TDC adjustment

[coolbikr4684]

I'm not sure if I'm doing it right but TDC is mi point between when the no.1 stops going up to when it starts to go down correct? On mine the timing wheel shows TDC when the piston first stops not at mid point. Can I readjust to be correct without any issues? The indicator needle does not appear to have been moved it has some kind of paint glue on it. Right now I have new air and oil filter, new clutch and springs, rebuilt carbs, new seals and new mikuni jets with new boots all synced and adjusted still run rich and power stops at 5000 in 5th gear. I'm hoping fixing TDC to check timing might help.

[motoman]

I'm not sure if I'm doing it right but TDC is mi point between when the no.1 stops going up to when it starts to go down correct? On mine the timing wheel shows TDC when the piston first stops not at mid point. Can I readjust to be correct without any issues? The indicator needle does not appear to have been moved it has some kind of paint glue on it. Right now I have new air and oil filter, new clutch and springs, rebuilt carbs, new seals and new mikuni jets with new boots all synced and adjusted still run rich and power stops at 5000 in 5th gear. I'm hoping fixing TDC to check timing might help.

more info as to what you've done, such as cam chain replacement or removal, etc. would be helpful.

[coolbikr4684]

more info as to what you've done, such as cam chain replacement or removal, etc. would be helpful.

No chain removal just adjustment via cam chain adjuster. New plugs, electrical fixed, had lots duct tape and electrical tape added by PO now soldered and heat shrinked. New battery.

[TopCatGr58]

Hey there,

Okay, new carb mount boots, but are you running OEM airbox or PODS?? IF pods, if cheap emgo brand, they have prominent lips on the mounting area that are known to interfere with the airflow ports of the carbs, and have caused folks to hit a 5K wall due to the vacuum slides not being able to function properly due to air flow restriction!

Next, you fixed the PU wires, but did you inspect the mechanical timing parts to make sure that they move easily and that the timing plate easily rotates with the action of the cent. weights as the vac. adv. pot.??

You can use a STRAW, or long piece of wood to stick into the #1 piston hole, put a homemade degree wheel on the end of the timing plate....or just use the OEM pointer and a fine tip marker to mark the OEM timing plate with 3 marks. Use the stick in the plug hole to visualize when the piston stops moving up when approaching TDC, mark the timing plate with that mark in reference to the pointer, then rotate engine farther to where the stick just starts to drop again, mark the timing plate again, and then mark what you can figure the CENTER position between those two marks would be. That mark is your TRUE TDC mark. See how close it is to the OEM TDC mark on the timing plate and where the pointer is pointing to.

AND, I did receive your PM regarding the SOFA, apologies for not replying, but have felt badly/mentally/conscience wise. I have recently contacted a member that has access to proper machining equipment, CNC and such, and is still determining if he can make the SOFCA's/Oil cooler adapters at a similar price to what I charged. He may also be able to make the plain SOFA's as well, but he was out of town and hadn't had a chance to review all of the technical info/specs/dimensions I had provided to see if he could produce them easier, quicker, and hopefully not too more expensively.

I only have some hobby level of machining equipment from Harbor Freight, and have to do all of the work manually...no fancy CNC here, and it takes a few hours for each unit. Last year I had injured my right arm/elbow with severe tendonitis, and took months to heal, and I didn't want to re-aggravate the injury doing the cranking action required to make these things, so that's why I wasn't able to make any last year, along with all of my other personal aggravations....caring for my 89 y/o mom, wife's pre-cancer, etc.!

T.C.

[coolbikr4684]

Hey there,

Okay, new carb mount boots, but are you running OEM airbox or PODS?? IF pods, if cheap emgo brand, they have prominent lips on the mounting area that are known to interfere with the airflow ports of the carbs, and have caused folks to hit a 5K wall due to the vacuum slides not being able to function properly due to air flow restriction!

Next, you fixed the PU wires, but did you inspect the mechanical timing parts to make sure that they move easily and that the timing plate easily rotates with the action of the cent. weights as the vac. adv. pot.??

