brucey

I machined and fitted the kick shaft oil seal last night. The recess is 28mm od x 4mm deep and just broke through the housing where the flat is (as anticipated). I'm not too fussed as I will put a smear of sealant in the recess on final assembly. I will also be fitting the double lip seal with the spring facing outwards as I think there is more chance of water entering the gearbox through the kick shaft spindle than oil coming out. If you want to fit the seal the other way around, I would recommend you machine the recess 5mm deep to allow the seal lip to clear the outer step on the shaft. Photos below. I hope this helps someone else.

I managed to obtain the 22 ID x 28 OD x 4 W oil seal from a local supplier (£2.50) and tried it on my spare kick shaft spindle. It looks like it will be fine especially with a bit of 'O' ring grease on the shaft. Next job will decide if I need to add a bit of weld. If not I will machine a Diameter 28 x 4 deep recess into the case to fit the seal. All set up and ready to go.

Today's Progress: (Just in case anyone is still interested!) I managed to source a metric oil seal ID 22, OD 28, W 4. (Thanks for making me look again Oldas) So I ordered 2 off. I made a 1:1 paper template and placed on the kick start spigot, it will just fit. (see photo) If necessary, I will get a blob of ally weld put on the end of the flat but I'm not too bothered if the seal OD just breaks through. I will need to buy a cheap boring head for my mill or get a 28mm cutter to modify the housing to accept the seal. I fitted the Ally end cap I made to my modified design cam bush which all looks o.k. The cover is a light press fit over the bush and I may loctite it in place if I need to remove it to open out the bush on final assembly. I couldn't resist a little go with my polishing wheel. I think it looks o.k. My next job after the kick start spring and oil seal arrives will be to check this part of the assembly to see if I can design and make some form of cover. As the 22mm oil seal ID is 0.23mm smaller than 7/8", I will need to check how freely it turns on the kick start spindle. As it isn't constantly rotating, I can't see this being a problem as I can always make the seal ID a bit bigger if necessary. 14/01/18 progress. The selector rod and kick start return spring arrived. This let me check the repair bush I fitted to the gearbox case for the selector rod and fit the kick start spring to see how much room I have for a cap. Unfortunately my kick start shaft oil seal didn't turn up but the boring bar for my mill did! I can probably get an oil seal from a local bearing company. I have attached photos of my progress. I would love to know if this is the same design of kick start cap that other people fit as I have never seen one 'in the flesh'. I'm also still trying to decide if I should counter bore the fixing holes slightly for aesthetic reasons. I guess I'll also need to get some shorter 2BA bolts to hold the new cover on.

Today's Progress: (Just in case anyone is still interested!) I managed to source a metric oil seal ID 22, OD 28, W 4. (Thanks for making me look again Oldas) So I ordered 2 off. I made a 1:1 paper template and placed on the kick start spigot, it will just fit. (see photo) If necessary, I will get a blob of ally weld put on the end of the flat but I'm not too bothered if the seal OD just breaks through. I will need to buy a cheap boring head for my mill or get a 28mm cutter to modify the housing to accept the seal. I fitted the Ally end cap I made to my modified design cam bush which all looks o.k. The cover is a light press fit over the bush and I may loctite it in place if I need to remove it to open out the bush on final assembly. I couldn't resist a little go with my polishing wheel. I think it looks o.k. My next job after the kick start spring and oil seal arrives will be to check this part of the assembly to see if I can design and make some form of cover. As the 22mm oil seal ID is 0.23mm smaller than 7/8", I will need to check how freely it turns on the kick start spindle. As it isn't constantly rotating, I can't see this being a problem as I can always make the seal ID a bit bigger if necessary.

Yes, I also looked at 22mm ID seals (7/8" is 22.23mm) but still couldn't find any with a small enough OD (needs to be 25mm max) which is really 'O' Ring territory. Unfortunately it doesn't fit on my face plate so machining an 'O' Ring groove into the boss becomes difficult. I know Bob at UPB adds weld to the boss (I'm assuming he fills the flat on the outside of the boss) to allow an oil seal to be fitted. But I have never seen this mod. I'm waiting for a spare kick start return spring to arrive so I can see what space I have available and decide my options. I need to balance how much effort/risk I'm going to put into modifying the side plate to prevent what is probably a very small oil leak! I made the cam shaft bush outer cover last night and that looks great. I've made the schoolboy error of starting to polish out the casting marks and now don't know where to stop!

