RH side running hotter than LH

[kevxs]

Hi guys new too this site and new too Yamaha xs650.
Great site and info.
Have run an old 1983 gs1000e for a few years now gone and fancied a new experience.
Bought a 1978 XS650 and slowly polishing painting and modding this winter a flat tracker here in Essex.
Problem.
Starts OK but after running for a while the RH cylinder and exhaust heat up too too hot too touch yet the LH cylinder /exhaust runs cool easy too touch.
No smoke from exhausts
no oil from exhausts
foam air filters. some back firing and smoke from filters when kicking over engine.
the Rh exhaust has a lot stronger flow when felt with the hand compared
with the LH exhaust.
Honestly Iam a mechanical novice but am willing to get my hands dirty
Please could you Help
ATB
Kevin

 

[deadchef]

how do the plugs look? confirm that they are both firing. have you cleaned & synced your carbs?

 

[peanut]

Hi kev and welcome.

Sounds like you might have a problem with your RH exhaust valve not seating or burnt. I would start by checking you have the correct valve settings.

Then do a compression test to make sure that you do not have a burnt or sticking exhaust valve or leaking head gasket etc .

I take it you have tried swopping the spark plug and HT lead and made sure you are getting fuel to the cold cylinder ?

ps we have another member in Essex

 

[wherearewe]

Personally i agree with deadchef. I'd start by inspecting both plugs, ensure they are firing well and replace if needed. If they are, asses the carb function. These bikes really do run rats when out of sync.
The backfiring and smoke from the carbs could indicate a timing issue - points and timing?

 

[DaveO]

Its probably not a problem that the RH is hot. You shouldn't be able to touch the exhaust for example.

Basically if you have fuel and a spark and compression a bike will often run. (not well, but run). Any of these three (or combinations) lacking could be causing the problem.

You have two cylynders and two pretty much totally seperate systems running each side. (OK years differ and there is some crossover)

Spark problems - bad plug, bad plug cap, bad lead, bad coil, closed points, timing badly out, poor electrical connections.

Fuel - blocked air filter, blockages in carb jets or circuits, low fuel level in carb (badly set floats), fuel line blockages, throttle cable come unhooked, splits or hole in carb diaphram.

Compression - rings, valves burned out, badly set tappet gaps (too tight).

Check each of these out in turn. I would start with the easiest. Have you got a spark? If not trouble shoot why not. Basically pull the plug and leave it plugged into the cap earthing against the cyclynder head. Turn the bike over with ignition on. Do you see a spark jump the gap? If you have one working system (you DO. the RHS) you can swap components from one side to the other to eliminate the problem. So try swapping the plugs over, the leads and the caps, perhaps coils. (BTW a plug which fires happilly up against your cylynder head may sometimes fail under running conditions so swapping over is a good check.)

I have suggested starting at the plug because it is the simplest thing to check out out but you do have some clues which point to badly set timing (the backfires)..

Fuel. - Do you have a wet plug after it has run for while. If it is dry you need to start checking out the fuel system and find out the problem there.

Compression - Apart from badly set tappets gaps bad compression is going to often mean more serious problems. So I would leave this till last to get into. (While you have the plug out though you might stick your thumb over the plug hole and get your mate to kick it over. You will soon see if you have NONE. try this both sides and you will soon see if they differ significantly.

Check out spark, fuel and compression. If you have an obvious problem with one find out why. Don't forget you might be lacking one of these, or two, or all three. So if you have fuel and it still doesn't fire, check out spark. YOU MUST HAVE ALL THREE. If you are logical and methodical you'll sort it.

Come back if you get stuck.

 

[kevxs]

Personally i agree with deadchef. I'd start by inspecting both plugs, ensure they are firing well and replace if needed. If they are, asses the carb function. These bikes really do run rats when out of sync.
The backfiring and smoke from the carbs could indicate a timing issue - points and timing?

Thanks for your replies
Gonna swap the ht leads and plugs round tomorrow.
the Rh carb flooded out the foam filter on switching on the fuel ! switched off
removed the filter and pushed the diaphragm up with my finger.Turned fuel on and stopped pissing fuel . have added some 8inch baffles recently only adjustment I have made.

