brucey

After 18 months, I finally fired up the Cub today. This is the 1st bike engine I have assembled and although pleased to hear it run, was slightly dissapointed at the amount of smoke and various oil leaks that need sorting. I have the following questions: How long does the engine need to run before it stops smoking? Mine has run for about 5 minutes which I thought would be enough to clear any assembly oil but it still smokes! The barrel had a good bore (hone marks still evident) and I fitted a new piston and rings during the rebuild. Is there meant to be a small quantity of oil seeping into the RH (Side point side) case? There is a vent hole near the bottom. My engine has the Alan Whitton Gear Shaft Seal Mod and Breather in the top. About an egg cup full of oil came out when I removed this cover to relocate the kickstart return spring. The oil was found before I started the engine but after I had pushed it for about 50 yds with the spark plug out to get the oil circulating. Do the rocker cover feed pipes normally have copper or fibre washers. For some reason I am finding it hard to get them to seal. I modified the pipe to fit my top tube oil tank and have just fitted 'dowty' washers to the outside to see if that helps. Looking on the bright side, it starts and it moves! It may need a bit more running time to identify some other leaks and sort the faults. Bruce.

Alan, Many thanks for your clear and concise answer. I plan on turning the engine over with the spark plug out until I can see oil flowing down the return pipe. Then I will start it and run the engine for about 15 mins on and off before changing the oil. I plan to put 15/40 mineral oil in the engine and gearbox (I got a gallon of it cheap in Wilkinsons!) and a drop of ATF mineral oil in the clutch to keep the primary chain wet. Should I be changing to semi synthetic once run in? I'll be off up the shed then! Bruce.

Charlie, Thanks for your reply. Surely the return (to the oil tank) is above the supply which comes from the bottom of the oil tank. My Triumph Tiger Cub has 2 oil pipes coming from a small manifold beneath the crank Cases (dry sump engine). I guess if the worst comes to the worst, I can pour some oil into the crank case and turn the engine over to see which pipe the oil comes out. This will be the return! Even though I have fitted a Morgo (upgraded) oil pump, it still looks very small to start pumping oil around a Citroen 2 CV oil filter! I'm also not sure if the increased back pressure on the return line will affect the lubrication my tappets receive further along the oil return line.

Hi, I am carrying out the final assembly of my Tiger Cub and can't find which oil pipe is 'supply' and which oil pipe is 'return' on the bottom of the engine. I am fitting a top tube type oil tank and have put a feed from the return pipe for the rockers. Also what is the general view on fitting an external oil filter to Tiger Cubs? I have one but will get the bike running before I consider fitting it. I intend to change the oil regularly any way, so the only advantage I can see is that it would add another 1/4 litre of oil to the system. The disadvantage being that there are more possible leaking points! Any help would be appreciated, Bruce.

Also worth considering Alan Whitton's mod. I am at the final stages of assembling my Cub with Alans mod already done. He machines the case to accept an ecentric bush. This allows you to extend the clutch rod operating lever which in turn makes it lighter to operate. I don't know if anyone else has tried this. Bruce.

Tanks OTF. That excellent explination has to be worth a positive feedback from me. Now you only need 59 more!

Just out of interest, Can anyone explain what the 'Reputation' tag means and why mine has gone from 1 to 2 since opening this topic? I'm assuming it isn't good but have no idea what I have done wrong! Bruce.

Jack and Alan, Many thanks for your replies. This sort of information is invaluable and difficult to get from books and manuals. If I make a couple of phosphorus bronze bushes to replace the thackery washers, I guess I can leave 2 of the thrust washers out. I'll be grinding down my ring spanner tonight while I wait for the tap and die to arrive! Bruce.

Just a few questions:-) I need to buy a tap and die to clean up the cylinder head studs and nuts. What size thread is it ?(Square barrel and head if it makes a difference). It looks 5/16" but not BSF Do the oil feed holes in the Rocker Spindles have to face any particular direction? The rocker spindles seem to go into the head further than my old oval head. Is this normal? The lube holes are visible on the feed end of the spindles. How many thrust washers are there on each rocker spindle? I have 1 either end of the shaft but not between the spring washer and the head but the Haynes Manual says 3. What are the inlet and exhaust valve clearances for an R cam? Is there a torque setting for the head nuts or do I just 'pinch' them up? As usual, any help would be appreciated. Bruce

OTF, Thanks for the information. I just wasn't sure how much difference the piston and cam make to ignition timing. I guess I can always phone Alan and ask! (he has never been anything but helpful). I have seen the fantastic job Alan does on the push rod inspection hatch but will have to do it myself as I spent the remainder of my budget on one of Alans cnc machined gear change levers instead! I have also recently discovered Classic Dirt Bike Mag and obtained back issue 16 which has an article on the Comerford Cubs. In the Article Donald from Armac reccomends setting the clutch using a DTI. I'm assuming you operate/disengauge the clutch and adjust the 3 springs until the pressure plate runs true (using the DTI to check). Has anyone else done this? The VM22 Mikuni carb advert said the following in reference to its size: "PLEASE NOTE 26mm IS THE WIDTH OF THE OUTLET SIDE. THE SLIDE IS 22mm." Bruce.

