Replaced the fibre rocker cover gasket... it was really fragile & brittle and broke easily when I removed it. I replaced it with a new 'flexible' fibre one with a very thin smear of clear silicone sealant on both sides. (after cleaning off the mating surfaces with MEK). Whilst I was 'in the area' I thought I'd check & retorque the ten head bolts again, a couple of the exhaust sided bolts moved a little when the torque wrench was applied... all the bolts on the inlet side didn't move at all. Once the rocker box was fitted & properly retorqued the tappets were adjusted too.
Got fed up with the cables flapping about in the breeze so I made some guides up using stainless steel welding rod.
526 miles since the rebuild and she starts on the first or second kick. She vibrates more than I would of thought especially after getting the crank balanced... the front wheel looks like it has Parkinson's it shakes that much on tickover at a standstill! No oil leaks since the rocker box weep, a peep into the deep, dark orifice shows that the oil is turning black but its still putting out a steady stream of oil from the return pipe on tickover. Front end seems alittle harsh riding over the bumps/craters/dead animals that litter the UK roads so I might change the new standard spring I fitted for a progressive version.
840 miles... Changed the front springs for a Progressive Spring set from 'Tricor Andy'... What a difference its made to the ride, still not modern day ride standard but I can get round lumpy corners a bit quicker now. (Might need to look at the rear shocks now tho…). Oil now weeping from base of the RH side of the exhaust Rocker Box... so I've bought 'wire reinforced' gaskets off FleaBay to fix it... again a slight smear of silicone sealant on the gasket faces to seal it then get the torque wrench out and 'bingo' job done! 925 miles... After a good run of 85 miles the oil leak is back but now on the base of the LH side exhaust Rocker Box FFS... Hells teeth this bike is doing my feckin' head in!... I've rebuilt loads of Jap engines over the years using OEM & non-OEM gaskets with no silicone, Hematite, Wellseal or any of that shite without them weeping oil... No wonder Brit bikes never corroded away... they were nigh on 100% waterproofed from engine oil! Rant over... All gasket faces cleaned with MEK, rocker box bolts holes in head which had oil in were cleaned out with cotton buds soaked in MEK. A new reinforced gasket fitted with a slight smear of silicone sealant again on both sides. Bought a new rack for the back end as I'd been told that the mudguard would start to crack if left unsupported. (Plus I needed a rack for the toolkit & spares I now have to carry about). I've also changed the 'breeze block' rear light to the earlier smaller version. Sorry for the dark photo... I ran out of 50 pence pieces for the lecky meter...
All going well so far then Rocker box pressure even on later primary breather engines is the main problem, i have used old r/cover caps in the past and drilled a hole to accept a threaded barb in each one and use a 3 way connector with some clear plastic pipe for a discrete top end breather setup.
That was going to be my next question... I saw a breather set up on a Bonnie the other day which was located at the timing plug position... does anyone sell this particular set up or do you have to make your own? Does anyone have a oil catch tank for the primary case breather fitted at all? My breather pipe (re: bit of garden hose) is currently angled onto the rear chain where it does a great job of chain lubing (but also puts it on the rear tyre).
Crankcase breathing is already fairly adequate but as the revs rise it creates an in balance in the rocker boxes and letting them breath is by far the best solution Yes you could use the timing plug but you still have the r/b inballance :-( On 70 onwards bikes with the primary breather the factory fitted a silver coloured d shaped breather pipe that follows the line of the rear mudguard, do later bike not use this ??
I seem to remember 73/74 cranks had to vent into an airbox for emission reasons, not a great idea :-( if you pipe is just venting to air then you could fab a small catch tank
My bike (140E) is supposed to have a pipe to the airbox but that has been removed at some point and an earlier airbox fitted (which doesn't have the later pipe fittings/tubes). I don't like the look of the 'D' pipe running along the rear mudguard so I'm hunting for alternatives... A small catch tank maybe the way to go.
Phil, you could run the pipe so it just goes to seat height that maybe enough to stop exiting the end. also re the gaskets. are the faces in good order on the head and rocker box?? also have you tried a copper gasket. ?? Not sure if you have done this already but thought it may be worth mentioning
Phil, you could run the pipe so it just goes to seat height that maybe enough to stop exiting the end. also re the gaskets. are the faces in good order on the head and rocker box?? also have you tried a copper gasket. ?? Not sure if you have done this already but thought it may be worth mentioning
Phil, you could run the pipe so it just goes to seat height that maybe enough to stop the oil exiting the end. also re the gaskets. are the faces in good order on the head and rocker box?? also have you tried a copper gasket. ?? Not sure if you have done this already but thought it may be worth mentioning
I like the idea of running the pipe upwards, if I can stick a small filter on the end that would sort it.. The casing faces are good, smooth and level with no 'nasties' that the liquid gold can escape from. Not tried a copper gasket as yet... I'm a bit of a tightarse so I'll try all the cheap alternatives first! I'm looking at brazing a pipe onto a TDC timing tool and fitting a length of tube and a filter on it at the moment (similar to a 'Bunn' filter set up).
Talking of being a tightarse… Today (30th Sept.) 'Buster's Motorcycle Accessories' on Fleabay are selling Motobatt batteries (MB9U) for £35... Bargain! I can swop it between my Bonnie and H1 500...
My 650 Tiger vibrates like that too , so nothing to worry about i dont think. a nice job you have done
One thing to remember is at that mileage a rebuilt engine is the rings are still going to be bedding in and you will have more blow by so this is the likely cause of the breathing issue.
I decided to get something made up last weekend that I'd seen on a Bonnie a couple of weeks ago... I 'acquired' a 3/8" (10mm) adaptor from work and used part of my Triumph timing tool as part of a cunning plan to make a crankcase breather. The timing tool was machined out at one end to take the 3/8" adaptor (also turned down). The parts were made to be an interference fit. Once together they were silver soldered. I had a small air filter in the garage which fitted nicely... just waiting for the horizontal rain to back-off a bit before I take it out for a test.
