brucey

Guys, I really do appreciate all your help and advice. Judging by the number of posts you have both made you share a passion for trials and you both take the time to help other people out with your valued opinions and advice. For the sake of this brilliant website, please maintain the dignity it deserves. Bruce.

Thanks again Oni ?? I pretty much came to the same conclusion after a web search. Tempted by the Jitsi unit but I contacted Splatshop and they will service my existing Showa unit for £120 as long as nothing too seriously wrong with it. This will be fine for my ability. I have also made enquiries about a stronger spring.

I removed the seat/mudguard last night and adjusted the knurled knob in both directions as far as it travelled. Is made no difference to the shock 'topping out' in any position. I then removed the shock and as Oni predicted, I found oil around the shaft and on top of the damper unit. I have to say, I'm slightly disappointed on a quality 2014 machine, however, I don't know the history. My Tiger Cubs are a lot easier to work on! There are no labels or manufacturers markings on the unit so I will assume it is a SHOWA unit as suggested. I cleaned it and was going to remove the spring and test it but I couldn't work out how to get it off, I ran out of time and also decided there seemed little point as it probably needs replacing or rebuilding anyway. So, can anyone recommend where I can get the unit serviced and indicate what sort of price I should expect. Or should I buy a replacement. It should be noted that I am a very average (slightly over weight) 59 year old club rider and bunny hopping isn't in my repertoire. Thanks for your help so far.

Are most trials riders 80kg? Maybe I should bolt a sidecar to it ??

Thanks guys, that gives me something to work on.

I was practicing on the above bike (which is fairly new to me) at the weekend. When going down long hills with the clutch out and brakes on, the rear wheel 'judders' as in jumps up and down during the decent. On closer inspection, when I compress the rear suspension and release it, there is no rebound damping. It clonks as it hits the top stop. This bike is in good mechanical condition with little or no free play in the swing arm or rear suspension. I'm assuming I can adjust the rear shock to stop this. What are the guidelines for adjusting the spring tension and dampening and rebound settings on my bike? I weigh 'just over' 100Kg (with my clothes on). Any advice appreciated.

Out of interest, has anyone used the nylon balls and slightly different springs which I believe are available from a Cub specialist? apparently they seal better and are less prone to contamination.

Many thanks for the info. I must type faster! The pump is brand new (has done 8 trials sections!) I have cleaned everything with carb cleaner and reassembled with fresh engine oil in almost operating theatre conditions! :-) . Chris is supplying gaskets, springs and balls.

This is the pump disassembled. I'm assuming the grooves in the return plunger are for lubrication and are not meant to have 'O' rings in! I have removed and cleaned the balls and springs behind the end caps and ordered additional ones to put in the countersunk holes in the base when I refit the pump to the engine. I will also be reverting back to SAE 30 straight oil on this pretty standard engine. I'm hoping these actions will solve my issues.

Cheers Paul. Chris at Meriden happens to be my expert ?

I pulled the plungers out of the pump. Balls and springs are located in both ends. I'm now not sure what make it is as it has LFH stamped on the body. I'm also not sure if it should have 'o' rings in the grooves on the oil return plunger. I'm assuming not.

O.k. Just had a chat with an expert on Cub engines. He confirms the bike is wet sumping and it is probably a bit of muck in the oil pump internal return valve. I can (and will) fit additional balls and springs as a 'belt and braces' measure although they are not really required on the late (slider) pumps. I have also been advised to run the bike without an external oil filter and to replace the semi synthetic oil I'm currently using with a standard SAE30 oil. While I'm at it, I will also replace all the plastic oil feed and return pipes as they have become a bit stiff over the last 10 years! That should keep me busy for a while :-)

Managed to upload a couple of photos by deleting some old ones :-) Should the oil pump chamber have oil in it? Countersunk holes on back face of pump may indicate it should have balls and springs to stop wet sumping in my opinion.

collyolly, The pump is brand new. I looked at the Morgo Website and it appears the latest type (square slider) pumps don't have springs and balls under them! Interestingly, my pump doesn't have Morgo written on it. I think it as a 3 digit number. naichuff, Thanks for the info. I believe that is what I have but the dowel was fully inside the crank case and only popped out when I had the feed pipe off and turned the engine over!

