ISO-Malossi 187; Wheelman Big-Bores
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Hooked
2010 S50 Modified "Punkin"; 2003 ET4 150 "ISO"
Joined: 18 Feb 2017
Posts: 463
Location: Deepinnaharta, Texas
Tue Aug 11, 2020 6:30 am quote
Greetings:

A few points and pics to follow:

Casting imperfection on the crankcase initially blocked the bigger Malossi cylinder skirt from Penetrating the crankcase. Had to Dremel about an inch of slag. It's a risk, but oiled rags and simultaneous vacuum minimized Aluminum in the case. I'll change the oil promptly.

Rest of installation went smoothly, but spent an hour figuring out the weird decompression mechanism.

Buttoned up and re-hung the engine from the frame. I thought I had everything necessary to fire it up, but Click-click. D'OH! Engine ground strap is not "Optional". At least I remembered to connect the spark plug!

Fired up and runs, but idle was very low. Air screw needed at least 1.5 more turns OUT! This was weird, one would think more displacement would make the jetting Lean, not Rich.

Now there's a flat-spot just off idle. Otherwise it PULLS!

I promise not to post a pic of how much bigger the new jug is than the old one. Don't want Piston Envy on the board.
Hooked
2010 S50 Modified "Punkin"; 2003 ET4 150 "ISO"
Joined: 18 Feb 2017
Posts: 463
Location: Deepinnaharta, Texas
Tue Aug 11, 2020 4:28 pm quote
Prepping for Swap
Greetings:

Few preliminary pics.
Removing the rear fender "Duckbill" required 4 fasteners and unplugging the license illuminator bulb. Makes rolling the engine out infinitely easier. The exhaust header bumps into the engine mount bracket, easily lifted over. The shock absorber tries to snag the belt cover, just have to rotate the engine CCW on the stand. Comes out like Buttah, but there are a LOT more connections than on Honda 2-Smoke and 4 - Count 'Em! - FOUR clamps guiding the brake cable.

Engine pull-out clocked about 90 minutes, Wheelman being a bit TOO careful.

ISOMalEngineOut2.jpg

ISOCylPrep1.jpg

Hooked
2010 S50 Modified "Punkin"; 2003 ET4 150 "ISO"
Joined: 18 Feb 2017
Posts: 463
Location: Deepinnaharta, Texas
Thu Aug 13, 2020 7:34 am quote
Making Ready
Greetings:

Examining the stock cylinder, there was a triangle of black suggesting a chronic head gasket leak?

Stock head was prepped on a glass plate with a sheet of 1000-grit taped on.

ISOStkHeadPrep.jpg

ISOStkCylPnd.jpg

Hooked
2010 S50 Modified "Punkin"; 2003 ET4 150 "ISO"
Joined: 18 Feb 2017
Posts: 463
Location: Deepinnaharta, Texas
Thu Aug 13, 2020 7:43 am quote
Wheelman Hits a Snag
Greetings:

The Malossi instructions state to check the cylinder fit BEFORE installing the piston and gaskets. Good advice! It wouldn't go on, and it wasn't immediately clear why. I suspected this might be a common problem for this upgrade, since Malossi went to the trouble to specify this check.

Found the offending obstruction in the form of a little casting imperfection as shown in Pic 2. Dremel resolved without further issue.

ISOMalCylStop.jpg

IsoCylSnag.jpg

Hooked
2010 S50 Modified "Punkin"; 2003 ET4 150 "ISO"
Joined: 18 Feb 2017
Posts: 463
Location: Deepinnaharta, Texas
Thu Aug 13, 2020 7:49 am quote
Mighty Malossi 187
Greetings:

I managed not to lose a wrist pin circlip in the crankcase. Fitted the piston part-way into the cylinder first, then dropped the assembly into position to install the second circlip. Triple-Checked that installation. That is one thing you DON'T want coming loose!

ISOMalInstl.jpg

Addicted
GTS 250ie Super, Italjet Velocifero, Scarabeo 150, S50,ET4
Joined: 22 Nov 2016
Posts: 507
Location: Winston-Salem, NC
Fri Aug 14, 2020 1:27 pm quote
Well done Wheelman. Waiting with baited great about your impressions.
Hooked
2010 S50 Modified "Punkin"; 2003 ET4 150 "ISO"
Joined: 18 Feb 2017
Posts: 463
Location: Deepinnaharta, Texas
Fri Aug 14, 2020 9:14 pm quote
It's Faster!
Greetings:

Job 1 today was to lighten the 85 gram variator load to allow the engine a little more rein to rev. Dropping the hammer now nets 7550 RPM, right where the stock engine peaks, but apparently at the foothills of the Malossi Torque Mountain. I'm not much of a wheelie fan, but I think I could pull one with this engine on stock gearing. It feels to have about as much grunt as my late, unlamented 250 Reflex, but it weighs 150 pounds less. It blew on by 65 indicated on my Test Road, ar a point where I previously would only be approaching 60.

I had a couple other projects going, so the Polini Primary Gears are still on the workbench. Not quite ready to do the top speed trial.

20200814_221933.jpg

Addicted
GTS 250ie Super, Italjet Velocifero, Scarabeo 150, S50,ET4
Joined: 22 Nov 2016
Posts: 507
Location: Winston-Salem, NC
Sat Aug 15, 2020 9:30 am quote
Lighten the weights to increase RPM to get into the Malossi power. 14grams sounds a little heavy.
Hooked
2010 S50 Modified "Punkin"; 2003 ET4 150 "ISO"
Joined: 18 Feb 2017
Posts: 463
Location: Deepinnaharta, Texas
Sat Aug 15, 2020 1:28 pm quote
Gram Weight
Greetings:

Yeah for sure a full load of 14.5s was choking the revs down too much but they came with the Malossi variator along with a 9.5 gram option. I favor incremental adjustments to avoid Overshooting, so I purchased a set of 12.5 and one of 10.5s. The 12s are in there now, along with that bit of extra contra spring preload from the yellow Torsion Controller. Overall pretty good match with stock ratio of 8 to 1 or so. I will probably drop the 10s in when installing the Polini primaries,
Hooked
2010 S50 Modified "Punkin"; 2003 ET4 150 "ISO"
Joined: 18 Feb 2017
Posts: 463
Location: Deepinnaharta, Texas
Tue Sep 01, 2020 4:13 pm quote
Tuning to Primary Gears
Greetings:

So I documented the Polini primary gear installation separately. To complement the longer legs, I dropped from 75 to 63 gram variator load, and added the yellow Malossi clutch triplet springs to raise clutch stall a bit. 18% taller than stock, at about 6.63:1, there's only a minor penalty in the 0 to 5 MPH, and the cruising RPM is a little more relaxed around town at 30-45. I'm giving the engine a bit more run time before I test for top speed. I don't think it'll be 18% higher than previous best (72 MPH) but expect it to go up some.
This goes here so I can dig up & read what I have in the tranny 6 months from now.
Hooked
2010 S50 Modified "Punkin"; 2003 ET4 150 "ISO"
Joined: 18 Feb 2017
Posts: 463
Location: Deepinnaharta, Texas
Sat Sep 12, 2020 12:36 pm quote
Malossi 187 + Polini Upgear
Greetings:

Confident that engine is sufficiently broken in, I went out to my Testing stretch of highway and let 'er rip in light (for here...) winds, cross behind and cross-ahead. No faster; still riveted at 72 on GPS, but RPM was at 9000 before, touching 8500 only now at that speed.

ISOMax72.jpg
Speedometer said 81 MPH. Italian Propaganda

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