Hi, I am just building the engine for my Trials Cub Project. I am fitting a PVL ignition which I purchased second hand about a year ago. I'm sure Alan Whitton said set the timing 5mm BTDC but the guy who sold me the ignition said 2.0 - 2.5mm BTDC. I'm running a +40" 7:1 piston and 'R' Cam in a Square barrel, side points engine. I know Alan uses a higher compression Kawasaki piston (I've got one but couldn't bear to bore a perfictly good barrel). I can just about get both timings but would like to set the correct timing in the middle of my adjustment. I'll be running the engine on a Mikuni VM22 (26mm) pit bike carb if it makes any difference to the timing as I believe these are the kiddies to fit. Also, what valve clearances do you use for an 'R' cam? I was also going to do the mod that puts a plate in the head to make fitting the push rods easier. Does anyone have any photo's or sketches of this? It's taken me a year on and off to build this bike but I can see the light at the end of the tunnel now! Any help would be appreciated. Bruce.

Thanks for the information MatchlessMan. As I've already got a small external filter, I'll stick that on first to give a bit of additional oil capacity and see how I get on. The engine is currently with Alan Whitton waiting to have the crank cases machined for the PVL ignition. I was going to get a set of later (fully ball raced) crank cases modified but can't find an affordable crank to fit them. Someone mentioned it may be possible to get my plain bearing engine modified to accept a fully ball raced crank but Alan said not to bother! I seem to have hit a wall building this Cub as I keep spending money but don't seem to get any closer to finishing it. I'm also looking for a square barrel with all its fins and a Kawasaki Z200 piston to fit it if anyone can help! Best Regards, Bruce.

Stick, Thanks for the information. I may have confused you slightly by not giving my full engine number in my previous post. I was afraid it may be cloned, although we are all friends here! My original (complete , oval barrell) engine number has T20 87031 stamped on the front engine mount. The new cases I have just bought have T20 3164 stamped on the left hand side of the cylinder base. Both cases have side points. I just wanted confirmation that the bits from the complete engine would fit the new cases before I send them away to have PVL mountings machined. I also note that I can fit a higher output oil pump to the new cases (

Dan, Now you've done it! This topic will open up a whole can of worms. Basically it all depends on how much you want to spend. I'm building a Cub myself. The previous one I had had std heavy weight cub forks that I reconditioned. Quite frankly they were awful compared to slightly more modern trials bike forks. This time I tried the following: 1. Bought a cheap pair of Honda CM250 forks from ebay and turned the sliders down so they fit inside the original Cub sliders. This saves making new spindles to mount the front wheel. 2. Bought a gas gas yolk and tapered head bearing assembly that had been modified to fit the cub headstock. This also fitted the Honda stanchions (I made adaptors to go from 32mm to 35mm) Note: You need access to a good lathe to do the above! Cost approx

Stick, Many thanks for the information. The number on my complete oval barrel engine is T20 870-- so it looks like it will have a ball race crank (and I'm assuming big end). The New cases I have bought are from a 1965 engine. Ray Small built my last Cub engine so I have never pulled one apart untill now! My intention was to get the new crank cases modified for PVL ignition (I prefer the original set up), and sprocket change mod, then swap the other parts over. I have aquired a square barrel and head also. Saying that, I seem to have bought a trials cub to upgrade and ended up replacing almost all of it! At this rate, I'll have almost 2 bikes! Bruce.

Blimey, that one on ebay went for

Dave, Very nice looking Cub. Is that the tank that was on e bay recently? I'm thinking about running my silencer (which is the same as yours) up the front of the rear sub frame. I also have a remote oil filter to fit and intend to make an oil cooler. The standard trials swing arm which I lengthened and widened looks good. I'm also going to have a go at unbrazing the front end of my late Bantam swing arm which is cranked both sides. I will make some lengthening pieces and scollop out both sides where the tyre goes. This will move the shock mounting points back a bit but leave the width unaltered. If anyones interested, I'll post some more photos as I progress with the build. Bruce

Just a quick update. I've attached a couple of photo's of the frame build to date. There is still a lot to do! The rear swing arm went pretty well but I have to cut an extra piece out as the widened portion hits the rear subframe when it travels up. I'm not sure what I'm meant to do with the RH shock mounts as the bottom is now 20mm further out than the top one. (See photo) I have fitted taper bearings and Montesa yolks and will try turning down my spare Montesa sliders so they fit inside the Cub ones. I may just use the Montesa set up as shown in the photo as it all seems to fit nicely. I haven't a clue what the Montesa wheel spindle looks like though! Does anyone know what happens to the Montesa slider bottom bolts (are these used to hold them into the Cub sliders) and oil drain holes when they are turned down?