You can use a STRAW, or long piece of wood to stick into the #1 piston hole, put a homemade degree wheel on the end of the timing plate....or just use the OEM pointer and a fine tip marker to mark the OEM timing plate with 3 marks. Use the stick in the plug hole to visualize when the piston stops moving up when approaching TDC, mark the timing plate with that mark in reference to the pointer, then rotate engine farther to where the stick just starts to drop again, mark the timing plate again, and then mark what you can figure the CENTER position between those two marks would be. That mark is your TRUE TDC mark. See how close it is to the OEM TDC mark on the timing plate and where the pointer is pointing to.

AND, I did receive your PM regarding the SOFA, apologies for not replying, but have felt badly/mentally/conscience wise. I have recently contacted a member that has access to proper machining equipment, CNC and such, and is still determining if he can make the SOFCA's/Oil cooler adapters at a similar price to what I charged. He may also be able to make the plain SOFA's as well, but he was out of town and hadn't had a chance to review all of the technical info/specs/dimensions I had provided to see if he could produce them easier, quicker, and hopefully not too more expensively.

I only have some hobby level of machining equipment from Harbor Freight, and have to do all of the work manually...no fancy CNC here, and it takes a few hours for each unit. Last year I had injured my right arm/elbow with severe tendonitis, and took months to heal, and I didn't want to re-aggravate the injury doing the cranking action required to make these things, so that's why I wasn't able to make any last year, along with all of my other personal aggravations....caring for my 89 y/o mom, wife's pre-cancer, etc.!

T.C.

OEM air box and PU cables were checked and mechanism does rotate freely. I also did the TDC with a stick and have made the lines I just wasn't sure if I moved the indicator needle to the new TDC if it would interfere with something else with the new timing or break something. What would cause it to change?

No worries about the SOFA I always figured people have lives outside the forum so didn't think twice about the lack of response. Thank you again for the response though, the help is always appreciated.

[TADracer]

Not to override anything TC has written above because it is all true and doable. But the accuracy of the stock timing plate/pointer are not to be relied on for anything other than checking things. Put a real timing wheel on and use a piston stop to find the true TDC and then if you check ignition timing you might be surprised to find it is a couple degrees off.

I know some people do not have access to such equipment but if you have moved the pointer and want to make sure it is back to exactly where it should be then I recommend a timing wheel and piston stop are used.

Piston Stop


Timing Wheel

[coolbikr4684]

So I checked the timing with a degree wheel and plug stop. Now I have the engine at true TDC and the timing was redone. Still have problems getting past the 5k wall. It stumbles at WOT. I got it to 5500 RPM today, I crept the throttle open but after 5500 it started to stumble and went back to 5k and couldn’t get it back up.

[TopCatGr58]

Okay, hitting a 5k wall...could be the mains not big enough, could still be the ignition timing not advancing like it should, could be the valve timing may be off??

You might want to put a timing light on it and verify that you're getting the 35 degrees of centrifugal advance at the IIRC 4500 rpm, remember to cap off the vac. adv. you only want to check the cent. adv., that's what gives you the amount of timing advance that is the max adv. for the most power. The Vac. adv. just kicks in for cruising low load speed for fuel economy.

I know it's a PITA, but you'll have to pull the valve cover to check the valve timing to make sure that it hasn't skipped a tooth....I think you said that you had put a ACCT on it, or something....unless I'm remembering another member's bike by mistake??

What have you done to the carbs, cleaning, new jets, their sizes,etc.?

T.C./ADMIN

[Rasputin]

Timing would have to be very far out to not exceed the 5000 to 5500 range. It is either carbs, exhaust or valve clearances. Valves too tight will not let the engine breath and you do not mention if you have checked/set them. Same to be said for exhaust as plugged or restricted exhaust will limit the engine breathing, and again nothing mentioned.
However the one thing you mentioned that you have done is to rebuild the carbs. I would center my attention there. If you have used the mikuni jets and completely cleaned them, cool. Question is do the jets match the machine or the carb set? Many have accidentally read the wrong chart or gone by the guide for jetting on the site (which is totally bunk in my experience).
Question is what do the plugs look like after it runs down the road and then idles for 3 minutes? What do they look like after a high speed/Rpm chop? That will tell you if it is lean or rich at 5500 in a heartbeat.
No need for a 100MPH chop like I use (cause I can) just a higher gear and WOT to see what it burns like. The color of those plugs will tell more than any encyclopedia will ever tell you.

