76 replies to this topic

[Medmonic]

And today i received my head gasket for the 900e cylinder block ...yupieee time to work 

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[Medmonic]

So Head in Place , time  to torque  and  make the correct timing of the engine 

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[wicklamulla]

welcome back,  we were wondering where you had gone.  Please keep sharing your knowledge with us even after Brexit!

[dandywarhol]

Have you checked the piston deck height compared to the 850? from memory Emmett had to have his pistons machined to get the compression ratio correct. I would grease the piston tops, lightly tighten down the head and carry  a combustion chamber volume test by adding paraffin down the sparkplug hole at TDC until it comes halfway up the plughole. Use this formula to calculate the compression ratio:

 

Cylinder volume (CC) + combustion chamber volume and divide that figure by the combustion chamber volume. You should be aiming for around 11:1.

 

Then remove the head, put modelling clay into the valve pockets in the pistons, refit the head, time the cams and slowly turn the engine over to see the imprint of the valves in the pistons, remove the head again, remove the clay, cut in half and measure the clearance - OR risk terminal engine damage.

Edited by dandywarhol, 09 December 2020 - 06:56 pm.

[Studley Ramrod]

That's exactly what I was about to say..........honest.

 

Good work Medmonic.    Did you replace the valve stem seals ?

[Medmonic]

Have you checked the piston deck height compared to the 850? from memory Emmett had to have his pistons machined to get the compression ratio correct. I would grease the piston tops, lightly tighten down the head and carry  a combustion chamber volume test by adding paraffin down the sparkplug hole at TDC until it comes halfway up the plughole. Use this formula to calculate the compression ratio:

 

Cylinder volume (CC) + combustion chamber volume and divide that figure by the combustion chamber volume. You should be aiming for around 11:1.

 

Then remove the head, put modelling clay into the valve pockets in the pistons, refit the head, time the cams and slowly turn the engine over to see the imprint of the valves in the pistons, remove the head again, remove the clay, cut in half and measure the clearance - OR risk terminal engine damage.

I did check the piston deck  height against the 850 and they were the same , and iam using a 850 head , the valves dont touch the piston deck  regarding the compression ratio it will increase a litle bit due to larger pistons , but dont know how much ....... well if does not work i have to do as you said , will be more correct !! But thaks a lot by the advise , it will help me in the next engine 

That's exactly what I was about to say..........honest.

 

Good work Medmonic.    Did you replace the valve stem seals ?

yep all valves with new steam seals  from Athena brand 

[Medmonic]

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Edited by Medmonic, 11 December 2020 - 07:50 pm.

[Snowbird]

Progress is looking good there Med, be good to hear how it goes afterwards.

[dandywarhol]

Nice work!

 

You should find the combustion chamber and gasket volume to be 44.65cc which gives a 10:1 ratio for the 850 engine.

The additional bore size from 89.5 to 92, assuming the same head/gasket will give 11:1. Spot on. All you need now is a pair of Kent Yam09 cams 

[Medmonic]

Nice work!

 

You should find the combustion chamber and gasket volume to be 44.65cc which gives a 10:1 ratio for the 850 engine.

The additional bore size from 89.5 to 92, assuming the same head/gasket will give 11:1. Spot on. All you need now is a pair of Kent Yam09 cams 

dont make me dream   

Progress is looking good there Med, be good to hear how it goes afterwards.

already preparing the bike whi will receive the engine , lot of work coming specially on the wiring , iam installing some extra sensors to monitor the engine   

[dandywarhol]

dont make me dream   

already preparing the bike whi will receive the engine , lot of work coming specially on the wiring , iam installing some extra sensors to monitor the engine   

 

Sorry, typo - the 850 should have read 10.5:1 stock

[Coxylaad]

i always get an involuntary shudder when i think about having to rebuild engines. My philosophy has always been, 'if it needs more power, fit a bigger engine!'

 

fair play to you you are doing a top job 

[Medmonic]

hello again , 

i have being  away in work , so not much updates  ...

just restarted  the project 2 days ago ..

basically the engine is installed  on my red tdm , the engine removed will be installed on my black tdm , since her engine had oil mixte  in the water .

so basically iam installing  two engine at same time   

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this is the 850 3vd engine with 4tx gearbox installed that goes now to the black tdm 

[Medmonic]

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the 3vd900 engine already in position 

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my black tdm waiting for her new engine 

i always get an involuntary shudder when i think about having to rebuild engines. My philosophy has always been, 'if it needs more power, fit a bigger engine!'

 

fair play to you you are doing a top job 

thanks  man 

[Medmonic]

Well, the project have some updates , finally the engine is running , but with small changes in the engine .

First i had to remove the carter that was from tdm 900 and it was deeper than the original tdm 850 , the reason was that the exhaust was touching in the carter , no clearence at all .

then the upper case carter had to be replaced , was leaking oil due a small diference in shape , so removed the 900 top case carter and install the 850 original .

the engine is running fine , but now i have to instal new cluster and wiring to run 3 sensors ,

- engine oil pressure 

- engine oil temperature 

- engine coolant temperature 

But for starting the engine the old setup was fine , just had to make the exhaust and install all in the frame 

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[Studley Ramrod]

Congratulations Medmonic.

[leehenty]

Well done Sir

[Snowbird]

Good work that man, I bet that was satisfying to hear it crackle into life.

[dablik]

Good job medmonic 

[dapleb]

Noice! I may have missed it, but how did yet enjun brackets go? Fabricated or original?