Italian Aftermath...GTS250 engine rebuild
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Addicted
2005 GTS 250ie
Joined: 28 Jan 2012
Posts: 793
Location: Stamford, Lincolnshire
Wed Jul 30, 2014 1:14 pm quote
I know that many others will have done what I hope to do, rebuild a modern vespa engine. However, I haven't done this before and hope to use this thread to document my efforts and of course to mine the knowledge of the rest of the forum.

Introduction:
In June this year I took my 2005 GTS (10000 miles on the clock) to Mantova for Vespa World Days( 2000 mile trip). On the way back the engine stopped and I had the scooter recovered from just outside Calais.

A couple of weeks ago I managed to get the scooter into my local dealership. The scoot was in for a couple of days before they came back to me with the diagnosis. A seized camshaft.

The main bearing surface was seized in the head and the small dowel that is driven by the timing chain was broken off the camshaft. The bearing surface in the head is scored and the dealership have quoted 1400 (parts and labour) to put the fault right. So I have decided to pull the scooter back home and rebuild this myself.

Some of you might think that a camshaft replacement and head replacement does NOT constitute an engine rebuild. However, the technician in the dealership went berserk looking for the problem. Rather than starting at the top he started at the back! The variator is off, the clutch off, the water pump off, and pretty much everything on the RHS of the scooter. Before I knew the extent of the strip down I considered that what I paid out for the diagnosis would be a "head start". I now think of it as a handicap as I have far more to do than I thought.

Last edited by waspman on Tue Aug 05, 2014 7:35 am; edited 1 time in total
Addicted
2005 GTS 250ie
Joined: 28 Jan 2012
Posts: 793
Location: Stamford, Lincolnshire
Wed Jul 30, 2014 1:16 pm quote
Picture of the offending article

IMG_1946.JPG
broken camshaft

Veni, Vidi, Posti
1975 Vespa GTR 125, 1976 Vespa V90 (Resto), 2001 Vespa ET4 125 (Sold), 2009 Vespa GTS300 Super
Joined: 05 Sep 2010
Posts: 6062
Location: Northants UK
Wed Jul 30, 2014 1:39 pm quote
Ciao Ricardo.

Checking in to follow your progress. Any luck with parts supply yet?

Paul
Addicted
2005 GTS 250ie
Joined: 28 Jan 2012
Posts: 793
Location: Stamford, Lincolnshire
Tue Aug 05, 2014 7:40 am quote
Transmission side all assembled, except for tweaking the variator nut up. (Waiting for the kind loan of tools from Mr Brown Beret).New rollers again! Only changed them 2000 miles ago. The old ones had burn spots on due to the variator getting very hot during the engine seizure. Tonight I'll do a dry assembly of the right hand side and make a list of all the bits I'll need before doing it for real.
Addicted
2005 GTS 250ie
Joined: 28 Jan 2012
Posts: 793
Location: Stamford, Lincolnshire
Sun Nov 23, 2014 8:20 am quote
So the drive side is done. No problems there as I had replaced belt and rollers on this scoter and on the GTV 125. So spin the engine around and have a look at the alternator side of the engine.
The vespa shop had stripped pretty much everything off he engine without splitting the engine case.

Hopefully I'll find all the parts in the boxes!

The box with the transmission and some of the alternator parts.
[IMG]http://i.imgur.com/NRRXLns.jpg?1[/IMG]
To make things easier I mounted the engine on a workmate and put wheels under it. This allowed me to spin the engine around for access. It is really great working at the right height. Memo to self: buy a bike lift!

Using the Haynes manual and the Vespa manuals (thanks JimC) putting the bits together was like making a lego model! I borrowed a compressor from work and cleaned all the parts before assembly. A friend had recommended that everything got a dose of oil before assembly.

So far so good.
Veni, Vidi, Posti
1975 Vespa GTR 125, 1976 Vespa V90 (Resto), 2001 Vespa ET4 125 (Sold), 2009 Vespa GTS300 Super
Joined: 05 Sep 2010
Posts: 6062
Location: Northants UK
Sun Nov 23, 2014 8:23 am quote
Great job!
Addicted
2005 GTS 250ie
Joined: 28 Jan 2012
Posts: 793
Location: Stamford, Lincolnshire
Sun Nov 23, 2014 10:35 am quote
Now to the business end!

