Glowgeek

Hey, that's looking good Dave.

I thought your mini lathe had a half nut. Why not cut your own threads?

rowdog_14

My Feedback: (5)

Question with fuel spitting out of one of my saito carb. I have checked the clunks, changed the fuel line, changed the low speed needle setting and even the high, carb to fuel tank placement is good. The only thing I have not checked are the o-rings, which I feel would lean the mix if they were bad. I changed out the motor with exact same motor and that motor runs good with no spitting. Engine actually runs good considering...

Ideas,Feedback?

It is a 60t...

Glowgeek

Could be a leaky intake valve. Open throttle to wide open, roll the engine over by hand and listen right at the carb for hissing during the compression stroke. On a twin it helps to remove the glow plug from one cylinder while testing the other.

rowdog_14

My Feedback: (5)

Will check...I have noticed spinning the engine a loader than normal sucking/compression sound vs my other to 60t. I did check the clearance on the valves but will perform your suggestion. Thanks

Hobbsy

My Feedback: (102)

Thanks Lon, It can't be set up for metric threads, it has nine different gear sets for US threads. I have three of those 50's, one GK one plain and one Black Knight. Oh, black with Chrome rocker covers.

Dwayne

I have a Saito 91, would it have the same cam as my 125?

Glowgeek

Yes. SAI6535A. Does the cam look bad? Pics?

Dwayne

I've tried most everything else, but I just now pulled the valve covers from my 91 and 125 and compared the rocker arm throws, they are the same so now I'm thinking it may not be the cam.

Glowgeek

I never thought the cam was the problem. 900 to 1000 rpm loss is never caused solely by a worn cam in my experience. A worn cam can contribute to power loss however.

Have you tried a new glow plug?

Does the engine turn over very freely between compression strokes?

Dwayne

Yes and yes, it turns over very nicely

Glowgeek

Dwayne, you mentioned in an early post the the bearings are new and the timing is correct.

How did you check the timing?

Dwayne

By opening the gear housing and resetting the timing, I suppose I could have done it wrong twice you never know...lol Going to be windy tomorrow maybe I'll try again.

Glowgeek

No need to tear it down again to check the timing Dwayne.

Put a tooth pick or something through the glow plug hole so you see when the piston reaches tdc (top dead center). With the rocker covers off rotate the engine in the normal direction until the piston reaches exactly top dead center on the exhaust stroke. You can recognize the exhaust stroke because the exhaust valve will be closing as the engine reaches tdc. Once the piston is at tdc on the exhaust stroke rotate the engine back and forth slightly to both sides of tdc and watch the valves move in opposite directions (one opening while the other is closing). The valves should move equal amounts in opposite directions (opening or closing) with equal crankshaft rotation (clockwise or counterclockwise from tdc).

Hard to explain but works for checking cam timing.

Dwayne

I get it, thank you.

the Wasp

My Feedback: (1)

Dwayne,

could you have put the wrong carb on it when replacing the bearings ?
and are you sure the carb is fully opening ?
and how did you measure the strokes of the rockers ?

Jim

Dwayne

I made a sorta degree wheel using a school protractor, not 100% accurate but it it's good enough to see the intake valve starts to move at about 45 degrees before TDC that seems a bit early to me, btw how do I delete a pic I've already posted? Please ignore second pic.





Hyjinx

Nice summation GG.👍

Dwayne

So I decided to ignore the dot on the cam and use my degree thingy and set it up the same as my 91, that is I set it so the intake opens the same as on the 91 and it worked, I'm now getting 8900 on a MA 16X6, much better, thanks for all the help.

the Wasp

My Feedback: (1)

I'm almost speechless



to remove a photo just hi-light the photo and click your "back key" I'd do it now but you would not be able to read this

Jim

Dwayne

Thanks.

Glowgeek

Had to be something, glad you found it.

Dwayne

It's like my daddy used to say, Rosanne Rosanadanna, it's always something.

Glowgeek

No, that's Club YS. Saitos run great forever, but you do have to assemble them correctly first.

the Wasp

My Feedback: (1)

I like to say> "if it ant 5/8s of something it's 7/16s of something else, so don't do it",,,, but in your case you did and it worked out goOd

Jim

Glowgeek

Jim, I'm not surprised that matching the intake opening event between Dwayne's 91 and 120 got the timing right, makes perfect sense. What I am surprised at, or rather pleasantly pleased about is that Dwayne had the wherewithal to recognize it would work. Undoubtedly that's why he asked a few posts ago, "Does the 91 and 120 use the same cam?".

Perhaps Dwayne knows more than he's letting on, or at the very least, more than I gave him credit for. Now I feel a little like I was preaching to the choir.