!

Here is a short vid of the first startup. Running really rich, but at least it's running!
Unfortunately the iPhone sound quality doesn't do it any justice, but you get the idea..
Let me know if you can't view it via Facebook and I'll try to get it up on YouTube

https://www.facebook.com/photo.php?v=665764763459672

 

[JohnGoodenough]

Sounds amazing!!

 

[goodgollyjosh]

Nice!

 

[xs650-4-me]

Not sure if anyone is still following this, but;
- about how much would cost to build a 750 stroker ?
- Would the orig cyls work ? is there enough room ?
- would there be more vibration ?

IMHO, a stroker 750 might be the perfect xs650-rider, not to race.

 

[hotdog]

For the hassle involved in modding the standard crank to accommodate or building a custom crank to suit is not worth the hassle, let along the prohibitive cost. If 750cc is all you're after just but a bore kit and be done with it.
Or alternately get yourself a 533 crank and some xt500 pistons and build yourself an 880cc on the standard 533 crankshaft. Still lots of work, but I'd wager less costly than playing around and stroking a crankshaft.

However, in answering your questions
- How much would cost to build a 750 stroker ? Many thousands of dollars to do it correctly - a 750 bore kit can be done well for about $1K
- Would the orig cyls work ? is there enough room ? Yes the cylinders would work - you would need to install a spacer plate to accommodate the increased stroke and then run sans top engine mount or modify to suit. Or have customs pistons manufactured to suit your engine stroke/bore combination.
- would there be more vibration ? Potentially yes, you're wanting to add additional weight (longer rods + 750cc pistons) to an engine that already has a reputation for vibrating. Engine components and the assembled crankshaft assembly would need to be balanced after the machining operations needed to stroke the crankshaft are completed.

With the numerous pistons kits available for the XS engine there are plenty of 750cc options available. There is even a very competitively priced 706cc kit available that has been having good reports/results.

Personally, I would buy an SV650 or a new Enfield 650 twin before pouring big $ like you're considering into an xs650 engine.

Good luck with your engine build.

*Edited*

 

[xs650-4-me]

Has anyone (following this) ever ridden a...I will post a new TOPIC about this instead...better.

I started a new TOPIC, XS vs Triumph vs Norton.

I don't really want an oversquare engine...