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TDM850 engine modifications


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#1 Guest_Emmett_*

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Posted 29 November 2006 - 09:33 pm

So.....................................................my '98 model burns some oil, more oil than petrol, well not quite, but enough to pish me right off. I also wouldn't mind a bit more power, without sacrificing reliability. The general consensus is that the steel liners matched with ally pistons cause the excessive oil consumption, and we all know theres no substitute for cubes, soooooo, I (with the assistance of a Yamaha mechanic friend, that is a friend who is a Yamaha mechanic and not a Yamaha mechanics friend) am in the process of putting TDM900 pistons and barrels onto my 850.

So far the engine is out, the head and barrels are off and the con rods are out. The 900 barrels are definitely a straight fit, but the900 has lower compression, so to offset that I (we) have decided to skim 0.4ml off the head. Which according to Jimmys(my mechanic friend) calculations should raise compression to about 10.8-1. The only other complication is the con rod small end eye needs to be 1mm larger diameter, which could be reamed out, but I have 900 con rods which will go straight in, so I'm gonna use them.

The compression issue has been raised before on a TRX owners site, and rick, who did the conversion, decided to skim the top of the pistons and the bottom of the barrels to remove the concave surface of the piston, and increase the compression. We have decided to skim the head, as it is easier than skimming the bottom of the barrels, the liners protrude so machining around them could be costly. I also have a spare head, so if it doesn't work out, I can undo anything and use ricks method.

So far I havent machined or skimmed anything, but all the bits are apart and the measurements are done, so if anyone knows of any reason these two things shouldn't be together, let them speak now, or forever hold their peace(or piece, I'm not sure)

I will keep you updated, but the whole job should be finished by next week..................I hope.


Sorry, you have to sign into the TRX forum to view it, but it's well worth a read, so sign up.

Edited by Emmett, 29 November 2006 - 09:40 pm.


#2 dapleb

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Posted 29 November 2006 - 10:40 pm

The 850 liners are iron. I still don't fully understand why increased pitoon to bore clearance on the 850's would lead them to burn oil once the boike is warmed to operating temp but hey, the 900 barrel replacement seems to solve the problem.

I would really suggest talking to Rick about why he skimmed the base of the barrel and piston tops before you do any work. He would not have gone to that hassle unless he felt it neccessary. Mayhaps something to do with Pistons whacking valves or depth of valve recesses in pistoon tops or stroke or summat loike dat. I don't know anything about 900 enjuns to know the differences.

Got his email addy if you need it.

G'luck with it. Please take lots of pics as I think Wicky might need them when he does his.

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If you want to mark your location on the Carpe map: http://www.carpe-tdm...opic.php?t=5117

Doin valve clearances? Use dappers valve shim exchange program and the job will be carroty - Free (other than you postin me yer shims) for sporting members.

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#3 Guest_Emmett_*

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Posted 30 November 2006 - 12:00 am

His email addy wud be great tanx PK good.gif

#4 wicklamulla

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Posted 02 December 2006 - 11:42 am

lol this 900 conversion is really on me mind at the moment as i had a dream about it last noight !!! i have all the parts (except gaskets) required plus me mudder gave me £350 towards the cost of the job, what a woman !!! just gotta get No.7 to start first as i still have not fixed the fried alarm problem !!!

spyball alarm/immob, bluespot brake calipers and Stainless hoses, Fournales air adjustable shock with Remote Resevoir, forks raised 10mm thru yokes, racetech linear fork springs in 15 wt oil, Kappa wingrack/luggage, heated grips, Kedo handguards, dual heat controller to power heated jacket liner and or pants!!, Stebel 136DB horn, K&N air filter, colour matched Baglux tank cover (magnetic tank bag modified to fit cover), osram +50% headloight bulbs, headlight protector,"NitramSpecial" parking loight, tail light indicators all running on LED's & incorporate "Lite Buddies", MK7 Scottoiler fitted, taller screen, 2-2 stainless steel CCC's, Devil stainless down pipes. MKI Renntec engine crash bars & sump guard.
engine changed july 2007 on a dyno run it made 79.1BHP / Torque 59.9Had a brief flirtation with a 1999 MKIIa but it blew an exaust valve on the M5 so was sold on to be repaired.

I loike tay and hang sangwiches !

