XS Special test run

[oldman prof]

Morning gents,well the black monster took her first run,the second last test run before I finaly strip her down to give her the full treatment,I just have one problem, the popping from the exaust at idle,realy not so bad , light pop every few seconds or so but riding in the traffic,every time I gear down and use the compression to slow down it gets a bit loud,maybe its just because I'm between the cars.Ok the silver part of the pipe is the piece I've added it was to loud even for me,and I made the pod filters and i used scotch brite to filter the air(just one layer,maybe to thin???). I just need to get to small things sorted before I do a final strip&redo.
I'll find a place to put pics, and post again
Thanx
Anthony

[oldman prof]

Ok found it
http://s200.photobucket.com/albums/aa90/anthony-yamy/
I'll put up new pic if you need them,not much to look at now but she go's realy well so far.

[AlanB]

Hi Prof,

Popping on the over-run is usually down to a leak in the exhaust somewhere; often up near the ports, but anywhere will do it!

For idle, a vac leak could also do it; Check the nipples on top of the carb boots and the nac lines to the advance unit and the octopus (if it is still there.....)

Wildly out of tune carburetion can also give popping and banging....... How does it run?

AlanB

[oldman prof]

Well carb boots are sealed,exaust has no leaks but could it be my baffle is not giving enough back pressure,there's very little in there.I'm going to balance the carbs the weekend,other than that she went lovely, it was just a test run we did about 80 kms/50miles and only thing that stopped working was the starter button, one time I pushed up to 100mph and I got a slight crackle at about half way though but other wise smooth,I have no rev counter yet so I cant say were,octo is out and all the nipples are sealed,and I will check advance unit line.
Thanx I'll let you know how far I get.
Anthony

[TopCatGr58]

Hey Prof,

Popping on Decel with Indy pods and aftermarket pipes is common. Ensuring good exhaust gaskets, and no intake/vacuum leaks will go a long way in reducing them, but when you close the throttle plate, it is running lean. You could also try turning your pilot screws out a 1/2 turn, test, another 1/2 turn, etc.!

Mine pops a fair amount during heavy engine braking, but I'm usually doing that from 7krpm while running the twisties! I just think of it as Godzilla Growling! When I'm on the throttle it runs very strong to redline and beyond if I wanted to push it!

Watch your plugs, and as long as they have decent color, and you know you don't have any vacuum leaks, then enjoy!
T.C.

[oldman prof]

This might be me but I hav'nt found any pilot/air screws on these carbs , were should I find them,motor side,airbox side or sitting on the bike-right or left,I've had them stripped down and have two jets inside the bowl up in the main body,main and idle I think and what looks like a large air jet on the intake side , blowing air through it tells me it's connected to the idle circut(spelling), I did'nt have time to take pics last night but I will,I have the feeling that the PO had put on another set of carbs,I'll take pics tonight and put them on photobucket tomorrow morning.
Thanx
Anthony

[mro]

BS34 III carbs had the pilot screw covered with a plug at the factory to keep it from being "adjusted" .

Center top air box side. Plug can be removed by drilling small hole in plug, insert a screw and pull out with plyers. Carefull not to drill to far past plug as the pilot needle is right below it.

mro

[oldman prof]

Ok, thanks mro,I thout it a bit strange that these carbs had no pilot screw,but then I've realy only been working on CB 750 Hondas and small two strokes but live and learn,it took me one ride up and down the road,and I gave my CB to my son and took on this project.
Sorry no pics but Cape Town is living up to it's name again"Cape of storms",it started last night and my "workshop" is out side,but it may clear by the end of the week.
Another thing is, I've cleaned the carbs so many times and no.2 cylinder is always cold at start up, I use high pressure air line and there are no more blocked passages,could it be that the pilot jet/passage is blocked and do I have to cover the pilot screw again.

[AlanB]

Hi Prof,

Once the screws are uncapped, there is no need to re-cover 'em.

Cylinder not running on start-up will either be a blocked pilot( you CANNOT clean the circuit properly without removing the screw!)
Or possibly the choke jet, which is pressed into a passage in the float-bowl. Thet are usually first to block, and are often missed during cleaning.

Take care when working that adjuster; some years have teeny washers and O-rings down there, and the years which have the needle tapered to a point are very prone to breaking points if screwed down too far; When the book says "X turns back from lightly seated"...... They mean REALLY light; only just touching!

Don't ask how I know that...........

AlanB

[oldman prof]

Thanx AlanB,now I REALY feel like an idiot because I found the pilot screws and they are allready uncapped I don't know how I did'nt see them,anyway I think that is the problem,it HAS to be because believe me all the passages I found are clean,that might clean up that cough that I sometimes get when I pick up the revs,not alot almost like a light sneeze.I worked out the fuel consumtion last night from the test run and got 12km per litre/7.45miles per litre,once I do one more clean I can finaly do a carb sync, I was holdin back untill the carbs were done, I'm just hopeing the PO did'nt wreck the needles,because all the driver slots in the jets are f**ked, sorry thats the only way to put it,don't be supprised if I ask how to remove a broken pilot screw monday morning.
Thanx again gents.
Anthony

[AlanB]

Hi Prof,

You don't need to ask: there are a TON of threads/posts on this........
There is probably an "official" how-to somewhere!

If the tip has been broken, and is then extracted, the usual issue is that the orifice is also distorted, stretched to be an exact match to the shape of the needle. This means that even "lightly seated" makes a tapered joint between the needle and hole, so it is almost impossible to touch 'em together without breaking the tip off the needle..........

This was the main reason I changed away from XS carbs.

If you are lucky, your carbs will have the heavier, blunt-ended adjusters.

AlanB

[oldman prof]

This was the main reason I changed away from XS carbs.
AlanB [/B][/QUOTE]
If I have that prob , which carbs are the best to use???

[pggg]

Looking at profs pic, now that's just gotta be the coolest hard-out special I've seen, the carbs are they cable slide type on that bike, they seem a different shape

[oldman prof]

This is the first big Yammy that I've worked on so if you mean do the slides get pulled up by cables then no they not, the cable opens the butterfly valves and the slides work with vacume(spelling),you can't see the top because the were rusted an I've painted them black,well 99% of the bike is going to be black anyway. After this weekend I'll put pics of the carbs on as I strip an reassemle them,because I think all the probs will be sorted out once I finaly "found "the pilot screws.(I still don't believe I did'nt see them)

[AlanB]

Hi Prof,

I can't tell you what are the best carbs to use, I can only tell you what I did. I have put the link up to my original write-up so often that I kind of assume most people know I have Suzuki Slingshots on it!

pggg has done a similar job, with equally good results, but there has been a couple of threads recently telling us that theory says that the modern carbs can't make any real difference. I assume this line of thought means that modern bikes don't make any more power than the old ones.........

With apologies to the "regular" readers who have seen it before, my carb experiences are .... HERE! (CLICK!)

Unfortunately, the two converted bikes I know of are not particularly close to you....... New Zealand and Scotland!

AlanB