125cc won’t fire - Page 2

Nicthegreat420 · 09-10-2020, 03:48 PM

Quote:

Originally Posted by bogieboy

I would check that your flywheel key is intact then, as you have tried fuel in the cylinder and it still wont go, i am guessing that the spark timing is off then...

I have correct spark gap and the flywheel is good as is the key... not sure how to check spark timing but I’ve again had several mechanics come over and do all of those correctly..most don’t know what the start chain noise is as it comes with an adjuster that’s automatic.

I tried the stock carb. It had this no start n putter issue with the old one.
and this is what this entire problem was started with. A no start condition. (Bought a new motor and it fixed it temporarily)

I swapped to a 26 mm intake carb and it’s not running nor idling.
I believe I could get my stock carb back n try that out, but the needle is not as quality and only has 1 setting for richness.

Nicthegreat420 · 09-10-2020, 06:25 PM

Here’s an example of how to set the needle, yet my stock needle only has one slot to stay on.

My stock carb needle has ONE slot, this 26 mm carb has all 5, and both an AIR &FUEL mix screw, plus an idle mix screw. Total of 3 screws not 2.

dirtbkr188 · 09-10-2020, 06:51 PM

I've never seen a carb with an air and a fuel screw, it's normally one or the other, plus the idle adjustment screw. I'd like to see a few more pics, if you don't mind.

1. some pics of this 3-screw carb
2. some pics of the main jet and pilot jet shown above, out of the carb to get a better idea of what style and make jets they are, along with some basic measurements in mm, including the overall length of both, the width of the main jet head and the width of the pilot jet also.
3. have you tried working from a set baseline that you can return to? From what I can tell in the above pics, it looks like a Mikuni-clone VM26/22 with a butterfly choke that is cable actuated. Knowing what size and make the main and pilot jets are is key to being able to jet it correctly.

4. How many turns OUT from seated is the fuel screw? What slot on the jet needle is the e-clip located?

Nicthegreat420 · 09-11-2020, 04:37 AM

Since I’ve had this carb it hasn’t ran once at idle. Not at stock factory out the box settings or any adjustments thereafter..
it is on the 3 rd rn. On the needle. Gas is in the tank n bike is indoors due to the fires.

franque · 09-11-2020, 05:39 AM

Try spraying some carb cleaner in it and see if it'll run on that, if it does, you know it isn't a timing issue.

Nicthegreat420 · 09-11-2020, 11:42 PM

Quote:

Originally Posted by franque

Try spraying some carb cleaner in it and see if it'll run on that, if it does, you know it isn't a timing issue.

Won’t run on starting fluid or Fresh 91.

Nicthegreat420 · 09-12-2020, 12:01 AM

Here’s my Carb
Tho I didn’t Buy it from eBay.

https://www.ebay.com/itm/192106772478

franque · 09-12-2020, 03:58 AM

It's almost definitely timing then. You could make an engine stop from an old spark plug and verify timing from there.

Nicthegreat420 · 09-12-2020, 05:17 PM

Quote:

Originally Posted by franque

It's almost definitely timing then. You could make an engine stop from an old spark plug and verify timing from there.

As posted earlier I’ve tried with 4 new spark plugs with correct timing n valve clearance. Any internal issues that can arise from using an engine for too long ...?

franque · 09-12-2020, 06:00 PM

If the spark isn't happening at the right time, it doesn't matter if you have spark. Either the static timing is wrong, or, even if the camshaft is timed correctly to the marks on the flywheel, the marks on the flywheel are wrong for some reason.

That's why I said make a piston stop, and physically verify the timing. Not just, 'do these marks and these marks like up'? But actually checking the flywheel marks against actual crankshaft position, using a piston stop, and to get really precise, a degree wheel, but I doubt it'll be necessary, it's probably off by a ton. Did you spray the fluid directly into the combustion chamber?

You could do a leakdown test, but odds are that if it passes a compression test, the leakdown is fine. How much compression psi did you have?

Nicthegreat420 · 09-12-2020, 10:31 PM

Quote:

Originally Posted by franque

If the spark isn't happening at the right time, it doesn't matter if you have spark. Either the static timing is wrong, or, even if the camshaft is timed correctly to the marks on the flywheel, the marks on the flywheel are wrong for some reason.

