TDM900 Engine conversion?

Post by **Max** » Wed Dec 06, 2006 9:28 am

Could be. You rev them hard enough and the oil has no time to escape!

cheesie · Post by **cheesie** » Wed Dec 06, 2006 7:19 pm

phuk72 wrote:I seriously looked at this when I blew my motor last summer and decided against it for a number of reasons.

You may be able to get the motor for Ãƒâ€šÃ‚Â£900 but that will not include the loom, CDI, injectors etc and the cost of those will add up. You can make the electrics work (inc the speedo with the right senders etc) but then of course you will have the extra cost of the TDM instrument cluster. I'd be surprised if you could get the bits you need for less than Ãƒâ€šÃ‚Â£300. The alternative, it to use the TRX head on the TDM motor with carbs (preferably flatslides) - about the same cost as a PCIII (ish).

Then of course, the TRX frame needs modding - not a massive job but you need to know someone who can weld. And then you'll need to powder coat the frame to tidy it all up!

And for what? OK, a 6 speed box would be nice - but then I've never felt myself wanting an extra gear. 86bhp? Only 4 more than the claimed figures for the TRX. Then there is very limited tuning potential on the TDM motor unless you want to spend big (no off the shelf big bore kit, hi comp pistons etc.). Lower mileage - perhaps? Less oil consumption - perhaps?

PM Dandywarhol if you want to know how much power you can realistically extract from a TDM lump. His has been tuned by TTS (can't remeber exactly what has been done but it involves PCIII and aftermarket cans) and that makes 88bhp at the wheel.

In the end, I opted for a very low mileage TRX lump and tuned that (again!).

what was the reason your first motor died was it tuned is your curent motor tuned or just the fcrs

jpe · Post by **jpe** » Wed Dec 06, 2006 8:24 pm

Max wrote:Could be. You rev them hard enough and the oil has no time to escape!

No, that doesn't fit either. I always use the red area on track days, the oil still escapes me. Maybe I have an oil that's too damn fast? Made for R1's perhaps...

Post by **phuk72** » Wed Dec 06, 2006 9:26 pm

Did the first engine smoke a lot? A little? None visible?

Nope - and no leaks. It just seemed to drink the bloody stuff

And I'm not renound for having any mechanical sympathy so the not thtashing it argument doesn't apply to me!

what was the reason your first motor died

not 100% sure - piston decided to unattach from rod and smash into head leaving rod to destroy barrel

was it tuned

nothing major - kent cams, flowed, ported and skimmed head (making at a guess between 80 - 85 bhp)

is your curent motor tuned or just the fcrs

very! have a look at the links for more info

http://trx850.motomaniac.net/forum/viewtopic.php?t=491

http://trx850.motomaniac.net/forum/viewtopic.php?t=652

cheesie · Post by **cheesie** » Wed Dec 06, 2006 10:16 pm

thanks for the info phuk seems the fcrs are the best pound for pound mod, did a bit of work on my xjr 1300 and although the extra oomph is good when charging about with my mates on thier r1s and stuff the motor is just not as flexible actualy think I might put standard cams back in and retire it for touring with the missus

wicky · Post by **wicky** » Wed Dec 06, 2006 11:36 pm

some peeps seem to think the 900 uses no oil cos the barrells/bores are 1 cast alloy piece along with the bores having a Nikasil coating (or what ever it's called). This allows fer better oil retention and the alloy barrels allied with alloy pistons allow a tighter ring to bore tolerence as they expand and contract at a more even/equal amount where as TRX'x have alloy barrels with iron liners (i tink ??) which has a larger (ring to bore) tolerence which possibly allows more oil to escape around the rings. i am amazed however that some of you folks have TRX's that seem to have the tits tooned off of them and they seem to use no oil !!!!! Yamaha probably had to fix "the TDM/TRX oil problem" as the 900 has cat. converters in the zorst pipes and too much oil smoke would kill em off i suppose

dandywarhol · Post by **dandywarhol** » Wed Dec 06, 2006 11:44 pm

burty wrote:Anyone know the reason why the 900 engines don't use any oil?

Even after the rebuild mine uses oil like it's going out of fashion. I know it burns a bit on start-up. I also think that probably it's a rings thing, Even with the new rings my bores were slightly out of spec, but the engineer I used reckoned it would be OK wth just a hone and new rings. Personally I think it may have been a better deal to have rebored and fitted new pistons.

The 900 has ceramic coated barrels so has a much tighter piston/bore clearance than the ferrous lined 850, 0.025 - 0.050mm compared to 0.065 - 0.085mm................and thats when the engine is cold!!!

The pistons will have less "rock" during the warm up period so should cause less piston/ring/bore wear I.M.H.O.

philk · Post by **philk** » Thu Dec 07, 2006 1:10 am

So this is probably a strange question then....

Does the TDM 850 also suffer from bad oil consumption?

The reason i ask is know a few people who have had them and no one has mentioned it.

John M · Post by **John M** » Thu Dec 07, 2006 4:53 am

Max wrote:Could be. You rev them hard enough and the oil has no time to escape!

I have to tell you that this hasn't been my experience. As a general rule the harder i ride mine (read use more revs) the more oil it uses. I recently changed from Motul 5100 to Castrol Synth S and it seems that consumption has reduced, so oil choice appears to be a factor too.

Post by **Max** » Thu Dec 07, 2006 6:09 am

Umm... I was joking. If a bike is already burning (using) oil, reving the guts out of it won't slow that down.

Those of you that have an oil user, did it do it from new or did it begin after a certain milage period? Just for the record, I used Motul 5100, 300V for track / race and now 7100 (or whatever they changed it to) in 15 or 20W /50W.

HansJ · Post by **HansJ** » Thu Dec 07, 2006 9:10 am

Ehrmm, maybe we should start a new oil consumption thread?

I bought my bike with 23000 k's, and it has now 48000 on it. The oil consumpiton was very moderate in the beginning, but curiously enough, it varied a lot. Sometimes I had to top off after just 500 ks, and sometimes it could run the double. It seemed that constant high speed was the clue, consumption while on track and in the twisties were never an issue, although beeing run much harder? Last winter I had the cylinders off, measured them, and although they were worn, none of the values were out of the specs from the workshop manual (one was clsoe), so I just honed them and fitted new rings. I also put in new valveguideseals. Oil consumption after that dropped to almost nothing, but in the end of the season I noticed a somewhat higher consumption (but not close to what it previously was). I guess there's a limit where new rings will only cure the phenomena for a short period of time...

jpe · Post by **jpe** » Thu Dec 07, 2006 10:33 am

philk wrote:So this is probably a strange question then....

Does the TDM 850 also suffer from bad oil consumption?

The reason i ask is know a few people who have had them and no one has mentioned it.

Yes, they behave exactly the same (essentially same engine). Some don't but most do use a bit of oil.

Whatever bearing this has on the subject of 900-conversion...

Post by **phuk72** » Thu Dec 07, 2006 10:36 am

Whatever bearing this has on the subject of 900-conversion...

The conversion cures the oil useage

philk · Post by **philk** » Thu Dec 07, 2006 8:00 pm

JPe, the bearing the question i asked re oil consumption between the trx and tdm, was that the main difference being compression ie i understand that the trx has higher compression.
so logically i was wondering if that was the case, if i were to raise the compression on the 900 would it start using oil like a 2 stroke!!

Post by **phuk72** » Thu Dec 07, 2006 8:06 pm

Phil

without high comp pistons, the only way of raising compression on the 900 engine is to skim the barrells or the head and that will not make enough of a difference to start forcing oil past the rings or through the valves.