Modern Vespa

two things about the head were bugging me.
1. I need a good place to mount the CHT sender but all the nuts are recessed
2. the fin profile leaves a lot to be desired.


parmakit profile leaves lots of mass, not a lot of fin area, and no clean place to mount the CHT

by extending the slot between the 3rd and 4th fin the stud is exposed to mount the CHT and more fin area is created

Intake buttoned up. Went with studs as the manifold doesn't leave enough room the get the supplied allen head. Also had to clean up the holes in the manifold as they didn't line up well with the reed and cylinder.


Studs in place

hylomar between the reed and cylinder

3-bond on the other surfaces.

Found the manifold on the parmakit does not clear the frame, so the hammer of persuasion and some nibblers had to be employed.

The frame needed to be bent in to clear the manifold and the hole needed to be enlarged to clear the manifold when compressed, and the rubber mount wen fully extended.

To test the clearance I removed the spring from the shock and mounted it and the engine in the bike. This allows moving the engine through the actual range of motion. Engine must have gone in and out of the bike 10 times today.


fully extended

fully compressed

fully compressed from the other side

One week to go and the bike's not done, but is on its own feet.

Not a lot left to do but not enough time either.

Just fired it up for the first time. :)

That's the best feeling...

Excellent bike Patrick.

Feels really good to have it on the road again. Have 5 days to get it broken in, jetted and ready for a 1000 mile ride. First ride was around the block, second was to the gas station for some fresh fuel. Both trips with no drama. Need to adjust the clutch and rear brake. I don't like the new brake lever I installed, reach was worse than the old one and that was bad enough.

Figure I should give it 30min of run-in time before going for full throttle. Not sure if the CHT sender is messed up or just not getting hot on these short rides.

Got the CHT sorted out, had the wires crossed at the gauge.

Did a few trips yesterday and today around town, EGT is staying under control. just about ready for some high speed runs I think.

Also got new bungee nets attached to the legshield, and bought a box of sparkplugs.

More pics, more pics!

Sorry, I'm down to the wire on getting the bike done, only one day left to have everything ready.


party trick, balanced on the footpegs

stock tank in, still need a hose barb for the vent and some M7 bolts to secure it.

Cargo net attached to legshield

gathering spares and tools.

Run-In is the time it takes to convince yourself that it's not going to explode

I'm not there yet. I've got a little over an hour on the engine, the temps are good maybe even too low. The power is great, I've started giving it some full throttle here and there.

Went to do the first high speed run today, down the street, on to the freeway, everything felt fine but I still wasn't sure, rolled off took it easy to the offramp. Then I blasted full throttle through the side streets home.

so:
explode putting around at 1/2 throttle? No
explode blasting stop sign to stop sign? No
explode sustained WOT? Not sure

Last edited by oopsclunkthud on Fri, 24 Jun 2016 13:16:26 +0000; edited 1 time

fortune favors the brave, mr. owens, fortune favors the brave. jet it rich and let 'er rip. we believe in you.

besides, you already did the home work. you know it's fine!

outstanding job, as usual.

-g

Thanks for the pics, looks fast even sitting still. Kudos.

Good luck Patrick!

great scooter, love small frames.

thanks for the well wishes!

changed the oil last night and noticed that the side wall of the tire was rubbing on something. Thought it was the bolts on the clutch cover but after pulling the exhaust and rear wheel found it was mostly rubbing on the cover itself.

Took the washers off the bolts, took a grinder to the cover, had it back together by midnight.

I'll try and post some pictures during the ride, but if not, see you all when I get back.

Got through day 1, bike is running rich, had to change the plug at lunch. Also jumps out of 4th, but I can hold it in, not ideal but I can finish. Dropped down a jet size for tomorrow as we are heading over some mountains.

Moto Melee Day 1

The first leg of the trip is a hop on the freeway to quickly get out to the good roads. I hate this part on a scooter and as I didn't have any sustained high speed runs on this engine yet I was worried. The temps were fine, if not too low and with the freeway done the fun roads could start.

Took most the morning getting use to the bike again. I went with a heavier flywheel this time and I was having a hard time at first matching revs on down shifts. The CHT was rarely above ~125C and the EGT was really low as well. By lunch the plug was fouled but the bike was running really nicely.

The route after lunch includes a long fast climb over a pass and down into the central valley. I change the plug but left the jetting rich for some added safety. Pulling the hill in 3rd at 7000rpm finally saw some heat build up in the head but still only to about 150C. On the other side of the pass we took an optional dirt road I've never been on (bear valley Rd of hwy 20). Turned out to be really well maintained and was able to do about 50mph most the way. It also cut a huge corner off the distance and given it was over 40C out it was nice to get to the finish quicker.


Bike loaded with gear, tanks full, quick stop for a photo before getting to the start.

Quite a few other two strokes this year

Moto Melee Day 2

Just about every road on day 2 is on my favorite list. Took the first half of 36 a bit slower than usual but still fast enough to enjoy the rollercoaster nature of it. At Wildwood the route took a detour north to hayfork and then back down to 36 again. Not only does this add some really nice sections of Wildwood Rd and hwy 3, but also takes you past a reasonable fuel stop near the middle of a 180 mile leg.