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#5 Guest_Emmett_*

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Posted 02 December 2006 - 09:05 pm

QUOTE(wicklamulla @ Sat 2nd Dec 2006, 11:27 AM) <{POST_SNAPBACK}>
lol this 900 conversion is really on me mind at the moment as i had a dream about it last noight !!! i have all the parts (except gaskets) required plus me mudder gave me £350 towards the cost of the job, what a woman !!! just gotta get No.7 to start first as i still have not fixed the fried alarm problem !!!

Don't rush, I should be finished soon, and I'll tell ya how it goes. I ended up using the 900 conrods by the way, just to avoid machining the small end eye. The big end is a straight swapsey.

#6 dapleb

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Posted 02 December 2006 - 10:05 pm

QUOTE(Emmett @ Sat 2nd Dec 2006, 08:50 PM) <{POST_SNAPBACK}>
The big end is a straight swapsey.


..when you say straight swapsie....how did you match the correct shell size? Anyone give you any insight into effects of fitting the lighter conrods?
"Whats up", "Piston Broke", "Yeah me too...hic"

If you want to mark your location on the Carpe map: http://www.carpe-tdm...opic.php?t=5117

Doin valve clearances? Use dappers valve shim exchange program and the job will be carroty - Free (other than you postin me yer shims) for sporting members.

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#7 Guest_Emmett_*

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Posted 02 December 2006 - 11:14 pm

The shell sizes were green, makes little or no sense to me, but luckily I'm not doing the work. The lighter con-rods might cause some problems with the balance and cause some vibes, but if that happens I'll use the 850 ones. As far as I know it shouldn't cause any serious problems................ huh.gif

#8 Hartside Man

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Posted 02 December 2006 - 11:26 pm

QUOTE(Emmett @ Sat 2nd Dec 2006, 10:59 PM) <{POST_SNAPBACK}>
The shell sizes were green, makes little or no sense to me, but luckily I'm not doing the work. The lighter con-rods might cause some problems with the balance and cause some vibes, but if that happens I'll use the 850 ones. As far as I know it shouldn't cause any serious problems................ huh.gif


the fact that the 900 is commonly quoted on here as being the "gay" bike laugh.gif

will that make Emmetts half breed "AC - DC" rotflmmfao.gif

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

I have a Ghost S and i'm not afraid to use it !

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"Four wheels move the body. Two wheels move the soul".

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#9 Guest_Emmett_*

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Posted 02 December 2006 - 11:29 pm

QUOTE(amarko5 @ Sat 2nd Dec 2006, 11:11 PM) <{POST_SNAPBACK}>
the fact that the 900 is commonly quoted on here as being the "gay" bike laugh.gif

will that make Emmetts half breed "AC - DC" rotflmmfao.gif

I think it'll be bi-sexual wub.gif






Amotorbi-sexual unsure.gif


I'll get my Coat.

#10 Hartside Man

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Posted 02 December 2006 - 11:31 pm

QUOTE(Emmett @ Sat 2nd Dec 2006, 11:14 PM) <{POST_SNAPBACK}>
I think it'll be bi-sexual wub.gif
Amotorbi-sexual unsure.gif
I'll get my Coat.



Please do smile.gif it's rather chilly out wink.gif

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

I have a Ghost S and i'm not afraid to use it !

A Beast in Orange Called KaTie eM 

"Four wheels move the body. Two wheels move the soul".

"So you just ride somewhere, eat cake and then ride back".


"Normal people believe that if it ain't broken, don't fix it. Engineers believe that if it ain't broken, it doesn't have enough features yet."

 

" I We're Ridin so Fast , I we're sucking Rabbits from the Hedges "   {Guy Martin}


#11 dapleb

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Posted 02 December 2006 - 11:32 pm

QUOTE(Emmett @ Sat 2nd Dec 2006, 10:59 PM) <{POST_SNAPBACK}>
The shell sizes were green,


Okkkk. Shell sizes are calculated by finding the difference between two sizes (which are coded by numbers). Crankshaft journal size and con rod size. Haynes tells you where these no's are located.

