Yet Another M900 Build - Page 44

PPuxley · 26-09-2021, 12:22 PM

Brads method for checking float levels.

Hook up to the overflow vents and open the drain screws. Ensure no trapped bubble at bend and run the tube close to the protrusions on the float bowls for comparison. I think he proposes doing it on the bike , but its a lot easier off the bike.
Its critical to level the carbs in the transverse direction and to tip them as close as possible to how they would be on the bike.
He says he’s never known them to be out.

VIDEO HERE

PPuxley · 26-09-2021, 03:58 PM

Well, its running but, I dont think whatever I did in the carbs has cured it.

It feels "flat" to me and I dont remember from when I ran the bike before the rebuild, 1st being so tall when you pull away.

Its running much hotter on the horizontal than the vertical.
The horizontal plug looks weak.
The vertical plug looks wet.
But I get no sign of oil type smoke at any engine state. In fact I get no smoke of any kind at any time
Its not using oil.

All Ive got left that I can think of is checking the timing when that strobe comes. Then Im out of ideas.

350TSS · 27-09-2021, 02:30 AM

It is not unusual for the pilot jet settings to need to be quite different between the front and rear cylinders by as much as up to 2 turns.
Having said that the pilot settings should not be impacting running much above 1/8 to 3/8 throttle opening. So unless the issue is confined to that range I would look elsewhere.
Do you have any vacuum gauges? I can lend you some if that helps.
As I have said before if the strobe you have is not functioning properly on the vertical cylinder I would suspect an electrical issue, crank sensor, Kukosan igniter unit or coil.

PPuxley · 27-09-2021, 05:12 AM

Thanks. Yes I have vacuum guages. I've swopped the cdi units and the problem stays with the vertical.
I'm waiting for another strobe to arrive so I can confirm the timing.
And the problem appears outside the pilot range.

PPuxley · 27-09-2021, 03:52 PM

Quote:

Originally Posted by 350TSS

As I have said before if the strobe you have is not functioning properly on the vertical cylinder I would suspect an electrical issue, crank sensor, Kukosan igniter unit or coil.

This morning I did a resistance test on all the coils

Coil Primary 5 Ohms both, (spec 3.8-5.2)
Secondaries both a bit high at 18Kohm, but both the same ( spec 10.8 - 16.2)
Pick ups both 101ohms (spec 95-105)
Caps both 5 kohms (spec 5kohms)
Leads without caps 0.5ohms, although I acknowledge that under load all sorts of things can happen

I then swopped the coils with their HT leads.

Just test ridden and the fault with the wet plug remains on the vertical.

Need the strobe now, but fast running out of ideas.

350TSS · 27-09-2021, 08:55 PM

Given that i cannot find a spark on my M900 I am probably the worst person to offer advice. My mate said I had the "best ever off road bike" but I was not sure what he meant?????

PPuxley · 08-10-2021, 02:57 PM

Ive been away a bit sorting out a misfiring rear cylinder, which some of you may have been following on another thread .

I think that problem is cured, but the bike now needs to be ridden to shake it down properly and that will depend on what the weathers doing. Hopefully theres still enough of the decent late autumn stuff to put some meaningful miles on before winter.

But tomorrow the Jota is getting a leg stretch around Berks, Oxon and Bucks, with a couple of Brough Superiors (yes genuine 1930s ones!) and a couple of other Laverdas. A Monster or two would be most welcome to join this strange mix- pm me if youre interested.

LITTLE AND LARGE

Darren69 · 08-10-2021, 03:56 PM

Look how low the seat is on the Monster compared to the Lav?

They're very tall , heavy old bikes but very roomy.

PPuxley · 08-10-2021, 04:33 PM

Quote:

Originally Posted by Darren69

Look how low the seat is on the Monster compared to the Lav?

They're very tall , heavy old bikes but very roomy.

Amazingly I find both pretty comfortable, my knees seem to fit fine on the Monster. The Jota is a heavy beast, but over walking pace it all goes away.

enbee23 · 08-10-2021, 04:46 PM

[/QUOTE]

What a beautiful pair!

