Malosi reed block tuning

kim jensen /

I read that some of you have tried different reed thicknesses on your Malossi reed block. Curious to what you have found.

I have one on my Puch Polini kit and while the low & midrange acceleration is excellent, the top end suffers compared to other carbs and setups I have used.

Taller gearing only makes it worse ( weird I know with all that extra power).

Question: would a thinner (or thicker) reed on one side allow the engine to rev up more and improve top end?

Setup E50 polini, 21mmPHBG, techno estoril pipe. Stock points stator with gap at 13-14 thousandths and 1.3 - 1.5 mm BTC timing settings tried.

17 - 45 gearing seems to max out at 9000 rpm & 44mph.

This kit and pipe have revved out to 10,500 & 50mph before with a 15 bing carb and polini flat reed.

let me know what you have tried!

Re: Malosi reed block tuning

I haven't messed with different reed material, but I have a roughly similar setup that goes a fair bit faster:

E50 polini, VM20, malossi four petal reed block, techno estoril sidebleed pipe. I'm using a CDI with no curve (powerdynamo) at 1.5mm BTDC. 18x42 gearing. On a flat road I max out at about 52 mph (about 9500 rpm); I've taken it up to 54.1 (just shy of 10k rpm) on a slight downward slope. I have a gps speedometer.

I'm currently running this setup a hair rich, so there's a little more room for performance if I was feeling froggy. (edited)

Re: Malosi reed block tuning

Probably Fred /

44 mph you’re doing something wrong with point gap, timing and jetting maybe off.

With 19-21mm phbg, 4 petal, estoril pipes I get 55-60mph and about the same speed with 15mm bing, do also but I use polini cage with rubberized true 4 petal reeds (they seem to work better then malossi block) and two reeds not the single flat one for the bing

13 thou is too small the point gap for good kilovolts (you want 16-18 thou) and 1.3-1.5 mm is like 19° before top dead center so with points ignition that is too high of timing for a polini kit

Static timing with millimeters/micrometer is not the best way to get perfectly accurate with points ignition for a kit, it’s is best to use timing light at speed so you could actually see when the points are opening at rpm instead of guessing.

You should be at the lower end of the e50 scale (.08-14°) for a Polini kit and pretty much the same for Za50 even though it’s shows higher that’s for stock cylinder

EA417B6F-D3E1-4581-9B9A-9AF06DDC0B0A.jpeg

If you feel like you’re hitting a wall rpm wise you could be too high of jetting but that high jetting is probably saving you from seizing if you’re running that high 1.3-15mm-19° of timing

You need to invest in a head temperature gauge to see how hot or cold you’re running, If your running very cool it could be that your timing is low (from the small point gap maybe) not high and or you’re super rich and if you’re running 400° you’re overheating

Re: Malosi reed block tuning

Sometimes the malossi reeds can hit the casting inside the intake port. I use a spacer with the Athena reeds to let them clear and open all the way. The polini reeds barely open, I think on purpose to clear the casting.

I think Ken is right. Too much timing and too rich, at least for now. Bringing the timing down to 1.0 will make it easier to feel out your jetting. Once your jetting is right you can start creeping back up to 18-20 degrees if it doesn't get hot.

Re: Malosi reed block tuning

kim jensen /
kbj OP

Great info guys. Seems like I need new points - again, as the stator is all the way retarded and I have dremmeled the holes.

I have used a timing light to verify the 1.3 mm BTC setting.

I am currently using a Polini flat reed intake and its running too hot.

Want to put the Malossi back on. It ran cooler before with that, but had the 44mph problem I talked about.

I'll get the Malossi set up, check reed clearance, get new points and the timing down where it should be.

May try some thinner reed material on one side for the heck of it.

Re: Malosi reed block tuning

Kim... I've known you for like what 10 years and everyone tells you the same thing every time. You need to change once thing at a time. You have problems that aren't being caused by the reeds, every time you switch stuff around you introduce air leaks and new variables, here you are going in like 5 directions again with no plan.

Seriously at this point you would be way better off with a treats Reed and VM 20, that will run all day at 50+ mph, they are super forgiving to tune.

Re: Malosi reed block tuning

kim jensen /
kbj OP

Hey Graham, I hear you and have learned to do things one step at a time, even though my description here may not indicate that.

