small newbie service project

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rednikmarto
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small newbie service project

Post by rednikmarto » Sat Jun 04, 2016 7:14 pm

Hello all,

At the beginning of March this year, I bought a tired horse, Yamaha TDM850 (year 2000) (as some write about it here, "tedium").
The bike was obviously not maintained/serviced well. New import from France.
It had signs of drop/crash on the right side.
When I saw it, I realized its a bad deal. The only reason to buy it is I love TDM850 too much. Had bike like this years ago.

Will come to the point where I ask you for your advices, at the bottom of my story.
Please excuse me for low resolution of the photos, will use high-res. if needed further.
I am electrical engineer, and by working on this bike I am outside my zone of comfort/knowledge. So please forgive me if I do write some nonsense.

First thing I noticed was some brake parts were not original - pad retaining pins/clips, and missed the pad springs (all 3 of them).
Bought a second had braking system for about 50 Euro - just to take these minor parts.

Image

The next encounter was the main switch. It was not the original one, so I had 2 keys. Took the main switch to a local key service technician, and had it readjusted for the original key of the bike - here in Bulgaria this costs 15 Euro. The pins where main switch is screwed (crown, handle), were straighten for about 12.5 Euro.

Image

Improper cable routing had cut one of wires of the main switch, some others had isolation frayed. (Cooling fan's propeller had reach the wire harness).
Poor bas**rds had fixed the problem at the rear of the igniter unit connector, as the bike won't start with the wire's cut.

Image

The plate were main switch locks the handle to the frame was rusty, scratched and I did what I could to have it filed and painted myself.

Image

The non-OEM handlebar goes to trash bin. The bike is kept at a guarded parking. Just asked the security guy to throw it away.

Image

With an OEM handlebar, about 35 Euro total. Had an issues with broken pins at electrical swtiches/gas - they appear to essential, preventing rotation.

Image

One of the large water pipes, thermo-unit to radiator. Almost leaky, after intense friction somewhere.

Image

Hard to describe the amount of dirt/oil around airbox and carburetors. Photo is taken after 3-4 wash/brush cycles. Ordered new inlet rubbers (carburetor to inlet manifold).

Image

At this time carburetors went to specialized technician for service, oil and cooling liquids - off the bike.
Did compression test, 11 bar @ cyl.1 and 11.5 bar @ cyl.2.

Image

Removed the rocker cover, ordered new seal.

Image

Ordered some valve shims, as 4 of all 6 inlet valves had clearance of 0.10mm. The limits are as on TRX, 0.15-0.20mm.
All exhaust were inside the 0.25-0.30mm limits.
Unfortunately I saw inlet camshaft has some scratches (at plane bearings). Scratches become more intense, approaching to timing chain/sprockets. Could describe it as slightly detectable by passing a finger nail over them. The inlet camshaft lobes are nice and shiny, no scratches.
As yet do not have purchased micrometer, I could not properly measure the inlet camshaft wear. Also do not have plastigauge strips to get measurement of cam to caps clearance.
The markings of inlet cam and sprocket are gone by 1.50mm retarded. The markings of exhaust cam and sprocket are almost lined.
Probably the timing chain is stretched and will have to buy new one. Camshaft sprockets will cost me about 75 Euro / piece. But still in doubt if I need to change the entire cylinder head.

Awaiting your opinions, how to go further.
Last edited by rednikmarto on Sat May 21, 2022 3:40 pm, edited 1 time in total.

cobbadiggabuddyblooo
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Re: small newbie service project

Post by cobbadiggabuddyblooo » Sun Jun 05, 2016 5:14 pm

The ignition wiring you have 4 wires.
Power and earth being red and black and the other 2 smaller multi coloured wires connect to the ECU and run through the side stand, clutch lever cut out circuit.
It's a safe guard to stop anyone hot wiring your bike by just cutting the wires and joining the red/black.
You can run a 2 pole ignition using the red and black, And from memory you just keep the 2 striped wires isolated from each other, or was it joined??? If you don't have spark 1 way you should have it the other way with the 2 striped joint together..
If still no spark, then start to look at your side stand switch or the switch on your clutch lever as the next culprit.
laughter is the best medicine

rednikmarto
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Re: small newbie service project

Post by rednikmarto » Sun Jun 05, 2016 5:39 pm

Have posted same thread at the local TDM society in my country. Till now two guys replied, one asking me why I did the mistake of buying old bike, another called me by phone, told me he would borrow me his micrometer.