 

[DaveO]

You may have carb problems. Curious about what happens if you raise the revs a bit. Can you get it to fire on the bad side? The low speed circuits in the carb are going to be smaller, more delicate and more likely to get blocked. The bigger circuits less prone to blocking, I reckon. Don't rev the nuts off it cold, just raise the revs and see if it kicks in at any point. Could be illuminating. Good luck. Bit cold for the garage.

 

[nj1639]

Yep, headers should be too hot to touch so you may have an issue on the left side.
My '77 would idle rough, no heat on the left side....throttle it up to around 3 grand on the tach and a spit, sputter and the left side would come on. Turned out to be a plugged choke circuit in the left carb bowl. I cleaned it out using carb cleaner spray and a small torch head cleaning wire. Put her back on using Allen head screws for ease of future removal and all's well.

 

[kevxs]

OK so the HT leads and plugs are ok good spark both sides also when swapped .
Compression good both sides. does not feel uneaved as far as a thumb can tell.

Both cylinders fire when sprayed full of wd40.
RH Plug wet with fuel.
LH plug dry.
So sounds like a carb problem so tommorro they come out for a clean.
Checked in fuel tank and the lining is peeling up so could be the cause of blockage
Tank debris got a spare tank so after cleaning carbs will use this tank with fresh fuel.
Bought the other tank of EBay looked fine when I inspected it but the fuel has lifted whatever it was lined with. DOH.

 

[kevxs]

Hi
Gonna check the fuel lines first as could be as easy as a blocked LH fuel line
Regards
Kevin

 

[plane_ben]

All good advice above. One thing to keep in mind when you've got it running well. XS's naturally run a hotter right hand cylinder than left. Mine is around 20 degrees difference. If you look up XSJohn's old posts, he went into great detail on why this was and how to rectify it. He even manufactured his own needles. Sadly he was killed in a car accident before the needles made it into big production numbers, but he has specs in his posts. Good trouble shooting.

 

[plane_ben]

Opps. Double post.

 

[kevxs]

Opps. Double post.

Hi Guys Happy Christmas
Bike is running as follows
Cam chain tentioner sorted.
Set inlet and exhaust valves.
Cleaned points mini file.
removed carbs cleaned internally and jets set float heights
New plugs
Stripped down fuel tank emptied removed petcocks cleaned filters.
fresh high octain fuel.
chargad battery.
It now runs sweetly YET A BUT
The Left hand cylinder starts too smoke a little after it warms up five mins or so RH cylinder clear.
have not ridden the bike as no tax insurance m.o.t etc so just
idielng in garage.
atb
Kevin

 

[Johnt3]

I'm glad you got her cleaned and firing kevxs. Maybe she'll runout fine after you get a few miles on her.

 

[peanut]

well done Kevin.. glad she's running at last.

 

[kevxs]

well done Kevin.. glad she's running at last.

Thanks my friend
Now more polishing painting and tinkering
Love it

 

[peanut]

Have we seen any pics yet???

my shed is finally finished this week , I'm just puttng up the tools . Hoping to get the bike in there by Xmas Eve

Rebuild starts soon and I can't wait.

Merry Christmas everyone

 

[kevxs]

Have we seen any pics yet???

my shed is finally finished this week , I'm just puttng up the tools . Hoping to get the bike in there by Xmas Eve

Rebuild starts soon and I can't wait.

Merry Christmas everyone

Dont know how too post yet
New year mission atb with the shed and Rebuild
Kevin

 

[XSLeo]

If you look just below where you write a post, you will see a go advanced button. If you push it it takes you to another page where you can do more than just write, add smilelies, . Scroll down and you will find a manage attachments button, push it. Up pops a window with browse buttons, these will take you to the pics on your computer. find the pic up want to upload and when it uploeads it will appear in your post.
there are size limits to pics so be sure they are small enough, listed at the bottom of the window.
Leo

 

[XSLeo]

Oh yea, you might want to read this, www.amckayltd.com/carbguide.pdf
Leo