That's why I said make a piston stop, and physically verify the timing. Not just, 'do these marks and these marks like up'? But actually checking the flywheel marks against actual crankshaft position, using a piston stop, and to get really precise, a degree wheel, but I doubt it'll be necessary, it's probably off by a ton. Did you spray the fluid directly into the combustion chamber?

You could do a leakdown test, but odds are that if it passes a compression test, the leakdown is fine. How much compression psi did you have?

Put a pencil into the spark plug hole and see the timing that way?
Psi was below 100 ��

Bruces · 09-13-2020, 04:06 AM

In post 4 above you stated compression was 160-180 ,not sure how you came up with a 20lb difference with a single cylinder engine ,and now it’s 150 ? Are you just guessing at this ? I cannot remember even an original Honda horizontal ever getting near any of those numbers ,are you using the same tool every time ? The compression testers are not all accurate but they should be consistent with the same tool being used .

OneLeggedRider · 09-13-2020, 11:19 AM

I agree Bruces, even with a new motor that was broken in properly I would be surprised to see anything above 135lbs and would typically expect to see about 120lbs with an accurate gauge on a little engine like this.

Has the pick up/sensor coil been tested? And if adjustable the clearance between it and the flywheel? After that it's time to verify TDC with a piston stop as previously mentioned, check timing chain and tensioner and cam position (visual confirmation that the lobes are pointed equally down) at TDC. After that tested with a timing light to see when the spark is actually happening.

At this point the carb has nothing to do with it not starting. It should run with just squirting gas or ether down the intake.

Nicthegreat420 · 09-14-2020, 06:48 PM

I’m gonna go and rent out another compression tester and I’m also going to get a air compressed can to check with leak down test.I’m gonna go and rent out another compression tester and I’m also going to get a air compressed can to check with leak down test

So I was going over the owners manual and maintenance manual of these hellcats and I’ve come to the conclusion that the intake valve is supposed to be 0.03 to 0.05 mm and the exhaust is supposed to be 0.05 to 0.06.
I Current intake is 0.05 as well as my exhaust valve lash.I Current intake is 0.05 as well as my exhaust valve lash
The psi was around 115. That is what I wrote down last year. Hasn’t ran since. I’m starting to think this is the original engine and NOT THE new one with less than 400 miles. This one has 1236 on it.
Pickup coil n the sensor at the flywheel have been lined up at a shop. Overcharged was usual but done by a “professional” but it’s a china bike so he’s the only “shop” that will “risk” working on it. Honda shops and Kawasaki shops won’t cuz it’s a liability.
As I was using a pos compression tester it was above 150psi. Didn’t test more than 5 times and this is the average. Now off to get a true compression tester, a spark plug tester, and a flywheel pulled and clutch holder tool.
Btw my cdi has that led light that shows when it’s sending spark.

Nicthegreat420 · 09-14-2020, 08:11 PM

92 psi first run.
93 the second time. 92 the 3rd time.

Could be 95. Idk if it’s increments of 5...

09-12-2020, 06:00 PM	#25
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	If the spark isn't happening at the right time, it doesn't matter if you have spark. Either the static timing is wrong, or, even if the camshaft is timed correctly to the marks on the flywheel, the marks on the flywheel are wrong for some reason. That's why I said make a piston stop, and physically verify the timing. Not just, 'do these marks and these marks like up'? But actually checking the flywheel marks against actual crankshaft position, using a piston stop, and to get really precise, a degree wheel, but I doubt it'll be necessary, it's probably off by a ton. Did you spray the fluid directly into the combustion chamber? You could do a leakdown test, but odds are that if it passes a compression test, the leakdown is fine. How much compression psi did you have? Last edited by franque; 09-12-2020 at 07:16 PM. Reason: Punctuation
	3

