Source for XT350 piston

[xwhatsit]

Hullo,

Where do we buy cheap Yamaha bits around here? An 86mm XT350 piston (rings, too, please) would be nice to have right now.

[Ixion]

Which XT350 ? DOHC or SOHC?

[xwhatsit]

Which XT350 ? DOHC or SOHC?
I couldn't tell you to be honest -- it has an 86mm bore, I believe circa 1983-85.

[pete376403]

Have you tried Yamaha? I bought a piston for a FZR1000 recently (older, pre-EXUP model) $130 IIRC 13 days ex Japan. (no rings, pin or clips)
The only option was Wiseco, but would have meant buying a set of four at around $600-something.

[xwhatsit]

`Tried Yamaha' -- do you mean go through a dealer? I've never spoken to one of them before. I've seen a few Wisecos on eBay, but they're expensive, and tend to be oversize or high compression.

Rather hoping there was an Econohonda/David Silver equivalent for Piano Bikes?

[Motu]

How about a nice XT400 piston at 87mm.Take some photos and measurements.

[pete376403]

`Tried Yamaha' -- do you mean go through a dealer? Yup, that price was from Motomart in Lower Hutt

[Ixion]

86mm is common size. Lots of bikes used it. G80 Matchless, B34, short stroke Manx Norton

86 x 86 gave a square 500cc.

If it's just an 86mm bore you need you could have a pretty wide choice.

[xwhatsit]

I think the important bit is that it can bolt up to a CB250RS conrod without hassle, and clear the valves. Apparently the XT350 can fulfill that.

I believe, based on some basic googling, that it is the DOHC.

I would also assume that the TT350 would have the same basic sort of piston?

@Motu -- I'll try and track down some specs about the piston. Gudgeon pin, height etc. New sleeve at +12mm or +13mm; don't think it'll cause too many problems.

[Motu]

The XT400 piston is 87mm - 20mm gudgeon and 27mm gudgeon height,and about 1mm dome.Looks nice - you wouldn't think I'd thrashed the ring out of it to look at it.I did weigh it once....oooh?....about that much.

[xwhatsit]

CB250RS (and therefore presumably XT350? Trying to find specs on the piston but turned up SFA) uses a 19mm gudgeon pin, so no joy there.

Then again, just checked the crank I had in mind, and there does seem a tiny amount of radial play in the small end, at least when using the old gudgeon pin from a fecked piston. Except if going from small pin to big pin, you normally bush the piston, not bore out the small end, right?

[FilthyLuka]

Wiseco XT350 Piston:

- 9:1 compression ration
- 86 x 59.6 (bore x stroke)
- Available in 1mm and 1.5mm oversizes aswell

Piston part no = 4674M08600
$172.82 USD per piston

Repl. Ring Set part no = 3386xc
Repl. Pin and Clips part no = S475

Grand total = $219.92 USD and you can order straight from wiseco

[xwhatsit]

Problem is with the Wisecos, is that the piston crown tends to be pushed to the limits in order to raise compression ratios (although 9.1 is a mild increase). When you're sticking a different cylinder head on top, valves hitting worries me. Plus, I think I want slightly lower compression ratio as well, save the bottom end from too much pain.

Once I've worked out crankshaft situation, I'll call some of these Yamaha dealers.

[FilthyLuka]

Problem is with the Wisecos, is that the piston crown tends to be pushed to the limits in order to raise compression ratios (although 9.1 is a mild increase). When you're sticking a different cylinder head on top, valves hitting worries me. Plus, I think I want slightly lower compression ratio as well, save the bottom end from too much pain.

Easy solution. Get two head gaskets and some goop. Put the two head gaskets together with goop inbetween em. Extra 5ft/lbs on the cylinder head bolts.

Worked on a cortina with a skimmed head...

[xwhatsit]

Easy solution. Get two head gaskets and some goop. Put the two head gaskets together with goop inbetween em. Extra 5ft/lbs on the cylinder head bolts.

Worked on a cortina with a skimmed head...
What I mean, is that putting an XT350 piston in a CB250RS motor is a marginal thing to begin with. The only reason I know it works is that it's been tried a couple of times and that it works. Fiddling with it by using a high-crowned high(er)-compression piston is fiddling with the magic formula to great success :)

Yep, I remember you posting up that double-head gasket trick; was just thinking last night that'd be a good solution to employ.