I religiously leak down test every engine due to my infamous history of weird air leaks. The latest being this Polini cylinder with a pinhole leak in the cylinder skirt - that Treats & Polini replaced. (The reed block screw hole was drilled too deep)

So more backstory:

With this new cylinder I wanted to try the Polini flat reed intake and made a custom intake so I could mount the PHBG without cutting any cylinder fins.

Works well, but got too hot on hard acceleration. Changed idle jets, tested, changed main jets, tested, changed needle , tested, changed timing, tested, etc. Including different timing and needle settings for each jet.

Runs well, but always too hot.

Worn cam and timing out of specs is likely the main issue here.

Moving forward, I have bought the Polini head which will help cool things down no matter what but will need to cut the fins and put the Malossi block back on as the new head wont work with the current intake.

(The malossi block did not have overheating issues)

So it will be a whole new round of step by step tuning once I get the new points and timing in spec. Cam must be worn as stator holes are widened and still can't retard timing fully. Also why I narrowed the points gap in an effort to retard it.

I do use a timing light to verify timing as well.

So once I get the new setup dialed in I will see where temps and top end are at.

The reed thickness performance question, as you pointed out, is now well down the tuning list. Just curious if anyone has tried different thickness reeds and what results they had.

But yeah, I obviously have a lot of steps to do before I mess with that.

As a PS> what cam lobe grease do people recommend these days?

Re: Malosi reed block tuning

Yeah sorry didn't mean to sound harsh, just thinking it doesn't make sense worn points lobe would do that, maybe if the points are really old and shitty. The more closed the points get the more they retard so it seems like maybe you are going the wrong direction? Another good reason to invest in a timing light.

I probably replace points more than necessary but $25 points is cheaper than my time spent too diagnose some weird issue. My rule of thumb is always to change jetting first and look for a temp change, then if that doesn't seem to make a difference, reduce the timing. I would definitely leave the intake alone for now. I forgot what jet is in my phbg polini right now but it's a clone 19 so probably doesn't help you. I feel like anything over 92 is pretty big for a basic 2 petal but I dunno.

I use 'superlube' Teflon grease.

Re: Malosi reed block tuning

kim jensen /
kbj OP

No worries Graham.

Yeah tru dat on worn points retarding.

Going to have to recheck that stator. Going to upgrade the lighting coil anyways.

I do use a timing light to verify what the setting is. Maybe I'll try a timing wheel as well.

Jetting has cooled down cruising temps, but any hard acceleration jumps temps too high. I ran an 84 main with the Malossi block for several years. Now going to try 86 again with the flat reed, but I think it will four stroke.

Anyways going to port the intakes, cut the fins, put on the Malossi and new Polini head and start over. Mopeds.

Thanks for the cam lube tip!

Re: Malosi reed block tuning

> Graham Motzing wrote:

> -------------------------------------------------------

>

> I probably replace points more than necessary but $25 points is cheaper

> than my time spent too diagnose some weird issue.

This is why I run CDIs on nearly every one of my bikes. :P

Re: Malosi reed block tuning

> Brian F wrote:

> -------------------------------------------------------

> I haven't messed with different reed material, but I have a roughly

> similar setup that goes a fair bit faster:

>

> E50 polini, VM20, malossi four petal reed block, techno estoril

> sidebleed pipe. I'm using a CDI with no curve (powerdynamo) at 1.5mm

> BTDC. 18x42 gearing. On a flat road I max out at about 52 mph (about

> 9500 rpm); I've taken it up to 54.1 (just shy of 10k rpm) on a slight

> downward slope. I have a gps speedometer.

>

> I'm currently running this setup a hair rich, so there's a little more

> room for performance if I was feeling froggy.

I was wrong, this bike is currently timed at 1.2mm BTDC

Re: Malosi reed block tuning

kim jensen /
kbj OP

Thanks for the info. Yep sounds similar to my experiences.

Have had mine up to 10k and 50mph before with different setups.

Just haven t been able to duplicate with the Malossi.

Just put the new cylinder on with the Malossi and a large matching Polini head.

Had to make a spacer to raise the block up higher to clear the new head, but it works!!

Also got the stock points timing down to 1.1BTDC.

So I'll see what it revs to once its tuned.

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