You have GREEN for both cyls? (I am assuming these are the 900 shells?)......but although you have the same con rod size (assuming you are using 900 shells), you now have a different crankshaft journal (i.e. your 850 crank), so you MAY need different shell sizes! Don't know how critical getting the size correct is (i.e. if the wrong size will make yer rods flap in the breeze...or starve the enjun of oil). I guess if you are having a Yam Mech do this then he will know best.

I will try and dig up my engine notes as I'm sure there was some oddity from the Haynes but cant remember if that was for Main or big ends.

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"Whats up", "Piston Broke", "Yeah me too...hic"

If you want to mark your location on the Carpe map: http://www.carpe-tdm...opic.php?t=5117

Doin valve clearances? Use dappers valve shim exchange program and the job will be carroty - Free (other than you postin me yer shims) for sporting members.

Active member of TPLQHCSRSFC and TSRMCMAS (even though a year off) and avid fan of PM not sent.

#12 Guest_Emmett_*

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Posted 02 December 2006 - 11:35 pm

QUOTE(dapleb @ Sat 2nd Dec 2006, 11:17 PM) <{POST_SNAPBACK}>
You have GREEN for both cyls? (I am assuming these are the 900 shells?)......but although you have the same con rod size (assuming you are using 900 shells), you now have a different crankshaft journal (i.e. your 850 crank), so you MAY need different shell sizes! Don't know how critical getting the size correct is (i.e. if the wrong size will make yer rods flap in the breeze...or starve the enjun of oil). I guess if you are having a Yam Mech do this then he will know best.


He did mention Green, he also mentioned getting some number using a small mirror which he said was a pain in d'ass. I ruh roh.

#13 dapleb

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Posted 02 December 2006 - 11:53 pm

QUOTE(Emmett @ Sat 2nd Dec 2006, 11:20 PM) <{POST_SNAPBACK}>
He did mention Green, he also mentioned getting some number using a small mirror which he said was a pain in d'ass. I ruh roh.



That'll be crankshaft journal ones printed on the web....though I think they are also be tatooed on the outside of the head too in a group of 5 numbers (3 for mains and 2 for big ends).

If you give me:

850: numbers printed on rods (in ink and stamped on cap/rod join), shell colours.
900: numbers printed on rods (in ink and stamped on cap/rod join), shell colours.

It would be possible to work back and find new reqd size.
"Whats up", "Piston Broke", "Yeah me too...hic"

If you want to mark your location on the Carpe map: http://www.carpe-tdm...opic.php?t=5117

Doin valve clearances? Use dappers valve shim exchange program and the job will be carroty - Free (other than you postin me yer shims) for sporting members.

Active member of TPLQHCSRSFC and TSRMCMAS (even though a year off) and avid fan of PM not sent.

#14 Landy

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Posted 03 December 2006 - 05:57 am

This may help in working out the required size.
Plastigauge
The web page description is not very clear (much better in the paper catalogue) but this works by taking a strip of putty like material of a know size, when you flatten it it becomes wider and from this you can workout the size of the gap. To use you place a gauge in the journal then bolt up, when you undo it the gauge has been squashed and measuring the width gives you the internal gap.
If you Google Plastigauge you get lots of links to vehicle based forums.

And Yes I know its silly o'clock on a Sunday, I just love this insomnia stuff!

Edited by Andy K, 03 December 2006 - 06:01 am.

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#15 dapleb

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Posted 03 December 2006 - 10:00 am

Yamaha just do the numbering/colour system, it was a real mission to get the actual shell sizes from Yamaha. Plastiguage is worth using to double check you have the right shells.
"Whats up", "Piston Broke", "Yeah me too...hic"

If you want to mark your location on the Carpe map: http://www.carpe-tdm...opic.php?t=5117

Doin valve clearances? Use dappers valve shim exchange program and the job will be carroty - Free (other than you postin me yer shims) for sporting members.

Active member of TPLQHCSRSFC and TSRMCMAS (even though a year off) and avid fan of PM not sent.

