Cam Timing Issue/ Valve Adjustment

[Ki Hyun Ann]

Hello members in UK,

My name is Ki, living in the Netherlands and riding Hyo to reminisce my memories back home in Korea.

 

Although people stopped me from buying one, I did it anyway and had been preparing for about a year.

 

From this February, I started riding and yesterday on the road, found a severe problem.

 

Prior to this, I had symptoms like

• 1 Cylinder is not igniting properly
• Rough crank sound

I would like to clarify if the problem can be solved by replacing:

Cam Chain Tensioner and

Ignition Coil,

Adjusting the Cam chain timing.

I also understand that it is difficult to figure out the actual issue from a video, but I am trying to get any possible help as mechanics here refused to do maintenance on the bike nor do I have any other means of transport…

Adjusting cam timing- Adjust the Crank to TDC, R and F depending on the position I am setting, then check the alignment of the crankshaft to the manual? I was wondering if there is something more to it.

Additionally, would valve clearance adjustment require changing the shims?

I was wondering if that is the only option for the most cases.

Kind regards,

Ki

\

 

 

[Simon]

It sounds pretty serious to me, only way to find out what’s broken/failed is a strip down.

[♠️ M77]

What Simon said , it sounds poorly 🙁

Do you know if you can remove fairings and use your ears to find the closest area thats making noise?

Cam tensioner?

Clutch basket?

Cam shafts?

Cam chain grinding noises?

Dont rev it too hard incase something snaps as it sounds poorly 🙁

I literally just sent you parts lol.

Screw those mechanics anyway. You could learn a lot better than them and this forum has every 650 manual i could find and its uploaded in manuals section for you.

Clearances = Shims yes because Hyosung did the same thing when they helped Suzuki with their old suzuki gsx engines.  I think most suzukis and Hyosungs today still use Shims. The 2020+ GV125/GV300 uses adjustable tappets (on certain models)

Tensioners = Automatic, cant be adjusted but better to safe than sorry is getting new cam tensioners anyway. That 650 is a beast that a tensioner failing can ruin a lot of parts.

I tend to replace tensioners as soon as i hear funny sounds from cam tensioner on customer bikes i work on just to be safe than sorry later.

[Ki Hyun Ann]

Dear Simon and Marcel,

Good day and thank you for your kind replies.

 

I stripped down the bike to the stage before opening the cylinder head.

The problem is that I took the tensioner out before I set the crank to TDC.

 

Now, I am a bit afraid to turn the crank as it might be at the wrong timing at the moment because of the above.

 

Would it be okay to set the timing as the manual suggests at this stage, setting the crank to TDC, and then aligning the cam by turning itself to the correct position?

Secondly, I was wondering about the shim sizes, not sure if it is a normal size that is commonly used, I am planning to change the shims but the manual says all different shim sizes and I was a bit confused about which one to use.

 

[♠️ M77]

If the tensioner came out , it means you will have to remove the stator casing or clutch basket   (depends which cylinder you touched)  and check the chain did not fall out of the teeth at the bottom of the crank

Then use the manual as if you were installing a cam chain again , and setting up new camshafts again

While the cam shafts are removed , check under the tappets for shim sizes currently on the bike  =   Eg.  Rear cylinder might have 125 and 145 for intake and 200 210 for exhaust ,  so  keep those in mind….

Put everything back together properly and follow the manual until you are safely able to spin the crank a feel times by “hand” to make sure the timings are good.

if the timings are good, then follow the manual again, to find valve clearances.

Eg.   If  1x shim is saying 0.35mm on exhaust but the manual says you need 0.20-0.30 clearance.  You have a 21o shim. You will buy a 200 or 205 shim to reduce the clearance from 0.35 in to maybe 0.29 healthy.   The manual will explain further but hopefully i made sense ?

Let us know if we missed anything  , be patient and you got this! 👍  – If you master this well, it won’t scare you next time.

[Author]

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