244cc Honda Clone Intake valve malfunction By scooterfan86 (Read 1,563 times)

[JR]

On the 250cc engines I've never found a F mark, in fact the Linhai doesn't even use a T but rather a V notch. I pull the plug, put a wire in the sparkplug hole and turn it to it stops, look for the V mark and if it is on then I adjust the valves, don't see the V I turn it another 180. I never even look at the cam marks anymore.

JR

[scooterfan86]

Ok, I found a mark that is probably a faded T before the F. I was able to rotate the flywheel by hand. I got everything to the point of starting up the bike and it does start and runs on the center stand. I haven't taken it for a ride yet.. the rpm meter jumps more than it used too, and when the engine wasn't very warm it did die going from idle to higher rpm (3-4000). It feels groggy at low rpm still, and there was also a clinch point in the ignition where something was binding, took my finger off ignition and tapped it again, things went back to normal. And the flywheel feels like it's turning too easily; there is no difficult point where the compression stroke should make it hard to turn.

Could this still be the timing not being right?

[scooterfan86]

Ok engine no longer starts without sitting on the ignition button for a long period of time.. I have a feeling I'm not getting compression with the flywheel turning so easily. When things cool down enough to take out the spark I can test that.

The shop manual I have says not to use the 1mm metal head gasket, that it can damage the cam. I can't find the .25mm head gasket advertised as such and the kit I purchased only had the 1mm. It looks like a sandwich of 2 .25 mm gaskets with a .5mm steel one in between. Is there a chance I could dremel off one of the .25 mm gaskets and use that? I reused the old one with several coats of Permatex Copper SPRAY-A-GASKET... and have a feeling it is the culprit with a lack of compression. Help!

[alleyoop]

Well take the plug out and do the finger compression test. At least that will let you know if it has descent compression IF it lifts your finger off the hole. Now remember you need to hold the throttle wide open doing the test so it sucks in as much air as possible otherwise the test will show low compression.

Also if you can take a short Video of you trying to start it, if it is loosing compression you normally can hear the difference has a wush sound to them air escaping.

But I would still question your timing setup, reason is at first you could not turn it past a point which means it was hitting on something and binding.
And now you are saying it dosen't appear to hang up at all which means no compression or very little.

Did you turn the flywheel to align the timing mark at the "T" and THEN loosen the Valve cover and Cam and moved the cam and chain WITHOUT having the FLYWHEEL move to this position?
Alleyoop

CAM SPROCKET ALIGNMENT when Flywheel marker is pointing to the "T" :

[JR]

Nov 9, 2014 18:00:10 GMT -6 scooterfan86 said:

Ok engine no longer starts without sitting on the ignition button for a long period of time.. I have a feeling I'm not getting compression with the flywheel turning so easily. When things cool down enough to take out the spark I can test that.

The shop manual I have says not to use the 1mm metal head gasket, that it can damage the cam. I can't find the .25mm head gasket advertised as such and the kit I purchased only had the 1mm. It looks like a sandwich of 2 .25 mm gaskets with a .5mm steel one in between. Is there a chance I could dremel off one of the .25 mm gaskets and use that? I reused the old one with several coats of Permatex Copper SPRAY-A-GASKET... and have a feeling it is the culprit with a lack of compression. Help!

1986 to 1995 Helix Shop Manual

Page 29

This engine has a TDC inspection hole with a mark on the cam at the top of the engine. Turn it to that mark and then look for the mark on the flywheel, if it's not there rotate it 180. Can then look at the cam if it is not aligned then pull it and put it where it belongs in relation to the chain. Then rotate again, look at TDC mark and flywheel mark.

Also you are forgetting this engines timing is fine tuned with the side adjusters as noted on page 29 of the manual and it later came out to even fine tune it farther with the engine "running.

The copper coat BS won't work, all a waste of time and a mess to clean up, get the right gaskets and then put it together right. Need to check the valves while you have it apart, the slightest leaking valve means no compression. It's easy to take them out and use some valve grinding compound and rest them just for good measure.

