keihin carbs, Banshee Alternator, Pamco Ignition

[Miguel]

Hello all,
As is the case with most here, I begin my first post with a love/hate situation...I'm about to set fire to my labour of love...! Ok not quite but I am very befuddled!
I began this xs 650 journey 2 winters ago- a buddy of mine had the bright idea and thought we could build a couple bikes for a few G's and have fun ripping around by summer. We all know how that theory plays out! I ended up driving 10 hours to Saskatchewan to pick up my ride. The guy said he was a mechanic....hmmm ok! The bike was running a bit rough but I figured with some new parts and TLC she'd be right as rain. I ended up buying the soft tail kit for this one, Pamco ignition, Banshee alternator system, and some Keihin carbs. I took my time and did everything as well as expected for a first timer and it turned out pretty good. My buddies bike was turned into a hardtail and he did everything minus the Banshee conversion. His bike ran like a dream, I was pretty impressed but the power that little enging could put out. Mine on the other hand ran about 75% of his. The charging system was awesome but I couldn't dial the engine in like his. When I removed the charging system, I didn't make any marks on the new flywheel where the old ones were- I simply followed the directions of the swap. My buddy says thats where my problem lies. I took a spark plug out, found TDC of one clylinder, and set my valves at 3 thou on intake and 6 thou on exhaust. I figured maybe these carbs that were supposed to be preset may not always be so I tweaked them too and now the bike only idles- it sputters and backfires when I try to rev it. I can't find any info on setting the carbs to original. It appears that someone might have had the engine apart once, is it possible that the cam chain is on the wrong link? So I guess the areas I need help in are 1; what is proper sequence to tuning an engine, 2;what should valves be set at (found 2 different opinions in the Haynes manual), 3; Any help with timing this Banshee alternator, 4; any help with tuning these Keihin carbs, 5; Pamco ignition hints, I have tried to adjust this alot of times, seems there's something else.
If anyone has suggestions for me, please remember that though I have tinkered with engines, I don't know the abbreviations/tech words so please keep it simple!
I can see that these are pretty tough engines and the maintenance may be minimal once all is in order...
Thanks a bunch!

 

[alwaysmonday]

Sounds like you need to begin with the process of elimination. You are questioning many different components all at the same time. Start with the easy and cheap items and confirm they're right. Then move on to the more sensitive items such as the carbs. Maybe a video illustrating the issues at idle would help those more knowledgeable than me diagnose your troubles.

Jon

 

[650Skull]

Welcome, a lot going on at once.

Did you get your carbs from MikesXS. Here is a history on them.

 

[ippytattoo]

A little clarification on what type of Keihin carbs would be benificial since Keihin makes at least a few different models of carbs. For instance myself and other members on here are running Keihin CVK34's off of Kawasaki EX500's with great success, I am sure that you could probably get genuine Keihin PWK carbs working well fairly easily with info that has been posted on the site but if you have Mikes PWK knockoffs then you may very well end up going down the same road MrRiggs went down consuming many many hours and lots of money in brass only to find that the build quality is subpar and they are extremely difficult to get right and keep right. just my $.02.

 

[Miguel]

Thanks guys, I did buy these carbs from XS650Direct, the Canadian version of Mike's XS. Not sure the model, there was only one at the time (not by my bike at the moment) The website only references PWK so I'm assuming those are the ones. My buddy's bike ran excellent with the same carbs....I am in the Rockies, what jets should I use?
My bike is a 1977 if that's any help.

 

[650Skull]

The only thanks i want is for you to read the link i posted, use that info for your jet sizes, (no one else has done as much with these as mrriggs), and if you are having problems then come back and ask others that have had nothing to do with these carbs and you will get the answers asked for.

As ippy said lots of info on Kwaka Ex 500 carbs and they work well.

 

[Miguel]

Wow, alot of info on the carbs, thanks to mrriggs for all that! Have to clear out garage again to put his settings to the test!
I'm hoping the carbs adjustment is what it takes....we'll see....

