wrinkleyp

Many thanks for all the ideas and advice. Finally took the engine to Dave Rowlandson at Sapphire motorcycles. The big end turned out to be fine and all that needed replacing were the Main bearings and oil seals. No damage elsewhere - guess I was very lucky! The misfire continued however until I ran a separate earth to the HT coil and condenser (on the top frame tube). the engine is now sweet as a nut! Now all I need is a v good rear rim to complete the rebuild. Wrinkley P

Thanks very much to everyone - especially the reassuring ones! It's great to know there are so many helpful folks about! I guess I'll just have to be brave and try rebuilding the motor myself. Only thing I cannot do is is split the crank to inspect the big end but I was most probably intending to replace this anyway in view of all the effort involved. (When I played with the conrod during the top end rebuild I could feel no up and down play at all, neither could I rock the conrod from side to side (diagonally?). What I could do however is slide the rod bodily from side to side along the line of the crankpin just by a tiny amount - is this sufficient reason to replace it?) Any suggestions where I can get this done, preferably within 50 miles or so of Penrith, Cumbria? Any other bits that anyone would recommend replacing while the engine is stripped - I will be replacing the crank oil seals? Thanks again!

I have a 1980 Sherpa 199a which I have just partially restored. i.e. frame, brakes, rebore, new carb, repaint etc etc. (Trying to relive my youth according to the wife- rode a DOT in the 60's and a slimline Bultaco 325 in the early 70's) Up until yesterday it was running sweetly. Then a misfire developed which gradually worsened with backfiring etc. Checked spark seemed fine but changed plug...... no improvement. Bike starts no bother but misfires as soon as I ride it. Checked wiring and cleaned earth connections...... No better. Waiting for a condenser from Dave R so haven't been able to try that yet. Decided to check timing and points. Points had closed down a lot so thought I'd cracked it! .No chance - bad as ever. Checked timing, seems fine. Decided that is was time to change the crankcase oil seal as I was this far in! Removed flywheel and stator plate with no hassle. Began to wonder when I saw oil seal retainer.... surface rust on bolts, but they came out OK NOW FOR THE HORROR STORY. The oil seal was full of dirty gunge including bits of metal!!!! Examination of the main bearing revealed that the ball cage had disintegrated and disappeared - all I have are 9 loose balls. Amazingly the crankshaft has no significant play. The engine starts and ticks over in spite of this. HAS ANYONE ELSE HAD THIS HAPPEN? When I first bought the bike (running) it seemed a bit rattly, and when I stripped the top end I found the top piston ring hammered into its groove and small punch marks on the head, but no piston or barrel scoring. Some blow past marks on the piston. I assumed that some grit or similar had got in via the carb. Now I guess I know the real reason!!! Or could this be the cause of the misfire? (No signs of any leakage past the oil seal). I am terrified at the prospect of splitting the crankcase and gearbox but unless anyone knows a friendly mechanic in the North of England I guess I'll have to try. ANY SUGGESTIONS OR ADVICE VERY MUCH APPRECIATED. WrinkleyP

Just had my Sherpa MOT'd. Everything tested as usual but no lights so certificate issued with an advisory about not using in dark. MOT 1st issued without registration, no insurance requ'd if bike taken on trailer. Speedo is NOT tested. Can confirm electric cycle horn OK - as long as continuous tone. Got mine for pennies from eBay. Think it might be worth talking to MOT guy to be sure HE knows the rules! (This is particularly true when fitting number plates. I have one set to please the MOT tester and another set which are smaller but still legal according to the details on the gov's transport website! WrinkleyP

Hi, - Not so new actually, Born 1944 so ancient really. Used to ride in the 60's & 70's but never very good only ever managed to win a novice event. Had a Fanny B, then two DOT's and finally a 1973 Sherpa. Having a nostalgic trip down memory lane - second childhood I guess! Have nearly finished restoring a Bultaco Sherpa T 199a. Scared myself half to death when I first rode it. Guess I'll have to learn all over again if my arthritic old body will let me -heart bypass, new knee and new hip!!! Having a problem at the minute trying to repaint my plastic tank. Looked absolutely great until I left petrol in it. MAGNIFICENT BLISTERS! It's stripped again ready to try a plastic adhesion promoter so we'll see. ANY ADVICE WELCOME.