What Have You Being Doing With Your Non-triumph Today?

It's my last rest day before I go back to work tomorrow, so we took advantage of the sun and went to the Baffle Haus on the Mutistrada and Hyperstrada.....quite a few other people had had the same idea and we even got into the festive spirit by wearing Christmas jumpers .

 

The gearboxes are pretty straightforward to play with. I changed a gearbox mainshaft on a C90 (uk) which is a similar engine when I was 14 after busting 1st gear

 

It seems very simple compared to the jets I used to fix decades ago in the Air Force. Only capability I don’t have here at home is a machine shop.

 

Engine rebuilt on theYamaha after a hole in the piston.

 

Good old simple air cooled two strokes, a nice genuine looking example

 

So Christmas day dawned and with the MiL in a home we did a flying visit via Seaways for breakfast.



It's in the none Triumph bit as we went by car and was there early, 08.30 with only x2 bikes in the carpark, but more upon our leaving.





Anyone else on here go?

A nice idea that the cafe opened up for half a day and gave people the option.

 

What was the cause of the hole in the piston, lean mixture?

Without resolving that then you are just going around in circles. I once had a Honda H100 as a skint 17 year old apprentice and I couldn't afford a new head gasket....... yep, a hole in the piston was the end result

 

yes, running lean. I’ve went up a good bit higher on the main jet size to begin with and will come down one size at a time to try and get it right - well that’s the plan. What do you think

 

A plug chop will quicken the process.

Heat cycle the motor to run in the new piston.

Get the bike up to full operating temperature.
Make sure the pilot circuit is somewhere near by judging the air screw number of turns, 1.5 to 2.5 out covers most bikes. More or less than these and it probably needs the next size pilot jet.
If the screw is on the air filter side of the slide then it's an AIR SCREW.
If the screw is on the barrel side of the carb then it's a PETROL SCREW.

Note which one is yours, likely an air screw.
Go for the highest tickover with the air/petrol screw then a quarter turn richer.

Now go for a ride on a long straight bit of backroad.
Run it flat out for a mile or so ( if you think the mixture is somewhere near, USE CAUTION!) and then cut the ignition with the clutch in.
DONT COAST TO A HALT IN GEAR WITH THE CLUTCH OUT.
Remove the plug and post a pic of the colour at the tip, plug gap end.

"Rich Tea" biscuit colour is good.

Hope that helps?

 

That’s great advice, thanks for that. It is an air screw it’s at 1 1/4 turns but I’ll set it as you describe. I’ve only run the engine for an hour and have been taking it easy, this is what the plug looks like with this initial running. I’ll do a plug check flat out next time I am out. What do you think of how it looks while running in?

 

Posted this on my new bike thread, but I'll put it here as well...

Put a replacement exhaust bracket on - also Unit Garage - in addition to the new end can and link pipe as it matches the frame. All done, though, and I'd describe the whole job as very fiddly rather than difficult.

Look and sounds amazing.





Happy Boxing Day, everyone

 

That looks something like colour wise, but it doesn't indicate main jetting unless run flat out then ignition chopped.
1 1/4 turns out sounds ok but try adjusting for the highest tickover once warmed up. Doing it in 1/8 turn increments and allowing time to judge the effect, should show a sweet spot. You want to aim to be just slightly on the rich side of that sweet spot.

 

Come on, let's see the faces!

 

I have shown my face on here once I think....but we're very shy .

 

I am still a bit scared to hold it flat out so gave it a quick rev through the gears for a bit then cut the engine flat out in fourth. I’m thinking still a bit lean?
what do you think

 

Yes looks slightly lean so I might be tempted to go up x2 sizes on the main jet and then note the result.

Another option is to give it choke when warm and flat out, you'll soon know (safely) if you are pushing the too rich boundary.
The above was an old trick for trials bikes used on fast road sections, don't forget petrol also acts as a coolant on the piston crown.

 

Excellent thanks very much for that, much appreciate you giving your knowledge and help. I’ve ordered more jets from wemoto they are usually quick. I’ll post a plug chop pic when they arrive.

 

For the youngest sons Kawasaki kmx 125, we bought a Chinese set of pilots and mains. I think they only worked out about £10 a box of x10 sizes, so £20 in total.

 

Helmut and I took the Ducatis out to meet some friends at HR4K today, it was chilly enough to be a multi - layered trousers day. A very short ride, but nice to go and have a coffee and a chat .

 

Excellent, Marco! Can't wait to see it (and maybe even ride it ) in person.