1978 XS650 Special Project

[Melnic]

5twins, no I have not done a wet measurement like you show Only a dry.
I did get the float gauge from Mikesxs and yes, I made sure the floats were just barely touching the gauge on both sides and YUP, I had to twist them to get straight.

To do a wet measurement, I don't have a fitting like what you show there. This carb does not have a drain like my XJ650 does.
Where do I get that?

 

[5twins]

I got mine from this eBay seller, very nice little "tool" that I've used many times ......

https://www.ebay.com/itm/274881260720

 

[Melnic]

Thanks! Ordered !

 

[Melnic]

NGK 5K resistive Caps came in and changed out the caps. I have yet to receive in new plug wires.
Old Caps measured 8.2K and new ones are about 5.2K

Incidentally, I had replaced the pilot and main jets with the MikesXS jets that came in when I rebuilt carbs. I recall looking at the numbers and they were stock numbers but I did not write anything down unfortunatly like I did on my last bike carb rebuild last year.

I also got in a center stand from ebay and replaced that as well. The on on the bike had the foot lever missing so I could not even use the center stand. Putting the XS650 onto the center stand is noticeably harder than my XJ650. I'm 195Lbs and can't imagine how hard it would be if I was at my wishful thinking target weight of 150lbs.

 

[5twins]

Keep the centerstand pivots well greased and the bike will go up on the stand very easily. This makes an amazing difference ......

And as you've discovered from your old stand, the tangs tend to break off, lol. Best you add a brace to it ......

That is, unless you were lucky enough to acquire a later stand that the factory braced already .....

 

[Melnic]

Bingo.
Bike on Center stand.
Wish I knew about this float tool at the beginning. I do know importance of wet measuring float but did not know It could be done on this bike.
You can see the right carb float is shutting off too soon.
I will pull carbs then wet set the float levels on the bench before putting back and test running.
I'll have to set the idle mixture and sync again.

Left (good) float level (may actually be a tad high by 1mm)

Right (lean) float level

 

[Melnic]

Thru trial and error I got them both to be the same level while on the bike and on the center stand.
Tuned the idle mixture screw by ear (I do have a colortune so will set that tomorrow).
Then checked sync. They were still in sync.
Then I cleaned off the plugs with a wire brush then took a 10 minute ride at 35-45mph.
I feel I need to take a 30 minute ride and check it next but so far, I like what I see because they are nearly the same.
I also noted that the Main jets were the factory spec 135

 

[Kevin Werner]

Thru trial and error I got them both to be the same level while on the bike and on the center stand.
Tuned the idle mixture screw by ear (I do have a colortune so will set that tomorrow).
Then checked sync. They were still in sync.
Then I cleaned off the plugs with a wire brush then took a 10 minute ride at 35-45mph.
I feel I need to take a 30 minute ride and check it next but so far, I like what I see because they are nearly the same.
I also noted that the Main jets were the factory spec 135

View attachment 255321

I am doing similar 1000 miles into my project. Getting it running pretty decent and really good is miles apart (for me). Stay focused.
The joy of figuring jetting and discerning the high speed and low speed differences.....

I am such an amatuer...

 

[Melnic]

30 minute /15 mile ride today after Physical therapy before work.
Plugs.
Will be putting onto the 4 lane that is 55mph speed limit tomorrow.
its running good but once and a while will misfire. I still have not changed out the plug wires nor condenser.
I've changed plugs, points and caps only.
I"m liking the brownish on the inside ceramics. The Ground lead on the right one is a bit frosty but Perfection is the enemy of "good enough"

EDIT: One piece front reinforced Brake cable came. I'll be replacing the 2 piece one where the top is too long with this on Saturday.
I still have not changed the oil and it needs it bad. Will stop by Walmart to get some T4 Rotella oil. Its only $17 there I recall a gallon. I also use that on the XJ650 too. I have a NOS Oil filter but the SUMP screen is not in yet.

 

[5twins]

When you change the sump filter, you may find the original torn. Save it as they can be repaired with JBWeld .....

It's very common for the filters to rip around that point at the right end, as shown above. Best way to avoid this is to take it easy and keep the revs down until the oil has warmed up and thinned out.

When installing new plug wires, I like to prep the ends like so .....

I feel this insures a good connection when attaching to the cap or coil.

 

[Melnic]

Thx 5twins. I'll take that into advice when changing wires.


I changed the oil but could not get the front drain plug off so only used the rear one and pushed on the back end while on center stand to get oil out. Pulled somewhere between 2-2.5 quarts I think. Changed the main filter on the side.
I then replaced the 2 piece front brake line with a single piece steel reinforced line.
Took test ride in the neighborhood and never could get out of the neighborhood before I was misfiring.
Rode some w/ fuel enrichement on and it did not really help So suspected ignition issues.
Came home and pulled out dwell meter and timing light.
Timing was noticably retarded. About half way from T to F marks. That was not where it was at when I set them.
Dwell was way up at 66. That dwell really is the key I think cause I know that lowering dwell advances the timing.
I"m letting bike cool to to see what is going on before I mess with points again.
I was in a local Yamaha shop looking at tires and asked if they had NOS of Points for this bike and low and behold. yup.
Cause I'd patronized them before, they sold them for the old price tag that was on them , $19.95
If I have to, I'll put the yamaha points on there.
uggg, was so hoping to take a long ride today.