Thanks for your attention cobbadiggabuddyblooo,

Anyway the wiring was repaired. The cut-off was at the red cross.

Image

What would you or other experienced with TRX850 recommend me about the scratched inlet camshaft ?
Maybe first I should measure camshaft diameter / wear ?
Next - plastigauge at the caps/camshaft plane bearing ?

added, 21.June.2016 ->

.. Here the story continues.

Thanks to a colleague, i received 0-25mm micrometer, and measured the camshaft necks - they are all within the limits. Could not measure the camshaft lobes, as they fall into next micrometer range (above 25mm). After short cycle of retries, finally assembled the camshaft, lifters, timing chain and wheels. Thanks to cobbadiggabuddyblooo who wrote that camshaft is willing to roll, as valves put tension onto lobes. As i am not a professional, but a first-time valve clearance enthusiast, every useful tip was appreciated.
Anyway, all valve clearances i measured were fine, after i placed some new shims (1.85mm).

Here is a place, where some garbage of cooling system is located, the housing of thermostat:
Image

Here the carburetors are fitted, and have attached two transparent hoses for measuring the levels of float chambers:
It appeared that carburetor #2 has perfect level with its float tang straighten. Carburetor #1 had to be adjusted twice, to get the proper level. It had too high level with its float tang being straighten.

Image

Today filled the cooling system, and started the bike. It started at once, no leaks observed, so i was happy.
Here is a preparation for synchronizing the carburetors, the thing hanged on the right handlebar is Carbtune.
The hardest issue for synchronizing i faced, was finding proper screwdriver to access the synchronizing screw.

Image

to be continued...
Last edited by rednikmarto on Sat May 21, 2022 3:31 pm, edited 1 time in total.

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Overlord Neil
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Re: small newbie service project

Post by Overlord Neil » Fri Apr 21, 2017 9:01 pm

rednikmarto wrote:to be continued...
How goes it, any further progress?
C90, TS50, H100, H100, CB250, GS500, Tiger 955i, TRX850, Tuono, ZZR600, CBR954RR

rednikmarto
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Re: small newbie service project

Post by rednikmarto » Sat Jun 24, 2017 12:38 am

Overlord Neil wrote:
rednikmarto wrote:to be continued...
How goes it, any further progress?
Hi Overlord Neil,

Further i went into replacement of needle jets(emulsion tubes).
Reason: ovaling of needle jet orifice.
(comments:
That operation on my BDSR38 carburetor appeared quite rare to see.
So i Improvised.
As the size of jet orifice is 2.65mm (Mikuni size P0) - i went on tapping a thread in it, then pulling it out.
So i used all the three taps conic, intermediate, deep of M3x0.5 to get a thread inside needle jet.)

Did a visit to a colleague from university, and he made a set of simple tools for me, to help me remove/install the mysterious press-fit needle jets of my Mikuni BDSR38. Because my PVC covers of vacuum chambers were bent, i replaced them also. Also replaced the PVC vacuum slides ($$$). Here are photos:

1. BDSR38_NeedleJetRemoverKit
2. BDSR38_Emulsion_tubes (new & old)
3. Threaded M3x0.5 over M6x1.0 class 8.8 stud (using lower class stud leads to stud break)
4. BDSR38 plastic cover
5. BDSR38 Needle Jet - pulled out
6. BDSR38 Needle Jet - pulling it out
7. BDSR38 Needle Jet - tapping M3x0.5 in it
8. Needle Jet mandrel - view
9. BDSR38 Throttle Valve - Slide
10. BDSR38_Mandrel_for_NJ_must_be_made_of_aluminium

Where to buy new needle jets for BDSR38 (press-in).