.partsforscooters.com/180-78_Cylinder_head_gasket_v3-v5" rel="nofollow" target="_blank">.partsforscooters.com/180-78_Cylinder_head_gasket_v3-v5

.partsforscooters.com/180-104_Cylinder_Gasket" rel="nofollow" target="_blank">.partsforscooters.com/180-104_Cylinder_Gasket

You can ask these good people about their head gaskets, I'm thinking the brand they use require no sealant of any kind, the base gasket can be sealed better with red high temp silicone. The 1mm gasket will cause no issues.

Also very critical you torque the head bolts properly and not guess, in fact after initial torqueing and warming the engine up it is recommended to re-torque them again.

Good video on how to adjust the valves with it running.

thescooterprofessor.proboards.com/thread/373/valve-adjustment-helix-cfmoto-engine

Take note here, NO gasket glue on the head gasket and his parts came from the vendor I mentioned>

thescooterprofessor.proboards.com/thread/3273/yy250t-cfmoto-vertical-engine-replacement

He did not replace the base gasket, here, can get away with it if you are careful.

JR

[scooterfan86]

Okay, I'll give the 1mm gasket I have a try then. Sounds like I need to find a torque wrench that can precisely do foot-pounds between 10-20... I've been looking for quite a while for a tool that does this. Even the expensive name brands start at 20 foot pounds. Any ideas of where to look?

I did have very good compression before the first start so I'm not too worried about the valves. But if I have it off to replace the head gasket I might check them out too. The rentable tool I used at autozone to remove the valves worked well at putting them back on but I had to improvise a bit to get them off and the keepers out. It was a royal pain with all that potential energy in those springs.

Do you know of any videos or threads about regrinding valve seats with the compound described?

Thanks for all the help and advice, I really appreciate it!

[alleyoop]

Here is a NEAT VALVE GRINDER TOOL:
Alleyoop

.ombwarehouse.com/Valve-Grinder.html" rel="nofollow" target="_blank">.ombwarehouse.com/Valve-Grinder.html

And Here is a Video using the TOOL:

[JR]

Here is also a simple style cheap valve grinding tool that you can find at most any auto parts or order off Ebay:

One just puts it on top of the valve and push down which will make it have a good suction. Put a little "fine" grinding compound which again you can get at the auto parts store and spin the valve back and forth with steady pressure. This does what we call seat the valves and make a perfect fit for nothing to pass by such as exhaust or your compression on the compression stroke. It's simple, cheap and a very good thing to do while you have the head off. Be sure to clean the head and valves of all grinding compound before you put it back together.

This is a video of using this simple tool. Also valve grinding compound comes in tubes or small cans, and again ask for "fine".

More video help:

thescooterprofessor.proboards.com/thread/1504/gy-valve-lapping-spring-replacement

JR

[alleyoop]

Here is the cheaper valve grinding tool:
sales.shopthedude.com/prd.cl/ATS648448

[JR]

Thanks Alley I had a picture up and it disappeared?

[scooterfan86]

Looks like the compression was lost from the gasket ring on the cam//valve cover not sealing properly. I was able to get compression with that off and the valves closed which was a bit of a relieve to not have to take more apart. It looks like the copper spray on stuff actually got me another use out of the metal head gasket. If there are any issues I have the replacement and I'll know what's the first thing to check out.

The timing is now either very very close or completely spot on. Did a wire test through the spark plug and matched it to a mark several times. The camshaft is perhaps a chain link off of top dead center. I'm not sure if I could have done better even by taking everything apart, so I didn't. Hoping that theres a tiny bit of wiggle room on that.

Got the gasket ring where it needs to be and used some assembly lube all around. Things sealed up nicely and the engine ran very well tonight. Warmed everything up, then got things up into the 5-6 thousand rpms and held it there like I was going for a ride. Theres a slight waver in the rpm meter at idle but it could be that I haven't lapped the valves or a slight compression issue still. If it doesn't sort itself out I'll dig into it. But after warming up did some rev and break tests; it was the first time I was able to do those cleanly without the engine stalling, not once. Turned everything off after adjusting the valves. Came back an hour later and everything started up nice on the first hit of the ignition.

Next test will be to see what it does tomorrow cold and untouched. I'm hopeful though. Thanks so much for all the advice and help!

[alleyoop]

FANTASTIC!! Great Job, you got it now
Alleyoop