hot side?

Irish · Full Member Joined: Jun 12, 2007 Posts: 250

Is it normal for the right cylinder to run much hotter than the left? If so, why is this true?

INXS650 · 650Rider Supporter Joined: Mar 22, 2007 Posts: 645

Johns does, haven't noticed on mine. May be something in the casting of the cylinders.

Joseph · Full Member Joined: May 22, 2007 Posts: 767 Location: NY

i have an 80 special when i got it w 8k mi i noticed this i set the mixture screws which seemed to help but after a valva adjusment i cant feel the difference by hand. John got down to 4-+degree i think

xsjohn · Posted: September 14, 2007, 7:26 am Post subject: Re: hot side?

Looks like it is inherent with the xs650........not just the newer ones.........I have the tin top kits pretty much figured......plan to work on a 38mm also....
Has nothing to do with setting the valves but richening the mixture screw helps a tad.....the problem is more extensive than that and will cause damage if these things are really put to work.....the longer it runs the worse the proplem gets........been there and done that.......

John

Joseph · Full Member Joined: May 22, 2007 Posts: 767 Location: NY

John i conseed you are alot more knowledgeable than i about eingines but the faact is after i adjusted the valves thee heat diff got 90% less. It was probably the 1st adjusment the bike ever had.

xsjohn · Posted: September 14, 2007, 8:59 am Post subject: Re: hot side?

Go for it...........bet you haven't measured it........the differential can take 20 miles or so to really become obvious........would like to find one that actually didn't do it with the stock carbs......most people rather buy a bunch of junk to throw on their bikes instead of investing a few bucks for a thermometer to actually see what is going on....the ones that do are surprised........

John

Joseph · Full Member Joined: May 22, 2007 Posts: 767 Location: NY

I do plan on getting a inf therm next month, and following your post on richening carb i have the link to that post w the pics. I'm looking forward to that and after that the top end cooler.

Irish · Full Member Joined: Jun 12, 2007 Posts: 250

the difference in mine is very noticeable, and it doesn't take long. 5-10 minutes of idling.

xsjohn · Posted: September 15, 2007, 8:03 am Post subject: Re: hot side?

I have heard lots of theories on why this is happening....from something in the head to because it's on the drive side ..... ....I did find on mine the intake where the carb mounts is 50 degrees hotter on the right....air may be preheated more on the right as it enters the cylinder.....this woud raise the temperature of the intake air reducing the cooling effect......only possible explanation so far....richer mixture on that side is a must........I even use a hotter plug on that side to keep it clean because of the richer mixture......

I am more than 100% convinced that controlling heat is the single most important factor on these air cooled engines if you wan them to last.....

I will put a feather in my hunting hat for bringing this issue to you guys attention and offering some simple solutions also.......

Even though I have been beat plenty for this discourse.......

John

cfinn1 · Posted: September 15, 2007, 10:36 am Post subject: Re: hot side?

hey John, I would put two feathers in your cap. One for the work you have done not only quantifying the magnitude of the right side problem but also a well documented solution. Second feather for your work on the top end cooler, which I think is probably even more important, to just cool these HOT rods down.
Those who discount are sticking heads in the sand. Heck, you don't even need a thermometer to know you have an issue when the right leg tells the story.
I greatly appreciate your sharing your experience on this forum.

xsjohn · Posted: September 15, 2007, 10:43 am Post subject: Re: hot side?

Will do -----and thanks......

John

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

Ok - It's funny you mention this John - My Right plug (as I sit on the bike) is a picture duplicate of your plugs - grey electrode - black outer ring. My left plug is richer and runs darker grey in the electrode to gradually black over a month or two - indicating that side is richer/cooler. I did the temps like a month ago - I don't remember a huge difference between the two cylinders - I will have to run temps again.

On another note - did you see the new bolt-on oil coolers at MIkesXS? They looked pretty cool (pardon the pun) so I ordered the kit. Will be putting it on this weekend.

Also ordered two new slides and diaphrams. I think I have got a sticky spot in mine. In any case I Know the stock diaphrams from 81 are old and streteched - I am want to try some new tight ones to see if the it picks up the throttle response. Once those are in - I am going to try your Needle lifting tweak.

Take a look at the oil coolers..

Jim

xsjohn · Posted: September 19, 2007, 9:42 am Post subject: Re: hot side?

jimdi.....

I am offering drop in performance carb kits including custom needles to solve lean running and and hot right side heating problem.....if you can be patient for another week or so I plan to give the first 2 away.....and someone like you with a thermometer would be good.......first 2 to speak up gets them.....34mm 80-84 stock carbs......these are custom needles.....pre set .....

This is what the kit will do.....
1. Help ballance the cylinder temperatures and lower overall cylinder temperatures 20 degrees....
2. Give it more torque and reduce engine noises dramatically.
3. Much improved mid and upper throttle responce.....
4. Much smoother crusing..and more low end torque....
5. Way better starting epsecially when it is hot....

John

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

Cool - I would be interested. I've got 81 34's with foam floats.

Thanks

xsjohn · Posted: September 19, 2007, 1:44 pm Post subject: Re: hot side?

jimdi.....Will send it out next week........this will just be the needles.....would be good to have some 135 MJ but it will be ok for now........PM you address.........

1 free set left..........

cfinn1 · Posted: September 19, 2007, 2:16 pm Post subject: Re: hot side?

xsjohn... definately interested as well, but won't be able to do any testing until spring since I will tearing down shortly to replace cam chain guide Sad

Might have to find another candidate if you are looking for someone who can test this fall.

xsjohn · Posted: September 20, 2007, 1:16 pm Post subject: Re: hot side?

Jumdi........Finished your custom needles today.......ran them down the express at 65 mph and there is 5 degrees difference when it is fully warmed up after 30 miles.......better quit cause it runs so good and is smooth........you might could catch 2 or 3 more degrees on the right with the pilot set 1/8 more turn on the right ......I had bothof mine set the same ......1/4 turn out from when it starts to act a little funny like it is starving a bit and let the needles do the rest........plugs look great........will send today....no engine noises what so ever.........

77 degrees ambient------top end oil cooler covered........right 237 degrees ---left 232 degrees.....much cooler onthe slower back roads...Hope you enjoy......

John

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

Cool - thanks -
Installed the Oil Cooler from Mikes yesterday. Pretty cool design and easy to install.
Will give the needles a try when I get them.

Thanks again

Jim

Irish · Full Member Joined: Jun 12, 2007 Posts: 250

John, since I am running unrestricted exhaust and pod type filters, should I use your kit, or put in bigger main jets?

JDoza · Posted: September 24, 2007, 8:04 am Post subject: Re: hot side?

I am willing and able to purchase a carb set for my 81. Please let us know when they are ready.

xsjohn · Posted: September 24, 2007, 10:47 am Post subject: Re: hot side?

could use 137.5 but the rest of the kit will be fine....with this kit that thing is gonna fly....maybe 140mj.....

John

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