-> option 1: Kedo ( www.kedo.com ) article number 29364; (its 1:1 with the OEM needle jet of Mikuni).
-> option 2: Dynojet kit DJNJ002 The kit has four identical NJ within, size P0; These are nickel plated.

after this all done, i still could not stand to say engine runs ok.
because i got popping into muffler/exhausts at both idle and in gear (deceleration).
popping occurs after revving and closing the throttle (below 2300 rpm).
the popping noise occurs 1-3 times while rpm were decreasing.

Why the hell? My "air cuf-off" valves are new, carb is shining.
The seals at throttle valve shaft are new (OEM), all o-rings are new (OEM).
The only parameter that is out of range is the vacuum at intake manifolds.
For TDM850 (4TX) vacuum should be between 27 and 29 cmHg, and i have about 25.5 cmHg (measured with Carbtune).
Is this possible source of my problem ?
....

did some test with various positions of clip of jet needle and tests with pilot screw turns out.
results were informative - making fuel/air mixture leaner increased popping, and richer - decreased popping (but still far from zero popping).
well, i did not have popping at all before engaging carburetor interventions..clip at 4th position, about 3 turns out for pilot screws. This ain't worked anymore.
...
so i purchased new pilot jets, size that is next larger than the stock is #20 (stock is #17.5).
Mikuni N224.103-xx is something that EBC (UK) do well.( Link ).
Installed the new #20 pilot jets.
Suddenly things got almost 100% OK.
Popping was almost completely gone. Yet a small degree richer mixture is needed. Since my pilot screws are 3 turns-out, will try next size #22.5 pilot jets.

to be continued with #22.5 pilot jets.
Last edited by rednikmarto on Sat May 21, 2022 2:50 pm, edited 1 time in total.

cobbadiggabuddyblooo
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Re: small newbie service project

Post by cobbadiggabuddyblooo » Sat Jun 24, 2017 7:25 am

Quite common to see scoring on inlet shaft / cylinder 1.
It gets starved for oil on initial start up and some have drilled and placed a bleed screw like you have on the exhaust camshaft / cylinder 1.
I always use assembley grease and syringe to prime all oil galleys when removing cams or changing oil.
I had heard the last model TDM had different carbies with press fit needle jet/ tube but they also mentioned they where a 40mm not 38????
Can you please clarify if they are 38 or 40mm please.
laughter is the best medicine

rednikmarto
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Re: small newbie service project

Post by rednikmarto » Sat Jun 24, 2017 9:33 pm

cobbadiggabuddyblooo wrote:Quite common to see scoring on inlet shaft / cylinder 1.
It gets starved for oil on initial start up and some have drilled and placed a bleed screw like you have on the exhaust camshaft / cylinder 1.
I always use assembley grease and syringe to prime all oil galleys when removing cams or changing oil.
I had heard the last model TDM had different carbies with press fit needle jet/ tube but they also mentioned they where a 40mm not 38????
Can you please clarify if they are 38 or 40mm please.
Hi cobbadiggabuddyblooo,

The last TDM with carburetor is TDM850 from 1999-2001. It has Mikuni BDSR38/2 with the press-fit needle jet. These are 38mm venturi. All photos i posted are from my carburetor, of this model.
Some Suzuki VL1500 have the very similar carburetor (BDSR36). I have used the excellent papers of Suziki about BDSR36 to get better idea about my own BSDR38.
( Link ).
Thanks for sharing valued practices. Cheers.
Last edited by rednikmarto on Sat May 21, 2022 3:00 pm, edited 2 times in total.

cobbadiggabuddyblooo
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Re: small newbie service project

Post by cobbadiggabuddyblooo » Sun Jun 25, 2017 1:39 pm

Excellent, thanks for clarifying that for me... =D> =D>
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rednikmarto
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Re: small newbie service project

Post by rednikmarto » Sun Jun 25, 2017 5:40 pm

Hi Cobba, do you or anybody knows, if here on the forum is a detailed text on how to remove/install camshafts ?

(i wish if there is something more clear than the text on official manuals, its especially the installation sequence that is my problem. Yamaha manual claims the M6 bolts of camshaft caps are not lubricated and tighten to 10Nm.. Is this the way you all do it ?)

Thanks.

