SH300i transmission problem

[TommyXP]

From what I can recall......Hypoid gears 'meshing', tears the synthetic molecules apart. Synthetic OK for bearings rolling around and up-down motion, but meshing gears bend and break them into jagged little pieces.

Robert57 did a nice explanation on it with photo's (I think) and I haven't found it yet, as I have been busy discovering that the oldest writing known to Man was found and recently deciphered IN............ Bulgaria!

Thracian - ~5,000BCE - First and earliest known writing of 'Man'.....The tablet said:
"O Three-One God of the land of Thrace,
I vow in Truth to bring You all due offerings,
O great Son of God,
and only you shall I praise and exalt,
O my God for you are great!
You who are now in your temple, I pray, hear me,
keep me safe and deliver me from all evil!"

Seems Egyptian hieroglyphs came from you guys.
Small World, and the guy probably chiseled it out begging to get some extra help fixing his scooter!
BTW.....your link is non-functional.

[boiski]

...the guy probably chiseled it out begging to get some extra help fixing his scooter!...

Definitely.

Now the link should be ok:
https://drive.google.com/file/d/0B-kBF1 ... sp=sharing

The belt had been too loose, but under what conditions I don't know. I will measure the belt length and count the teeth.

edit: I found that topic:
viewtopic.php?f=12&t=1133

Synthetic gear oil usually contains a lot of additives to stabilize the viscosity index, these additives are solvent like and may eat the seals , cause them to swell or dissolve the plasticizer in the elastomer after which the elastomer of the seal becomes brittle ,forms cracks and start to leak.
Its like soaking the seal in paint thinner.

[TommyXP]

That 300 service manual you found on-line sure is handy and shows the same 'type' of belt with the nubs on top too......
Not much room in there and the nubs probably double belt height.
Could the burnishing of the case have happened in the distance past caused by an old worn belt or caused by excessive drive-face pulley wear as you showed in your photos?
Ultimately, it would be something I could live with IF everything else worked out well.

[boiski]

Yes, 300's belt has teeth/nubs on both sides.

I found probably the cheapest brand new genuine belt on internet:
https://bikerzbits.com/honda-forza-nss- ... 4-931.html
It's for Forza, but should be the same and costs about 50 Euro total with standard delivery (10-30 days) from Thailand or 60 Euro with DHL Expess delivery (3 days).

The problem with brake light was the bulb. I have 12V on the connector when press each lever.

I changed final drive oil with engine oil (10w30 mb). The old oil was dirty, mixed with metal dust. Definitely needed oil change.

I tried to pull out the spark-plug, but my special spark-plug socket 16 was too fat and couldn't fit the nut. There isn't much space around the spark-plug head. I will look to buy suitable socket until my new spark-plug arrive.

That's all for this week. Tomorrow I'm going on a little vacation in Greece and White Sea. Will continue the work when I get back next week. Have a nice weekend.

[robber57]

New list of your problems and/or experiances:

Grinding sound:clutch

Bike tries to run away without any throttle:clutch

Deceleration stronger then expected:torque driver is erratic-worn-dry(hardened lube?)

Abrasion wear in beltcase:torque driver does not keep belt tension constant because it moves erratic, when decelerating the front vario opens up so the belt becomes loose , the rear vario has to follow and keep the belt tension constant but because it moves erratic at some points the belt goes slack and drags on the inside of the case, sometimes under heavy acceleration you may actually hear the belt slapping on the inside.

This to me sounds like a +50.000 km scooter and possibly even +75.000 km....
Or just bad maintenance.

Gear oil: when synth oil gets hot it has a tendency to dissolve the plasticizer in the rubber of seals , plasticizer is what keeps the rubber soft, the gearbox can become quite hot on highway so you may get small hair cracks in the seals which then start leaking, its not worth the risk.
Synth gear oil doesnt lubricate "better" , it has a longer lifespan which is pointless in a sh as we are talking about cents and dimes , just use mineral 75w90 80w90 gl4/5 and replace it parralel with the engine oil, as the gears wear quite a lot you will see tiny silver flakes or a grayish color, that is why you want to change often so the gearbox stays clean on the inside, once settled down on the bottom as sludge it will stay there fouling up the fresh expensive synth oil you change not enough.
Use mineral and change often is a better way and costs about the same, filling goes very easy with a medical syringe with a piece of aquarium hose.

