Why would the airflow slow down? Air is drawn in by the engine past the butterfly. Open the butterfly, engine sucks air in past the slide. One gob...
"I believe when the airbox is eliminated there is less pressure difference between the inlet and the diaphragm chamber, requiring a weaker spring"...
A simple test would be to add some spacers under the springs - say 5 to 10 mm. this would add to the static spring pressure, making the lift point...
When you remove the airbox the inlet pressure goes up - are we agreed? This follows because the airbox and filter is a restriction (lower than...
Actually @Simmy , I'm going to disagree with you here, what you need is a stiffer spring (to counteract the increase in inlet pressure (the bit...
No, it goes up in response to the vacuum below it (between it and the main jet), which connects to the area above the diaphragm. Essentially to...
Almost impossible to price, or sell I would imagine... Nice!
You could look around for a used 4 into 1? I'm sure somewhere on Earth there must be some for sale?
Yes, just putting them through an ultrasonic cleaner will not do - you still need to check all the jets and passages, replace the throttle seals,...
This makes sense to me. Some things that can throw you off here - oil film under the followers is one, another is cam bearing wear/clearance (and...
Yes the idle mixture screws contribute at all throttle openings, but I would suggest the effect is tiny, given the size of the jets etc.
"The frame has some rust and the upper crankcase has a couple of the threaded holes for stator bolts partly broken. when I get it going and if I'm...
Lol at all this - yes it might seem a good idea to make a load of noise, peeing off the neighbours is never a good idea. Having said that, my Seca...
Time to pull all the jets to check whats where by the looks of it...
If he had your fingers and brains he would have done it for you...
Don't make this hard. Compressed air won't shift it - get a piece of steel dowel, cut. slot in the end and drop some emery tape in there. Stick...
The "headers" is usually term for exhaust downpipes. The bits you need to clean are the machined surfaces - bores, top of the cylinders, underside...
Well yes you can, but I just do it by feel, and then use a dti on the cam, (dry), lifting it up and down to indicate clearance. I've used valve...
Now, don't cock up drilling out those studs - you can use a left hand drill, left hand tap even, but m4, or max m5 is the limit. I would drill 3mm...
You can "refit" the cam caps to an extent, but you have to be clever about it - it needs metal removing from the mating face, very carefully, and...
Nooooo. Put the engine in, if it runs and is anywhere as good as it looks it will be fine. Splitting the cases to inspect the starter clutch is...
Shine a torch in the tank - 90% of the issues with these is rusty fuel contaminating the carbs, jamming the float valves open etc. The frame looks...
I uploaded some pics here because I couldn't seem to do it in private message.
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Well done, threatening to drag my maxim out to mot test it. Just so wet here at the moment..
are you after a working set or a mint set? I have a set I used after cleaning, they worked fine, but I would need to check if they are complete...
The slide is lifted by the vacuum under the bottom of the flat bit being fed to the top of it - yes I know, with the turbo there is no vacuum, but...
Lotus Esprit turbo (Dellorto carbs), MG Metro turbo, MG Montego turbo (single SU), Renalt 5 turbo , Renault 18 (Solex). Loads more... With your...
Yes, never a good idea I agree, but of course the head is the same as the 650, so the gasket sits against the head - I've no idea what the...
one thing I noticed - the head gasket overhangs the bores (by a mm or so) - is this normal or has someone slung on a 650 gasket?
Today I removed the head from a "spare" 750 engine - the camchain was broken, so I expected to see bent valves, but they were ok? Anyway, the cam...
No, less cr equals less likelyhood to knock. Assuming you maintain squish bands of course, which might not be that easy
[ATTACH] This is a 600 diversion slide - at least I think that's what they came off... note that it doesn't have an "ear" perforated or not, there...
Yes, but there is a risk, well more than a risk, that you will do the job twice otherwise?
"The smaller ID apparently spins the turbo faster, that will make a difference for the main jet needle." Maybe it spins it up quicker - as in...
Sudden carb flooding has more to do with rusty bits than carb faults - time to empty and wash out the tank?
Seals are cheap, false economy not to renew, especially wit @chacal in the same country as you..
without the hole in the lip you don't get vacuum above the slide to lift it, assuming there is a port in the carb that directs the vacuum upwards...
You're correct. In which case I too would recomend buying some used carbs. I do have an incomplete manky set here if the op wants some cross checks.
oh dear, do a search, this has been done and done, but to my mind it has not been explained why there is a difference. I have no idea why there...
No from me. original colour is better
Don't buy those - they are Diversion carbs...
if you have needles from aliexpress bin them. your slides must be identical in all respects, holes are important, but no reason why you can't...
Here we go then. Your carbs are constant vacuum - often referred to as constant velocity, but that misses the point. As air flows under the slide...
Indeed, why bother, little to be gained on these old bikes... But, the theory is correct - when I build a race engine I have a process I go...
Original which? the ones from the restricted slides? Do they have a number? post it here. New? from where? generic ebay? again post numbers, I've...
So, in the reverse, is your filter one of those uni things?
No, just tilt the bike over as far as you can. If you accurately measured those rollers someone might be able to give you a definite answer?
Good question! My first choice answer might be are you sure it's a 650? Have you looked at the barrel casting size, bust behind the headers? If...
So maybe they did change the springs - measure the diameter with a digital vernier, and the number. I have a set of 600 carbs here, I can check.