 

[Miguel]

So, I changed my main jets(?) to the 40s, I didn't have the 115s so left the 120s that were there, turned the air screws to the bottom and backed them 1 1/2 turns. I'm not sure how the whole 'measuring the floats' etc thing works (I know there's talk of it but it still sounded confusing) so I buttoned the carbs back together and fired it up again. It sure idles nicely but still getting that popping and white smoke. The weird thing is that my bike had a 'passing button' which turns the high beam on when you push it. The RPMs went up and while holding it, I could really rev the engine! It still smoked me out of the garage but I could get the RPMs above 1500 doing that- otherwise it will choke out or backfire.
Any input greatly appreciated!

 

[ippytattoo]

The only change there would be by turning the high beam on would be an increased load/draw on the electrical system. Pete recommends hooking up the Pamco and the coil to a seperate known good charged battery when testing the Pamco. This may be a good test for you to perform to test and see if you have a fault some where in your charging circuit causing an over voltage condition. Another good idea would be to test the charging system output voltage at various RPM's while you have the Pamco and coil hooked to a seperate battery using a volt meter. I could be all wet behind the ears but in my experience white smoke is generally from burning oil. You could have a few different things going on with this bike.

 

[Miguel]

Well I feel kinda silly but in case anyone reading this has the same issues...
I decided that I hadn't hooked a charger to the battery since new (2 years ago) I figured that with the banshee alternator system, the battery was mostly just completing the circuit. Well, I had the trickle charger on it for about 2 hours and decided to kick start it and...whoom! She purred like an aggressive kitten! The other thing I did was re tighten the carbs boots as they might not have been on perfectly (the pods are tight against some sheet metal)
I coudn't believe it so put the charger back on it and the next day fired it up and it was like a new machine! I'm guessing the spark for the plugs still comes from the battery so although the charging system works good- if the battery is near dead, it may have enough spark at idle but not at higher revs???
The past 2 evenings were spent cruising around on the bike for over an hour each time and she never missed a beat. No problems even to highway speed. I should get the 115 jets this wek and will try them in case but now I have a bike to ride!
A quick side note, I like to ride this bike up to about 80-90KMH, after that the revs are around 4K and vibration is very noticible. Is this when guys talk about 'rephasing' the motor? To make it smoother at higher revs?
Thanks a bunch.
Miguel

 

[retiredgentleman]

Well I feel kinda silly but in case anyone reading this has the same issues...
I decided that I hadn't hooked a charger to the battery since new (2 years ago) I figured that with the banshee alternator system, the battery was mostly just completing the circuit. Well, I had the trickle charger on it for about 2 hours and decided to kick start it and...whoom! She purred like an aggressive kitten! The other thing I did was re tighten the carbs boots as they might not have been on perfectly (the pods are tight against some sheet metal)
I coudn't believe it so put the charger back on it and the next day fired it up and it was like a new machine! I'm guessing the spark for the plugs still comes from the battery so although the charging system works good- if the battery is near dead, it may have enough spark at idle but not at higher revs???
The past 2 evenings were spent cruising around on the bike for over an hour each time and she never missed a beat. No problems even to highway speed. I should get the 115 jets this wek and will try them in case but now I have a bike to ride!
A quick side note, I like to ride this bike up to about 80-90KMH, after that the revs are around 4K and vibration is very noticible. Is this when guys talk about 'rephasing' the motor? To make it smoother at higher revs?
Thanks a bunch.
Miguel

Do you, by any chance, have a 36 tooth rear sprocket? If you change the rear to a 33, you will only have about 3700/3800 rpm when at 100 km/hr. I use the 17/33 gearing and I have no vibration problems, even on trips riding 6 hours/day.

 

[Miguel]

My rear sprocket is 32 teeth and front is 17. Maybe I'm just a wuss! I have straight pipes with a small baffle and I've been riding with a half helmet so maybe that's all it is

 

[scabber]

All motors vibrate. The 650 has a sweet spot where almost no vibration. Mine is at 4500 RPM. Find yours gear accordingly.