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OzzieDave
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Re: small newbie service project

Post by OzzieDave » Mon Jun 26, 2017 10:19 am

Hi, download the Haynes workshop manual from this forum, it goes into more detail than the Yamaha manual.
I have just done the valve shims on my two engines using these as guides.
One thing I would recommend is using zip ties to tie the chain to the sprockets, you don't really need to take the cams out completely when doing the shims, it makes it much easier to keep everything alligned.
I also used an assembly grease, smothered the cams, cam followers and shims with the stuff. I only had to remove the inlet cams, as both exhaust cams were within spec.
The most difficult thing is removing the chain tensioner and putting it back, I ended up removing the engine support so that I could get spanners and allen keys in.
I purchased a 3/8 square drive tension wrench 5-25nm just to do the cam retainer bolts.
Proudly Aspergian. Yellow 98 TRX850, Staintune mufflers, braided brake hoses, blue spot brakes, remote control ignition switch, Ignitech ECU. 17/42 525 chain.

rednikmarto
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Thanks OzzieDave

Post by rednikmarto » Mon Jun 26, 2017 1:23 pm

Thanks OzzieDave.

The Haynes manual at Chapter 2, pages 13, 14 and 16, 17 were that make the difference with Yamaha manual.
So from today, 1 knowledge absence is filled forever.

***
Here is another thing that is hard to explain myself, hope some of you may explain it for all of us.
It started after i cleaned up my BDSR38/2 carburetors, and replaced my oval orifice needle jet with new (same stock Mikuni).
At same time another serviced items/replacements were: twice camshaft shimming due out of clearances, new rubber boots at carb-intake manifold,
new enrichment diaphragms, new o-rings within carburetor, all screws of carburetor replaced with stainless hex screws, new timing chain, new exhaust pipes gaskets, new throttle shaft seals (included throttle plate remove/install with help from a friend for screw drilling).

It's popping at exhausts on both idle and in gear, when decelerating. Its all under 2300-2400 rpm. No popping over this rpm.
Its not a big-bang but a relatively quiet sound.
At the same time i observed intake vacuum is below 26 cm/Hg. (Used my Carbtune to observe vacuum).
So i tried all 5 positions of retaining clip of jet needle. At all positions popping was present.
At position 1 (leanest mixture) popping was constantly during engine running, no need to touch throttle lever.
That fact break my expectations.
It showed that needle jet/jet needle system is not only partly overlapping pilot system (slow system) but entirely covering it.
Mikuni claims different operation of these systems. ( Link: BDSR36 ).
After that i placed the clip at position 3, and its still there.
...
Anyway i removed my stock #17.5 pilot jets, tried the #20 with serious improvement (as pilot screws were at 3 turns out, i had to go next larger jet).
Then tried pilot jets #22.5 with even more improvement - popping now is only at gear, throttle closed, decelerating engine below given low rpm.
With the #22.5 jets and running engine the vacuum at intake is restored - ( Photo ). Pilot screws are now at 2.5 turns out.

I will be here, waiting to answer if somebody has additional questions to reveal these mysteries:
(1) Needle jet/Jet needle system affecting the idle mixture;
(2) Inevitably popping at exhaust.

(P.S. Condition of carbs when i bought the bike: clips of jet needles at position 4 (almost richest position which is 5); pilot screws at about 3 turns out; do not remember if popping was present, or lets say no popping issues but needle jets had oval orifice - 16 years of operation should matter).
Last edited by rednikmarto on Sat May 21, 2022 3:22 pm, edited 2 times in total.

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OzzieDave
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Re: small newbie service project

Post by OzzieDave » Tue Jun 27, 2017 12:37 am

Have you checked the "air cutoff valve covers" for cracks, usually the outside one, it can be repaired with superglue or replaced. This resolved the popping on mine.
Proudly Aspergian. Yellow 98 TRX850, Staintune mufflers, braided brake hoses, blue spot brakes, remote control ignition switch, Ignitech ECU. 17/42 525 chain.

rednikmarto
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Re: small newbie service project

Post by rednikmarto » Tue Jun 27, 2017 8:43 am

OzzieDave wrote:Have you checked the "air cutoff valve covers" for cracks, usually the outside one, it can be repaired with superglue or replaced. This resolved the popping on mine.
Yes, i had new air cut-off diaphragms (brand TOURMAX). On TDM850 (1999-2001) their cover is solid metal. In high rpm even decelerating i have no popping which is explained with good operation of this enrichment system (air cut-off).
..
About mystery 1 (above) - here is a hypothesis that i drew as a graphic:

Image
Last edited by rednikmarto on Sat May 21, 2022 3:44 pm, edited 1 time in total.

rednikmarto
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Re: small newbie service project

Post by rednikmarto » Mon Jul 10, 2017 10:47 pm

Well, Saturday went for replacement of the clamps that hold the intake boots to manifolds and carburetors.

