High Temp after motor build

[lankeeyankee]

Ok I just got done building my motor. The bike fired up fine but measuring temp the right rear cyl ran hot went up to 380F.
All the other cyl are fine running at 180 220 at idle. I checked cam timing which is good. What may this be or what do I need to check?

Thanks Yankee

 

[maleko89]

Coolant/water jacket problem? Oil flow problem? Rings? What's the compression of that cylinder?

Mark
#1098

 

[shawn kloker]

Syncronize the carbs! That cylinder is lean!

 

[shawn kloker]

Possibly the coolant is not fully flowing yet.Air pocket?

I would still sync the carbs. I also recommend retorquing those heads after letting it warm up and cool down a few times.You can get through the cams by pulling out the cam cap rubbers.Rotating the motor till it lines up for the allen nut.

 

[lankeeyankee]

Possibly the coolant is not fully flowing yet.Air pocket?

I would still sync the carbs. I also recommend retorquing those heads after letting it warm up and cool down a few times.You can get through the cams by pulling out the cam cap rubbers.Rotating the motor till it lines up for the allen nut.

Shawn
Thanks for the info. I have Synched the carbs. I am sorry I wasnt in full detail.
The first time of starting the engine I use an infrared temp gun to measure exhaust gas temp at the base of the header where it meets the head. Within 1 min of runtime it reached 380F (Right Rear) when the other 3 were normal 190 210. I shut it down and thought maybe a slide was sticking in the carb which was fine, figured maybe. I let the engine cool down for a few minutes, Thought the same as you, ohh maybe carbs out of synch. Put some mercury to it and it was a little low but nothing major, adjustement was made and took the temp again, same thing385-390 exhaust temp. I dont think its coolant due to the runtime is short and its 45 here in TN. I will check the coolant in the morning. But its the exhaust temp running high just on the right rear so that would elminate cams.
I did do some mild head work but all parts are factory in the head. Whacca think?:ummm::ummm::ummm::ummm:
Ohh the engine runs good quick throttle blips are fine and it idles at 850. All 4 cyl are hitting in Synch.

 

[Robbarrie]

What's the deal on your bike ? Have you checked the coolant flow yet ? I hope the problem went away on it's own...as I'd have to agree with a possible air pocket, however if it isn't that, I'd hate to be around when you do figure out what the problem is.

May I put it this way, if it isn't that, it won't be a quick fix. Please keep us updated.

 

[shawn kloker]

Wonder what the thermostat is doing?I am also still wondering if that carb is putting out even though it was synced.Plugged jet?

Coolant and fuel are the only things I can think of.

 

[hubeerjw]

I would take your temp gun (if it goes high enough) and check your exhaust close to the heads. Your EGT should tell you if your cylinder is lean or not... if your exhaust temps are close then you should be able to narrow it down to a cooling issue.... maybe an air pocket as prevousl mentioned. Keep us updated.

Jeff

 

[lankeeyankee]

I have tore down the carbs thinking it has to be a clogged inlet stuck float possible clogged main jet Dont think its a coolant issue a cyl EXHAUST GAS temp wont get that high within 45 seconds and if it was a thermostat all cyl would run hot Its just the right rear I will fire it up tomorrow Thanks everyone who gave there input on this matter
Yankee

 

[lankeeyankee]

I have tore down the carbs thinking it has to be a clogged inlet stuck float possible clogged main jet Dont think its a coolant issue a cyl EXHAUST GAS temp wont get that high within 45 seconds and if it was a thermostat all cyl would run hot Its just the right rear I will fire it up tomorrow Thanks everyone who gave there input on this matter
Yankee

Ok heres the deal. I just finished cleaning all the carb jets. No adjustments were made all checked out well.
I fired the engine up and now the rear cyl is cold not firing. I am also hearing a slight noise coming from this right rear cyl.:bang head::ummm:

 

[lankeeyankee]

Ok heres the deal. I just finished cleaning all the carb jets. No adjustments were made all checked out well.
I fired the engine up and now the rear cyl is cold not firing. I am also hearing a slight noise coming from this right rear cyl.:bang head::ummm:

Ok, latest update. Did a compression check. All cyl checked out fine. avg from low to high was 187-193.
The noise was the universal joint wobbling around (Swingarm still off) against the frame... Looks like weak spark.

 

[Rusty McNeil]

I've used an infrared gun on mine a few times just out of curiousity a few times and have never been able to get consistent readings due to the double wall pipes in front and single wall in back.

Have tried checking it on the head but had even worse results trying to get consistent numbers.

 

[shawn kloker]

He has hindle headers though.400 is closer to normal than 200.

 

[Rusty McNeil]

He has hindle headers though.400 is closer to normal than 200.

Sorry, I wasn't paying attention. I haven't tried it on mine since putting on the UFO's. I'll do it and compare when I get a chance.

 

[KJShover]

Ok heres the deal. I just finished cleaning all the carb jets. No adjustments were made all checked out well.
I fired the engine up and now the rear cyl is cold not firing. I am also hearing a slight noise coming from this right rear cyl.:bang head::ummm:

What does the plug look like? coils?