markparrish

well, I had a similar issue with my C15 (in recent post) The advice I got was to check no air leak between carb and inlet, which I did. I also stripped and completely cleaned the carb - I suspect there was some dirt or dried out residue in there... there was some visible gunge - especially in the bottom part of the main jet assembly. I seems to have done the trick. I have a very different carb but I guess these are common places to start from. Good luck

I've uploaded a clip of my old bike - hope it comes through!

normal sound I think - mine used to do it and I rather liked it!

Thanks for everyone's help with this. I have got it running quite well this morning - I carefully reassembled the cleaned carb and did my best to tighten it to eliminate any leaks (without over tightening it!). It idles quite well and picks up well from idle ok. I notice it won't idle on the side stand - seems to slow down and stall - I guess that's something to do with the height of fuel in the chamber (its a bent stand and it lays fairly low on its side). only a couple of tiny oil leaks too! Much better than before! I guess its hard to eliminate them all and new ones appear every time I try! by the way I was wrong - it's a monoblock carb not a Mk1, sorry.

well done!

Thanks Archie - it was a very special day and done in my daughter's unique way! I was a very proud daddy!

I'm going to say...exhaust goes on last. I think radiator second, frame first.

I've completely stripped the Amal carb and cleaned all the parts in ultrasonic tank. I've cleaned the jets which had a bit of gunge on them and made sure everything is clean and reassembled correctly. I can't see any way of adjusting the float height in the carb - it is a rigid unit which bears directly on the needle. I'll just have to hope it is right. Fingers crossed for re fitting it tomorrow!

I might do that - after giving it a thorough clean. I'm not sure what the throttle is - it doesn't seem particularly fast.

Thanks Huski - that's a good idea - I will try that tomorrow.

here it is on a better day!

Hi - I have just put my C15 engine back together after fixing a number of oil leaks (I hope!). It never ran very well before - it seemed to never idle properly. I've only owned it for a short while and managed to nurse it through for its first job which was just to deliver my daughter to her outdoor wedding (about 100 yards up a drive!) without getting oil on her dress! Now I have it all back together, it starts easily and I seem to be able to get a lovely, smooth, medium speed idle but as soon as I open the throttle it bogs and dies. I am out of my depth and need some help - maybe a sequence of things to eliminate/try? It is a fairly standard looking engine but has Electrex world ignition. I think I have put this back correctly as I made a couple of punch marks before removing it to fit a primary chain tensioner. I tried it with a newish Amal MK1 first which it was running with (but quite badly) before the rebuild (although I notice there was a fair amount of sticky residue in this when I removed it). It started well after a good tickle but no chance of ever pulling away because the throttle caused it to stall. I then swapped it for a newish Mikuni lookalike and with choke it starts first kick and runs with choke out. As soon as choke is pushed in it does the bogging/dying behaviour so I can't even rev it to keep it running. I've tried fiddling with the mixture screw and it makes a bit of difference when choke is out but still won't run with choke in. I think the valve clearance is ok, but maybe it's not - I used the Rupert Ratio trick of listening for the click when moving the rocker to get a nice quiet engine. I did back this off a bit on the inlet side as I thought perhaps it was too tight and this might be contributing, but it doesn't seem to have helped much. I'm happy to try anything but don't really know where to begin. Thanks in advance, Mark

I can't find a picture but I put my weight back on my Rev3 when I had it and remember it being about 5-6mm thick. From memory It was virtually the same diameter as the flywheel but had an "extended chamfer" which was from about 3mm thick at the edge rising to full thickness about 20mm from the edge. I think the main issue is making sure it doesn't foul the inside of the cover - you have to add a "spacer" which is an extra plastic lip, to move the cover out a bit.

Great job! I think we have all got garden envy now!!

Hi - I know you are looking for a number and hopefully someone will post one for you, but I go for "hand tight" if I can't find a figure - My Rev 3 had socket head screws (after I modified it) so I used a "standard" length Allen key, my Evo 4T has 8mm hex head screws so I do the same with "standard" length spanner. An old engineer told me that once and it hasn't let me down yet! I did check recently with some head nuts on another bike and the torque achieved with a standard spanner wasn't very different to that set using my torque wrench. I guess that is one reason why spanners are different lengths. Obviously different materials and different thread pitches come into play... I'm sure there will be wails of protest from those that know a lot more about mechanics than me! Good luck

Thanks Timdog - some great ideas there - what a nice job, whoever made that tank! Thanks for the helpful photos! Can you estimate how much oil it takes?

thanks Trialsrfun - yes those Terry Weedy tanks look great. I don't think my design would vary greatly from those. I think I'd like to make one because I enjoy a challenge and learning new skills. If it all goes wrong, I know where to buy one now though! Why do you say that the filter needs to be in the return? The current filter is in the tank and the engine is fed through this. The return line splits just before entering the tank. It's not a problem - just helpful to understand if I can. Thanks for your help.

some great links and advice there, thanks - I like the look of those Morgo parts! - a useful looking "T" banjo for the return too.

HI, I am considering making an alloy oil tank for my C15. It is in a B40 frame (I think) and currently has a bodged together "standard" steel oil tank. I would like to make a narrower tank with space for a re-routed air filter and neater and enclosed electrics. I have searched the forum and found lots of snippets of good advice but wondered if anyone could help me with some "first principles"? What should the minimum advisable capacity be? What is the best return route (can it enter high up or does it have to be a tube running up inside like the standard one?) What diameter tubes should be used at the return junction to cause the right amount of oil to split off to the rockers? Where should the breather be positioned? What oil filter should I use (standard internal one or are the "pit bike" type external ones ok, for example?) I'd appreciate seeing any examples you may have made (any bikes), or diagrams etc. If I have missed an obvious post elsewhere, please point me in the right direction! Thanks, Mark

Your logic seems spot on. I would suspect the thermostat switch too, given all the things you have described. I suppose it could have a very dirty connection as one last thing to check before buying a new one.

genius!

I don't know what gap size you are aiming for but maybe guitar strings could help?https://music.stackexchange.com/questions/33257/standard-guitar-string-gauge there are lots of sets available (different gauges). Most seem to be quoted in imperial sizes. The three thinest strings in any set are plain wire - the thicker three are usually a wound wire and wouldn't be suitable.

https://www.pressurewasher-spares.co.uk/water-intake-tube-clamp-clip/product.pl?pid=1420231 I can't help thinking it came from the washer, not the bike!

...well, I've looked all over mine and I can't see what this is! I wondered if it might be from a brake calliper? Mine is an older 4 stroke Evo, so perhaps it's a newer 2 stroke "thing"! hope you work it out!

Hi - I am a step behind you so I'd be very interested to know what size sprockets you are running internally and externally at the moment. I am having similar thoughts about my c15 as I'd like trials speeds but with the possibility of riding on the road without holding up the traffic! I have been told that non-standard internals are hard to come by. It is geared up for the road/greenlaning at the moment - I estimate it does about 30 in top gear (with a huge rear sprocket 72 teeth!). 1st is still a bit too fast though.