09-13-2020, 11:19 AM	#28
OneLeggedRider Join Date: Nov 2018 Location: Stockport, Oh. Posts: 1,442	I agree Bruces, even with a new motor that was broken in properly I would be surprised to see anything above 135lbs and would typically expect to see about 120lbs with an accurate gauge on a little engine like this. Has the pick up/sensor coil been tested? And if adjustable the clearance between it and the flywheel? After that it's time to verify TDC with a piston stop as previously mentioned, check timing chain and tensioner and cam position (visual confirmation that the lobes are pointed equally down) at TDC. After that tested with a timing light to see when the spark is actually happening. At this point the carb has nothing to do with it not starting. It should run with just squirting gas or ether down the intake. __________________ ~ Don't poke the bear ~ M.M.I. Dean's List graduate class of '95 and Specialty welder 2020 Ice Bear Terifecta 150cc Trike 2011 Honda Foreman 500ES 4x4 2001 Polaris Scrambler 400
	1

09-10-2020, 06:51 PM	#18
dirtbkr188 Join Date: Aug 2009 Posts: 496	I've never seen a carb with an air and a fuel screw, it's normally one or the other, plus the idle adjustment screw. I'd like to see a few more pics, if you don't mind. 1. some pics of this 3-screw carb 2. some pics of the main jet and pilot jet shown above, out of the carb to get a better idea of what style and make jets they are, along with some basic measurements in mm, including the overall length of both, the width of the main jet head and the width of the pilot jet also. 3. have you tried working from a set baseline that you can return to? From what I can tell in the above pics, it looks like a Mikuni-clone VM26/22 with a butterfly choke that is cable actuated. Knowing what size and make the main and pilot jets are is key to being able to jet it correctly. 4. How many turns OUT from seated is the fuel screw? What slot on the jet needle is the e-clip located?
	1

09-11-2020, 04:37 AM	#19
Nicthegreat420 Join Date: Oct 2019 Posts: 69	Since I’ve had this carb it hasn’t ran once at idle. Not at stock factory out the box settings or any adjustments thereafter.. it is on the 3 rd rn. On the needle. Gas is in the tank n bike is indoors due to the fires.
	0

09-11-2020, 05:39 AM	#20
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	Try spraying some carb cleaner in it and see if it'll run on that, if it does, you know it isn't a timing issue.
	0

09-12-2020, 12:01 AM	#22
Nicthegreat420 Join Date: Oct 2019 Posts: 69	Here’s my Carb Tho I didn’t Buy it from eBay. https://www.ebay.com/itm/192106772478
	0

09-12-2020, 03:58 AM	#23
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	It's almost definitely timing then. You could make an engine stop from an old spark plug and verify timing from there.
	1

09-13-2020, 04:06 AM	#27
Bruces Join Date: May 2018 Posts: 1,572	In post 4 above you stated compression was 160-180 ,not sure how you came up with a 20lb difference with a single cylinder engine ,and now it’s 150 ? Are you just guessing at this ? I cannot remember even an original Honda horizontal ever getting near any of those numbers ,are you using the same tool every time ? The compression testers are not all accurate but they should be consistent with the same tool being used .
	1

09-14-2020, 06:48 PM	#29
Nicthegreat420 Join Date: Oct 2019 Posts: 69	I’m gonna go and rent out another compression tester and I’m also going to get a air compressed can to check with leak down test.I’m gonna go and rent out another compression tester and I’m also going to get a air compressed can to check with leak down test So I was going over the owners manual and maintenance manual of these hellcats and I’ve come to the conclusion that the intake valve is supposed to be 0.03 to 0.05 mm and the exhaust is supposed to be 0.05 to 0.06. I Current intake is 0.05 as well as my exhaust valve lash.I Current intake is 0.05 as well as my exhaust valve lash The psi was around 115. That is what I wrote down last year. Hasn’t ran since. I’m starting to think this is the original engine and NOT THE new one with less than 400 miles. This one has 1236 on it. Pickup coil n the sensor at the flywheel have been lined up at a shop. Overcharged was usual but done by a “professional” but it’s a china bike so he’s the only “shop” that will “risk” working on it. Honda shops and Kawasaki shops won’t cuz it’s a liability. As I was using a pos compression tester it was above 150psi. Didn’t test more than 5 times and this is the average. Now off to get a true compression tester, a spark plug tester, and a flywheel pulled and clutch holder tool. Btw my cdi has that led light that shows when it’s sending spark.
	0