Thumper Club Forum
Technical => Bike Problems/Questions => Topic started by: Ian on November 06, 2006, 01:22:51 PM
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I have a MuZ Skorpion Traveller with a top end rattle /very loud ticking ,it's louder on the cam chain side.
I've pulled the cam cover off expecting to see XBR type damage ( cam eating head and followers ) but everything has very light wear on it and no damage ?
And I've pulled the head off ,cam chain is in good condition valves aren't bent and seat nicely .
Has anyone any ideas as I'm running out of places to look for it ?
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sticking camchain tension adjuster??
Just a thought, no experience of this, my MZ motor has been fine for the 4000 miles I've had it.
a
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Good try ,
But the cam chain adjuster is as free as a bird ..
I bought it with the rattle ,thinking that there isn't a lot that goes wrong on these motors ,simple to fix ?
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is the skid on the cam chain adjuster excessively worn? or are the valves in need of shimming?
bullet350
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From memory the cam has an automatic decompressor mechansim, could this be rattling/playing up.
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I think I've found the problem ! :(
There is scoring down the piston in 4 places and on the liner .
Looks as if it needs a re bore .
The next question is what caused it ?
Big end or small end failure maybe at 38000 miles ? £££
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They are big pistons and tend to rattle around a bit. If its the original then 38.000 miles isnt to bad.
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Big end or small end failure maybe at 38000 miles ? £££
The story of my MZ:
Bought new (by "Chap A"), and after about 12,000 miles, "A" decided to ignore a knocking bottom end. It eventually gave out when the big end wrecked the crankpin.
Bought by chap "B". For a bit too much money. He fancied a Supermono-type track bike. Why the hell he chose a standard road Skorpion I'm not sure!! He spent about a £1300 having the motor rebuilt and tuned at slipstream to 52bhp. Bodywork was RS250 stuff, and it was used on track for a year or 2. Anyway, following his divorce, he sold it to his neighbour, chap "C".
"C" is a bike fan, especially singles, and bought it just because it was interesting, and he likes trackbikes. He had sold me the SRX I'm currently racing, about a year or so previously.
C converted it back to road use, but it wouldn't sell.
Dr. "D" got it for a song, and although the chassis bearings were all knackered (yep, eee-every one!) its still good fun.
So Chaps A, B, and C all lost out somehow. And the motors (although strong) aren't failsafe.
Hmmmmm! Is there a point to this?? Sorry to hear about the scored bore. I know of some tuned motors and associated fast bits going if you want to build it up. They're still what I would call dear, but much cheaper than when new....
Cheers, good luck!
a
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Hi androo,
Sounds very interesting ,whats on offer ?
All though it's a traveller and I don't really want to tune it ,
This won't stop me putting fast parts on my sport !
So far I'm after a piston ,re bore or a cylinder barrel ,
I haven't looked at the crank and rod yet ,but I'm expecting the worst .
It might be cheaper to fit a replacement engine ?
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They are big pistons and tend to rattle around a bit. If its the original then 38.000 miles isnt to bad.
Hmmm that's a bit pessimistic isn't it Steve? (he says crossing his fingers). Mine is a good way past 30,000 now and still sounds nice and tight (crossing the other fingers and touching wood!!!) Mind you it gets warmed up and choke off quick and regular changes of good oil...
I didn't see the engine listed on Wiseco's website, is there a known source of replacement pistons/bores etc which doesn't involve remortgage??
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Don't worry I have no idea how this engine has been looked after ,
I've found 3 reports on MZ forums of the same problem , most seem to blame big end failure .
I'll be replacing mine if only for the peace of mind .
I would expect there to be standard over size pistons available ,though I've yet to phone BSA Regal .
Slipstream have 100 , 101 and 102mm Pistons
JE do 100 and 102mm (£110 on TTS website )
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Aye xbrmz,
Try Vic Eastwood's site mentioned elsewhere here. Same piston/ liner combo as XT660, SZR660, or Yam 'Grizzly' 660 quad.
Piston £90 - 110, liner £40 - 60. Fitting liner/honing to spec. by competant engineer £50 - 60.
Ensure honing to spec!!!!!!!!!!!!!!!!!! Wash in hot soap and water to remove ALL traces of honing abrasive, lightly oil.