PPuxley · 10-10-2021, 10:38 AM

Thought I might try a bit of gas analysis in due course.....not till I can remove the bungs , though!
No amount of heat cycling would do it. Am I going to have to resort to welding a bar to it?

350TSS · 10-10-2021, 04:19 PM

50/50 Acetone and diesel sprayed on it daily for a week before you resort to the MIG would be my suggestion. Also once welded in there are three potential issues:
1. the projection welded in loses its temper with the heat and when torque is applied, twists until it shears flush,
2. your welding of the projection is better than the boss to the pipe welding and it cracks/shears there, and
3. the pipe around the boss, internally corroded is less strong than the torque applied to the projection and the pipe lozenges.
I am either a realist or a glass half empty sort of person when it comes to corroded fasteners.
Good luck whatever you decide.

350TSS · 10-10-2021, 04:31 PM

A glass half full person would assume that the localised heat from the weld will be enough to break the corrosion bond, but if it didn't, a touch with an angle grinder on the perimeter of the plug and a sharp blow on a punch located in the perimeter notch would do the trick. Obviously a new plug will be required as soon as the MIG is utilised.

Mr Gazza · 10-10-2021, 05:25 PM

I've never attempted to remove my bungs, but if I did I think I would put a little grinding paste in the socket head as a precaution against rounding it out with the bit and then try a rattle gun on it.
I always find very short bursts work better with those and that might give you an advance warning of the weld breaking, but by the time you spot it it's broken anyway, but hopefully not ripped right out and weldable?

Good luck

PPuxley · 10-10-2021, 06:04 PM

Thanks for all the tips. Im not going to rush into it for now.

26-09-2021, 12:22 PM	#646
PPuxley Registered User Join Date: Apr 2021 Location: Reading Bike: M900 Posts: 600	Brads method for checking float levels. Hook up to the overflow vents and open the drain screws. Ensure no trapped bubble at bend and run the tube close to the protrusions on the float bowls for comparison. I think he proposes doing it on the bike , but its a lot easier off the bike. Its critical to level the carbs in the transverse direction and to tip them as close as possible to how they would be on the bike. He says he’s never known them to be out. VIDEO HERE __________________ Golf-My favourite game. While my wife plays I'm in the workshop. Last edited by PPuxley; 26-09-2021 at 03:51 PM..

26-09-2021, 03:58 PM	#647
PPuxley Registered User Join Date: Apr 2021 Location: Reading Bike: M900 Posts: 600	Well, its running but, I dont think whatever I did in the carbs has cured it. It feels "flat" to me and I dont remember from when I ran the bike before the rebuild, 1st being so tall when you pull away. Its running much hotter on the horizontal than the vertical. The horizontal plug looks weak. The vertical plug looks wet. But I get no sign of oil type smoke at any engine state. In fact I get no smoke of any kind at any time Its not using oil. All Ive got left that I can think of is checking the timing when that strobe comes. Then Im out of ideas. __________________ Golf-My favourite game. While my wife plays I'm in the workshop.

27-09-2021, 05:12 AM	#649
PPuxley Registered User Join Date: Apr 2021 Location: Reading Bike: M900 Posts: 600	Thanks. Yes I have vacuum guages. I've swopped the cdi units and the problem stays with the vertical. I'm waiting for another strobe to arrive so I can confirm the timing. And the problem appears outside the pilot range. __________________ Golf-My favourite game. While my wife plays I'm in the workshop.

08-10-2021, 02:57 PM	#652
PPuxley Registered User Join Date: Apr 2021 Location: Reading Bike: M900 Posts: 600	Ive been away a bit sorting out a misfiring rear cylinder, which some of you may have been following on another thread . I think that problem is cured, but the bike now needs to be ridden to shake it down properly and that will depend on what the weathers doing. Hopefully theres still enough of the decent late autumn stuff to put some meaningful miles on before winter. But tomorrow the Jota is getting a leg stretch around Berks, Oxon and Bucks, with a couple of Brough Superiors (yes genuine 1930s ones!) and a couple of other Laverdas. A Monster or two would be most welcome to join this strange mix- pm me if youre interested. LITTLE AND LARGE __________________ Golf-My favourite game. While my wife plays I'm in the workshop.