With each fill up I noticed that I seemed to be doing better on fuel than on the prior engine. Mostly because I don't dump so much out the overflow.

We then took Alderpoint Rd over to Garberville. The road is really messed up in a lot of places but a lot of fun as well. From Garberville to Leggett was just a blast down the 101, then the magic starts.

Hwy 1 from Leggett to the coast is just amazing. I worked my way past the few cars I encountered and before long I found myself in sight of a large V twin with girder forks, and the chase was on...


Wildwood Rd



fuel for the desperate in Platina.

Stop on Alderpoint Rd

Looks like you have great weather for it... nice pictures How far are you getting on both tanks?

...large V twin with girder forks, and the chase was on.

This was not the typical V twin you come across on these roads, not the kind decked out with chrome and the inability to lean. Nope, it was a 1000cc Vincent, nothing but engine, wheels, and a very capable rider. I could brake later, he could out accelerate me on the uphills. I thought to myself, "this is why I love this event. I'm on my favorite road, riding my favorite bike, and get to chase a Vincent".

The temperature was starting to drop a bit, a sign we were getting close to the coast. There was more downhill than up allowing me to keep up. Was not sure I'd be able to pass but was intent on getting close enough that if he picked a bad line I'd have the opportunity. We hit a short straight and as I tucked in I lost all power. I got to neutral and realized I hadn't turned on my second tank. Turned it on, dropped in into second and still nothing.

Pulled over and kicked it a bunch of times trying to get the pump and fuel line primed, nothing. Pull the side panel off and found the spark plug cap hanging, popped it back on and I'm on my way - for 50 ft. Pulled over again and notice that the spring in the cap has had it. Applied some 100mph tape over the top of the cap and set off again. This time it stayed but the Vincent was long gone.

Added up the miles and fuel and I'm getting 45mpg giving me a range of ~180 miles. The longest leg I actually did without fuel was only 100 miles.

Moto Melee Day 3:

Got off to a good start, got fuel on the way out of Fort Brag and headed down Hwy 1. I was riding behind a bunch of other bikes but resigned myself to stay there until we made the turn to head inland.

Then I see a bike heading the other way and I start to check the directions for myself, we had passed the turn. As I try to make up my mind to continue and take an alternate route or turn around I feel the power fall off at the lower rpms.

I know this feeling, I'm losing a reed. I turn around and try to get back to the main route but the power is fading. I find a good place to turn out and all goes quiet. Two hours later I'm in the wagon of shame and stay there the rest of the day.


the end

This was not the typical V twin you come across on these roads, not the kind decked out with chrome and the inability to lean. Nope, it was a 1000cc Vincent, nothing but engine, wheels, and a very capable rider. I could brake later, he could out accelerate me on the uphills. I thought to myself, "this is why I love this event. I'm on my favorite road, riding my favorite bike, and get to chase a Vincent".

Sounds like a real blast - sorry to hear you then ended in the truck.

Pulled the reed block today, and found that was not the issue, but did find a flat bit of steel that had no business being anywhere in the engine.

Pulled the head and found something had made a small mess of the head and piston.

joy :(

Oh no! So sorry Patrick. Any new info, theories, or pictures to explain what went wrong?

my guess is a circlip or part of the ring but not sure. will know more when I get the engine out and the top end off. from what I can see none of the port edges look damaged so may be able to save the cylinder.

I feel bad for you Patrick... so close but not quite finished. Having been there I can say it's far far better to blow up on the afternoon of the last day than the afternoon of the day before.

Is it possible that it all started with detonation? Looks like a pattern around the outer edge and nearest to exhaust. I remember you being a little concerned with compression ratio being on the high side?

I don't think it was detention. The head temps were very cool, almost too cool staying at 125C most the time. Hottest it got was 175C (350F). So I think that part of the plan was working perfect. When I get the piston off I'll look for carbon on the underside, that would be telling.

When I pulled the reeds there was a bit of flattened steel about 2mm wide and 5mm long just resting between the reed and the stop. More of that is what got smashed between the head and piston, just not sure where "that" came from.

Put the head in the lathe today to see if I could clean up the damage. Took a few passes just hitting the high spots from the damage and then a final light pass.

Cleaned up ok, I think.

Did you come any closer to finding out what the issue was? And what the mystery strip of metal was?

not yet. Was on a car rally last weekend and need to clean up the workbench, but should have it apart by the end of this week.

Found the issue, not what I ever would have expected.




Circlips are intact, rings are trapped but complete, ring locating pin is present.

Small end bearing failure!

Can't say I've never seen it happen before, not not in 16hr of running.

Sucks. How do the cylinder walls look?

Bugger. You don't see much of that happening... I wonder if the rod angle is increased with that kit putting additional stress on the bearing?

the cylinder wall looks surprisingly good. There are some vertical marks that correspond with the worst damage to the piston. The marks have no grooves and the crosshatching is still there.

So, I think the cylinder and head will ride again.

No point in playing the lottery from now on, you used up all your luck

Well, that is at least some good news.