The problem was that the drive dog on the camshaft had snapped off. The dilemma is "what caused it to break off?" Did it just fail, and debris caused the oil ways in the cam shaft to get blocked thus causing the seizure of the cam shaft OR was there oil starvation to the last journal bearing on the camshaft which caused a friction seize with the momentum of the crank breaking the camshaft? Mmm I'll ponder on this!

The head and the camshaft were not reusable. The bearing suface in the head was screwed as was the camshaft. SIP provided me with a new camshaft for about 80. I can't speak highly enough about SIP. Great website, availability of parts and speedy fulfilment of orders with quick dispatch. My other saviour was MVer "andythebuilder". I'd been promised a head and barrel from a member in the US but he chose now to stop participating! Humph. Andy however, had replaced his head and barrel whilst doing a Malossi V4 upgrade. We agreed on a price and I was outside his house at 08:00 on Saturday morning before his annual departure for sunny climes. The parts in question had been removed from his scooter after about 2000 miles and showed no signs of wear. I was further inspired with confidence when I saw some of the other project that he had undertaken. His own GTS 250 was in sparkling condition with as many gizmos as you could fit on it. The show stopper was a small nitrous powered rocket of a scoot that resided in the garage of his RV on the drive!

Deal done I returned with the bits and stated checking what bits I needed for the assembly.

I was thrown a bit of a curve ball when I tried to buy a base gasket to fit under the barrel. "would sir like 0.4mm, 0.6mm or 0.8mm?" Well, "sir" hadn't got a f**king clue! Back to the manuals! I invested in a set of vernier callipers and measured the distance form the top of the head to the piston crown at TDC and made my calculations. "Sir" would like a 0.4mm gasket please!

Another box of SIP goodies (and an erroneous purchase of a 300 head gasket[it's all yours Paul, I hope you never need it]) and it was time to start putting the head and barrel on the scoot.

I found this bit really weird. I had some engineering background, having served a mechanical engineering apprenticeship, but I'd never done engine bits before. I seemed to be procrastinating a lot. So I chose the day and got the books and the parts ready.... shit, I need a small torque wrench! No tool shops near me so I checked the internet and found the nearest cycle shop (Rutland Water) had torque wrenches for the assembly of carbon fibre parts on their stock of Giant bikes!. Back at home I found the parts just slotted together like a dream. Too easy I thought.

So I now had a "complete" engine on the work stand. Whoo hop!

IMG_2020.JPG

Addicted
2005 GTS 250ie
Joined: 28 Jan 2012
Posts: 793
Location: Stamford, Lincolnshire
Sun Nov 23, 2014 11:12 am quote
So I have an engine and a scooter frame, just gotta put them together! Thinks.

The manuals say I have to raise the frame and slide the engine into place! After racking my brain for a while I found two strong hooks and some bolts and fixed them to the ceiling joists. I rigged up a couple of ratchet straps and hoisted the era end of the frame up. I thought it would be more secure than it was so propped it all up on a batten and two axle stands. Solid!



Getting the engine to the exact position where I could slot the swing arm bolt through was interesting. I used the two castors that I has used with the workmate and placed one under each leg of the centre stand. The engine was now mobile on a combo of the rear wheel and two multi-directional castors. I wheeled the engine in and adjusted the height with the ratchet straps. BINGO!


The next part was a series of checking the dis-assembly routine and following back. Remember, I hadn't taken this baby to pieces! I was just working from the manuals!

I replaced all of the one use hose clips with proper Jubilee clips and first linked all the plumbing, then the electrics and then the fuel.

In truth I probably did all of this three times! Each time I thought of a better, more elegant solution to the routing!

I did a good cold flush through of the cooling system as it had been without fluid for some time.

New oil filter, exhaust back on and fill up with oil. I then lined the shocks up replaced the air box and dropped the frame back to the engine.