 

[5twins]

The dual points set-up on these really is a P.I.T.A. to deal with, lol. It's good you've got a dwell meter, it's the best way to accurately gap the points, only way to accurately gap used ones. The reading you get is inversely related to the gap so that 66 reading means the gap had closed up. So yes, correctly gapping the points will advance the timing and hopefully put it back in spec. I do like to run mine a little retarded, but only a few degrees. I set it over at the right slash mark in the idle timing "range". That puts it at about 12° or 13° BTDC (the "F" is 15°). I think the bike actually runs better like this, makes better and a bit more power in the higher RPMs, and it also wards off any chance of pinging.

 

[Melnic]

ok,

Gonna pull off the china made points I put on last week and put the Yamaha points in.

Here is what Mine looks like.
I'm going to set the gap with a gauge to the lower end of the range.
Then set the timing using an ohm meter looking for point closing so I get it close to the F range (lRight mark is what I'll target)
That should allow me to start the bike then set the dwell and timing.

 

[5twins]

Since points usually close up as they wear, I like to set them at the largest in-spec gap I can. I figure that way, they'll stay in spec the longest. On the dwell meter, that would be closer to 22° than to 24.5°.

It's getting hard to find good, quality points sets any more. The market is flooded with cheapo China sets now and they can be pretty junky. Look for Daiichi points if you can find them. They used to be the original supplier to Yamaha .....

 

[Wingedwheel]

I changed the oil but could not get the front drain plug off so only used the rear one

Sometimes it helps to use a heat gun in them. I’ve almost turned the bike over cranking on one before I discovered that. Now after a little heat they come out easily.

 

[Kevin Werner]

Thx 5twins. I'll take that into advice when changing wires.


I changed the oil but could not get the front drain plug off so only used the rear one and pushed on the back end while on center stand to get oil out. Pulled somewhere between 2-2.5 quarts I think. Changed the main filter on the side.
I then replaced the 2 piece front brake line with a single piece steel reinforced line.
Took test ride in the neighborhood and never could get out of the neighborhood before I was misfiring.
Rode some w/ fuel enrichement on and it did not really help So suspected ignition issues.
Came home and pulled out dwell meter and timing light.
Timing was noticably retarded. About half way from T to F marks. That was not where it was at when I set them.
Dwell was way up at 66. That dwell really is the key I think cause I know that lowering dwell advances the timing.
I"m letting bike cool to to see what is going on before I mess with points again.
I was in a local Yamaha shop looking at tires and asked if they had NOS of Points for this bike and low and behold. yup.
Cause I'd patronized them before, they sold them for the old price tag that was on them , $19.95
If I have to, I'll put the yamaha points on there.
uggg, was so hoping to take a long ride today.

Sometimes it helps to use a heat gun in them. I’ve almost turned the bike over cranking on one before I discovered that. Now after a little heat they come out easily.

I had a similar problem a year ago. The good advice on this forum, @jetmechmarty, if I recall, get a good purchase with a closed end wrench and hit the wrench with a hammer. There is a chance that POs opened only one or the other for oil changes. Remember to use a new crushable washer or anneal the copper washer.

 

[XSTime]

I do like to run mine a little retarded, but only a few degrees. I set it over at the right slash mark in the idle timing "range". That puts it at about 12° or 13° BTDC (the "F" is 15°). I think the bike actually runs better like this, makes better and a bit more power in the higher RPMs, and it also wards off any chance of pinging.

Look for Daiichi points if you can find them. They used to be the original supplier to Yamaha .....

Best advice I’ve taken. Yes, running slightly towards retarded does make for easy starting, steady idle, great engine feel !
Those Daiichi points say “set” on the box but that means one set, two boxes are needed.

 

[Melnic]

I think there is something up with my dwell meter.
I set gap to .016" for both and I'm still reading in the 60's (4cyl mode).
I have timing set up good enough for now w/ the light and idling well.
This pic was when the idle was running a tad higher, It moved to the right line when I lowered the idle.

 

[Melnic]

Hmm
Since I had to make an adjustment to the cam chain tension prior to setting points the first time and after replacing points the points came out of adjustment. I’m worried my cam cabin is end of life.
I also had some plastic bits on my oil filter when I pulled it out to replace.

 

[XSTime]

Just maybe the mechanical advance mechanism is messin with your settings ?
That advance rod does need to be lubed of course, and moving readily back to the idle position.
Are your advance weights original? Is the mechanism moving freely back to position after a manual check ?
I’d look there next