New member with a 71 Commando

Hi , I'm a new member here . I live in Southern California and I grew up on classics, customs and hotrods. I have had friends with Triumphs , Harleys , and one had a B.S.A. =?(Big ____ ___) ?J/K Matt ,,,it was a cool bike that turned a lot of heads.

That's were my story starts ,, I had wanted a Norton motorcycle for a very time . One day , when looking at the Online Cycle Trader. I spotted what LOOKED like a great deal on a super clean 71 Commando . Within 48 hours I was returning home from a 18+ hour trip with my nice shiny Norton in the back of my now ex mother-in-laws truck . When I got home and unloaded it I immediately terrorized the neighborhood .

The party ended in a hurry . A few days latter. It became hard to start with heavy exhaust smoke and oil dripping from the pipes . Without doing any proper research or trouble shooting , I pulled the head. There she has sat for over 7 years ,,,, yes I know,, ?

I'm looking to make it right and get it back on the road . The pistons look great ,, like new ,, and the cylinders look freshly honed . I'll mic the cylinders just to be sure .

I have the head disassembled to replace the intake oil seals . I want to check the condition of the valve guides but I'm not sure how to do this ? I have the Factory Shop Manual , the Owners Association Tech Digest , Commando Service Notes , and Interim Parts List . I have the guide bore spec but Im not sure how to measure it ? I would think the run out should be checked with a dial indicator, but I don't see a procedure for that . The guides appear to be bronze but I don't know if there the recommended 850 style . I know of a local machine shop that does motorcycle heads. I'm not opposed to having them do any necessary machine work . I'm just not sure I need any machine work done . If the guides need to be replaced will they need to be reamed ? If the valves and seats check out , can't they just be lapped ? Anyway , I have a lot of other questions ,,, , I'm glad to have found this forum and am sure to meet some new friends here . If anyone has the time to walk me through the head service procedure I very much appreciate it. It is the first small step to getting her back on the road . I'm now thinking the bike was wet sumping and might not have had a valve seal issue. I realize there will be much more to look at after the heads back on. Thanks for reading my ramble ,, Steve
Here's a before picture .

Steve where do you live in Ca? There are a few guys here that could help you out. Chuck.

Nice bike. After sitting for a few days they can wet sump & can display some symptoms similar to those you describe, although I would have thought it would have cleared after a while. All the best getting it sorted.

A bit more explanation of "wet sump" - the oil drains from the tank into the crankcase, bypassing a possibly worn oil pump.

So, when you start it up, oil drools from wherever it can, out the exhaust, into the airbox where the cars suck it up, etc.

Very typical and simple problem. Some folks rebuild the oil pump, others install various types of anti-drain-back valves (some can be dangerous if you forget to turn them on before riding).

it helps to park the bike with the pistons at the top of thier stroke (kick very slowly till it gets hard to push the starter)

Welcome, nice looking bike, for sure!

I live in Orange CA which is a few miles from Disneyland.

I figured out how to use the search engine here AFTER my original post.I was happy to find , The head reconditioning procedure has already been well covered here. I made a call to Rabers , they were very helpful as well. All my valves and guides are worn. Thanks to this site and Rabers I'll have it better then new .

I found a spare leaf center spring bolt in my garage . This is the bolt that goes through the center of all the leafs with a locating pin at one end for the axle . The diameter and head size are perfect to pull the guides .

Thought it would be a good time for a quick 7+ year update ! I did end up having a machine shop do the head work. I installed the head , pipes , new correct seat , a nice set of smaller U.K. bars. Bought a new cover ,, Set her in the corner of the garage and covered it up. That was well over 7 years ago. Yes I know ,,, a lot of projects have came and went. I've owned the bike for 15 years and maybe rode it 2 miles !

I have a 74 Vespa Rally 200 which I ride often. It's a 2stroke on 10" tires that tops out around 65MPH. Early 2stroke scooters are loud , smoky fun but ( with my Norton in the back of my mind ) I've felt the need for something much more.

2017 ,,Time to get the Norton sorted ! The covers off ,, I just sealed the fuel tank and installed the fuel taps. I'm having a alloy fuel tank made along with side covers , but that's going to be a 9 month wait. Secured up some cables and wires. Oil change with new fuel and oil lines will be done in the next few days.