[Muzz67]

I was the tinkerer who originally fitted an XT350 piston into a '79XR250 motor.
I had the XR piston reliefs machined into the XT piston, thats all. Cylinder was re-sleeved to accept the 12mm oversive piston, and case halves machined also. I used an XR500 head gasket as the 500piston is 89mm!! XR500 carb and manifold bolts straight on. Would have benefited from a mild cam and free-er exhaust, but went really well (Pretty sure it still goes!!) Muzz,0211320763.

[Muzz67]

"""I was the tinkerer....."" Well, I still AM that bloke!

[xwhatsit]

Cheers Muzz -- once I get the sodding thing back from Holeshot, might give you call. What do you mean by the XR piston reliefs? For valves? I don't remember the piston having any dishes to make room for valves -- my RS piston has a couple, but that's because the camchain jumped off, not because it was made that way :shit:

[Muzz67]

Not sure about RS pistons, but XR/XL ones have a raised dome with valve reliefs machined into them. Just had the positions,angles,and depth replicated in the XT's flat-top. Meybe a TT piston has a raised dome for a higher compression??

[jester_parks]

Hi guys, first of all let me introduce myself: I am a middle-aged German (52), who - incidently - is working on the same topic: getting the Yamaha350-piston into the Honda 250RS.
My wife is riding the Honda and I own XT + TT350 Yamahas and thus the idea as I has both pistons in my hands already.
If you are still looking for a Yamaha piston, let me know: "second-hands" I have some, but merely for getting an idea, not for using....
Sometimes there are also XT350 pistons on ebay (NOS)....and should I get two, I would be happy to post one to you.
Will stay connected via this forum to hear about your results and will post mine as soon as I get forward.
Cheers for now

jester

[xwhatsit]

Hey cheers for the post mate. Will be very interested to hear how you progress -- if you do end up with an extra one on your hands, it could be a good idea to buy it off you. You Germans seem to like big-boring CB250RSs -- a while ago there was a German-built ~280cc RS on Youtube, but now it's disappeared.

Right now the first task I have to do is rebuild my Super Cub so my sister can ride it to university -- then I can get stuck into the CB350RS :D

[jester_parks]

280cc is fairly straight-forward: just slot in a 78mm piston and its done.
335cc requires a bit more of work: this 86mm Yamaha piston needs another sleeve as the Honda sleeve won`t take the big-bore.....so start to lock for a Yamaha XT350 cylinder in time. This sleeve has to be pressed out and shortened. Next: the crankcase won`t accept the big sleeve!!....I am myself looking for a crankcase to do the machining there...the engine of my wife`s RS will stay untouched!
Please let me know more about your XR-crankcase: whick model is it exactly?As there are basically no XR`s around here, which XL model will do the trick also (exact Model would be helpful - RS is MC02 for example)...

[Squiggles]

http://www.bikebandit.com/houseofmotorcycles/yamaha-motorcycle-xt350n-1985-crankshaft-piston/o/m8347sch227992

That the one you were thinking of last month?

[xwhatsit]

280cc is fairly straight-forward: just slot in a 78mm piston and its done.
335cc requires a bit more of work: this 86mm Yamaha piston needs another sleeve as the Honda sleeve won`t take the big-bore.....so start to lock for a Yamaha XT350 cylinder in time. This sleeve has to be pressed out and shortened. Next: the crankcase won`t accept the big sleeve!!....I am myself looking for a crankcase to do the machining there...the engine of my wife`s RS will stay untouched!
Please let me know more about your XR-crankcase: whick model is it exactly?As there are basically no XR`s around here, which XL model will do the trick also (exact Model would be helpful - RS is MC02 for example)...
So you're going to use a sleeve from an XT350? I was thinking about getting one machined up from nothing.

If you're referring to me with the XR crankcase, I don't have one -- I have three RS engines in bits. All of them are MC02. As far as I can see (I have one crankcase split open), it just needs the `entrance' ground out to be a bit wider (6mm all round). Unsure what to use for a base gasket, perhaps have to have one made up as well -- the normal base gasket isn't much more than a centimetre wide anyway.

