Aligning cam sprockets

bobber · Post by **bobber** » Fri Oct 12, 2007 7:56 pm

Well after spending all yesterday fighting with the acursed cylinder finally got it down this morning!
In process of adjusting valves but will finish that tomorrow. However have a question about the cam sprockets. Manual says the indents on sprocket to line up with head surface with crank on T mark. The exhaust sprocket has its forward dot slightly lower than the rear dot when on the chain. If I reposition the gear back by 1 tooth then the rear dot dissappears. The intake sprocket lines up almost perfectly.
Thinking the main chain is stretched somewhat throwing out the sprockets.
Anyone else run into this? Should I leave as is or turn gear back 1 tooth?
As I sit here typng just hit me the crank gear!!! Its half the size! Damn, probably should take the cams back out and move chain on the crank 1 tooth. #$%&*%#

Chris · Post by **Chris** » Fri Oct 12, 2007 8:24 pm

Just want to make sure....................

are you using one of the revised shop manuals? On the bottom of page 6-22, you should have the paragraph that reads..........

"Turn the crankshaft 360 degrees unti the "T" mark is realigned with the front crankcase mating surface".

Its an extreamely important step that was left out of the older shop manuals.

EMS · Post by **EMS** » Fri Oct 12, 2007 8:55 pm

Sometimes, when the cam chains are a little stretched, the marks will not align und you will be constantly caught between two teeth. I heard that people solved that by elongating the mounting holes in the sprocket slightly.

bobber · Post by **bobber** » Fri Oct 12, 2007 10:05 pm

Manual says to align "T" mark with split in crankcase and install exhaust sprocket with indents aligning to head surface. Then R/H exhaust cam installed with lobes to #6 plug. Ditto for R/H intake cam. Turn 360degrees,making #6 lobes pointing away from plug hole, to install left cams with lobes pointing towards #1 plug.
Remember coming across this before when working on my '80. Should of made note of the crank gear being 1/2 the size... meant to write it in the service manual but forgot

.... wouldn't forget this time. Just have to pull cams and rotate chain 1 tooth on crank which will give me 1/2 tooth on top.
Never had anything better to do tomorrow rather than do that

And such nice weather here since put away the FJR, in mid to high teens but sure winter is just around corner. Sleds ready to roll once snow down.

alimey4u2 · Post by **alimey4u2** » Sat Oct 13, 2007 4:39 am

Mike (EMS) is spot on......Chain stretch makes accurate degreeing impossible. Advance half a tooth, retard half a tooth & see what runs best....

bobber · Post by **bobber** » Sat Oct 13, 2007 8:29 am

Once get a Timmies coffee ready to tackle the bike again. Just thinking how sweet it would be to be able to get a high reduction DC motor set-up, wiper motor??, to turn the engine when doing valves. Something with a 17mm recess into it to fit over nut on crank and would mount via the 3 R/H crank cover bolt holes with a 4-5 foot control switch. Would be able to rotate engine either way slowly with flip of a switch!! Espicially when on the left side.
Don't think chain is stretched. A new chain would re-act the same way if positioned 1 tooth out on the crank. Chain stretch then the adjuster should take care of it unless way too long.

EMS · Post by **EMS** » Sat Oct 13, 2007 9:38 am

The adjuster takes care of the slack but not of the stretch. In a stretched chain, the number of links on the pulling side between the sprockets are longer than the same number in a new chain. The adjuster is mounted in the return. That's one reason you should not turn an engine backwards. The return becomes the driving side and the cams index totally different against each other. In extreme cases you could have inlet and outlet valves touching each other.

bobber · Post by **bobber** » Sat Oct 13, 2007 3:12 pm

"In order to improve airflow, the carbs were mounted more horizontally on the Prolink models. To achieve this, the rubber manifolds were wedge-shaped- thinner on the bottom and thicker on top. They had a mark to ease orientation during installation. As a result, the rear end of the carbs drop down. This means, together with Prolink manifolds, you will need to use a Prolink airbox, if you run one, because the holes will not line up. However, there are plenty of guys who are able to use early manifolds with late airboxes and vise-versa. Same guys who can take the airbox off without tilting the engine.
Carbs as such will go into either manifold. I have found several sources for new early manifolds but not for Prolink ones. I think CBXMan sells them, though. Using 79 carbs on a Prolink model, you will lose the vacuum valve, unless you retrofit."