#16 wicklamulla

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Posted 03 December 2006 - 01:03 pm

QUOTE(dapleb @ Sun 3rd Dec 2006, 09:45 AM) <{POST_SNAPBACK}>
Yamaha just do the numbering/colour system, it was a real mission to get the actual shell sizes from Yamaha. Plastiguage is worth using to double check you have the right shells.



k'inell does that mean one shud really split the crankcases (Emmett did you split the cases to access the conrod big end cap bolts or did ya cum in from the bottom (sorry Tom) of the engine???) in order to use this plasticine stuff or ???? Dappers ya know too damn much fer my loiking !!! rolleyes.gif

Edited by wicklamulla, 03 December 2006 - 01:04 pm.

spyball alarm/immob, bluespot brake calipers and Stainless hoses, Fournales air adjustable shock with Remote Resevoir, forks raised 10mm thru yokes, racetech linear fork springs in 15 wt oil, Kappa wingrack/luggage, heated grips, Kedo handguards, dual heat controller to power heated jacket liner and or pants!!, Stebel 136DB horn, K&N air filter, colour matched Baglux tank cover (magnetic tank bag modified to fit cover), osram +50% headloight bulbs, headlight protector,"NitramSpecial" parking loight, tail light indicators all running on LED's & incorporate "Lite Buddies", MK7 Scottoiler fitted, taller screen, 2-2 stainless steel CCC's, Devil stainless down pipes. MKI Renntec engine crash bars & sump guard.
engine changed july 2007 on a dyno run it made 79.1BHP / Torque 59.9Had a brief flirtation with a 1999 MKIIa but it blew an exaust valve on the M5 so was sold on to be repaired.

I loike tay and hang sangwiches !

www.kenhogantreeservices.co.uk

http://s33.photobuck...77/wickla/?sc=6



http://reg.imageshack.us/v_images.php

post-1-1150550733.gifpost-1-1150550726.gifpost-1-1150559830.gif


#17 dapleb

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Posted 03 December 2006 - 01:25 pm

Nah he will have got to the bassads from the borrum, which looks a tad fiddly. Splitting the cases is a major operation and only needed for main burrings.
"Whats up", "Piston Broke", "Yeah me too...hic"

If you want to mark your location on the Carpe map: http://www.carpe-tdm...opic.php?t=5117

Doin valve clearances? Use dappers valve shim exchange program and the job will be carroty - Free (other than you postin me yer shims) for sporting members.

Active member of TPLQHCSRSFC and TSRMCMAS (even though a year off) and avid fan of PM not sent.

#18 Guest_Emmett_*

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Posted 03 December 2006 - 09:38 pm

QUOTE(dapleb @ Sun 3rd Dec 2006, 01:10 PM) <{POST_SNAPBACK}>
Nah he will have got to the bassads from the borrum, which looks a tad fiddly. Splitting the cases is a major operation and only needed for main burrings.

Yup from it's bottom.................................................unsure.gif

Edited by Emmett, 03 December 2006 - 09:39 pm.


#19 Hartside Man

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Posted 12 December 2006 - 07:04 pm

QUOTE(Emmett @ Sun 3rd Dec 2006, 09:23 PM) <{POST_SNAPBACK}>
Yup from it's bottom.................................................unsure.gif



so hows the conversion going ??? is it running yet ???

UPDATE REQUIRED (and yes i am shouting ) tongue.gif

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

I have a Ghost S and i'm not afraid to use it !

A Beast in Orange Called KaTie eM 

"Four wheels move the body. Two wheels move the soul".

"So you just ride somewhere, eat cake and then ride back".


"Normal people believe that if it ain't broken, don't fix it. Engineers believe that if it ain't broken, it doesn't have enough features yet."

 

" I We're Ridin so Fast , I we're sucking Rabbits from the Hedges "   {Guy Martin}


#20 Guest_Emmett_*

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Posted 12 December 2006 - 07:11 pm

QUOTE(amarko5 @ Tue 12th Dec 2006, 06:49 PM) <{POST_SNAPBACK}>
so hows the conversion going ??? is it running yet ???

UPDATE REQUIRED (and yes i am shouting ) tongue.gif

I'm waiting on the barrels and pistons coming back from the engineer, I've copied rick from the TRX site and I'm skimming 10thou off the bottom of the barrels, and the same from the top of the pistons.

I brought the head in to be skimmed last tuesday, and 2 hours later it was done. Then after reassembly, the measurements (by the mechanic) showed that we still needed to increase compression, so on wednesday we sent the pistons and barrels into the same engineer, and I'm still waiting to get them back. ranting.gif

Hopefully I'll have some news tomorrow evening.....................................................hopefully dry.gif


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