9 1/2 Engine rebuild

[VesaII]

Dear fellow Morinists

I am a new member and proud 9,5 owner. Bike is -07 version and i bought it as a project. It has a serious blow by issue as it did throw air box full of oil. Reason for this is not all clear.

Cause of this, engine is now disassembled and my plan is to write short story of project as i sure will have some question and someone else might find this usefull aswell. Will also make it short, as my English and writing skills does not allow me to be more poetic.

Primary goal with rebuild is reliability. Second goal is to get much better fuel efficiency. Third goal is to keep heat out of cooling system of engine and make power of it or lead it out thru exhaust. Fourth goal is to make bike even more fun to drive.

Taking engine apart was not very complicated and you can do it without expensive tools. Only three of them are needed
1)M38x1,5 puller https://www.motionpro.com/product/08-0306
2)Puller for cylinders can be modified of a cheap puller
3)Piston pins was very tight so these 'tools' was needed.
(see pictures below)

Inspection
1) Rear piston oil ring is broken.
2) One rear cylinder exhausta valve was not seated properly as there was lot of burnt oil debris on seating surface. Propably cause of excessive blow by.
3) One front cylinder exhaust valve guide was badly worn out. Valve did 3mm sideways and it surely created some exhaust blow by. All other did some 0,5mm.
4) Piston pins have some coloured marks on them.

Conclusion and assumptions
1) Piston rings are very delicate and i might have harmed one while disassembling.
It is better to have some linen around them immediately after cylinders are removed.
2) Valve guides are originally of iron and can easily be fitted with k-liners. If this is not possible, like in my case, then Renault guides are perfect. They need some work on lathe to put minor grooves on them for similar stoppers as orginals. My mechanic also suggested not to cut them short but leave as is, cause of originals are very short.
3) Valve stems are exceptionally long, which makes valves prone to shake and to retain heat.

Couse of curiosity.
1) Heads will be slightly ported and shaved for straightness and hopefully for more compression
2) Proper valve job with radius cut seats and 30 degree back cut for valves
3) Special coatings will be used on valves, valve stems, pistons, combustion chambers, exhaust channels and headers http://www.camcoat.com/main/coatings12.html
4) Tech line coatings (TLML) on cams and maybe even on cups, as this makes valve train life
easier. Choises are professionally TLML or DFL-1 coating https://www.youtube.com/watch?v=8ZoZjUn9szs Maybe this is more acute on Corsaros though... https://martelius.com/en/ceramic-coatings/
5)DLC coating for piston pins
? Fine tune for cam timing, if i find offset-keys that fit.
6) ? In case original ECU is not possible to remap properly, then Power commander V for Guzzi might do with MoMo ECU https://www.ebay.co.uk/itm/Dynojet-2009 ... 0033.m2042
7) Brisk spark plugs https://www.briskracing.com/buy-spark-p ... lug-detail
8) Final touch with RVS https://www.rvs.fi/en/
9) Dyno tuning for economy and driveability.

These are my first impressions and initial idea of how to proceed with the engine. Your comments and further questions are highly appreciated.

And if you have some parts over for this engine, please let me know

Will be continued...
VesaII

[mikebbikes]

Excellent write up.
What mileage was on it?

[VesaII]

Thanks

Some 35k+ i recall

[VesaII]

Hi all

Some work done and some mistakes understood afterwards.
You should never take cylinders of straight away, but together with pistons. RTFM would IT people say.

Measured piston top ring gap and it is near maximum. So replacing them is best to do now.

Cat will be removed, so i took a saw and had that bulky think cut in half. Hard stuff with hand tools. You need angle grinder with thin wheel.

And the most beautiful thing! Initial porting and combustion chamber cleanup done. Next step is to bring heads back to shop and they continue with porting and do proper valve job.

Pity, just three pictures allowed...

Best,
Vesa

[VesaII]

Heads dropped for professional treatment. Next will be new valve guides (Renaul/Nissan/Dacia 1.5 Dci K9K) They are ,02 thicker cause of more slippery material, little longer which does not harm and lack original lock ring. Guides also has good quality seals. Cause of this they need a minimum amount of modification: Similar lock rings will be put on them as originals and cone done on lathe.

Groove must be done so that upper end of the guide is at same level or lower as original!!! Otherwise retainer may hit the valve stem sealing when on top of the lift

Did a new inspection for pistons and found some places for improvement. There is minor darkening and scores in the middle of wrist pin and this i like to polish away gently. This might be cause of pin and connecting is of same material and do lack bronze bushing, which do not sound as very good idea. Luckily this can be solved with DLC coating and is is not even expansive, but wrist pin must be in absolutely top condition. Surface must be mirror like. Lets see if it can be achieved…

In future, if piston change becomes acute then DLC will surely be applied on fresh wrist pins.
https://www.oerlikon.com/balzers/de/de/ ... chichten/

Did put two exhaust pictures here too. They show most important places for modifications. On Exhaust1 picture there is protruded area in need for removal (2-3mm) You can feel it with your finger and sharp edge you can see with bare eyes. Similarly on Exhaust2 picture there is a weird group whic directs exhaust gases against header walls. Very easy to remove if you find it with your finger first and check with some straight too to be sure it is removed. Best achievable exhaust flow path is more difficult to figure out cause of change from round valve to curved and oval channel. Intake is easy. Just do not enlarge but blend and make smooth and straight.

[VesaII]

Grooves and cones done on new bronze valve guides. Pictures of DIY porting or rather smoothing and better fitting parts together. Took maybe 4h
Finishing is done by pro machinist. Peter will sharpen the intake dividers and glas bead blast intake channels.

Hope someone can measure the correct height.

[VesaII]

Will be continued in new thread viewtopic.php?f=3&t=5043