Only running on two cylinders ???

[inditime]

HI,

I have just put my head back on after installing two new exhaust studs. The bike has been running perfectly before i removed the head.

Now when I fire her up she only runs on cyl 1 and 4.?? Hand test on the exhaust shows its 2 and 3 not firing.
Go figure? Plugs are ok, spark on each when held on the head. Coils ok, as I swapped them over to test and they ran on 1 and 4 again. Plugs are labelled 1 -4, easy.

I cant see it being the cams, you can only put them in one way......T timing mark on mag lined up ok, and both punch marks line upwards (cams are labeled I and E so you can get it wrong)I only undid the sprocket on the exhaust to get the chain off, as its at the front and easier to get at.

So im now wondering if a bit of crud got dislodged in the carbs when i removed them. Any thoughts peeps?

[His Dudeness]

Are the plugs wet or dry on the cylinders that aren't firing? Have you tried swapping 2 and 3 just incase

[red98]

mmmmmmm...was thinking coils aswell  :rolleyes .....a comperssion test will tell you if its mechanical or not...might be a good place to start 

[inditime]

Thanks chaps. Im going to retry it tonight. Been too busy at MotoGP this weekend.

Ill do a compression test  and clean the HT leads as I wiped them down with an oily rag whilst cleaning and putting it all back together. Ill do a coil resistance check whilst im there then check the sparks on the head again before starting it up again.

[inditime]

Got to the workshop this evening and first thing i did was a compression test before taking anything else off. No compression on Cyl 2.

I did start her up the other day and found that pipes 2 and 3 were cold, and started to curse why they werent running. 30 seconds into the initial start I heard a rattling noise and switched off iimidiately. Scratched my head , was I hearing things? Started he rup again, still cold on 2 and 3 and that rattling is bad, so only ran it for about 20 seconds and thought, WTF, that isnt good.

Fearful of the worst, I did a spark test with all plugs out for about20 seconds in all. They were good. So I first removed the carbs and carb to head rubbers to see if I could watch the valves go up and down by hand. Where is number 2s first valve, cant see it.

Off with both cams, and its cam follower has popped up. Oh dear

So.....

Im getting good at head....removal. 1 hour from full strip to finding why i have NO compression on cyl 2. A broken valve stem, FFS.

I love my Fazer, even over my Ducati, but she is trying my patience.

So hell with it. Im stripping the carbs, doing all the shims (did valve clearance measurements before cam removal) reseating all the valves. (so I know the valves and the colletts are all snug)
The head is already painted, getting 4 new HTs and plugs, and full service kit.

Well, she's a keeper. So nice to ride, only done 14k for FOC sake. Happy days, itll all be done and back on the road by Friday.

[inditime]

All done, wow what a day. 12hrs of work and Im really pleased and just need to give her a wash and a blsat out on the roads.

[Dead Eye]

Great to hear it!

Another 600 back on the road ^^

[red98]

nice work inditime.......not a bad engine to work on 

[inditime]

Thanks, I did have to take the head off twice grrrr. It turned out to be a missing valve shim.( The colletts had popped off cos no shim) I think it went missing when a follower fell out whilst painting and cleaning it and I didnt notice the shim had fallen on the floor. So I was lucky that the valve and piston had no damage. Like I said i rebuilt the engine, and run it for about a minute before I found I had to remove the head again. So I did the valve clearance and it must of cured the low compression on cylinder 3. The carb clean might of helped it along with degreasing all the ignition components.
Any way its a great bike, and more loved than my Ducati. Am i allowed to say that.

[red98]

easy to loose those shims  :rolleyes ......you now have a well fettled fazer,and of course its more loved than your ducati......after all it is a FAZER 

[inditime]

I went to my local Yamaha dealer to get a replacement shim , I lost one. It cost me £7.50, flippin rip off. Anyway, when I got back and was putting it in, I dropped it on the workbench, but thinking it went on the floor, I looked down and found the one I lost. So annoying when that happens, so now I have a spare...shim. Woopy Foccing do. For Foc sake lol

[red98]

I went to my local Yamaha dealer to get a replacement shim , I lost one. It cost me £7.50, flippin rip off. Anyway, when I got back and was putting it in, I dropped it on the workbench, but thinking it went on the floor, I looked down and found the one I lost. So annoying when that happens, so now I have a spare...shim. Woopy Foccing do. For Foc sake lol

yeh.they are expensive at yam....wemoto do them for £3.50 i think...takes a couple of days though.....hang on to the spare shim it might come in handy one day