The XL250S (between 1978 and 1982 I think) and the XL250R between 1978 and 1982 (actually I can only see information on a 1982 XL250R, so perhaps that was the first year they made them) are the same engines as the CB250RS. Differences in piston compression, valve size, header size, and later on with the XR250R, only one balancer and 6 speeds. The crankcases should be the same though -- apart from the CB250RSD MC02E, which was electric start. I can't help you with the proper engine numbers, can't find information on that unfortunately.

http://www.bikebandit.com/houseofmotorcycles/yamaha-motorcycle-xt350n-1985-crankshaft-piston/o/m8347sch227992

That the one you were thinking of last month?
That's what we're looking for!

[jester_parks]

According to the Wiseco-list, the XL250 in the years 1979 - 82 and the XR250 up to 1983 should be identical to our RS-engines: 74 x 57.8 mm and 19mm piston-pin. Later on they had 75 x 56.5mm and 17mm piston-pin.
No idea about the gears and balancers though, but fancy the idea of 1 balancer shaft only "cog-driven"!!
Will keep an eye on that!
Base gasket I will use the original one and cut it to size.
Head gasket - I think it was mentioned earlier - XR500??

[xwhatsit]

No idea about the gears and balancers though, but fancy the idea of 1 balancer shaft only "cog-driven"!!
That would be the XR250R -- the last model they made before the move to 75mm piston (RFVC engine). 6 speeds, single gear driven balancer. A member on here converted a CB250RS engine to use the gearbox and balancer; he used an XR250R crankshaft as well. I have the 6 speed gearbox and balancer at home; will convert a CB250RS crankshaft to suit, as the XR250R crank I have has massive big-end float. I will just change the sprocket to a gear.

Is there enough meat in the base gasket to cut out? They look rather narrow, but I haven't done the measurements yet.

[tommorth]

sounds like a great project
you could just get some gasket paper and make a base new base gasket take 5mins its a magical mysterious product
dealers can be surprisingly helpful
the xr and xl pistons are quite different bigger dome on the xr and bigger again on the weisco
whats the bore size of the 500? maybe is sleive would work

[xwhatsit]

whats the bore size of the 500? maybe is sleive would work
89mm :crazy:

Now that's a piston :laugh:

Probably just as hard to find as an XT350 sleeve anyway, and with an 80mm stroke it'd need to be trimmed down anyway.

[jester_parks]

trust me: as soon as I`ve got my set (piston & sleeve, that is), I will get another set for you.
Yesterday my (japanese) wife translated an article about a japanese RS into english, which was quite interesting: this guy used a 84mm XR350 piston and in order to fit it to the small-end, made the conrod himself....
apperently his engive is revving to 10000 and would do more....
My Keihin FCR is ordered in Japan and things are falling into its place!

[xwhatsit]

trust me: as soon as I`ve got my set (piston & sleeve, that is), I will get another set for you.
Yesterday my (japanese) wife translated an article about a japanese RS into english, which was quite interesting: this guy used a 84mm XR350 piston and in order to fit it to the small-end, made the conrod himself....
apperently his engive is revving to 10000 and would do more....
My Keihin FCR is ordered in Japan and things are falling into its place!
Ah, I've been looking at a Keihin CR33 (also ex Japan) for ages. It lacks the accelerator pumper of the FCR though.

Do you have a link for that article?

[jester_parks]

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


:headbang: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-Motors/Motorbikes/Parts-accessories/Engine-drive-train/auction-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-Motors/Motorbikes/Parts-accessories/Engine-drive-train/auction-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!!! :clap:

[xwhatsit]

Well there's this sleeve (http://cgi.ebay.com/ebaymotors/Cylinder-Sleeve-LA-Yamaha-XT350-XT-350-85-00_W0QQcmdZViewItemQQcategoryZ35595QQihZ016QQitemZ 260274287767QQrdZ1QQsspagenameZWD1V), and this piston (http://cgi.ebay.com/ebaymotors/YAMAHA-NOS-XT350-XT-350-1985-2000-STD-PISTON-NEW_W0QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247 QQcategoryZ10066QQihZ002QQitemZ120295734962QQrdZ1Q QsspagenameZWD1V).

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.uk/Engineering/cylinderliner.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.uk/Engineering/cylinderliner.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.

[jester_parks]

Took some shots of the pistons to give a first idea:
Honda piston comlete with pin and rings =329gr, Yamaha XT350 =369gr

[xwhatsit]

Oh! So the RS piston is the higher crowned one? I thought Muzz said he trimmed out stuff for the valves to have clearance? Interesting. Then again, he did it with an XL250S, which is lower compression than the RS.