Oldaz, Nice idea but I have looked at this option and the only oil seal I can find at the moment is 7/8" ID x 11/4" OD x 1/4" wide. Unfortunately that won't leave enough material around the kick start spigot casting at either end! It's a bit of a shame as I was going to buy a cheap boring head for my mill to machine the recess! I need to check if the cover will fit on my lathe face plate this evening. If I can, I may be able to design a spring plate retainer and combined oil seal assembly to fit in a recess machined into the outer end on my lathe. Bruce.

Trialsrfun, Thanks for the info. I think I'll buy a sprare kick start return spring and see if I can turn a suitable ally cover on my lathe. I'm also looking to put some form of seal around the kick start shaft (7/8" diam). I can't find an oil seal with a small enough od (needs to be 1"). So I'm currently looking at O rings.

Did you happen to notice if you could see the kick start return spring on these bikes? Bruce.

Today's Progress:

Stan & Bashplate, I appreciate your comment but it is an 'itch I have to scratch' I'm modifying a spare gearbox side plate that needed the selector shaft location hole repairing. (now featuring a steel bush). It is one of those projects that suits my abilities (Ex Toolmaker from the 70's and currently a Design Engineer working on Hitachi trains). So it ends up as a nice little project for my shed. If I don't like it, I'll simply put the existing bits back on. (as the photo) It still begs the question, where does everyone else get their modified gearbox side plates and what is done to them. (there seems little point in reinventing the wheel) By the way, I have no interest in making any more after this one! I am a little surprised that no one is offering a slightly better looking new CNC machined part that has all the oil leak and other mods incorporated. Bruce.

I also have a 2009 TXT 250 Pro (Raga). I wouldn't worry too much if the noise disappears when you pull the clutch in, they all do that!. However, if it does it all the time, check the Idler Gear as they can loose teeth from over exuberant kick starting! (As can the 'Bart Simpson' Gear). They are great bikes but not bullet proof! As advised, check some other similar bikes out before pulling anything apart. A gearbox oil change wouldn't do any harm and it would give you the chance to check the old oil for debris. Hope this helps. Bruce.

I have just finished building my dream Armac Cub but am slightly frustrated at not being able to stop a minor oil leak from the gearbox side. I cured the clutch side by fitting a belt drive primary and diaphragm clutch I had a spare gearbox cover, a lathe and a mill so decided to try the Armac conversion and do away with the outer cover, however, I only have a photo to work from. I don't have access to ally welding equipment so am trying to avoid welding if possible. I have machined the flanges off the edges of the side cover, modified the case for a clutch lightener (I'll be using my original Armac clutch lightener on the bike), machined the selector housing for the modified seal plate and made the vent at the bottom into an M5 drain hole. I intend to make an extended camshaft bush from Phospher Bronze (with an open end so I can ream it 5/8") then make an aluminium cap to push onto the outside end sticking out of the side plate to seal the end and make a protective cover. This way I can take it apart again at a future date if required. I'm a bit stumped with the kick start side of things as I have no information apart from the attached photo. I was just going to make a large ally washer to simulate the now missing outer case but I'm not sure if I should make a cover to protect the return spring. I would also like to incorporate some form of oil seal as the kick start shaft has the potential to leak oil. Even if fitting the modified cover doesn't cure the leak, at least I should be able to see where it's coming from! Any help or advice appreciated. Bruce.

I had this problem on my Gas Gas. I found the rear pads were almost worn out and making the piston come out too far in the caliper and causing the rear brake to bind slightly. If the rear pads appear low, I would change those first. Then check the stuff above if that doesn't cure it. Hope this helps. Bruce.

I find the reduced capacity of having the oil in the top tube makes the oil hot during a trial. The additional capacity and position of the filter helps keep the oil a bit cooler. Bruce

This is my set up.

I have one of these fitted to one of my Cubs: http://www.trialsbits.co.uk/product_info.php?products_id=342 Oil filters are from a Citroen 2CV Mine is fitted under the seat as I'm using an under the petrol tank oil reservoir and foam air filter mounted directly to the carb. Among other advantages this filter adds around 1/2 pint of oil to the total volume and acts as a bit of an oil cooler. It is very easy to obtain and change the filters. Hope this helps, Bruce.

