New Zealand Based 1973 850 Roadster

Hi Mike
Good question I am hoping to have my 650SS finished [refer 650SS rebuild other classic m/c this forum] otherwise i will probably take the 850.
in the early 90's a group of us traveling to a Harley Rally in Hamilton stoped for fuel in Taupo, a freind on a Sturgis broke a primary belt there, had to trailer the bike to Hamilton no replacement belt there had to fly a second hand one from Christchurch- A chain will normally get you home.
Al

Hi again, thanks on the heads up with the layshaft replacement, am an engineer by trade so fitting a bearing shouldn't be to much of an issue this end and planned to give the gearbag a good going over once all is apart for the belt drive conversion which I seem to be convinced is the answer.
One less oil level to check and one less potenial leak area. When I got the bike had an issue with the LHS header being out of shape and didn't notice it had rubbed a flat on the inner chaincase, exposing the O ring. Luckily it doesnt leak at present, but annoying to say the least.
Regards Mike

Hi Possm, was the belt high mileage on the HD,I guess you mean final drive as well, exposed to a lot of elements and road debris, as I see a lot of bods get some pretty impressive m/k's out of them provided set up true and not over tightened.
Will be on the triplex chain going to the rally, hey what sort of m/k's before the layshaft bearing gives up the ghost?
Box is currently very good and I run Redline Shockproof (blue)in it and am very concious of good changes , with or without the clutch . Clutch mechanism retaining ring came unscrewed on the way back from Rotorua a few weeks back just to test my clutchless changes!!!
Regards Mike

Thats one nasty lookin' scar on the primary. Weld it up and file/polish it up. Oh yeah, the belt kit will not drip oil too... but try to install the pushrod seal kit to prevent any oil from getting in there. The layshaft ball bearing on my 70 S developed a " tic tic... tic " sound at first ,then the kicker lever would drop down and slap me back on the leg..ouch ! Stoopid me thought he could limp home gently then the whole rear wheel locked up solid with a honking car up my ass. Not nice. This with about 15,000 on the clock and not even a Portuguese crap bearing as fitted to 850's. So take note for safety's sake be safe.

Mike the Sturgis broke a primary belt.

Mike, The layshaft bearing is a must check item, if you cannot verify the history and the bike is low k's it could have the original ball race, that tends fail. Do some searches on the alternatives, N306 roller is good, but you then need to control the endfloat, or a high capacity ball is just a drop in. Check out the play on the 1st gear layshaft bush, symptoms are occasional drop out of 1st under load, but if there is a lot of play you may aswell fix it now.
On the primary, I have converted my Harley to belt primary, from chain. I expected increased smoothness and no snatch etc, but to be honest the improvement over a we adjusted chain on a big twin is marginal. And every HD person harps on about broken belts a long way from home, I have a spare in the shed and will replace hopefuly before failure, but a chain is more likely to keep going even after it is out of adjustment and making noises. Just my 2 bobs worth.

Cheers Richard

Chains , intresting the latest Ducati has gone to CHAIN cam drive , partly no doubt duue to compactness .
But also noteable that they consider it adequate for the 200 hp beast , with pressumeable somewhat radical camshafts and therefore chain loadings .

No harm entering the gear box , if youve a bearing extractor , an afternoons relaxed effort should cover it .

My gripe is seing the mounting bolts are secure and kept secure . Running loose and fretting out the lower bolt will make alignment questionable .
So a five million dollar bolt through there is a god investment . . Adjustment is get it positioned , nip up firmmly , check primary
( swinging it through, though uneven quality in the chain itself should mean dicarding it , and the sprockets shouldnt be eccentric )
Then , Bolt locked , reset the adjuster /s against it forward , firly . So as the drive chain action wont pull the box aft .

The big bolls up , is theres no crankshaft dampener . Discarding the alternator would make it easy to fit one .
Isolateing the irregular revolution from the trans . putting the ' cush drive ' in the rear wheels a bit odd .
Was ordinarilly the crank axis , or failing that , the clutch hub.

