Camshaft Top End Rattle

[Nessism]

Great looking bike Don. You have done a great job. Scratching my head about the 700cc part. Please explain.

Why do you say this? He makes more sense than anything I have ever seen written about it.

Don't get me wrong Tom, I believe in using the throttle early in the engines life, only this Motoman guy makes people think the "window of opportunity" is overly narrow which I don't believe.

 

[tkent02]

Great looking bike Don. You have done a great job. Scratching my head about the 700cc part. Please explain.



Don't get me wrong Tom, I believe in using the throttle early in the engines life, only this Motoman guy makes people think the "window of opportunity" is overly narrow which I don't believe.

That seems to be the most important part, the sharpness of the honing can't last very long. It's only the microscopic little peaks of the ridges that do anything, they will wear away quickly it seems. I get on and ride easy about a half mile, then harder and harder as the temp comes up. By one mile it's BWAAAAHHHHHuuuuuunnBWAAAAHHHHHuuuuuuBBBWWWAAAAAAAAAHHHHHHuuuu on and off the throttle at various fairly high RPM, but always wide open or closed, no in between. I do it on the highway when there is little or no traffic, so a can blast away at it, fast, slow, fast, slow.
I would never run the engine at all until it was ready to do this.

BBBWWWAAAAAHHHHHuuuuuuuuunn

 

[mlinder]

Great looking bike Don. You have done a great job. Scratching my head about the 700cc part. Please explain.



Don't get me wrong Tom, I believe in using the throttle early in the engines life, only this Motoman guy makes people think the "window of opportunity" is overly narrow which I don't believe.

He was rounding up from 675cc

The window of opportunity is pretty small.

When babied from the outset, the peaks of the hone are just rounded, leaving valleys in-tact. When under heavy acceleration (lots of load) the combustion causes the rings to expand more, and the early 'sharp' peaks are worn down more quickly and further. Eventually the heat cycles and such harden those and very little seating of rings is further possible. Getting them worn down and rings seated quickly before hardening (and a bit of carbon glaze that fills the valleys) is important for the best seating of rings.

 

[tkent02]

He was rounding up from 675cc

The window of opportunity is pretty small.

When babied from the outset, the peaks of the hone are just rounded, leaving valleys in-tact. When under heavy acceleration (lots of load) the combustion causes the rings to expand more, and the early 'sharp' peaks are worn down more quickly and further. Eventually the heat cycles and such harden those and very little seating of rings is further possible. Getting them worn down and rings seated quickly before hardening (and a bit of carbon glaze that fills the valleys) is important for the best seating of rings.

I believe the over sized pistons he used makes it work out to 699cc. Should be a rocket.
That explanation sounds good to me, I certainly see no advantage to waiting at all, get the engine working hard immediately, on and off the throttle.

 

[mlinder]

I thought he just used a 650 top end?
Which is 675cc?

 

[tkent02]

I thought he just used a 650 top end?
Which is 675cc?

Yes, with very oversized pistons. 699.

 

[mlinder]

Ah, had not read that.
About 63.25mm?

 

[tkent02]

Dunno .

 

[Suzuki_Don]

Dunno .

673 + 1mm o/s = 699cc

 

[mlinder]

Weird, I get 696 ccs from my math.

But that's cool, near 700cc's in a 550

 

[Suzuki_Don]

Weird, I get 696 ccs from my math.

But that's cool, near 700cc's in a 550

Correct again. It does work out at 696. Sorry for that. I will need to rethink my gearing now. I might need a couple of extra teeth on the back sprocket to compensate for the drop in HP. haha

 

[mlinder]

Correct again. It does work out at 696. Sorry for that. I will need to rethink my gearing now. I might need a couple of extra teeth on the back sprocket to compensate for the drop in HP. haha

hehe. Yes, those 3cc's are at least 7/20ths of a horsepower!

 

[Guest]

Thanks Pete, the new 550 badges belie to 700cc motor sitting in there.

Love this - reckon you'll give a few other riders a surprise with this one Don!

You must be almost 30kgs lighter than a 750 and only 50cc smaller (or 52cc...)

Looks sweet too.

 

[Suzuki_Don]

Thanks Coady, yes it's eventually coming together. A couple of years work, sometimes focussed, sometimes not. I am glad it's nearly finished and hope to get some miles on it now.

 

[Guest]

Great work Don, she's a real beauty. Thanks for writing this all up, very educational. Ray

 

[Suzuki_Don]

Great work Don, she's a real beauty. Thanks for writing this all up, very educational. Ray

Thanks Ray, it's been a fair journey for me as well. It might not be all over yet though, until I get it out on the road and get a few miles on it I will not know if their is more tuning, carb synching , etc. to be done. Here's hoping it runs without any further problems.

 

[Can_O_Tuna]

Bill, glad my thread is of use to others. Sometimes I think I am posting too many pics and sometimes I think this thread is developing from a query about a noise in my motor to a thread on an engine rebuild project. But as long as I receive encouragement from people like you I will keep going.

Thanks Bill for your suggestion.

I've been keeping close tabs on this thread as well Don. I have a similar noise and have not had the time or $$ (mostly time) to really get into it. Thanks for such a detailed record. As far as too many pics etc, keep em coming, its the detailed posts like these that are priceless when it comes to figuring out this type of problem

 

[Suzuki_Don]

Not Happy

Not Happy

I took the bike out for it's first run this afternoon. Plenty of power, the motor is very willing, lots of low down punch, but alas when it warms up you can hear the knock. It is quiet enough when first started when the motor is cold. But as it warms up the knock becomes apparent. You cannot hear it while riding, so i don't know if it is happening at higher revs or maybe I just can't hear it. Apart from the noise I am extremely happy with the motor.

The only thing I did not do when the motor was apart both times was to check the backlash in the gears of the transmission, could it make a noise like this.

What about the backlash between the crank gear and the clutch gear, remembering that I have straight cut gears on my motor.

My next task is to synch the carbs to at least see how far out they are.

Here is the video:


http://s226.photobucket.com/albums/dd105/donclifton/GSR%20Pics4/?action=view&current=P1010042.mp4



Comments please.

 

[almarconi]

I wonder if your carbs are out of sync enough to make the noise. Try syncing the carbs and see if the noise goes away.

 

[Suzuki_Don]

I wonder if your carbs are out of sync enough to make the noise. Try syncing the carbs and see if the noise goes away.

Yes that is my next move. I have the carbtune setup, but have never used it before. I have to set it up first, I think I have to cut some tubes and insert in the lengths of rubber pipes. I need to get the instructions out and read them to see what to do.