Have new insulators for carbs so figured should put them on, thank goodness has the old ones were VERY brittle! Remembered reading something about the orientation and hocus pocus here it is!! This site a wealth of info for these aging beasts!
Back out after my coffee to continue on. Hopeing to have running before SNL show tonite so ride tomorrow then store away for another year.
Did move chain one tooth on crank and indents lined up nicely on head surface for both gears. Once set adjusters though both moved slightly back.
Going thru my parts bins and didn't realize how much stuff I've accumulated over the years for these bikes!

bobber · Post by **bobber** » Sat Oct 13, 2007 9:35 pm

Back together, with time to spare before SNL. Fired up really quick. Put tank in place and fired it up. Sure loud with no pipes above 5000rpm's!

But at idle sounds nice, almost like its under water, with the burble. Finished up putting parts on then cleaned up.
Had a tough time getting carbs in the new insulators. Finally had to use a cinch strap wrapped around engine and one side of carb bank while I worked on the other side.
Out for a ride tomorrow, fresh gas, stabilizer, change oil/filter and put her away for another season.

Chris · Post by **Chris** » Sat Oct 13, 2007 9:38 pm

bobber wrote:Back out after my coffee to continue on. Hopeing to have running before SNL show tonite so ride tomorrow then store away for another year.

Let us know how it runs. Post a pic if you can.

bobber · Post by **bobber** » Sun Oct 14, 2007 5:10 pm

Tried uploading some pictures but no go. Must be doing something wrong. Printed off directions but no go.
Anyway took bike out for a spin towards the oilsands plants, about 70km return. Bike ran well but VERY high idle! It's had a high idle for somethime, about 2000rpm, but I could bring it back down to normal by slightly loading up engine... not anymore. 2500 rpm unless I shut it off and restart, then about 1000 rpms but creeps back up. The idle adjusting screw does nothing really. If I adjust slightly engine quits. There's a Dyno-Jet stage 1 kit in there with the mixture screws set at 2 turns now. Recommended from Dyno-Jet is 3 turns but either position still high idle. Scary at intersections.
Its had an oil change and carbs drained so now in storage for winter. Next year after a tank of fuel plan on re-checking the valves so I'll try balancing carbs again. Beginning to think there's a slide or 2 hanging up in the carbs.

cbx6ss · Post by **cbx6ss** » Mon Oct 15, 2007 4:31 am

Bobber,
I had a similar problem. I took the cab tops off, and cleaned each slide's "sliding surfaces, and top insides real good. Reassembled and problem gone.
Tell us if this helps.
/r
Brad

daves79x · Post by **daves79x** » Mon Oct 15, 2007 6:22 am

Brad's reply is one easy thing to try. Also, make sure your choke isn't being held shut EVEN SLIGHTLY, or you'll get the high idle. Also make sure you have a little slack in the throttle cables. If all this fails, you may as well pull the carbs, because your idle circuits are plugged. The idle screw has to be cranked too far to get the bike to idle because you are not flowing any/enough idle mixture through the low-speen circuits to properly idle. This is the most common cause of high idle.

Also, if someone has horribly misadjusted the sync screws, this can hang up several butterflies and give you a false, high idle. But the only real way to tell that is to pull the carbs also.

If working correctly, the carbs should chop to idle immediately when the throttle is closed. Good luck

Dave

bobber · Post by **bobber** » Mon Oct 22, 2007 8:50 pm

Had a couple of days off work so figured yesterday to haul the CBX out of back shed and remove carbs. Completely dissassembled, cleaned and adjusted whatever I could on bench. Did find a pilot screw with a damaged o-ring.
Put back into bike and third last carb side insulater clamp messed up. Had to change clamp in stitu.... fun job.
Fired bike up, idles very low (500rpm or less) until it warms up. Then about 1000rpm until I rev it past 3000 then idles at 2000 unless shut down or load engine up.
So next set of days off, unless we get snow, hopefully take for a short ride and attempt balancing carbs with a set of Motion Pro mercury tubes I had picked up. Follow manual to the word for that? Or anything I should look for/do?

Chris · Post by **Chris** » Mon Oct 22, 2007 9:06 pm

bobber wrote:So next set of days off, unless we get snow, hopefully take for a short ride and attempt balancing carbs with a set of Motion Pro mercury tubes I had picked up. Follow manual to the word for that? Or anything I should look for/do?

I use the balance sequence that is listed in the manual and it works fine. (I have had to repeat the sequence a few times if the carbs were way off of balance).

The International CBX Owners Association

Aligning cam sprockets

Aligning cam sprockets

carb idle