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Post by aeroxbud on Jul 16, 2022 4:58:25 GMT -5
I would think at least one bent valve if you kicked it over an felt resistance.
If so it might be better/easier/cheaper to buy a complete head.
Only a full strip down will show you for sure.
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Post by jstich on Jul 16, 2022 21:34:23 GMT -5
I took off the 4 bolts holding the rocker arms and assembly holding the cam in place. I was able to keep the cam in it's groove and was able to turn the crank and cam and the assembly did NOT have that huge interference I had with the cam holder and rocker arms bolted to the engine.I tried removing the rods that hold the rocker arms in place with no luck.tried unscrewing them and tapping them out with no luck.I'm starting to think I indeed screwed (buggered)up a valve but I'll wait to see if anyone has a comment.
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Post by 190mech on Jul 17, 2022 4:18:20 GMT -5
If your cam timing slipped a couple of teeth,odds are high that the piston is hitting a valve..If so,you will need to pull the head and inspect the valves and piston,also figure out why the chain slipped on the timing sprockets..That engine has a lot of miles on it,could be the chain has worn out beyond what the cam chain tensioner can tighten..Crankshafts are said to last around 5000 miles also on those engines,might be a good idea to shop for a complete new engine..Hopefully some of the 4stroke guys will comment also...
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Post by geoffh on Jul 17, 2022 8:07:27 GMT -5
If it,s true that a mcd,s costs the same the world over  then a used 4T should be same ish I had one shipped to me for £150 shame it turned out to be a short case ,I had had to transplant the Gubbins into the long case,it runs but other issues have left it parked in a dark corner an expensive spider home for a while. Geoff |
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Post by jstich on Jul 25, 2022 1:10:19 GMT -5
I took the head and cylinder off tonight.The cylinder seems fine along with the piston.The piston and combustion chamber has some soot but it seems normal.I've never done valve work so I think I need to actually take the valves out of the head to see if one is bent?As it sits the valves look normal.Then I went to PFS and tried to find a valve spring compressor to take it apart and I didn't fond one. Is there a trick to remove the valves/springs without a spring compressor?
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Post by aeroxbud on Jul 25, 2022 5:14:40 GMT -5
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Post by jstich on Jul 25, 2022 23:46:40 GMT -5
Thanks Paul, my search skills are lacking.I was mostly wondering if there's a way to remove valves without a spring compressor. It doesn't seem likely.I always go to PFS for scoot parts but I'm gonna make an exception here and get one for a third of the price.Most of the Amazon reviews were positive. Hopefully I won't be using it a bunch of times.People with big block V8engines are even getting good results with it. It can handle my little scoot valve springs.
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Post by jstich on Aug 1, 2022 21:25:38 GMT -5
Can't post pics but it doesn't really matter.It only shows a bit of a scatching going on where the 2 cam bearings sit in the head.I got to the valves and they're fine. I rolled em both on a flat surface and no wobble at all. I put them in the holes in the head most of the way in and turned them many times with no looseness no binding.They both easily but firmly can be fully seated when it goes through the guide(?)Piston and bore are smooth.Top of piston and combustion chamber has some soot but nothing close to excessive.Rocker arms move freely on their arms.There is no slop in them thank god because I have no clue how to remove the rocker arms from their shafts.
Now I have the cylinder and bore removed.I have good motion on the crank.The assembly didn't have that catch when I took the rocker arms /cam holder off.I held the cam in its place and it turned great. I could figure out how to post pics if that'll help.I was sorta hoping for a bent valve so my nightmare would end.It only has the catch thing with the cam holder is on.Makes no sense.Any ideas welcome.
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Post by jstich on Aug 1, 2022 22:25:13 GMT -5
5 different browsers and 2 different operating systems and postimage always shows server error.
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Post by jstich on Aug 1, 2022 23:19:02 GMT -5
one other thing.On one of the black chain guard channel looks like the black paint rubbed off where the chain rides.Is one of them bolted in the case where the crank is?The one attached the cylinder is showing the red under it. I've never touched the adjustment for it.Also if the cylinder and head are off can I fish a new chain for the crank side gear or do I need to pull the crank to change the cam chain?
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Post by 190mech on Aug 2, 2022 4:21:26 GMT -5
Yep, a new chain can be installed and should be!
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Post by geoffh on Aug 2, 2022 15:03:32 GMT -5
Here,s what I remember,the chain guide/guard just slots into place,fit the chain so any slack is on the adjuster side,then release the adjuster it,s automatic for the tension,but you need to bench test it before hand.I over came the valve spring pressure using a ring spanner and my grandkids nimble fingers to insert the collets.we still have kids cleaning chimneys I,m told . Geoff |
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Post by jstich on Aug 2, 2022 22:14:31 GMT -5
Yep the only thing I know for sure is I need a new chain.Geoff I just removed the adjuster and the bolts to remove it.That'll be something I need to deal with when I re assemble it I believe.The engine is in the frame what do you mean when you say I should bench test it?
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Post by aeroxbud on Aug 3, 2022 3:56:51 GMT -5
I think Geoff is referring to the chain tensioner. Test it to make sure it's working correctly before installation.
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Post by geoffh on Aug 3, 2022 14:37:22 GMT -5
Yes I did mean the to test the adjuster thanks for posting that vid Paul,
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then a used 4T should be same ish I had one shipped to me for £150 shame it turned out to be a short case ,I had had to transplant the Gubbins into the long case,it runs but other issues have left it parked in a dark corner an expensive spider home for a while.