Ensure fitted ring end gaps are spot on!!!!!!!!!!! Oil libreraly when assembling. Running in methods extensively discussed in previous posts on forum.
Regards, Bill
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i don't know about other skorpion's, but my Sport had a mph speedo, that actually read in km's.
the face and everything said mph, but the trip and mileometer both read in kilometers, although it said miles.
my bike said 14000miles but it was actually 14000km.
just wondered if it was just mine. it was probably cheaper to but km speedo's and just change the face.
bullet350.
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Hmmm that's a bit pessimistic isn't it Steve? (he says crossing his fingers). Mine is a good way past 30,000 now and still sounds nice and tight (crossing the other fingers and touching wood!!!) Mind you it gets warmed up and choke off quick and regular changes of good oil...
Perhaps I'm viewing it too much from a Yamaha air-cooled perspective (SRX). All the SRX engines Ive run have had slappy/scored pistons, maybe ist the frequency of engine strip down that make them more noticeable. To be be fair the RFVC engines seem to be more reliable in this respect.
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i don't know about other skorpion's, but my Sport had a mph speedo, that actually read in km's.
the face and everything said mph, but the trip and mileometer both read in kilometers, although it said miles.
my bike said 14000miles but it was actually 14000km.
just wondered if it was just mine. it was probably cheaper to but km speedo's and just change the face.
bullet350.
My sport has 24000 km on the clock and a cr#ppy mph sticker on the glass .
The traveller has a mph speedo face on it not sure if it measures km or miles .. yet to ride it !
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Hi androo,
Sounds very interesting ,whats on offer ?
Hello mate
Look at Ebay:
Item number: 260048352166
Item number: 260050075311
Item number: 260050077876
Also look at www.supermononewsletter.co.uk (race series). Their ads:
2 Yamaha 686 race engines for sale prepared by Slipstream speciall parts fitted, big valve head, close box, sliper clutch fitted.
1 standard road engine with 102 piston.
1 set of Keihin flat slides for Yamaha engine
1 set of Keihin round slides for Yamaha engine
only 1 CDi box left for Xtz engine 9000 limiter
cotact me on 07834272441 or arialane@yahoo.co.uk
or
Mikuni flatslides for sale. Condition: very good. It's a pair of 36mm carbs, centre to centre 80mm. Bought them 2 years ago but never used on my szr mono because i have a non symmetric head.
Price 200 euro's
Good race kit can be had quite cheap. Put a "wanted" ad on the site? Its a good time to buy old race kit as everyone is chopping their stuff in. (admittedly its had hard race use, but I have no qualms with buying ex-race kit. admitttedly I'm always working on my bikes!!!)
andy
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Hi Andy ,
I've already been in touch with Aria regarding his 1 standard road engine with 102 piston it's also had the head ported he wants £300 for it .
I think the price is very good ,but by the time I've travelled to collect it ( 300 miles there and back )
It's getting expensive and pushing my luck with the wife ..
Also the Ebay items are being watched :)
By the way it was the small end that had failed ,might be down to poor maintenance ?
I phoned BSA Regal yesterday ,
Standard oversize pistons are available in sizes +0.50 and +1.00 .
0.50 piston £52.92 , rings £16.61 , piston pin £10.37 , 54p clips ,
con rod £41.31 , big end bearing £33.09 , crank pin £26.42
Don't forget to add the VAT.
Many thanks for all your help .. I'll let you know how it goes :)
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I phoned BSA Regal yesterday ,
Standard oversize pistons are available in sizes +0.50 and +1.00 .
0.50 piston £52.92 , rings £16.61 , piston pin £10.37 , 54p clips ,
con rod £41.31 , big end bearing £33.09 , crank pin £26.42
Don't forget to add the VAT.
In my experience, Phil Albutt @ BSA is a great guy. And the prices are good. I mean
£50 for a piston?
£40 for a standard rod?!! Plus vat, sure, but that strikes me a pretty bloody good for a modern bike.
Anyone know if the corresponding Yamaha pars are the same price?? I bought exhaust rings for the SRX recently. Same as the skorp bits I got from BSA, but twice the price for the Yam part!!!
a
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Phil did say that they where Yamaha prices / parts .
And yes the prices are good .
But when it's all added up ,crank pin fitted ,gaskets ,re bore
your looking at the same or more than a replacement engine depending on what you pay for it..