Nevertheless, that's good, looks like it'll be fairly low-compression, so nice and flat and grunty.

[xwhatsit]

I spoke to a guy in Mt Wellington yesterday, a bloke at a place called Wade Automotive. Was just passing by but I saw their sign and it seemed an old-school sort of place. Popped in and wasn't disappointed.

The guy said they can have a crowd in Christchurch make one-off cast-iron sleeves for them, then they machine them etc. About $200-$250 to get one made, so probably just buy that sleeve if I can still get hold of it when the money comes through and have it machined to suit. He seemed quite interested and enthusiastic about it actually, which is a good sign, he was worried about taking 6mm both sides out of the cylinder itself (worried about getting to close to the fins/camchain tunnel and it turning to cardboard), but then again it's been done before.

About conrods and bottom end strength to deal with the extra piston weight; I take it there's nothing that can be done to strengthen the conrod? Other than very expensive and specialised work I suppose. Is it possible to lighten a piston? Take meat off the skirt? I would guess the best way of keeping the conrod in one piece is simply to keep the revs down; suits my plan of using just a 33mm CR33 carb and keeping the valve sizes as standard.

[Kickaha]

The guy said they can have a crowd in Christchurch make one-off cast-iron sleeves for them,

Cliff Bond in Ferry road, I've talked to them about making a one off for a big bore GN125


I take it there's nothing that can be done to strengthen the conrod?

Get a rod made for it :lol:,

you could have it shot peened which will supposedly help

[Motu]

I spoke to a guy in Mt Wellington yesterday, a bloke at a place called Wade Automotive. Was just passing by but I saw their sign and it seemed an old-school sort of place. Popped in and wasn't disappointed.


Behind Johnson Piston Rings.Wadey does good work and I've used him a few times when my guy closer was too busy.His brother used to be the bass player in Billy T James band,a renowned bass player....but was an upholsterer by trade.He upholstered the seat on the C50 for me......just to connect all the dots.

[Ixion]

About conrods and bottom end strength to deal with the extra piston weight; I take it there's nothing that can be done to strengthen the conrod? Other than very expensive and specialised work I suppose. .
Best thing is to polish and smooth it. Stress builds up in scratches and sharp edges. carefully smooth all edges, remove any flash, polish scratches out.

[pete376403]

If you know the rod dimensions, length between centres, big and small end diameters, etc, go and have a look here.\
The rod would probably end up being worth more than the rest of the bike, but you'd never break it. Ever.

http://www.carrilloind.com/PowersportsOther/tabid/83/Default.aspx

[jester_parks]

200 - 300 Dollars.....this is freaking lot of money for a sleeve....rather wait until I can send you one!
Carillo conrod is the premium way to go....but haven`t got a rod around to take the measurements....who has?

[xwhatsit]

I've got a couple of cranks sitting out of the engine, could take measurements if necessary -- one thing though, how would you get the bastard off? I think it's all one piece.

@Ixion: this is what shot peening does then? By smoothing it all over like that this is a poor man's shot peening?

The way I see it, the conrod would be the weakest part of this whole equation. Well, there's always the gearbox, clutch etc. You don't hear of many pre-RFVC engines exploding the bottom end, it's all valves, holed pistons, slow gearbox deterioration.

Right well I'll nab that sleeve on eBay. One thing, it says: `The castings used in the manufacture of these sleeves are made from an alloy of carbon chrome, and molybdenum of 200 brinell hardness which insures ease of installation, trouble-free boring and dependable long engine life.' Does that mean it's going to be a prick to shorten and machine?

I'm curious how much a Wiseco piston would be lighter. The std bore one I'm looking at (4674M08600 is the number) says it's forged, and says it's lighter weight. Would be nice to quantify that.

[Ixion]

No. If possible shot peen AND polish. Shot peening releases local stress left in the metal from the forging process. Sort of like a metallic massage. Polishing removes local stress point concentrations. Both are good, but polishing is free (except for your time).

Sleeve won't be too hard to machine, but it will need a competent machine shop.

[pete376403]

I've got a couple of cranks sitting out of the engine, could take measurements if necessary -- one thing though, how would you get the bastard off? I think it's all one piece..

