.also, i am a twat
Joined: Jan 2008
Quite so, it's certainly a distinct proba/possibility & it's very much on the list to find some soft wire + a can of carb cleaner, drop the carbs off (cables in place) & have a spray/gentle prod about. All carb galleries & apertures are of course subject to blocking one way or another*, but I am particularly thoughtful of the fact that I have Petseal in the tank and so there’s a remote possibility that this could lead to gumming up now that they've increased the percentage of ethanol in the mix over here in the Former United Commonwealth Kingdoms. Additionally I'm pretty sure I'm running generally toward or a little over the high end of the scale on oil level and the crankcase breather could be misting oil into the inlet pre-carb, adding to the potential gumming of galleries?
Originally Posted by Lornce
Is the aperature to the enrichening circuit reservoir clear and unobstructed.
Inversely & contrary-wise I think I'm running an early 'one sided' breather outlet venting only into the right carb inlet**, and the right side is always the first to catch when attempting to start, followed by the left, so there’s the vague potential any oil mist in that side could be helping keep things clear? Stranger things have been known… I'm also minded that the kind of coughing back I'm getting in the left inlet tract has previously been seen to leave a sooty deposit which could, after much mileage, block/restrict the idle circuit...
The bike is fitted with a round K&N filter in the aluminium (type 1) airbox and although that has only done around 25k miles*** I will be checking the whole of the inlet tract anyway. I’ll have a fiddle with the seating of the airbox/filter & test before even releasing the carbs to dangle for cleaning as such a solution would require least work, even if it’s not first on the list of potential sources for the fault. I’m lazy like that, and I don’t really have a work space. If I must dig deeper I’ll be sure to want to take a particular look at the left side Carb-to-Head rubber, as whilst they were both new at the main rebuild it got tweaked some time back during a previous carb fitting & may have an air leak.
Certainly, once they’re cleaned, setting up would probably benefit from the considerable stockpiled experience of our local Dave. Setting with vacuum gauges may be possible via the previous offer from DBD, tho/ough that would necessitate a place where we could run my barely baffled engine for a nuisance inducing length of time while we fiddle with the carb settings and I don’t have access to such a place. I can’t help but think that a snippet of the extensive accumulated knowledge of our Local Dave is possibly worth more than any amount of fiddling by me… I've not touched the adjusters he set on the (then new) cables, and the airscrews are as he last set them, which I found gave good starting & a happy tickover when fully up to temperature (if a bit low prior to temp), but the throttle lift screws have been fiddled with, not necessarily to good effect.
Anyway, as far as a stab at diagnostics is concerned, when I pull the sparkplugs after a bit of cranking I can smell fuel from the cylinders, but the plugs aren’t wet as such. If it won’t catch I can see puffs of mixture coming from the exhaust, which if you remember is comprised of just Supertrapp end caps (5 plates) direct on the end of the stainless (front cross over) downpipes. The end caps are sooty, and while I think the bike’s set a bit rich there’s no more sooty than one would expect the exhaust gasses to be at that point in the exhaust tract i.e. pre endmufflersilencercans. Generally after running the (6k mile old) plugs are a reasonable colour with no hard deposits, but maybe a little soot away from the post & arch contact. I seem to get a good spark, but I’m inclined to think that (combined with some loss in the electrical system) there’s a mixture problem, and the aperture to the enrichening circuit reservoir does indeed need checking just as you say. On attempting to start I sometimes find that slightly varying the (airbox based) choke lever and/or throttle while cranking can sometimes lead to the right cylinder starting to catch, and if the starter doesn’t jump to disengage I can churn it over till it catches & then the left jug chimes in.
