Post by gubbs on Apr 2, 2007 14:41:28 GMT
www.cjgavin.com/beam/scoot/
Working on an Vespa ET4 (four stroke 125cc) I picked up cheap as a means to teach myself engine overhaul fundamentals and just generally get my cherry popped on the cheap. Plus with the warm weather coming I want a scoot for pootling around on when its too hot for leathers.
Having sold my old (same model) scoot last month, I bought this one off ebay for 200 quid as a non runner. The woman I bought it off said there was no oil in it - and hadnt been for some time. I asked her if she would be so kind as to turn the engine off then! She then said, 'Oh its perfectly OK I went to Glastonbury on it last year .. ' 'YEAR?!?' I replied. I figured it was f*cked so I knocked her down from 400 to 200 anticipating a rebuild.
Anyway I was expecting it to be minced, but when I got it home, put oil in it, fired it up it started first time. No rattles, no smoke, no knocking. Rev'd cleanly and pulled alright - needs new rollers and tyres etc.
Anyway I flushed the oil and it was nasty, black and thick with carbon deposits. No worries, I figure if its been run on a whiff of oil for any amount of time its going to be a mess inside.
Flushed it out and stripped it down .. Got the head off and had a look today.
Now, when I removed the oil filters (paper and internal gauze from the other end) they both have little bits of metal in them. Small, granules. Like gravy or instant coffee size. Great, I figure its f*cked.
But when I go the top off, the valves are fine, the rocker arms are fine, the camchain is fine, the cams to my amazement are pitt/crack free and the piston is solid and looks very tidy for 20, 000 miles.
So where's the metal come from? Piston skirt, big end etc? Is there a chance the head is warped? How do you check for that, specifically?
Anway, first time with the head off on anything ..
What do I do now? I figure cleaning it all up and getting the valves out for inspection etc. What solvent do you use to decoke it all? Soft cloth or wire wool etc?
Assuming the top end is all within tolerance and nothing ugly rears its head I will have to have the con rod out and check/replace the main bearing and check the rings/skirt etc? Or given the 'if it aint broke' approach would you just chuck it all back together, tune up the valves and get on with riding it?
All advice welcome ..!
Working on an Vespa ET4 (four stroke 125cc) I picked up cheap as a means to teach myself engine overhaul fundamentals and just generally get my cherry popped on the cheap. Plus with the warm weather coming I want a scoot for pootling around on when its too hot for leathers.
Having sold my old (same model) scoot last month, I bought this one off ebay for 200 quid as a non runner. The woman I bought it off said there was no oil in it - and hadnt been for some time. I asked her if she would be so kind as to turn the engine off then! She then said, 'Oh its perfectly OK I went to Glastonbury on it last year .. ' 'YEAR?!?' I replied. I figured it was f*cked so I knocked her down from 400 to 200 anticipating a rebuild.
Anyway I was expecting it to be minced, but when I got it home, put oil in it, fired it up it started first time. No rattles, no smoke, no knocking. Rev'd cleanly and pulled alright - needs new rollers and tyres etc.
Anyway I flushed the oil and it was nasty, black and thick with carbon deposits. No worries, I figure if its been run on a whiff of oil for any amount of time its going to be a mess inside.
Flushed it out and stripped it down .. Got the head off and had a look today.
Now, when I removed the oil filters (paper and internal gauze from the other end) they both have little bits of metal in them. Small, granules. Like gravy or instant coffee size. Great, I figure its f*cked.
But when I go the top off, the valves are fine, the rocker arms are fine, the camchain is fine, the cams to my amazement are pitt/crack free and the piston is solid and looks very tidy for 20, 000 miles.
So where's the metal come from? Piston skirt, big end etc? Is there a chance the head is warped? How do you check for that, specifically?
Anway, first time with the head off on anything ..
What do I do now? I figure cleaning it all up and getting the valves out for inspection etc. What solvent do you use to decoke it all? Soft cloth or wire wool etc?
Assuming the top end is all within tolerance and nothing ugly rears its head I will have to have the con rod out and check/replace the main bearing and check the rings/skirt etc? Or given the 'if it aint broke' approach would you just chuck it all back together, tune up the valves and get on with riding it?
All advice welcome ..!