To answer my own question; Put the kickstart lobe at 6 o'clock (facing down) Make sure the Cam Plate is in roughly the right position and the spring plate is located in an indent. Make sure the selector guide rollers are in the correct cam plate grooves. Dry assemble (no sealant) holding the gearbox cover on with the 2 big screws. Note: The cam plate will sort itself out when you put the pin in. It is also easier to put the split pin into the selector pivot pin if the bike is in 1st gear. Check kickstart moves and engages and gears select (mine were both OK second time around). Remove cover again, apply sealant to faces and reassemble. All seems perfectly simple now! I'm trying some sealant as recommended by Chris at Meriden. I applied a thin layer of this to both faces. I'll let you know if it cures my slight oil leak. I'm assuming the chamber where the oil pump is gets engine oil in there which then drains back into the crank case through a hole near the bottom of the crank case. If I still have a leak I may need to use different colour oils for the engine and gearbox to help identify where it is coming from. I'm running a dry diaphragm clutch so no oil there. However, I'm pretty sure it's sorted now. I hope this helps someone else. Bruce.

Hi, I have just finished building my Armac Cub. During running it in I noticed I had a small oil leak from the inner gearbox case. I removed the outer and inner RH cases to re seal it and reassembled everything only to find I couldn't move the kick start or select more than 2 gears. I have now removed the covers again and realized I hadn't put the lobe on the kick start shaft at 6 o'clock which would explain why that was jammed! Before I put the side back on (for the 3rd time!), can someone just clarify what I need to do with the selector plate, selector forks, indexers and gear clusters. I understand the need to position the selector fork guides into their respective slots in the selector cam plate but where should the outer profile be in the spring? I'm assuming second notch in (neutral?). If the above is correct, then where should the 2 gear position indents be in the rectangular slots in the cam plate? Believe it or not, I have assembled at least 3 Cub gearboxes but I usually do them with the engine out of the bike and laying horizontal in an engine stand. I seem to be suffering the same crisis of confidence Tom Cruz had in Top Gun! I'm hoping it will all turn out good like it did for Tom and I'll be riding my leak free Cub off into the sun set sometime soon! Any help and advice appreciated. Bruce.

Fit a new clutch cable while you are working on it. An apparently 'free' cable can easily tighten up with a load applied. Originally, I extended my standard clutch arm to make it significantly lighter. I then fitted a proper Clutch Lightener Kit which is quite expensive, requires minor mods but gives a 1 finger operation. I never managed to cure my plated clutch from slipping when starting at anything other than just over tdc. After trying all the mods to the standard clutch (ally pressure plate, extra friction plate, stronger springs, setting it up with a dti, expensive oil etc.) I gave up and fitted a diaphragm clutch to my 230cc Armac Cub which is amazing. The primary is now belt driven enabling the clutch to run dry. It never slips. Hope this helps, Bruce.

Chris at Meriden for the gear lever.

Duncan MacDonald uses both on his Cub. I'm just building my Armac Cub now and will have the same problem as you as I have an Armac Clutch Lightener fitted and plan to fit a Pete Kirby Clutch Kit.

I'm the same age as you and have been riding for about the same length of time. The first time I got cramp was when I was riding a Greeves Anglian at the age of 14. My friends dad had to pull my fingers open to release my grip on the throttle. I remember it well! I also did quite a lot of windsurfing in my time. Both sports require a conscious effort to relax your grip to avoid cramp and improve control (as you already know). Unfortunately I now suffer from Tendinitis in my wrists which feels like they are broken until it wears off usually after 24hours! The good news is that it is a twisting motion (like using a screwdriver) that aggravates it and not a straight pulling action so I can ride trials bikes as long as I'm careful. Definitely worth getting a professional opinion though as there could be any number of causes and solutions. Not much help I know, but you are not alone! Bruce.

Many thanks robido and Trials Central. What other forum would supply an answer this quick! Bruce.

Hi, I'm rebuilding my Cub engine and notice that the Cam Followers have 2 small blind holes in each Follower presumably for lubrication. Do these face the back or the front of the engine, or doesn't it matter? My Haynes Manual doesn't mention rotation. I'm currently thinking towards the back to trap oil in them. I'm also fitting a blind outer Camshaft Bush. I presume I can now take the blanking screw out of the end of my side points Camshaft. The timed breather will also be redundant and I will drill a small hole from the oil return chamber into the blind bush to lube the camshaft. Any advice appreciated. Bruce.

Also check the master cylinder hasn't been over filled with brake fluid!