Anyway , playing with a straight edge across the clutch drum , when the covers off , will assure you its all aligned satisfactorally .
Id think the triplex is only capeable of malfunctioning through neglect in those respects , or running way tight or dry .
Besides , a few drips stop it rusting . :wink:

hi Matt, yes all over the alignment and tightening, thanks. Way back when, i had a Dommie with a moderately tweaked mill, beach raced it amongst its other uses, always had issues with alignment, so L made a second adjuster on the plate closet to the inner chain case, didn't know others did this( no inet in the '70's) and a couple of mates copied it for their Commandos.
Will do the same for this one.
After a lot of comments , pro and con, have put the belt drive on hold for now, sounds like I will need to get the inside of the gearbag sorted first.
So its a given, just open it up and change them anyway?
What if it's been done already, as 1st gear seems rock solid at this stage, any markings on the layshaft bearing to let me know i have a dud?
regards Mike

Hi Brooking 850,
I agree with everyone on the Lay shaft bearing it's a problem in the waiting! Last winter I replaced one in my Sons 74 850 (Same colors as your by the way) I've been putting in the Super Blend style Roller Bearing and they are quite expensive but bullet proof. Here in the States they are $70.41 from Old Britts part # 12-067710 and the type your most likely to find in your bike and want to replace cost around $5.00 and it's a ball bearing! You will need to shim the end play and there is an excellent Technical Article called "Assembling the Commando Gearbox" Fred at Old Britts did a wonderful job explaining and writing the how to article. Wow would I love to catch a fish like that sometime good eating to I suppose I don't know if I've ever eaten any of those or not. Are they commercially sold to other parts of the world or just a local fish?
Later
Nortarly

hi Nortaly, about to order the bits I need now, how much shimming is required and how much end float does there need to be? Will check out the tech info as you mention. Do the forum members have an opinion on the best replacement bearing. I bet they all do !!!!!!

The fish is a 36kg Bluenose (Warehou) and I caught it in 320 metres of water. They blow up (embolise) in the last 20 metres of water though, getting them started off the bottom is the hardest part. NZ record is 41kg and even at that size are fantastic table fish.
Not found in your part of the world i beleive
http://www.stuff.co.nz/sport/fishing/re ... se-warehou

Bluenose Fishery

Bluenose are found in the temperate waters of the Southern Hemisphere. They like rough ground on the outer shelf and upper slope, especially from 100 to 500 metres.

Bluenose are caught year-round, by trawl and longlining, mainly around or on offshore reefs, seamounts, or drop-off areas.

New Zealand's Bluenose fishery is managed by strict quotas, which allow only a set amount of Bluenose to be taken commercially each year. This Total Allowable Commercial Catch (TACC) was set at 2,335 metric tonnes for the 2009/10 fishing year.

Bluenose Meat Quality

Bluenose flesh has medium to thick moist flakes and is white when cooked. Bluenose has good levels of Omega-3. Can be cooked using most methods.

For meal ideas using Bluenose, check out the recipes on Greatest Meal on Earth website

Scientific Name
Hyperoglyphe antarctica

Maori Name
Matiri

Brooking 850,
That is interesting! I use Rear ISO shims of different thickness to get between .005 thou to .010 thou but the closer to .005 is better and they just fit over the kick start shaft next to the Inner cover. Some of the shims I have had a slight variance in the inside diameter but slight filing and de-burring took care of it. The Super Blend Bearing is by far better just like Super Bend Main Bearings in the motor are best. It's a two part bearing one part presses on the lay shaft and the other goes in the case. They are a fitted bearing so don't mix it or turn one part over I believe each bearing part has a number stamped on it and every bearing I've used had the numbers on the same side of the bearing! But you use what you feel comfortable using!
Later Nortarly

Brooking 850,
I meant to put a link in my last message to all the Tech articles on Old Britts web site as it can be hard to find if you never have been there. http://www.oldbritts.com/ob_tech.html
If you push in and pull out on your kicker shaft on your bike the movement you have is the amount of end play your lay shaft has now.
Later
Nortarly

Re the first gear lay shaft bush, maybe I am paranoid as I have recently done up to norton boxes with this complaint. But the bush in this gear is pretty minimal and on some occasions it trys to escape sideways from the gear bore, so a good visual inspection and if you are ordering parts anyway, for the sake of a couple of dollars get another one or machine one up yourself, that is what I did, you can mount the whole gear in a 4 jaw and bore and hone to suit!
Be aware the pinion side of the layshaft is held in a bush within the end of the kick start, that is in turn held in bushes in the inner and outer gearbox cases, so a little bit of slop here and there adds up. Again call me paranoid, but I re machined up all new bushes and am now rewarded with the sweetest changing gearbox I have ever had.
So whilst apart, hust do some checking of bush fits?

Cheers Richard

Thanks guys, will get onto it as soon as I get back to the bike, have just finished kitting my master cylinder and may post a thread and pics, with tech tips that might help others ,do you think forum members would be interested?
Regards Mike