850 mk3 Finally starting.......

..........to bring it back to life.

Hi Guys, I have an 850 mk3 Interstate that has been waiting my attention now for about 10 years. In a couple of weeks I will Finally start this process.
I’m not looking to have a showroom condition exhibition bike,obviously I want it to be a very tidy example but,it’s going to be a bike that is ridden,and ridden a great deal. Not just the odd 100 mile ride on the weekend, I want to be able to take this down to the South of France and be pretty confident it will do it and be reliable.So I want to make this Commando as reliable as a Commando can be.

I am planning on having Norman White rebuild the engine.I could put it together but am not an engineer, so couldn’t do that side of it at all, so figured it would be better to get someone with huge experience to get this engine as good as it should be.
I will be upgrading the front brake and the electrics .
What I would like to hear from you guys is..............
What cam would you fit,I’m not after top end I want mid range power but as said before reliability.
What electrical upgrades would you carry out....... alternator, switches,neg/ earth, what electronic ignition and coils would you use etc etc.
What brake upgrade would you use.
And any other bits of advice or suggestions you may have will be welcome.
I know a lot of what I will hear I may know about, but I also know a great deal of new and useful advice can come from you guys, which I would really appreciate.

I’ve recently finished a T140D that I did most of the work on and it looks and runs well,but that is more of a weekend runner. This Commando I want to be something better. I have already committed to riding it down to Biarritz next June for Wheels and Waves so I need to crack on with it.
Thanks in advance guys.

I would recommend the cam that Norman wants to use, since he is building the engine. Not trying to be a smart aas, just think that if you tell him what type of riding and how you intend to use the bike, like you stated here, then that will be all he needs to know. And of course the all important info of - how much money you have to spend on the build. Cj

I can't comment on cam choices, other than to say the factory profile is quite satisfactory for the average rider.

Front brake as a minimum should get a sleeved master cylinder, which reduces the piston diameter and adds significant stopping power. After that, it's a matter of how much money you want to spend on one of the aftermarket upgrades. I haven't found the need to do that.

Electronic ignition, lots of choices out there. I don't know of any that are a "bad" choice. Stock coils work with all of them, but again there are choices.

Most MKIII owners swap the black cap silencers for the better breathing "pea shooters".

Service your clutch. And also the primary chain tensioners.

Once it's running and you put some miles on it you should evaluate the condition of the carburetors. There are choices there, too... refurbish or replace.

Everyone will have a different view on what to do, as for brakes I would do a complete upgrade of the front brakes, myself went for the full Grimcia set up with 12" floating disc, calipa, MC, SS line, from RGM and works a treat, but of course there is Brimbo as well Madass set up as well, EIs there are quite a few around , new set of Amals if rebuilding the motor, as for cam a 2S or PW3 profile works great and are very reliable and work great around town as well out on the open road, no need to go overboard with the head but opening the ports up for better breathing is always a good idea but your engine builder should be doing all that anyway, Norton motors are very reliable if maintained regularly, just replace anything that is showing it age, but of course how deep is your pockets in how far you want to go.

Ashley

Specify what cam you want. A standard cam will give you a more reliable engine (less cam, valve gear wear)
also be aware that you will be charged approx £48 per hour so expect a bill in the thousands. The MK3 engine i have just rebuilt for a client (mk3 soft cam issue) Cost £1150. Cam followers can be refaced for considerably less than new ones (so keeping the cost down)
Both suppliers of PW3 cams will say that the PW3 cam is the best one. DO NOT be taken in by that statement. If you want an engine with the most longevity fit a standard profile cam.
PM me for more detail about some peoples service and further modifcations that will extend the reliability of the thing
Regards
Peter

I don’t usually promote a single Mikuni carburetor, but for an Interstate 850 MkIII, that’s the way I would go. The 850s are more reliable and better for long distance, just not my cup of tea. Also another vote for the standard Commando camshaft although do check the lift for wear as the factory 850 cams may have not been hardened completely.