Oh shit! I wish I'd put the spark plug back in before I lowered the frame! My hands are just too big for this!

Now for the scary bit. I've spent the last few weeks (a bit every night) checking a few components double checking etc etc and in a way putting off the big moment. I have a horrible feeling it is not going to start or it will make a horrible crunch.

So.....flip the key in the ignition three times, to make sure that some of that last fateful tank full of best French "essence" is through the system, pull in the brake lever and hit the start button.

It started first hit. Not even a prolonged turning over period! FIRST BLOODY TIME!!!! I nearly shit myself!

IMG_2017.JPG

Addicted
2005 GTS 250ie
Joined: 28 Jan 2012
Posts: 793
Location: Stamford, Lincolnshire
Sun Nov 23, 2014 11:32 am quote
First Run!

After starting the engine, I bled the coolant through and couldn't work out where all the warm spray was coming from? Aarrgh, left the oil filler cap off! Very messy, changing of trousers required. Oil topped off, coolant bled, pet carrier back in, windscreen fixed back on, Italian and French bugs wiped off, and a whizz down the road.

I took it very easy as there is still an underlying feeling that I have left something essential out! Very nervous!

No problems from the ride but on checking the oil levels I found a slight milkyness around the dipstick. Water! I was sure that I had done everything properly but the evidence was there! I re traced the steps of the assembly and thought hard about where water could be getting in. It dawned on me that I had drained the cold coolant without the oil filter in place, and that the water was dribbling over the outside of the engine in through the filter hole. Well at least that was what I hoped.

New filter more oil and a proper flush out using a flushing additive. No signs of water....phew!

I was out yesterday for the first proper ride since the breakdown on the French Autoroute. Wife on the back (first time since dropping her off at Verona airport). The scooter sounds fine and is running fine, when she shouts in my ear "so it's 100% fixed then?" turning to get a repeat (a bit deaf) the scooter stopped running and slowed to a halt. Shit! another seize?????? Pet carrier out and quick look around and I found the connector to the injector was astray! Popped back on and we were away!

Fingers crossed I've rebuilt my first top end and refitted an engine. I'll do the numbers later, but I am confident that I've beaten the 1400 I was quoted!
Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: 26 Aug 2007
Posts: 37213
Location: Pleasant Hill, CA
Mon Nov 24, 2014 11:14 am quote
Well done that man!

Hitting the start button for the first time is always scary.
Veni, Vidi, Posti
1975 Vespa GTR 125, 1976 Vespa V90 (Resto), 2001 Vespa ET4 125 (Sold), 2009 Vespa GTS300 Super
Joined: 05 Sep 2010
Posts: 6062
Location: Northants UK
Mon Nov 24, 2014 2:39 pm quote
Well you might not have chosen to do it, but you certainly took it on and won! Well done, I salute you! First large drink on me when I see you next.
Addicted
2005 GTS 250ie
Joined: 28 Jan 2012
Posts: 793
Location: Stamford, Lincolnshire
Thu Dec 18, 2014 1:28 pm quote
After checking the oil pressure earlier this week and getting "the blessing" from Father Jim, I bit the bullet and went for a long run.

Christmas shopping required (ok I could have done it on the Internet) i plumped for Stamford to Birmingham and back. Not everyone's choice I'm sure, but I did have to pick up my wedding ring from the Jewellery Quarter. At 80 miles each way on motorways and A roads it would be Kill or Cure!

On the outward trip I was convinced that there was something awry. I could only get the scoot to rev up to just over 7000. This was more to do with the horrendous wind rather than mechanical problems!

So I think I've cracked it, both the mending of the scoot and me being able to trust the scoot on a long run.
Molto Verboso
2016 Vespa GTS300ie abs/asr/ess Settantesimo '70'
Joined: 11 Jun 2011
Posts: 1910
Location: Not really sure but I think somewhere down South, in the engineering dept at Starfleet's UK HQ
Fri Dec 19, 2014 7:21 am quote
Very good indeed Waspman. Thanks for posting your story and the pics. It confirms my theory that these are a good diy bike for most folk to be able to look after. Enjoy!
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