Thanks guys, Looking at the pump I think I've been given some duff information. The latest type pump still has counter sunk holes in the back which indicates it should have non return balls and springs. I questioned this when I bought it and was told they didn't ! Can anyone confirm if the oil feed pipe should have hollow dowels in the crank case inlet and outlet holes? Unfortunately I seem to be unable to upload any photos even though I have reduced the file sizes.

Cheers collyolly. Makes sense, I just need to find out how and why. I need to check the hollow dowels (which I can do by checking my other cub. I'm still not convinced the latest type pumpdidn't have ball bearings and springs under the mounting.

Further to my post regarding the Cub oil return mod, I have now started stripping the engine to find a cause for the smoking. The engine was built from bits and pieces and put in my spare frame for my Son to ride. It starts and runs ok. He entered its first trial and almost completed the first lap with no issues. It then started smoking badly on tickover so we retired the bike. I carried out a number of the usual mods when I built it including adding a blind camshaft bush and putting a large breather in the unused distributor hole, Alpha big end, etc etc. I also fitted a new (later type) oil pump. I measured the clutch and gearbox oil when I removed it and am pretty sure it's engine oil thats being burnt. My findings so far are as follows: 1. Piston and rings look fine (I suspected a broken ring as a possible cause) 2. Oilways from head to crank case appeaer all clear. 3. I drained 300ml oil from crank case (virtually no oil was left in tank so I lost at least 300ml of engine oil) 4. There seemed a lot of oil in the cavity where the oil pump sits. May be a re herring. 5. There are no ball bearings and springs inder the oil pump as I was told the later oil pumps didn't use them. 6. I recently replaced the oil feed pipe gasket as the ild one split and was leaking. On removing the oil feed pipe and turning over the engine, a hollow dowel popped out of the front hole nearest the front! there doesn't appear to be a hollow dowel in the rear most hole. May be another red herring but could be missing. 7. Oil was evident in the breather pipe when the engine was running/smoking which would indicate too much oil in the sump.(especially considering how much I drained out of it!) I will be removing the valves to check the guides but they are phos bronze and look ok. I would dearly like to find something wrong before I reassemble the engine!

Same cam followers for both standard and high lift cams as far as I'm aware. Stronger after market valve springs are available from a number of sources to stop valve bounce at higher revs if you are concerned. I have used them in my 230cc Cub engine that uses an R cam. Hope this helps.

Thanks for the replies guys. I'm going to strip my old engine to find the cause of the sudden excessive smoking and oil leaks. My Armac Cub has a standard oil return set up with the Armac crank case breather and every other mod I can think of to eliminate oil leaks! I am using a large bore rocker feed pipe. I'm just in the process of justifying a 250 Max Heys barrel conversion with the associated oil return mod to see if I can resolve this problem once and for all!

I continue to be plagued by oil leaks on both my Armac Cub and my old 'bitza' Cub. Most of the oil seems to leak around the rocker covers and push rod tube. Both bikes have had various mods done to the breather system. My Armac Cub has a 230cc conversion and modern piston but I now thinking about fitting that to my old Cub and fitting a Max Heys 250cc barrel conversion to the Armac which I believe uses a modified oil return. I'm aware this mod returns the oil from the rocker area down the barrel studs rather than down the 2 small holes in the top of the barrel. I'm wondering if will help with my problem as I think this area is flooding with my current set up. Does anyone have any more information on this mod? As usual, any help appreciated.

Yes Joan :-) xxx Just recovering from having an adrenal gland removed a couple of weeks ago but hope to be riding again soon.

As requested, a photo of my Cub tank assembled.....and my other bike...... Can you see what I was doing with the orange now? :-)

Good shout collyolly, I just did a quick fuel test on my test sample and it failed miserably. Thinners couldn't have done a better job! So choice is no rattle can lacquer or take it somewhere for proper 2 pack lacquer to be applied. I guess I have very little to loose by putting it back on the bike without lacquer and seeing what happens. It will also give the blue more time to harden. I have all the materials (except the Triumph stickers) to do it again if necessary. Just my time. To be honest I quite enjoyed acquiring the new skill set.

Good point. I’ll check my test piece by dunking it in some petrol for a few seconds. If is softens it I’ll leave it unvarnished ???

Have a look at my post on the Montesa part of the forum page. A whole load of info there concerning your problem. Hope this helps, Bruce.