Thanks for all your replies guys! The latest on my Cub build is I have lengthened one of my std Cub Trials Swinging Arms by 1". I actually cut mine just in front of the wheel spindle slot (where it is kinked), chamfered all the edges and put a 1/4" thick x 1" wide plate in. Next job will be to widen it by 20mm. I will be cutting just to the rear of the RH pivot. I will cut to the middle of the swing arm, move it out 20mm then fabricate a pice of U section to fill the 20mm gap in the middle and take it to a local company to get it all welded up properly. I contacted a guy on e bay when he didn't receive any bids for his Bantam (both arms kinked) swing arm and ended up buying it! Oh well, I feel a Mk 2 Cub/Bantam swing arm comming on! One of the reasons I'm building this Cub is that I enjoy designing, modifying and making bits for it. It would be easy to spank

Thanks Alan and Stick for your replies. The last (and only other) Cub I built used a standard trials swing arm. I just scolloped a piece out on the RH side where the tyre got close. Also with the standard heavyweight forks clonking away, pulling wheelies was never a confidence inspiring activity on my previous Cub! Somehow, this time, I've ended up with 4 pairs of forks! 2 sets of Montesa Cota forks with yolks (I intend to make 1 good set to fit the Cub and possibly turn down the spare Montesa sliders to fit inside the cub sliders) , a set of Gas Gas yolks adapted to fit a Cub and a pair of Honda CM250 forks which I turned down to fit inside the original Cub sliders. God bless e bay! If the turned down Honda sliders and Gas Gas yolks are any use to anyone, let me know before I stick them back on e bay. The main problem with my previous Cub was that as soon as it got wet, mud used to build up at the front of the rear wheel on the swing arm and either side of the rear tyre. This could be a real pain with the sticky mud/clay we have in Kent. I wouln't have thought a extra inch on the length of the swing arm would make that much difference to handling but it should give enough room for the mud to travel through! Where are the tubes usually lengthened? Is a sleve added and brazed in somewhere? Can I assume 20mm on the width and 25mm on the length about right? I also intend to fit mounting points for a side stand (RHS) and chain tensioner (LHS) at the same time.

I want to widen and lengthen the rear swing arm on my trials cub. I intend to do the cut and shut myself then take it to a local fabricators for welding. Can anyone tell me where to cut and what to make. I have a pretty good workshop with a lathe and small milling machine. I have 2 standard trials swing arms to play with. I was thinking of removing the LH (brazed in?, cranked) arm from one unit and sticking it on the RHS of the other but this seems wasteful. I have seen a sketch on another post but it doesn't give any sizes. What do you do with the rear shocks when the swing arm is widened as the bottoms won't line up with the tops! Are both sides widened by the same amount? As far as I can tell, about 25mm is added to the length. Where is this added and how? Is the swing arm pivot mounting width affected (I intend to fit a Sammy Miller swing arm bush kit) Any help would be appreciated. A couple of photo's would be great! Bruce.

I planned on going to enjoy the bacon sandwiches at Hungry Hill this year but I'm hearing rumours it's been cancelled. Can anyone confirm either way before I drive 100 miles to see a load of old coddgers enjoying themselves on bikes that should be in museums! Bruce.

I've just fitted a Lionelli Ignition system to my Sons Techno. Apparently it fits a Rev 3 easily. (see prevoius posts for details). It seems a nice (good quality) piece of kit. Steve Hardaker told me it is a common upgrade for Rev 3's as it improves reliability and performance significantly. At around

Carrying on with what seems like an endless saga, I bit the bullit and purchased a complete Leonelli Ignition System for my Sons Beta Techno. Although it seems to phyisically fit, there are no instructions! I will ring the suppliers again tomorrow (they told my Son it was very straight forward), but in the mean time, has anyone fitted one of these systems to a Techno? I need to know the following: 1. I'm assuming the ally spacer goes behind the stator as this is the only way it fits! Is this right? 2. I've put the white (pulse?) coil at the 1 O'Clock position (looking at the stator) as this seemed to be near the mark on the flywheel at TDC. Is this right? 3 How are you meant to time it up statically? I've got a DTI showing TDC but have no idea what to do next! 4. What is the mark on the outside of the flywheel meant to line up with? 5. Did you have to cut down the rubber grommet to fit the plastic spacer ring? 6 Does the spare wire comming from the stator go to the fan/bridge rectifer (Beta yellow wire)? 7 Is the black/white wire comming from the CDI the cut out switch connector? Static Timing is my biggest issue at the moment! I could probably work the rest out. Somehow I've got to align the stator with the flywheel at TDC. I can't see anything through the 2 flywheel 'holding' holes. Any help would be appreciated. Bruce.

Just to wrap this up............I hope! I eventually sent the whole ingnition system off to Steve Hardaker [stevehardaker@telefonica.net] who operates from Spain. I have to say he is one of the most helpful guys I've never had the pleasure of meeting! Unfortunately after rewinding the Stator and testing the system, he found there was a problem with either the Coil or the CDI which could not be identified on his test kit. After spending what must have been a considerable time trying to sort it out, Steve only asked for the cost to cover his postage. Top Bloke! He also gave me the number for Matty at A.S. Trail Sport (01287 619150). Who were also very helpful. I have purchesed a complete new replacement system from them(Stator, flywheel, coil & CDI) for