lifan 140 noise

[loace]

hey guys just fitted a 150 barrel and piston to my 140,
i ported and polished the head with HD valve springs still waiting on my akunar cam to arrive, i have a vm 26 on the way

its making a noise to me of too loose of valve clearane ,and it only makes this noise when hot,

have a look at my vid and see what u reckon cheers
IMG 0393 - YouTube

 

[Stubsy]

hey mate i have heard the piston can hit the valves if you havent dremeled a spot out of the top?? not entirely sure but could be. Also could be cam chain slapping? i did have a similar noise when i dropped the bottom gasket out of my 140 lifan. put it back in and it was gone

 

[loace]

yeah it has the releifs already in the piston i checked clearances with plastisine, and thats with stock cam ,
cam chain is good tension throughout the stroke,

 

[The_GDFP]

Did you add a spacer under the jug? 140 iron cylinder is aboot 3mm taller than a 150. Piston's likely hitting the head and cam chain tensioner maxed out. 140 uses a 14/28 cam sprocket setup and 88l chain v 16/32/90 of the "normal" China mid-block.

 

[Stubsy]

Haha I'm all out of ideas then lol

 

[loace]

yeah mate 3 mm stroker plate, timing chain is fine , from what i can gather maybe i need to tighten up valve clearance

 

[sean01]

sure sounds like the piston kissing the head, id be pulling the head off to double check.

other than that what valve clearance did you give it??

or... the oil gallery in the cases is blocked

 

[loace]

I pulled the head to check for the piston touching couldn't see any visible signs,I set the barrel and striker plate to have 59mm stroke and it reaches tdc at deck height, I have set the valves to 0.5mm

 

[The_GDFP]

.5mm? lol
might be the issue
.1mm

 

[loace]

Sry i meant .05mm, could the higher compression 150 piston be a problem?, from what I've read the 140/150 run same head with different cams,

 

[sean01]

so you have zero piston to deck height.. these engines like to stretch the conrod which will push the push out of the bore when running..

add a base gasket and see what happens

 

[loace]

The piston comes flush with the end of the barrel at tdc, Im running 3 base gaskets ATM , if it is the piston kissing when hot maybe I should try a 4mm stroker plate???

 

[Stubsy]

im interested how u go cause i was thinking of doing the same mate.

 

[EngineNut]

I had the same noise when I installed a 150 cylinder with spacer, bought from Terry, on a Lifan 140.

What I found was the cam chain tensioner piston travel was limited by some casting flash on the crankcase which would not allow the chain to tighten. I also had the wheel end of the tensioner lever contacting part of the case before the chain tightened.

I would recommend removing the flywheel, stator, and cover to allow you to see that the chain tensioner is working correctly. You will be able to feel the tension on the chain with you finger.

I put some grease on the area above the piston to retain the peaces and used a small chisel with light and slow hammer blows. For the lever clearance I ground the lever.

I also put a ¼” spacer under the tensioner spring.

Ran a day of Mini-Motard and it ran fine.

Good luck

Ron

 

[loace]

This arvo I pulled the stator off everything is fine , I put the 140 barrel n piston back on , and the noise Is there U can just hear it very faintly,

Maybe the 150 cylinder emits more noise through the fins than the iron jug??

Also my crank moves side to side in the cases , not the bearings, with the stator off you can visibly see the bearings moving left and right in their machined housings. Almost like the cases have gotten wider

 

[The_GDFP]

Yes, the alloy jug will let more noise out. That's why many have rubber biscuits between the fins. If you're flush, with the cylinder compressing the base gasket/spacer combo, and running a composition head gasket, it shouldn't hit. Zero deck and a shim .25mm gasket will let it hit lightly. 3mm spacer with a gasket on each side has been plenty, on ones I've done, but if it's hitting, stack another base gasket or up the spacer size. If it's hitting, you should see signs on piston and head, and noise would increase with revs.

Check for coil bind, especially inner spring, when you add lift. Some Lifan heads have been a bit short on installed height.

Crank moving side to side isn't common. Check your cases for broken "stops" and pieces of aluminum in the bottom. XR100's do it all the time, but Lifan's not so much. Loctite 640 or similar will hold the float down, but it requires a good cleaning.

 

[loace]

cheers for the reply mate, i added another 1mm under the jug and all seems fine now, even tho when i pulled the head after the video there were no witness marks to be seen anywhere, but like seano said , once it gets hot the rod stretches,

 

[sean01]

yeah one thing i forgot to ask before, when you said you had flush piston to deck height, were you bolting down the cylinder when checking the height?

bit weird there was no signs of kiss marks on the piston tho..oh well at least you've fixed the noise now..

 

[loace]

Yeah I was bolting it down with the head but with spacers in between the base of the head and top of the cylinder, all I can think of seano it was just a bees **** within touching when hot ,

 

[sean01]

yeah all good, i had the same problem with a z155 engine.. zero deck height but kissing when running..

i use tube sockets to bolt the cylinder down when checking deck height