Thanks for the replies. Peter, I’ve always heard good things about PW3 cams, what is it about them you don’t like?
I’ll probably go down the full Grimcia route,but what is the Madass set up?

Thanks, Johno

Easy, realistically not a lot -

Standard cam, ideal for touring. Standard tune in southern europe, help the engine run cool.
13mm master cylinder.
Braided front hose, shrink wrapped, and the fittings are 3/8 - 24 UNF - they do exist as they are made for the mini restorers.
Standard disc and caliper, with the above it will be fine, I ride on the M3 and A34 in the rush hours and have no problems.
Modern rectifier,
Electronic ignition, the modern ones are all fine, just have some slight differences.
Carbs, personal choice but not the ones that are on the bike and made in the 70's and worn out before they even smelt fuel.
Tyres - Avon Roadrunners, last a little longer than the roadriders when touring. If you do short trips, 2 or 3K at a time Roadriders will be fine. If going for more than 4 or 5 weeks, go for the tyre that gives mileage.
Silencers - interstate type, or quieter peashooters, remember time on the saddle - best for noise comfort. Black caps OK, but the originals are most probaly rusted away inside by now.
Swap out the isolastics - most probably shot even the originals if they have not seen many miles.

JOHNO23 said:

Thanks for the replies. Peter, I’ve always heard good things about PW3 cams, what is it about them you don’t like?
I’ll probably go down the full Grimcia route,but what is the Madass set up?

Thanks, Johno

Click to expand...

Afternoon Johno
I,m not a fan of vendors pushing things onto customers that is not in their best interests, I have mentioned before on this forum when one of these cams was fitted to a customers engine without his knowledge and a vendor trying to push one onto another customer who had to insist that a standard cam was what he wanted.
I expect a few people will jump to their defence as happened last time i mentioned this. I reiterate that I,m only quoting the facts that i know about and my opinion about those facts.
regards
Peter

I have a LOT of experience with cams on engines of all types and MOST of the time, for street use, a performance cam is NOT what you want, despite (as dobba pointed out) the various claims. As far as cam replacement on a conventional engine, there is no magic involved. If you wish to gain top end power, you will lose low/midrange power. Good low/mid is what works best for normal riding. Sacrificing low/mid to have more power in an RPM range that you will seldom use is a losing deal.

Yes, modern engines with variable valve timing, variable intake volume, variable exhaust volume, variable ignition timing maps, etc can basically do it all - act like a very mild street motor in "normal" driving and do the boy racer thing any time you choose to do so. A 700+ HP Dodge Demon is as tractable at low speed as a 1975 Ford station wagon but will manage 10sec 1/4 miles if you choose to do so. The Norton has no such technology.

dobba99 said:

Afternoon Johno
I,m not a fan of vendors pushing things onto customers that is not in their best interests, I have mentioned before on this forum when one of these cams was fitted to a customers engine without his knowledge and a vendor trying to push one onto another customer who had to insist that a standard cam was what he wanted.
I expect a few people will jump to their defence as happened last time i mentioned this. I reiterate that I,m only quoting the facts that i know about and my opinion about those facts.
regards
Peter

Click to expand...

Ok, I understand that very well. There really isn’t much difference in the cost of these cams,so if a guy building an engine for me recommended one or the other then I would probably go with that advice.However, this was why I asked the question,I am looking for reliability and a decent midrange engine.I have heard the pw3 is very good but was under the impression it was more top end performance which isn’t for me, but if the midrange was still better than a std cam without any loss of reliability then that’s fine. I have also read that a 4s came is a better midrange cam. I’m really just looking for clarity...........

Edit. Peter, did you get my pm?

Afternoon again John
I have just noticed your PM, I will reply later on tonight as I,m now getting ready to ride to Squires Cafe for the Thursday evening 'classic' gathering, or to put it another way, the day some classic bikes come out to play!
regards
Peter