Source for XT350 piston

[jester_parks]

.....can`t find this damn homepage anymore, but the image I copied might be helpful:


EDIT:

Found it:

http://steed2-4.com/

[tommorth]

this would be an easyer way to get some more omf lecy start to ft400 motor
http://www.trademe.co.nz/Trade-Me-Mo...-173012631.htm

[xwhatsit]

this would be an easyer way to get some more omf lecy start to ft400 motor
http://www.trademe.co.nz/Trade-Me-Mo...-173012631.htm

I'm not so keen on those. Heavy as hell, unreliable (especially the electric leg), almost identical horsepower as the RS (albeit at a little lower RPM, but still). Much better off with an XL500 or XR500, but they're getting rare and it means new exhausts, troubles with WoF/police etc.

[deanohit]

Much better off with an XL500 or XR500, but they're getting rare and it means new exhausts, troubles with WoF/police etc.

But super fun I bet!!!

[xwhatsit]

Well there's this sleeve, and this piston.

The piston is a good price, and I suppose the sleeve is too. I wonder how expensive it would be though to have somebody turn up a sleeve from scratch? I suppose the hunk of iron or whatever they use would be pretty pricey on its own.

[Ixion]

/me is confused. That looks like a two stroke sleeve, with all those holes in it.

[xwhatsit]

/me is confused. That looks like a two stroke sleeve, with all those holes in it.

Heh it gave me a fright too -- awfully complex thing, four strokes are much simpler -- but he says `picture is an example only' or somesuch. Probably uses the same pic for all the sleeves he sells.

[jester_parks]

...he most definitely does!
This setup will fit....how much ist the postage and customs though?
Got my Keihin carb 37mm ....and my god, this is a moster of its kind!
Still looking for a XR250 gearbox (the six-speeder) and will start from there.
Frame is ready for powder-coating, needle-bearings for swingarm, clip-ons, round headlamp, Tomaselli lampholder, Kawasaki Mag-wheels with double-disc....everything waiting in the workshop.
Lots of work though at the moment and no chnace to go to the powder-coating shop during working hours.

[xwhatsit]

Sounds awesome Jester, do post up pics when you get there. I'm going with the round-slide CR33 -- looking for more torque than conrod-stretching RPM. I have the 6-speed gearbox but need to sort out the crankshaft situation to match the different balancer situation described earlier.

So has anybody ever had a cylinder sleeve made before? Is it a particularly technical job, or can any engineer munter with a lathe and a boring machine do it? Would it just be cheaper to purchase an XT350 sleeve (bearing in mind it has to be cut down in stroke anyway)?

EDIT: Here's a guy who did one at home. http://www.stallard-engineering.co.u...inderliner.htm How much would one pay for a massive great hunk of cast iron like that (he calls it Meehanite)? Would have to be 86mm + 10mm (enough?) x 2 for width, and stroke of 58mm, so around 100mm x 100mm x 60mm piece of cast iron.

[jester_parks]

another item came in:
BIG VALVES....and when I write BIG...I mean BIG!
Standard is 28 + 24 mm, I try to fit 32 + 27 mm...after all, this massive Keihin carb must not get restricted in any way!!
Space seems to be there in the Honda-head (not like it the XT/TT350 head from Yamaha, where there`s finished with 29mm oversize valves), but - you guess it, valves seats have to be made to size!
One thing leads to another.....

[xwhatsit]

I don't want to put you off, but the CB250RS heads crack all the time between the exhaust valves and the spark plug boss. Interesting to note the XL250S, with smaller valves, seem to be a lot less likely to crack here. If you take the valves too much bigger there'll be even less room and I reckon you'll end up with a leaking head in a hurry.

Anybody do performance camshafts for these motors? Being an XR250 motor I'm sure there were plenty of aftermarket suppliers doing them back in the 80s, must be a little old stock floating around to go cheap.

[jester_parks]

Yes, you are right, the head does crack and my workshop-mate said, he hasn`t seen a Honda head without cracks ever - in his opinion they use the cheapest aluminium, much worse than their competition!
Since my (cylinder-)head is cracked as well, I handed it in for welding, so the whole combustion camber will be welded up, new valve seats & new valve guides will be set, and a new thread for the smaller spark-plug cut.
Those modifications will allow for the big valves and hopefully this big investement (we are talking around Euros 600 for the head w/o valves) will pay off and last.
My main concern is the rod though....

[Ixion]

..

EDIT: Here's a guy who did one at home. http://www.stallard-engineering.co.u...inderliner.htm How much would one pay for a massive great hunk of cast iron like that (he calls it Meehanite)? Would have to be 86mm + 10mm (enough?) x 2 for width, and stroke of 58mm, so around 100mm x 100mm x 60mm piece of cast iron.

Don't even THINK about it. it's much much too dangerous. Trust me on this, I've been there.

In particular

Heat cylinder barrel in oven when Wife away at shops, liner overnight in freezer.
Drop liner into barrel and allow to cool, whilst removing oil-smoke from Kitchen before imminent return.

I assume he had the cylinder rebored properly after fitting the sleeve. I think the hardest bit would be keeping runout and parallelism within limits on a lathe. And getting Meehanite grade iron in NZ.




I'd go talk to the guy at carr Engineering. I think they can get utility cylinder sleeves, which would be a better starting point.

[xwhatsit]

Yes, you are right, the head does crack and my workshop-mate said, he hasn`t seen a Honda head without cracks ever - in his opinion they use the cheapest aluminium, much worse than their competition!
Since my (cylinder-)head is cracked as well, I handed it in for welding, so the whole combustion camber will be welded up, new valve seats & new valve guides will be set, and a new thread for the smaller spark-plug cut.
Those modifications will allow for the big valves and hopefully this big investement (we are talking around Euros 600 for the head w/o valves) will pay off and last.
My main concern is the rod though....

Ah, excellent, I managed to get a second-hand head with no crack, but after a while and a few ten-thousand kms I wonder how it's looking now?

Yes, I wonder what the respective weights of the pistons are. That said, looks like have to carve some metal out of the top of the piston for valve clearance (as said above from the man who's done it before), so that might help -- but even so, I think I'll aim for a `thumper' not a `revver'

[pete376403]

Burt Munro made a sleeve (or maybe a complete cylinder) for his Indian out of a piece of cast iron drain pipe found around the back of his motel unit at Bonneville.