08-10-2021, 03:56 PM	#653
Darren69 Transmaniacon MOC Join Date: Sep 2013 Location: Sutton In Ashfield Bike: Multiple Monsters Posts: 6,029	Look how low the seat is on the Monster compared to the Lav? They're very tall , heavy old bikes but very roomy. __________________ Roast Beef Monster! Termignoni and Bucci - Italian for pipe and slippers! S4 Fogarty, S4R 07T, 748, Series 1 Mirage

27-09-2021, 02:30 AM	#648
350TSS Too much time on my hands member Join Date: Jan 2013 Location: Shipbourne Bike: M900 Posts: 1,421	It is not unusual for the pilot jet settings to need to be quite different between the front and rear cylinders by as much as up to 2 turns. Having said that the pilot settings should not be impacting running much above 1/8 to 3/8 throttle opening. So unless the issue is confined to that range I would look elsewhere. Do you have any vacuum gauges? I can lend you some if that helps. As I have said before if the strobe you have is not functioning properly on the vertical cylinder I would suspect an electrical issue, crank sensor, Kukosan igniter unit or coil.

27-09-2021, 08:55 PM	#651
350TSS Too much time on my hands member Join Date: Jan 2013 Location: Shipbourne Bike: M900 Posts: 1,421	Given that i cannot find a spark on my M900 I am probably the worst person to offer advice. My mate said I had the "best ever off road bike" but I was not sure what he meant?????

08-10-2021, 04:46 PM	#655
enbee23 Registered User Join Date: Sep 2020 Location: Nairn Bike: S4r Posts: 99	[/QUOTE] What a beautiful pair!

10-10-2021, 10:38 AM	#656
PPuxley Registered User Join Date: Apr 2021 Location: Reading Bike: M900 Posts: 600	Thought I might try a bit of gas analysis in due course.....not till I can remove the bungs , though! No amount of heat cycling would do it. Am I going to have to resort to welding a bar to it? __________________ Golf-My favourite game. While my wife plays I'm in the workshop.

10-10-2021, 04:19 PM	#657
350TSS Too much time on my hands member Join Date: Jan 2013 Location: Shipbourne Bike: M900 Posts: 1,421	50/50 Acetone and diesel sprayed on it daily for a week before you resort to the MIG would be my suggestion. Also once welded in there are three potential issues: 1. the projection welded in loses its temper with the heat and when torque is applied, twists until it shears flush, 2. your welding of the projection is better than the boss to the pipe welding and it cracks/shears there, and 3. the pipe around the boss, internally corroded is less strong than the torque applied to the projection and the pipe lozenges. I am either a realist or a glass half empty sort of person when it comes to corroded fasteners. Good luck whatever you decide.

10-10-2021, 04:31 PM	#658
350TSS Too much time on my hands member Join Date: Jan 2013 Location: Shipbourne Bike: M900 Posts: 1,421	A glass half full person would assume that the localised heat from the weld will be enough to break the corrosion bond, but if it didn't, a touch with an angle grinder on the perimeter of the plug and a sharp blow on a punch located in the perimeter notch would do the trick. Obviously a new plug will be required as soon as the MIG is utilised.

10-10-2021, 05:25 PM	#659
Mr Gazza Lord of the Rings Join Date: May 2013 Location: Norwich Bike: M900sie Posts: 5,848	I've never attempted to remove my bungs, but if I did I think I would put a little grinding paste in the socket head as a precaution against rounding it out with the bit and then try a rattle gun on it. I always find very short bursts work better with those and that might give you an advance warning of the weld breaking, but by the time you spot it it's broken anyway, but hopefully not ripped right out and weldable? Good luck __________________

10-10-2021, 06:04 PM	#660
PPuxley Registered User Join Date: Apr 2021 Location: Reading Bike: M900 Posts: 600	Thanks for all the tips. Im not going to rush into it for now. __________________ Golf-My favourite game. While my wife plays I'm in the workshop.