1200cc ???

[Eveready1100]

Ok fellas. I didn't want to start a brawl..
I think I've found the thread you were talking about, Peter.
Here's a quote from Tom who is pretty mechanically minded :

Tom
Diamond Cutter

Re: Main Bearings
« Reply #3 on: March 05, 2011, 10:26:00 AM »
Quote
" the coloured bearings different dimensions are so close they all are for the same size crank, they're not undersize bearings for regrinding your crank like you get different oversize pistons for rebores, they're for selective fitting at the factory.

Any engineered part is made to a tolerance, a nominal dimension is given a + or - size it can be out by, the tolerance. The coloured bearings are for assembly when a crank would be measured and the appropriate bearing used, a crank ground to bottom tolerance would use a blue code bearing.

As our cranks have now seen a few miles and the difference between the shells is so little you could use the tightest bearing (blue) with no worries.

If you have a NOS or extremely low mileage crank then checking the diameter of journals would be wise. It might be worth measuring the journals to see just how worn your crank is, or alternatively, if you don't want to be frightened by how worn your crank is, don't  "

I'd say i'd be pretty safe in going for the thickest option, as my crank should be nicely polished by now.

[petejw1966]

hey jonesy,
that refers to a new crank and conrods,
one of the boys on the uk forum did a number of checks
with different size bearings using plasti guage
 a cpl of years ago i cant remember
who off hand,  maybe 1 of the uk boys  will chime in,
but it was recommended to go with the thickest, especially if
errolls bike has done so many k's.

[Jonesy]

No. I think its more than just a case of thicker the better.
The thicker or thinner is exactly the issue
I dont know what the difference between black and blue is?....but would assume sizing and matching sets etc
for example...you dont want to put a set of black bearings on a crank and conrod set there are sized for blue bearings you could end up with a too loose or too tight setup......being the difference between excessive premature wear, pickup (tight) or lack of oil pressure and subsequent wear (loose)

there is a chapter in the manual (Haynes) about ordering/assessing what size/colour plain bearings you need based on numbers that are stamped into the block and crank. Could be a final decision to make once its stripped?

[petejw1966]

Ok guys, opinions wanted.  Bearings, both crank & rods. Blue or black???

hey errol,
go for the thickest, theres not to much difference between sizes.
i think from memory the blacks are the thickest.

[Eveready1100]

Ok guys, opinions wanted.  Bearings, both crank & rods. Blue or black???

[Eveready1100]

The big bore kit arrived yesterday........ from Japan. Dunno if anyone can decipher Taiwanese or Japanese to try to work out where these were actually made but they look pretty good to me. The pistons are quite round and are new, they weigh exactly the same, according to my digital scales and the head gasket suits the pistons, so we'll see about the quality when the time comes for fitment, if required. Postage time only took 4 days, so that's a real plus as well.
Also have on order the complete gasket set including valve stem seals from the same seller plus a set of .50 rings to suit the original pistons if Steptoe's correct with his forecast that it'll only need a hone and a re-ring.
We'll see.................

[Jonesy]

Hmm, maybe I've been talking out my ask your mother.
My new chain measured up at about 994mm.

Take a 100 off the measure...started the first link at 100mm mark.
still be interesting to compare old and new

[Jonesy]

Pete
your tensioner looks like it would fit the bill perfectly
Yeah the chain length is a puzzle, I estimated it to be about 2mm longer than the used one over the total length, doesnt sound much, but if your replacing an out of adjustment chain......brand new it's already out of adjustment with the original tensioner.

 (EDIT) sorry pgnz you type faster than me you must have posted while I was looking for the any key

[pgnz]

ratchet-type auto tensioners by neccesity have to have slop for the ratchet to work,  blah they rattle and wear.  the wedge and ball type are too dodgy with too many components.  The yanks will rave about auto tensioners but they live in a fantasy world over there mmmwwwahhahaha. The manual type is the proven strongest,  one like petejw's is far superior to any of the the automatic junk.

  The camchain,  XS11 camchain distance between rivets(pitch)  7.774mm,  number of links 64, folded in half length 497.536mm   total length 995.072mm

[petejw1966]

i used this set up for years without any hassles,



jonesy, ive bought 3 chains over the years and they were all shorter than
the older 1's i replaced them with, not sure why ur new chain would be longer.

[steptoe]

not enough brain power , come on , hadn,t thought of it,,  but since we,re thinking of mods, have already thought of one,, will have to have a look at an old one to see if it would work,

where there,s a will

[Christian Raith]

When I was in Germany a few of them had auto tesioners. From VMAX etc.
Bill Elsey (Mad Bill)  made one up for me in his shed but as yet I have not fitted it.

There is much discussion on the UK forum about auto adjusters

[Jonesy]

Errol,
Ive got the measurements of the in service chain, but only over 9 links or 9 outer plates as that was all I could really measure while it was still in the motor. The measurements for old and new are in photos  in the 581 build topic.
The new (longer chain) I still have in the packet, and can measure over a given length or its entirity whenever you like.

Yeah I dont know about these auto tensioners either.......I'm sure theres enough brain power amongst the group to come up with an effective mod of the original tensioner.

[Eveready1100]

Paul, I think the last time I did the camchain, I put in a DID chain, so it is not a genuine one to start with. Did you happen the take and keep the measurements of both of the chains in the 581 thread?
As far as a modified tensioner with longer travel goes, it'd have to be worth having a look at that to optimise the life of these new longer chains, as this is my fifth one that I'm on now. In the past, I never bothered with measurements. I just ran out of travel on the tensioner and it got noisy, so I replaced it as a matter of course. This new chain length changes my outlook considerably and I'll pursue any avenue to rectify it.
I've read on the dot com site that some of the auto tensioners have longer travel than the originals so depending on how much it costs to pick one of them up for, might be a viable option, though personally, I'm not too keen on them.

As far as the refresh goes, it all depends what it looks like when I finally pull the head off. Geoff is of the opinion that it may only need a hone and fresh rings. If so, that will be great. If not, the rebore and new pistons, rings, bearings will happen. At least I'll have them at hand if that scenario unfolds.
I'm still a bit mystified by this oil usage business, not that I'm surprised that it's using a fair bit given it's mileage, but where the hell is it going? Admittedly, there is a leak at the rear of the base gasket, but not a bad one. If the rings were stuffed, it should be blowing blue smoke, but on the occasions that Geoff and I have been out "testing", he's said that it's only given a puff of black fuel smoke the first couple of times I've given it the gas. The only thing I can really think is happening is that the compression rings are worn, and it's getting a lot of blow-by past the rings and the crankcase vent is efficiently sucking up all the fumes and recycliing them back through the cylinders and burning it off there, but cleanly???And the plugs are a good colour???Even more???
Guess I'll find out soonish when we check the compression etc.

[Jonesy]

Hey Ev
be good if you could compare length of old cam chain with new, to go with the post I put in the 581 rebuild. Could be an opportunity to design or modify existing into a longer travel tensioner if new after market chains are longer than OEM chains from back in the day.  We all might be getting less life out of chains because the tensioners are to short for these new longer replacement chains.

Is the refresh just a hone and rings or the full 1200 kit?