Had my MC21 crank split before buying bearings etc to check it wasn't scrap, took it to be rebuilt and the guy has asked if the big end pins are offset (he rebuilds RS250 cranks and they have a 20deg offset). Yam TZR/valve ones are parallel, and I initially assumed the MC21 to be the same..........? I am 99% sure it is parallel, but that 1% could be expensive!!
Can anyone help or offer any advice - have tried the search option but came up with nowt!
Yep - not much help ta! Was maybe hoping for something a little more help!!
But anyhoo, in detail, with trying to purchase main bearings from the 4 corners of the earth, I fell upon a centre main supplier from Oz, and a guy some distance from me i the UK to supply the outers, who would also build the crank. We all know how difficult the mains are to get!
But before ordering the centre and some new big ends from Oz and travelling to my builder, I got it split locally. After all, it could have been scrap and I could have already spent my money for what?!
Yes measurements were taken, but it was assumed that the pins were parallel. Also under scrutiny on the bench, this was assumed to be the case(rightly or wrongly!), hence being 99% sure. The 1% is from the comments made about the RS crank from my builder. Aaaaargh!!
Andy if you know someone that has a jig, maybe you could pass me his details, or maybe ask him for me please? That would be a great help thanks.
treeboy wrote:
Yes measurements were taken, but it was assumed that the pins were parallel. Also under scrutiny on the bench, this was assumed to be the case(rightly or wrongly!), hence being 99% sure. The 1% is from the comments made about the RS crank from my builder. Aaaaargh!!
Alot of assumption going on there. Remember assumption is the mother of all f**k ups.
Isn't it a bit dissapointing that, after chastising him twice, no-one answered treeboy's question?
His crank man has got the parts now already so I doubt treeboy will scoop them all up and send some where else. You could have still said 'send it to us next time' to get the message across but told him the info he needs.
Oh please stop, it's blatently obvious from dozens of pictures on this site and various post on truing cranks that the answer is no, they are parallel.
Clearly the 20° offset in an RS is to stop the 70° engine shaking itself to bits
The thing that's somewhere between terrifying and funny is that a guy charging money to rebuild cranks doesn't know this, didn't check and worst of all can't work it out.
Actually as this crank rebuilder is in the midlands he's probably the one who put monkeys back togeather, that lasted all of 600 miles and took a set of cases with it, caveat emptor indeed. _________________ Please do not PM me technical questions, if you can't find it on the Forum start a thread
Gents can we stop giving the NSR rider a hard time? He came on here asking for advice like dozens of others and seems to be getting a sack load of abuse for it. I'm sure he's well aware that he made a poor choice of engineer, but giving him a hard time on here doesn't help does it?
I appreciate some on here have business interests to look after, but surely it's better the guy asked before it went back together? Isn't that what this forum is for _________________ MC21SP Plaything
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It's a bloody 90 degree V-twin, it's not rocket science. It's been discussed before, and I'm not only person in the world that knows the frikkin answer -- maybe the others that do have a similar amount of sympathy?!
It's not like it's a big secret that we rebuild cranks, and no secret that we are hardly expensive! In fact, bollox, maybe we won't rebuild them anyone any more and just have them done for ourselves? Go and find another builder that charges at least 50% more, or maybe one that doesn't even have the sense to measure it up BEFORE he spilts it.
Surely an acclaimed RS engine builder knows the difference between an NF5 90 degree crank and an NX5 72 degree crank, and therefore an educated guess will tell you the answer.
Give me a break, and the chance to get back to all the moronic e-mails about how to wire in an M-max that I get on almost a daily basis!
_________________ Andy.
NSR-WORLD.COM
Please keep all responses to Forum posts on the Forum so that others may benefit.
Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.
Oh dear, it never goes well disagreeing with a Forum owner! Lets Hope I don't get IP blocked.
Andy, relax, we were politely pointing out that teh guy needs help. How he got there is not necessarily his fault - I have taken stuff to places believing they were kosher to find out afterwards they were crap. This post will not change the number of M Max email quations you get, nor will it affect your crank building income. Your explosive rebuttal makes me think you in part agree with this.
Everything you said about the crank builder is true, but that doesnt help treeboy in his situation.
This forum is renowned for concise, accurate technical information. If he cant politley ask here, where can he ask? I'm sure you wouldn't want him to flog it off and get an RGV would you?
Lets all get along, Vincent _________________ NSRless again...
I've only ever blocked one Member IP, and he was an asshole, and I'm not proud of that either but it needed to be done.
I'm pissed off because I get it in the neck whenever information isn't immediately forthcoming. It's not my fault people get it wrong sometimes, but it's not my duty to put it right every time either.
I bite my tongue an awful lot, but not always. It's OK to disagree with me, but it's not OK for me to have my say? I don't think I abuse my position -- tell me if you think otherwise.
I'm also not prepared to insult the engineer who does our cranks by asking him for his information to pass on to another "professional" engineer. You wouldn't ask any professional company for their intellectual property FOC, so why ask me? _________________ Andy.
NSR-WORLD.COM
Please keep all responses to Forum posts on the Forum so that others may benefit.
Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.
Blimey!
Getting one thing straight, I didn’t wake up one day knowing all there is to know about NSRs, or the forum and the info held in it. I don’t have the time either, it’s a hobby, not an obsession. Like I said, I was 99% sure, all I was after was that extra 1% of confirmation. Didn’t really think that that warranted the torrent of wit I receieved, but hey ho! I use other forums and find them to be very helpful; they will point out where info is to be found and who can help. Being relatively new to this forum, I don’t know who does what and who has a financial interest in whatever. But yeah, whatever!
I didn’t really think that asking for confirmation on a crank being parallel was comparable to asking a ‘professional’ company for their ‘intellectual property’? I mean, you ring up Koyo and say, what is the dynamic load rating on a particular bearing, even the material the seals are made from – you could be from NSK or any other Chinese rip-off back street sweat shop! They don’t think twice about passing this on……….?!
As it happens, I did pull the crank from the so-called builder, and will be employing the skills of a reputable builder, more locally.
Andy, I didn’t realise that you had such a close involvement in building cranks or could get it done – maybe I could have used you?
Many thanks to those that have helped, you know who you are.
treeboy wrote:
As it happens, I did pull the crank from the so-called builder, and will be employing the skills of a reputable builder, more locally.
Well, that's a wise decision in my opinion, and probably in the opinion of several others here. I bet the "reputable" builder doesn't ask you the difference between a 72° and a 90° crank.
I actually expected an e-mail from you, and also expected someone (at least one person) to e-mail you with the confirmation anyway. The last post wasn't aimed directly at you, it was more a statement against the bashing that I get on occasions for choosing not to be the fountain of all free flowing knowledge sometimes. Hell, I've even been bashed before for not answering a topic that I didn't actually know the answer to!! _________________ Andy.
NSR-WORLD.COM
Please keep all responses to Forum posts on the Forum so that others may benefit.
Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.
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