Tires: the citygrips are nice but look for metzeler feel free wintec if you want better handling in rain and winter, a bit more expensive but worth it imo.
The rear is also available as radial which is even more stable.

Sparkplug wrench: if you have the original like this:

image.jpeg

Cut the hex end of and leave just enough for a 10 mm wrench and you can remove sparkplug without having to remove the sidepanel.

There is no iridium plug for sh300, my experiance with sh150 is that it is pointless as the plug becomes covered with ash and starts starting bad, i had to replace for 4x the plug at 10.000 km which makes it pointless so i stopped buying them.

The belt case should contain a ball bearing to support the driven vario shaft, i dont see your bearing?
The varioshaft should have a metal bush with a very thin o-ring, if this oring is worn the bearing starts rotating on the shaft,becomes hot, starts locking up, starts rotating in the belt case---> bye bye beltcase.

I think if you replace front+rear vario for new original honda with 15 gram rollers (19,5 original) and yellow malossi springs and give a full and complete service/overhaul you will have a nice bike, dont forget to check wheel bearings, steering head bearing, fusebox, empty and dry fuel tank, bearing in right wheel-arm,front fork oil (hydraulic oil sae10) etc etc, ALL connectors in silicone spray,

Dont try to tune it further unless you are willing to buy the malossi camshaft, 15 grams+3 yellow springs in the clutch is what will improve the bike, the rest is a waste of money.

You cannot check an original belt with a caliper on thickness as it will show no wear untill 100 km's before it breaks, you will have to replace according km's , if you dont know km's replace as precaution, it will break at +130% lifespan and possibly break your crankshaft.

[boiski]

robber57

Your post is very usefull. There is a lot of logic in your words.

Thank you for explanation about gear oils. For now i will use engine oil and on next engine oil change will change gear oil with mineral 75w90 or 80w90.

I don't plan to tune this bike. I like everything to be stock and want acceptable performance with good fuel consumption. I prefer smooth start at low rpms and as low as possible rpms at cruise speed (80-100-120kmph).

I like the tires you've recommended and requested them to the local dealer. They are not much more expensive than City Grip's. 49 Euro for front and about 85 for radial rear. More grip on wet is always welcome. If I'm lucky I will try the radial rear tire.

I don't have this special wrench for the spark-plug but will find/make something suitable.

There is bearing in the belt case, probably is too dirty on the photos and you haven't seen it. It rotates smoothly, but I will check it's condition again. On the driven varioshaft behind the bell nut there is a metal bush with 2 small rubber o-rings.

I will order new genuine belt and keep the old one as spare for long trips.

New genuine torque driver with clutch and bell is ordered from Italy. I only have to find another variator - new or used in better condition. But anyway I'm planning to disassemble the old torque driver to check what is the situation inside and what has caused the 'abrasion wear in beltcase'.

I almost forgot - have to check the intake/exhaust valves clearance.

When remove the wheels for tire change I will inspect all bearings. I don't have experience with fork maintanance, but if notify any problem will follow the steps in service manual and ask questions here.

I didn't understand about the fuel tank. You advice me to check if there are any dirt deposits inside or?

BTW Why belt breaking can break the crankshaft? And what do you think about new belt width. Why service manual says 25.7mm service limit and new Bando belt is only 25.2mm wide?