I'll need a battery. I need to research that ,, not sure what type I should get.

I know the Dunlop tires on it are at least 15 yrs old ,, It has Dunlop Roadmaster TT100 4.10 tires on Akront 19" 2.15 rims front and rear. I'll need to research my options here as well.

I'll post a few pictures after I get it all sorted and cleaned up.

I remember ordering parts from Old Britts , Rabers , Fair Spares. All were great. Fair Spares was always very helpful with technical info ,, They are maybe 9 hours up the coast from me and I wouldn't mind having them go over some fine tuning once I'm to that point.

Thanks for reading and tips / suggestions.

High RPM ,, Crazy high rev's at start up !

Another update ,,
Sealed the fuel tank , flushed the oil tank , new lines & fluids , new battery. Corrected some of the wiring mess . A new harness is now on my list. Other discoveries ,, my rear wheel is offset far far to the left , the chain guard is missing , a Boyer ignition is installed . I have a signal round slide 32mm Mukuni carb which looks new but sticks .

With the fire extinguisher ready ,,,
5 kicks and it started . Then just started reving crazy like a rocket ,, as if the throttle was wide open . This is a bad time to find the kill switch on the bars non operational . I was able to key it off within a few seconds but ,, not the best thing to happen .

Next , I disassembled and clean the carb. Found very minor wear on the slide bore but otherwise very clean.The slide still sticks.

With the fire extinguisher ready ,,,
5 kicks and it started. Same thing , the engine just took off . I was ready with my hand on the key this time .

Even though the carb sticks , I know 100% the slide was completely closed at both start ups. I was aware of the issue and insured it was before kicking it over.

I'm not sure where to go from here. Am I sucking air at the intake , problem with the carb that looks near new , timing advance issue , maybe a issue I caused installing the head ?

I was hoping to get it running with the Mukuni but planned on a set of Amals anyway. Seeing how the Mukuni sticks maybe a set a Amals should be my next move regardless of the issue .

Any suggestions ?

I'm not totally opposed to taking it to a shop but would much rather make all attempts possible to sorting it myself .

I wd begin by ensuring that there is some small amount of slack in the throttle cable itself, and that it moves smoothly throughout its travel. The stock arrangement has a splitter which pulls 2 cables for the single one at the handgrip.
Next is to see if the spring in the carb is pulling the slide all the way down when released. If it's sticking, as you say, this must be addressed, of course.
I don't think an ordinary air leak cd cause this condition; you'd need both fuel and air (and probably timing advance too) to make the motor race like that.
Sharper minds will be along soon, I'm sure. Good thinking, to try and sort it out yourself. Have you called Phil?

Hi , Thanks for your reply. Yes , there's slack in the throttle cable. I also visually insured the carb slide was closed before kicking .
Reading online ,,
" The Mikuni "choke" is really not a choke, it is a "fuel enrichener" because it adds a shot of gas to the existing volume or flow of air. "
Maybe I'm getting to much fuel through the enrichener ,, If that's even possible.
I was planning on Amal's anyway.
My last order of small parts was through Fair Spares and Phil was helpful. I'll make a list and give him a call.

Yeah, I wasn't a big fan of dual Mikuni's back in the 80's. I bought a set from Reg Pridmore and had my '71 head ported to 32mm. It was a hard starter, but at WOT pretty strong. I went back to Amals and it was more civilized. I gave up top end by a fraction, but didn't have to practice voodoo to get it started. Something sounds amiss with your situation. An engine should not rev that high without the carbs supplying adequate A/F ratio. Have you started it without air filters and observed the slide positions? They should be almost at the bottom when idling.

Sounds a lot like an air leak on the intake manifold.

New carbs and intakes are on the way.
I'm hoping my 20yr old compression gauge is lying at 70psi in each cylinder !
I'm heathy 220lbs and the compression feels strong to kick but I don't have anything to compare it to.

I'm sure you know this but.... Throttle needs to be open or the carbs off to get a proper compression check. 70-80 is about all I would expect with a kick start and no intake air.

Both the carbs and the intake manifolds are quite sensitive to over-tightening.

Yes , Thank you ,, carb. off ,, My gauge was faulty. Cold dry compression is 120psi both sides with a new gauge.
I'll look up and follow procedure when carefully installing the new carbs. I think I'll be investing in a tool to sync them as well.