RE 5 Throttle Cable Adjustment

[nicholr]

HI all, It has been a while since I visited this site. WOW, lots of Norton stuff now. Very interesting. Two years back when I did visit I noted an article that took much of the black magic out of setting up RE5 throttle (et al) cables. Is it possible to get directed to that article or have someone post a reprint. I have the guage, have the manual and can do it 'that' way but I recall the article having a very sensible approach I would like to use to set up my 2 RE's for summer riding. If anyone has a set of good cables for sale (the 2 cluster and 3 cluster) I would very interested in purchasing them. All info is appreciated. Ron Nichols Calgary Canada

[kanonkopdrinker]

I think you might mean this ....DC---------------------------------------------------------------------------------------As I notice that there are plenty RE-5 owners whom have problems with theset-up of their carburettor I like to explain how this set-up can be madewithout the need of special tools .The only special tool you need are your brains.Everybody is talking about how difficult it is to adjust the RE5 carburettorbut in reality it is very simple. There are usually two main problems:1. The carburettor. itself2. Tuning the cables. Let’s start with point 1Typical problems : spark plugs whom are getting wet , irregular idle , badstarting ,erratically running engine in medium and high speed range.How to begin (For those who have the manual pages are mentioned)Remove the tank and fan . It’s not necessary to remove radiator, oil cooleror exhaust. Now it’s easy to remove the carburettor. (3 bolts and the oilline). Remove & clean all the jets mentioned on page 65 & 66 . Don’t worryabout the adjustment of the pilot screw , that’ll be mentioned later. Ignorepoint 7 because that never causes trouble . The float level normally neverchanges ,alltough avoid to tough the arm by force . And now comes somethingimportant !! If you don’t want severe trouble , don’t use the same floatchamber gasket again!!! This gasket is fabricated from a kind of rubber andis in most of the cases about 25 years old and totally hardened. This meansthe sealing between the cap and the carburettor body is allmost nonexistent. This means that a twist of the grip results in a injection of fuelin the air passages of several jets (secondary main system) . This causesthe spark plug to get wet in a few minutes. When the engine (and thecarburettor ) is hot .The fuel vaporises and is getting through the leaksconstantly in the air circuit. So the engine runs erratically in all speedranges.How to check if your gasket has hardened . See at the outside if thecarburettor has a wet or greasy spot around the gasket area. Normally thismust be completely dry .If your sparkplug is wet (in a warm engine) andyou’re certain the plug is OK suspect the gasket.Page 68 d. will be mentioned later . An other problem ( a floodingcarburettor) is often caused by a leaking fuel cock. Change the fuel cockgasket ( the one with 5 holes in it) and the problem is solved.Now we’re ready for point 2.2. Adjusting the cables :Typical problem is the powerdip between primary and secondary system andloss of power.Don’t use the service manual for this because the information in it isupdated by Suzuki Service Bulletin NR 9 (page 4,5,6,7,8 & 9)A little explanation:Point 1 : Be sure to turn in all the cable adjusters or you’ll haveproblems with the adjustment of the oil metering pump.Point 5: This adjusting screw is not available on the early RE-5M typesPoint 6: Not necessary to remove the carburettor.Point 8: As I found a way to adjust the cables without the carb. angleindicator the rubber plug doesn’t has to be removed. For those whom have theindicator , they may follow the service bulletin.Punt 11 till 14 can be ignored unless the carburettor has dropped to theground or something like thatPunt 15 b.2.: The proper angle is 78 to 82 °Here we need some further explanation. Even if the primary throttle valve istotally closed ,the angle of it will be 8° compared with the inlet (primarybore) it closes. ( Service Manual page 58 rule 8). So , if one mounts theangle indicator as described in point 12 of SSB9 , the throttle valve hasstill an opening angle of 8° whereby the indicator shows 0° . So, when theindicator angle shows 82° , the throttle valve has it’s maximum opening(82° + 8° = 90°) and that’s something you can easily verify by looking inthe primary bore. What they only want to say with point 8 is turn thethrottle grip totally open and check if the primary throttle valve has it’smaximum opening .Point 15 b.3.: Check if the throttle valve closes till it’s minimum (8°) .Punt 15 d.: Port valve timingNow I shall explain why we don’t need the angle indicator . To understandthis you have to know a little theory how the carburettor is working. Ofcourse you can read this theory also in the service manual on page 58 andthe next pages. As you noticed yet there are two throttle valves in thecarburettor. The primary throttle valve in the primary bore which has beenmentioned yet and an other one which is located in the secondary bore (underthe primary bore) and which is called the secondary throttle valve. Well, tobe correct there is an third valve (port valve) which is also situated inthe secondary bore but which can’t be seen because this port valve islocated in the trochoid housing and behind the secondary valve This port valve and the primary throttle valve are commanded by the throttlecables. The secondary throttle valve is actuated by the vacuum developed in theprimary bore by opening the primary throttle.What is the now the meaning of the throttle cable set-up?Never more or less than when one opens the grip the secondary throttle andthe port valve will open perfect simultaneously on a certain moment. Andthat seems to me perfect logical because when in the same inlet 2 valvesare situated behind each other and only one opens the inlet will still beclosed by the other .How this really happens is explained here:The moment that the two valves are opening together is when the primarythrottle valve has opened 43°To prevent the secondary throttle valve from opening to soon ,(this valve isas I said actuated by vacuum),it is blocked by the limiter plate (see service manual page 59).When theprimary throttle valve has reached an opening angle of about 41° the limiterplate deblocks the secondary throttle valve. And this is something you can see very good if you look to the front side ofthe carburettor (between the radiator and the carburettor) with help of atorch . If you twists the grip you can see the limiter plate move on acertain moment. This moment should be the moment too for the port valve tostart opening. After this theory we will continue with our SSB.point 15 d.1.: The correct timing is 35° on the angle indicator ,( when theprimary throttle valve opens 35 + 8° = 43°) . With other words a fraction after the limiter plate beginsto move.To be short , in place of looking to the angle indicator one even canobserve the start of movement of the limiter plate . When it has moved about1 à 1,5 mm the port valve has to open too. In practice this works perfect onmy bike and several others I’ve adjusted. Point 19 : adjustment pilot screw: You can do it as described but inpractice around 1 ½ turns is a good basis.Some more theory : the pilot screw is necessary to make the fuel-air mixturein the primary circuit the same as in the secondary circuit. With a badadjustment (weak mixture) the dip around 3500 rpm never disappears evenwith correct adjusted cables.And the last points of interest : the air filter . Only use a genuine onebecause if it isn’t made of the original material , the mixture can get toopoor or too rich too.Be sure the fuel pipe don’t touch the air inlet collector . When thiscollector gets hot due to very warm and humid weather it heats the fuelbefore it enters the carburettor and can cause vapour lock.