[MaximPhil]

Hi coolbikr,
Often it's the silly stuff. Have you checked the fuel lines are free and clear including filters. No Kinks in the line when you put the tank back on
Try running with the petcocks at Prime setting.
.
Phil

[coolbikr4684]

Hi coolbikr,
Often it's the silly stuff. Have you checked the fuel lines are free and clear including filters. No Kinks in the line when you put the tank back on
Try running with the petcocks at Prime setting.
.
Phil

Now that you mention it I have the little filters that go in tank and an in line paper filters on each petcock. Should I remove the in tank ones

[TADracer]

When you say it runs out of power at 5000 in 5th, does it pop or sputter or just top out there smoothly? As a rule of thumb I go for the carbs last but if it sputters or something like that ta 5000 then maybe go back to the carbs.

[coolbikr4684]

Okay, hitting a 5k wall...could be the mains not big enough, could still be the ignition timing not advancing like it should, could be the valve timing may be off??

You might want to put a timing light on it and verify that you're getting the 35 degrees of centrifugal advance at the IIRC 4500 rpm, remember to cap off the vac. adv. you only want to check the cent. adv., that's what gives you the amount of timing advance that is the max adv. for the most power. The Vac. adv. just kicks in for cruising low load speed for fuel economy.

I know it's a PITA, but you'll have to pull the valve cover to check the valve timing to make sure that it hasn't skipped a tooth....I think you said that you had put a ACCT on it, or something....unless I'm remembering another member's bike by mistake??

What have you done to the carbs, cleaning, new jets, their sizes,etc.?

T.C./ADMIN

Carbs were cleaned, rebuilt with mikuni jets all the sizes spec for oem airbox. I want to say 137.5 and 42.5.

Timing would have to be very far out to not exceed the 5000 to 5500 range. It is either carbs, exhaust or valve clearances. Valves too tight will not let the engine breath and you do not mention if you have checked/set them. Same to be said for exhaust as plugged or restricted exhaust will limit the engine breathing, and again nothing mentioned.
However the one thing you mentioned that you have done is to rebuild the carbs. I would center my attention there. If you have used the mikuni jets and completely cleaned them, cool. Question is do the jets match the machine or the carb set? Many have accidentally read the wrong chart or gone by the guide for jetting on the site (which is totally bunk in my experience).
Question is what do the plugs look like after it runs down the road and then idles for 3 minutes? What do they look like after a high speed/Rpm chop? That will tell you if it is lean or rich at 5500 in a heartbeat.
No need for a 100MPH chop like I use (cause I can) just a higher gear and WOT to see what it burns like. The color of those plugs will tell more than any encyclopedia will ever tell you.

Have not done a plug chop but the valves ate tight. I couldn't get in my smallest feeler gauge I have. What would cause them to be so tight?

When you say it runs out of power at 5000 in 5th, does it pop or sputter or just top out there smoothly? As a rule of thumb I go for the carbs last but if it sputters or something like that ta 5000 then maybe go back to the carbs.

In 1-4th gear it will redline but once in 5th it will hit the wall. If I go WOT it starts to stumble

[DiverRay]

Have not done a plug chop but the valves ate tight. I couldn't get in my smallest feeler gauge I have. What would cause them to be so tight?

The valves will get tight as they wear, not loose. You should go through and get the valve adjustment correct BEFORE trying anything else. I like to set valves at the high, or open end of the spec. They make a little noise, but they also will not tighten and burn any time soon.
AFTER adjusting the valves, then do a chop test with the plugs. If they are white, you are probably running out of gas. Black would be too much gas.

[coolbikr4684]

The valves will get tight as they wear, not loose. You should go through and get the valve adjustment correct BEFORE trying anything else. I like to set valves at the high, or open end of the spec. They make a little noise, but they also will not tighten and burn any time soon.
AFTER adjusting the valves, then do a chop test with the plugs. If they are white, you are probably running out of gas. Black would be too much gas.

When replacing the shims and valve adjustment, how do I do it if the shims are tight. All the threads I find mention I measure the space between but my thinnest shim won't even go in.