So which way would you go ??
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But when it's all added up ,crank pin fitted ,gaskets ,re bore
your looking at the same or more than a replacement engine depending on what you pay for it..
So which way would you go ??
If you rebuild it, at least you know whats inside, that said if you buy another engine you could recoup some of your costs by selling the old cases/head/crank etc on Ebay.
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So which way would you go ??
Personally, I'd wait, and look around, save, then pay the price and buy a complete race motor (or hot road motor), and bolt it in. Preferably with carbs, less set-up hassle. But thats not everyone's cup of tea, and will be pretty lumpy... However, I actually enjoy commuting round lndon on the skorp, with a big lumpy hi CR piston, lumpy cam, noisy carbs etc.
Phone martin sweet at slipstream tuning. He often has good stuff on the bench. Its not cheap, but a standarrd motor would be..., I dunno... £250? More? and thats used, maybe thrashed, and standard.
The cost of parts sometimes just doesn't justify a rebuild...
ie. to do a valve on the SRX cost
25 for the valve
25 for the head gasket!!!!
About 20 for all the valve seals
About 10 for the 2 exhaust rings
plus vat
plus postage... not much off 100 notes. For a 25 quid valve!!!
But its a good motor. When my first SRX motor gave out, I stripped the top end, and peered in at the knackered 5th gear. I kept it, as it could still be rebuilt, but wasn't going to pay daft money in parts for what is only a standard motor. I ended up buying a complete 400 motor with carbs, plugged that in and used the bike for another 2 years.
Re. the skorp, I have Slipstream receipts for 1300 quid. Daft money, not spent by me. Thats built up from scratch, and repairing all the damage due to a sheared crankpin. And thats still only a 660, plenty of room for improving things with a big piston and flatslide carbs. So NO WAY would I sell the bike with the motor. The thing is so ugly, I'd get about 500 quid for the whole thing (I paid 650).
But you must ask yourself if you need more power. Otherwise the money is wasted.
(then again, I hardly need it for london, but it makes me feel good, so maybe disregard the last comment!)
Also (this is always my dilemma), can you not renew the bearings etc when you're in there? Will you put the standard cam back in? Why not flow the head while its off....
And then can you live with the fairly crude standard chassis, with your "bells and whistles" motor??! Is an extra 10 horses worth all that cash??
And at the end of it, you've spent a *fortune* on a bike, which is still only an MZ (to most folks eyes, not mine!), and is still only worth 800 quid, and puts out 50 horses instead of 40-odd. A money pit, but we like that in this club...!!
My advice is get a cheap standard motor and get your use from the bike (ie reduce your £s spend per mile ridden). But thats probably not what I would do...!!!
The choice.... (as they say on telly).... IS YOURS!!!
Cheers, let us know!
a
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Going to contemplate my options for a week or 2..
If I go for a semi race engine it would have to go in the sport ,
Just for testing :)
Probably rebuilding the engine a later date to keep it as a spare ..
Still totally undecided ..
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I've just come back from the sea side !
With a XTZ engine in the boot :)
It's had a 102 piston fitted and the head cleaned up ,
But it has never been started since the fitting of the new piston .
I blame Andy ...
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Ho Ho!!
Well done mate! Good lad!
Is that Aria Lane's motor?
Let us know how you get on. And throw away all recepts, lest "she" find them, and never speaks again...!
best
andy
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Yes It's Aria lanes motor .
He's a great bloke ,could of chatted all day ,also he runs his Renault on a cooking oil and diesel mix ,
must be something to do with racing ?
I've no need to throw receipts away ,
She came along for the ride and knows how much I've spent and saw the sea ! ( 1000 brownie points )
M25 was like going banger racing in a pond ,
Saw a least 5 accidents or should that be attempted suicides ,some total nutters where out on Sunday ! including me .
I did manage a nice piece of aquaplaning in the fast lane ,scared the Sh#t out of the wife .
Just need to sort some decent carbs out to go on it ,
I have a pair from a DR ( I think ) that need moving closer together and a spacer for the inlet rubber made to make them fit .
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Who doesn't use 'veggie' mix or straight these days? The road past my place smells like the arse end of a 'proper' Manx with worn rings!
Sorry andy230, but you know what I mean!
Ciao, Bill