Probably it would be simplest to buy Astrals K75S**** which has just blown a gearbox, fit the suitable K gearbox I have from the as-yet-unrebuilt Me-MW K75 Rat & do a total rebuild on the Boxer DMW***** I could ride the standard 75S for a suitable period, reconstitute my sorry excuse for a ’79 Rat Airhead, and then sell the 75S, ride the DMW & rebuild the Me-MW 75 Rat. Now if only such a thing were possible…
* And take into account that while I have the stack filters inside the tank on the tankpetcocktaps I don’t run any inline filters.
** I seem to recall there are other configurations that breathe into both sides via a T junction in the airbox? I seem to recall the (type 2 square airbox) ’84 R80RT (‘The Standard 1’ –see post 1) had a double sided system accompanied by blades on the oil feed pipe to induce swirl in the inlet airflow?
*** The K&N site indicates up to 50k between cleaning/oiling.
**** Which I sold him ages/many miles back.
***** Because, as previously mentioned, the quality of my builds is so poor that they need redoing every three years or so.
The bike’s a bitsa on a ’79 reg/chassis, and it’s a Boyer Micro Digital Ignition KIT00086 in a (hacked up) ’79-‘80 loom with early coils etc., running a post ’82 block & jugs with late front cam-end so it’s a late Beancan repacked with a Boyer trigger receiver, with advance weights removed. The Beancan doesn’t seem to have shifted since last strobed by Local Dave. I’ve no rev counter fitted, but I seem to recall he hooked a line onto an HT lead when setting timing?
Checking the ignition timing is on the to-do list as part of a general spruce up, and may be possible via the aforementioned kind offer from DBD & his strobe, depending on a space to run the engine as required by the process without getting shot at by the neighbours. Valve timing should also be checked given the opportunity to get a running jump at the jobs list. Also I’d have to reboot into the personality that remembers how to set the valve timing without undue faff :-D
Originally Posted by Kai Ju
Mine did that following a Boyer Bransdon Ignition install, had been fine with the points. Retarded the timing a bit to where I still have full advance around the 4000 rpm mark, as per their instructions, and it starts a lot easier now. Mind you, I have no idea what kind of ignition is on your bike........
Asterixualisation very wise :-D Underground Bajan Bunker Fund blown? – BLAST!?! As an Executive Director of this here imaginary motorcycle manufactuary you do of course have the authority to initiate such orders, so fair dinkum, and I observe that many a workshop full of spanner monkeys have branched out into the merchandising strand of income generation before they’ve even built more than 5 bikes, but may I bring your attention to the recent filing of insolvency papers by OCC Merchandising with a net loss of $300k, and be so bold as to suggest that were this exciting venture to suffer a massive tankslapper then unsold units could be wrapped around my mancave at the Shedquarters to improve insulation & heat retention, thereby going some way toward providing me with a simulacrum of a working space within which to sort out all my shit? Please?
Originally Posted by pjcr12
No, you didn't sign off on the Corporate Apparel Solution, planktonnn, because I knew you wouldn't like the un-aerodynamic properties of the trouser-width....so, I went ahead anyway and ordered 10,000 units from John G******* over at Fuckwit-Fashions in Gay Paree and paid for them with the secret slush-fund account you were saving for your underground bunker in Barbados. I've already sold one pair to rightsideup, so the rest should go pretty quick..... ******** asterixs used to save a potential libel court case
Whatever you've ordered, at least they are sans tassel...
Cheers fella, thanks for your kind help, hope you didn’t forget a return address so I can cover postage & a couple o’ beers :-) I don’t expect Astral to part with the 75S* so it looks like rebuilding the Me-MW is going to be my only option of staying on the road whilst refreshing the DMW airhead.
* If he were to feel inclined to accept an offer so that he could finance the ongoing running & repairs to his Robin Reliant & eating 'n' stuff I’d have to do it on fortnightly payments, but I’d need to ensure there was a little book to keep track of what was paid & exactly when slices were due. Such things can get very messy – see past posts way back for tales of the extensive snags encountered when the roles were reversed :-D
Originally Posted by jings
hang tuff brother theres a k75 clutch heading you way
...using the wrong spanner since 1964...