If its a one piece rod then the crank must be a built up unit - crank pin pressed into the flywheels (like just about every two stroke ever built)
If you have access to a press you can push the crank pin out of one of the flywheels and then remove the rod and bearings, otherwise any shop competent in repair of motocross bikes should be able to do it.
If you do have the rod shot peened make sure the bearing surfaces are protected.

[jester_parks]

I`ve ordered the Wiseco in the US and it should be well on its way - will tell you the weight as soon as I`ve got it.
Valves will be made in China to size - sending the samples this week and wait for the quote!

[jester_parks]

....and will give you an idea, what size sleeve I could give to you: the sleeves I`ve got are all oversize (bored once or twice), so all you have to do ist to get hold of a Wiseco-o/s-piston of 87 or 88 mm....still cheaper than spending lots of Dollars for a custom-made-one.
Check ebay-USA for those pistons - I`ve got a good deal over there.

[jester_parks]

or else:

check here:

http://cgi.ebay.com/ebaymotors/Cylinder-Sleeve-LA-Yamaha-XT350-XT-350-85-00_W0QQitemZ260274287767QQcmdZViewItem?_trksid=p45 06.m20.l1116#ht_781wt_0

[xwhatsit]

Right, saved up some money and ordered that eBay sleeve. Shame the NZ dollar has taken such a dive compared to the US dollar, makes $US120 + shipping for the Wiseco piston actually relatively high. I'll see if I can get it cheaper locally -- where do people think is cheapest to get Wiseco bits and pieces?

There's a $40 new std OEM piston on eBay, but no rings or gudgeon pin -- and did the Wiseco piston turn out to be lighter in the end, Jester?

[jester_parks]

gudeon pin I can send you - just get this OEM-piston - the rings will pop up sometimes, somewhere!
I will put the pistons onto the weight-scale and tell you if there`s a difference - only know at the moment that its a handfull more heavy than the RS-piston, so we can expect a load of stress on the rod

[jester_parks]

So, last night I took my wife`s digital weight-scale and took the pistons for a test:
Honda CB250RS = 328 gr, Yamaha XT350 = 369gr, Wiseco 87mm(o/s) = 361gr....all with gudeon-pin and rings.
Still over 30 gr more heavy and I can`t see a chance to shave off material....
My cylinder is out to have the sleeve fittet and after return it will go for boring and honing....and the bike itself is also in the process of being completed...things are falling into their places!

[jester_parks]

the clubman-racer is being modelled: clip-ons and single seat are lined up and soon I can show you the final result - however without "big-bore-unit"....

[xwhatsit]

Hahah, excellent! What did you pinch the gauges off? Those are some hefty brakes -- may end up going over the bars with such a light and short bike!

I lost that cheap piston auction, now that exams are over I will knuckle down and get stuck into this. There's still a cheap one on eBay though. I see a couple of auctions for rings, but separate shipping etc. may just be better off paying the extra for the Wiseco kit.

Doing anything special for exhaust system? My existing exhausts are horribly rooted, I'm going to get a 2-into-1 made I think.

[jester_parks]

still willing to send you a piston with rings and pin that will do - just say something!
Don`t get what you say: "What did you pinch the gauges off?" - what is gauges?

Brakes and wheels is Kawasaki GPz305 and they slot in without big problems, but I am going for the classsic spoke wheels, which are in the making also:
rear-hub is Yamaha XT350 with 2,15 x 18 Akront rim - going to be lighter than the original as I am converting to 428-chain: big savings in rotating masses!
Front hub not decided yet; can`t find something that will fit "as is".

[jester_parks]

Yes, this is a japanese racer based on the RS....and the other picture is retouched by me to see how a "civil"-version could look like!
Otherwise a Micron 2-1 would be the easiest way to go, I guess...

[xwhatsit]

Sorry -- maybe a colloquialism, I meant what bike did the gauges (gauges mean the speedo, odometer) come from? They look quite at home there.

Is that first one really a CB250RS?! Good lord. I've thought about high pipes, but might wait until I have a tank/seat combo so I know where the pipes should go first.

Thanks for the offer -- how much do you want for the piston/rings/pin? I may have to give in and accept :laugh:

I got a nice little package earlier this week, have been too busy to post up pics though. It's a lot lighter than I expected. There are two things I'm not quite sure about; #1 is the little `lip' or flange around the top of the sleeve. I don't think the 250RS sleeve has such a flange; given that there will be less metal after boring out the cylinder, is it wiser then just to have the machinist stick the sleeve in the lathe and take off the lip? I might just ask the guy at Wade Automotive what he thinks.

