1982 honda magna v4 750 problem?

Question

i bought this bike a month ago. recently i realized the right front exhaust wasn't very hot. i pulled the plug wire on the right front cylinder with the bike running and it did not seem to make a difference in rpm's. i pulled the plug and checked for spark. it did have a spark when cranking the motor over. one would think the carb is not working correctly. there is a small screw on the intake near that cylinders carb, i took out the screw and put a small cap full of gas near the hole and let the motor run and suck in the gas. that did not seem to make any difference in the way it ran. the motor did not surge or anything. i believe the compression is ok but have not checked it. also, i have gotten 47 mpg. that seems to be normal, i think, for a good running bike. pulling the plug wires on the other cylinders makes a difference in rpm's. any ideas as to what gives with the right front cylinder?

one person mentioned abnormal cam wear with these bikes. this i have read about. but i would like to point out that this bike has only 7000 miles on it. also, even if there is low compression, shouldn't the exhaust pipe still get too hot to touch? i am heading to my local dealer today to see what he thinks about the problem. i am leaning towards a low compression problem. another thing to mention is that this cylinders spark plug was somewhat dark colored. maybe similar to being fouled. plug was replaced but made no difference in the way the bike is runs.

Answer 1

check the compression
if it is not ok check valve clearances

then synchronize the carbs
with the guages it is fairly simple but the adjustments are kind of hard to reach
more than likely the carbs are the problem

Answer 2

Those bikes had problems with the cam journals wearing down, creating erratic valve clearances.
Try adjusting the valves - you'll need a special tool to adjust them due to the problem I mentioned.
You can only get the tool from Honda.
They also had a problem with weak valve springs,
The springs wouldn't close the valves fast enough allowing them to float.
The pistons would touch and bend them - ever so slightly. But enough to cause them to leak.
Perform a cylinder "leak down" test.
Tester -
http://www.motionpro.com/motorcycle/tools/4-stroke_leak_down_tester/
If you have access to a compressor and air blow gun -
Remove the spark plug.
Bring that cylinder's piston to TDC of the compression stroke (all valves closed).
Blow into the cylinder and listen at the muffler and air box.
If you hear any hissing, then the valve clearances are either to tight, or it needs a valve job.
Purchase a shop manual before they go out of print.
http://www.motocom.com/motorcycles/

Answer 3

Sounds to me like that cylinder is low on compression and is not running. Do a compression check and if it is low adjust the valves to factory specs. Check compression again. If it does not help it could be a burned valve,carbon build up at valve head,loose valve seat,or bent valve. If you are not handy with this kid of thing take it to a reputable shop. Hope this helps. ;-}

Answer 4

CHECK the compression.. sounds like the bikes a three cylinder.. this site might help with trouble shooting the problem..
http://www.dansmc.com/MC_repaircourse.htm

if you need a manual.. (free download) get it here..
http://hondatech.info/downloads/Moto/

Answer 5

it incredibly is the jewellery.the only treatment is to drag the engine down and replace them.Any additive you put in the oil will wreck the grasp.what's got here approximately is the bike sat for a protracted time and the oil administration rings are caught.or it incredibly is have been given 106700 miles on it and it incredibly is wiped out.