So i had a chance to see how exactly throttle valve plate(s) meet the pilot circuit outlet ports.
Its not what i wanted to see but its expected view, since my compression measurements showed 0,5bar or more difference between cylinders.
Manometer at cylinder #2 reads about 0,5bar higher than cylinder #1.

So i explain myself that suction difference existing between cylinders leads to different plates positions at vacuum synchronism.
Here it is as a drawing:

Image

All text above leads consequently to a conclusion..
..that the valves/head/guides/cylinders/piston rings/ (or at least some of them) have developed wearing.

Stupid popping is almost gone, carburetors now run two steps larger pilot jets (#22.5 instead of stock #17.5).
Vacuum is 27cm/Hg when the engine comes to operating temperature.
Bike runs well.

rednikmarto
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Re: small newbie service project

Post by rednikmarto » Sun May 22, 2022 10:53 am

Hi All,
Few years after my last post here, i have now disassembled the engine because of high oil loss, >1Liter/1000km.
To the last day engine pulled well, no smokes, oil topped engine.
Found connecting rod's small ends partially scratched, the wrist pins also, likely have picked some material out of conrods.
Also cylinder bores with acceptable wear (visited a workshop for measurements), and some glazing and tiny vertical scratches.
Had the head serviced by one of local workshops, they claim the old valve seals were bad.
Have photos and will insert links to them very soon..
1. Image

The 5/8"-11TPI UNC threaded rod was bent while removing the rotor.
2. Image

Scratched
3. Image

That's 50% scratched, the one of cylinder/piston 2 is only 30% scratched.
4. Image

Worn cylinder bores
5. Image

6. Image
After light hone with diamond in specialized workshop. Small dot-peaks are dirt in the oiled bore. Scratches remained there.
7. Image

8. Image

9. Image

10. Image
Nasty screw is about to be rounded.
11. Image

Cryed, then loaded the engine to my car and visited a friend who has welding machine.
12. Image

Bores again. After light hone with diamond in specialized workshop. Small dot-peaks are dirt in the oiled bore. Scratches remained there, its cyl./piston 2.
13. Image

Main journals of lower crankcase.
14. Image

Purchased puller but had a lot of troubles with it, at the end the central screw is bent.
15. Image

This resin is now cracked and falls apart, flakes of it are at crankcase bottom, and luckily stopped by the strainer.
16. Image

17. Image

The wrist pins are damaged. Mostly that of cyl./piston1.
18. Image

Wish to ask for advice, about how to tighten properly the standard conrod bolts/nuts of trx/tdm crankshaft ?
The manual says a specified torque of 48N.m. obtained by continuously applying force once 35N.m. has been reached.
The better way doing this, by measuring bolt stretch would require method/data about allowed stretch, and its not provided by Yamaha. How to proceed ?
Would like to have my plane bearings inspected/revised in proper way, that is the reason to ask.
I hope that spirits of all trx jedi still here and wish to share knowledge.

Subject: What did you do today? Cobba's rebuild
cobbadiggabuddyblooo wrote:So lesson learnt today..


Now I know when I contacted Carrillo themselves last night to get a little clarification and I understand when I torqued the bolts up 2 of the 4 come under the .005-.007 thou stretch specified..
Measuring the bolt stretch under load is a far more accurate way than using a torque wrench to eliminate the variables of friction.
So day two and a little practice I found the desired result all the while remembering not to exceed the maximum toque load given by Carrillo. In my case I needed to go just a couple of extra lbs on 2 of the bolts from TRX 35ft/lb spec to get the desired stretch..

So even though I still used a torque wrench I can get exactly the desired amount of stretch on each bolt.



Image

Image

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