[robber57]

You never know what the previous owner has been fueling and how it was maintanined, you know km's on odo meter are not right but you dont know how much, there is the possibillity that it has been in storage for a while, storage with a almost empty tank leads to condensation in the tank so there may be water deposit at the botttom rusting your tank on the inside.
So open up the fuel tank with the fuelpump/meter assembly and inspect the inside of the tank and if you see any water,rust,particles,hamburgers or whatever floating around at the bottom take out the old fuel and use it for cleaning or such and put in fresh fuel.
If there is already rust you will have to take out the tank, remove all technical parts from it , fill it with water+pebbles+sand+some soap and shake the tank untill it is clean
From the last time i was in romania and hongary ik also know that you can have some pretty bad fuel in the east with lots of water and dirt in it, especially in the country side.
Maybe it is now better, i dont know, last time i was in romania was in 2000 , anyway rather safe then sorry, a fuelpump costs over 500 euro....

Btw: the fuel filter on the end of the pump (like a big bag of cloth) is , for as far i know, not replacable so be carefull with it and dont try to wash/blow it as you will ruin it.

If you buy the metzelers make sure you get the "Wintec" version as this is the winter-tire with the extra cold weather/rain-grip, the normal version is the summer tire which behaves more or less like the michelin citygrip.

I am telling you all this because of the state of the driven variator, this tells me that this scooter has seen very little or no maintenance at all and as the sh300 can go like roadrunner you may kill yourself on it if you dont check everything to the last nut and bolt, there is very little room for error on motorcycles and 1 bolt falling out can kill you so make sure.
That means removing all the plastic and check every little detail.
Maybe the bike is fine and the zclutch was just a sudden failure but you have to be sure.

[edit]
The belt is made of 1 (sometimes 2 or 3) long continuous strings of fiber-yarn cast in rubber, these fibers are very strong and maybe 100 of meters long, if it is a malossi belt they are kevlar fibers, these are even stronger then steel, if 1 fiber comes loose and wraps around the crankshaft and the rear shaft it will break the weakest, in my case it was the crankshaft of my derbi scooter, The whole front vario snapped of and luckily didnt wreck much else.
If the big-end would have snapped the whole engine would lay in parts on the street probably
I think it is a bit like a broken chain, usually nothing happens when a chain breaks but sometimes it can go really bad like getting your rearwheel to lock up at 120 kmh , failures on brakes or drivetrain on a modern bike can have severe consequences.
So the potential damage can be that expensive that you cannot take the risk for a 65 euro belt, buy the original, dont buy malossi or any other brand including Bando, the original may be a bando belt but not every bando belt is like the original honda.

[boiski]

Today I received and installed the new torque driver. I have also new belt Honda-Bando, but will not use it until new front variator is installed. Now the start and acceleration are smooth, but there is noise from the belt in beltcase between 30 and 40 km/h. I think this is the same noise which causes the wear in belt case. I don't know, probably the front variator is too worn. The guy who sold me the rear variator set is now selling front variator for 73GBP, but the drive pulley face is missing. So I requested him to check about that part.

[boiski]

The new tires are available:

IMG_20160627_181314.jpg

Feelfree Wintec with radial rear. DOT 3015. Front is made in Brazil and rear in China. Strange combination. Today will install them.

I checked the bearings. Front tire and handlebar bearings are ok, but on rear side are not so good. The swingarm bearing has to be replaced...and there is noise from the final drive over 60km/h. Probably bearing noise, because there is chattering/clanking when rotate the shaft slowly by hand. I will open the final drive today and see what is the situation inside. Regarding that noise I purchased some tools for my future 'bearing' adventure:
http://www.ebay.co.uk/itm/371509724802? ... EBIDX%3AIT
http://www.ebay.co.uk/itm/290980958250? ... EBIDX%3AIT

BTW I thought the spark-plug nut is 16, but it's actually 14. I solved the problem with simple combined 14/15 tubular spanner + tommy bar for less then 1 euro. Just cut 3-4cm from the 15 side and now is perfect. The spark-plug has gap over 0.90mm (service limit 0.80-0.90mm).

IMG_20160626_141256.jpg

IMG_20160626_163406.jpg

[boiski]

Final drive is dissasembled. The gears inside look fine, no traces of serious wear. The driveshaft and countershaft bearings have to be replaced. Final gear shaft bearings are ok.

Variator:
I have to choose between new genuine front variator or new Polini 241.650. The prices are almost equal. What do you think? Which one is more reliable and better for fuel economy?