Forum

[david w]

The faulty sprag clutch has been removed along with the starter motor and wires, all is well ,the electronic ignition has been fitted and it started 2nd prod and ran o.k. I haven't road tested her yet but upon restart the same gremlin that wrecked the sprag has surfaced yet again, a pretty severe spit back through the carb. Any suggestions out there ? I am leaning a bit towards the carb but who knows. The machine is a bullet 65 military version!!!

[PeteF]

I don't wanr to teach you to suck eggs but.....have a look here...http://www.whfolk.co.uk/REOCHUMBER/Arti ... arting.htm

[david w]

Thankyou Peter,
it's not my lack of ability, it's just that something has suddenly gone pear shaped . The bullet 65 has always run like a swiss watch until one day it stopped 30yds from home and wouldn't start. I wheeled it back to the workshop tried again ,it fired back with such force it broke the sprag clutch so i decided to remove this potentially weak point and fit electronic ignition at the same time to cure what I mistakenly believed to be faulty timing ( probably the mechanical advance unit). However this has turned out not to be the case as the machine has spit back badly on start up twice since then!!!. It seems as if the sudden occurrence of this gremlin has not gone as had imagined it would have so I am now looking at the next solution, possibly carb!! ( I still have the Mikarb on). Has anyone got experience with amal mk 1 carbs? versus the original. It is quite an expense but nothing ventured as they say.

[Gwilly]

Hi Dave, I assume you have the original carb fitted. Do a check on the rubber intake and the flange to head gasket.
Check for splits, Seems the problem will start gradually and get worse as the starting mixture becomes weaker due to the air leak. It has even been known for the spit back to blow the carb right off the stubb. regards gwilly

[Alan R]

Hi there, DAVID--------- I'm with GWILLY on this one re}--- leaking manifold rubber, etc...The 28mm MIKCARB as fitted is a reasonable bit of kit, it's one poor item being the "All-or-Nothing" choke system which -----a) Has no intermediate control---though our hosts do a cable conversion kit , and ---b) That long lever can get caught by your right knee and get deployed when least expected---in my case just as I was overtaking a tractor & trailer out on a B road !!! For everyday normal use on a standard bike it's perfectly fine.... have you discarded the PAV kit, the "Filter-in-the-toolbox" and fitted a "Tea Caddy" one instead ?? RIGGERS put some very useful jetting sizes on here a while ago and I have used them successfully on my Classic 500......so I would hold-off going to an AMAL for now...... As yours is the Military version I thought that this was the type of BACKFIRE you had in mind ?? }------- http://www.fas.org/nuke/guide/russia/bomber/tu-22m.htm ---------------- but then again, perhaps not, eh ??

[PeteF]

David, if it was working fine then suddenly it wasn't, I think you are complicating the issue by changing to electronic ignition and contemplating changing the carb. You need to work systematicaly through the ignition and carburation until you find what happened to cause the sudden lack of "go". The manifold rubber is a good place to start being pretty simple to check - if you can get it running at all try spraying the manifold with WD40. If there is a leak you will get smoke from the exhaust.

[david w]

Hi Gwilly ,peter and alan,
Yes it is a bit of a mystery and yes it is running on the original carb minus the pav system and is fitted with a conical s&b filter.
As far as I am aware it is running the standard jets. I have already tried the wd40 trick on the rubber carb mounting, no smoke to speak of from the exhaust but their are a lot of tiny cracks in the rubber so I will replace it. One thing worth mentioning is that the electronic kit is now fitted, if I catch it just right it will start first time and run although I do feel as if the tickover appears to be fast perhaps 1500 rpm (thats a guess as its not fitted with a rev counter). When it is running apart from the fast tickover which before it broke down it didn't have it runs fine ,no misfire or pinking or anything it is just the start up ,if you don't just catch it right then beware of a pretty big spit back!!!!. Thanks for applying your brains mine are getting a bit shaken.
Regards David

[Alan R]

Ahhhhh, "I see" said the blind man to his deaf daughter---- So you currently have }--- CONICAL S&B air filter feeding a Standard 28mm (VM28) Mikcarb with NO change to the original jetting specs.---- standard piston and standard exaust(no PAV) and standard silencer( but which one ?? ie the original Bullet 65 OR the Long-Tom).....First, take a look at the R/H side of the inlet manifold. Has the old sensor pipe nipple been blanked-off properly ?? ( Sudden extra air here will cause weak running/difficult starting)------- With a conical air filter you should have fitted richer jets etc......... So there's 2 areas that could give the symptoms you appear to have......

[david w]

Thankyou Alan,
I have a more or less free day tommorrow, so back to the drawing board. I will reset Timing from the start and then check out the carb if their is no change. First the rubber and then jets, I'll probably take off the carb for the hell of it just to see what is happening in the fuel dept. I should be out riding though and don't want to use the almost mint R80/7 because the roads are too dirty for it!!. A lesson learned their I think ,don't have too good a classic or you get too precious with it . Why have it then ? I don't know really all quite daft but it has got two wheels and four have never done it for me really.
Regards David

[Alan R]

---------- have a look in our hosts catalogue for their suggested jet sizes..... The VM28 will give you a reasonable performance if you're not hoping for that "sporty" image !!!! LoL.