The other thing is the interior of the bore. It's supposed to be original size, from that I assumed it's all pre-prepared. The inside of the bore looked discoloured and felt very rough; however when touching it I realised some of it is just some very light surface rust from air exposure. Is this pattern in it simply the `hone' that they apply -- or do I need to have it prepared before I stick a piston in there?

[jester_parks]

This flange is absolutly correct and the Honda-sleeve has got it also, it prevents the sleeve from "sinking in". Obviously your sleeve needs boring and honing - this can be done only "with" the piston for exact size.
The piston I offered to you I will send for free - I think the pin and the rings can be reused - about the piston ask your machining-shop.
Drop me your address and I will forward it to you!
Cheers
christofbeck(at)web.de
the gauges are cb200 and have been a steal at ebay

[jester_parks]

How are things? My project is developing fine: the cylinder sits on the crankcase! Waiting for the head with bigger valves now.
In case there`s still need: could get a Yamaha piston 86mm with rings NOS - but decision must be made within the next two days! Price will be Euro 45 + postage

[jester_parks]

Piston and rings - NOS - ready to be sent to NZ:

[xwhatsit]

Hooray! Hey, if you have pictures of the XT350 piston in the 250RS cylinder you must post them too :)

[jester_parks]

So, my RS is ready for roadworthy...still 250ccm only, but clip-oms and Bol`Dor-Disc 276mm

[xwhatsit]

Gorgeous! Nice work with the seat :D Is that the stock rear mudguard, you just painted it silver? I've long wondered what to do with the rear end, but that's very tidy.

[jester_parks]

It is the original mudguard indeed - just powder-coated: it was the easiest way to get rid of the bulky spoiler-seat....and the chrome Yamaha-fender I experimented with did not work. "Learning by doing"
Here is my wifes RS: 2-seater "custom-seat" and standard otherwise

[jester_parks]

Hurray!!!.....the piston made it finally NZ!!....two months (!!) of waiting ....and expecting that the parcel got lost.
Now the CB350RS project will proceed

[xwhatsit]

Hurray!!!.....the piston made it finally NZ!!....two months (!!) of waiting ....and expecting that the parcel got lost.
Now the CB350RS project will proceed
I still think they sent it by canoe, or an early WWI biplane. The package was certainly pretty squished-looking when it got here, good thing you packed it well with bubble wrap :yes:

Only thing is now, the CB336RS project will take just as long... as I'm an even bigger procrastinator than Deutsche Post!

Many thanks for your help with the piston, Christof.

May I ask how far you're along now? I want to know what you did to the bottom end and compare my plans :msn-wink:

[jester_parks]

Everything has been sidelined due to roadworthy of 2 Yamahas, which is a pain in the ....
Everything had to be reconverted to pass the test: one made it, the other is going to go on Saturday.
Then I will take the photographs of the CB250RS-crankcase, which has to be "widened" for that big liner.
I am also pretty laid-back, so I guess we are a good match....

[Motu]

Stop farting around with that piece of crap - borrow your sisters make up earn some money at Hunters Corner and buy this thing all done for ya.

http://www.trademe.co.nz/Trade-Me-Motors/Motorbikes/Motorbikes/Classic-vintage/auction-220647338.htm

[xwhatsit]

Stop farting around with that piece of crap - borrow your sisters make up earn some money at Hunters Corner and buy this thing all done for ya.

http://www.trademe.co.nz/Trade-Me-Motors/Motorbikes/Motorbikes/Classic-vintage/auction-220647338.htm
Fuck a duck! That's fantastic :D Not a stupid price either. The motors are next to impossible to find anyway.

Would be nice if it came up for sale again in 6 months when I might be able to fork out for it.

[Ixion]

Yeah, I aw that. But I suspect one would never be able to register it. Sigh. It used to be *so* much easier.

[stew7]

i have a honda xl 250 s with a yam xt 350 piston (IN A 1982 YAM YZ 250 FRAME) with some extra work it goes very good ! stew7

[nzspokes]

Did any of these projects get finished?

Anybody know what I can do to a cbx250rs motor? Maybe the 280cc upgrade?