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Just Got A 900


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#21 thelodger

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Posted 31 July 2018 - 07:50 pm

Plenty of info on here about the Dobeck option.  The trick will be getting one at a sensible price as they are american , but if you are patient and leave a search on eBay worldwide you will be able to get one at a sensible price. I paid about £70 , which made it very worthwhile.

 

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#22 spike240

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Posted 31 July 2018 - 08:19 pm

Thanks, two good replies. 
 

 
spike.   
 
I also 'rev it' a bit more and slip the clutch, but we all know this is not solving the problem. I've had 3 Africa twins, 2 Transalps, a Cagiva elefant 900 (Ducati 900ss engine) all twins with none of this snatchy throttle boll***s.  The fact that people are doing all this stuff just to get what comes as standard with other bikes says it all.

Hi and thanks for comments. When I say rev it a bit more - with the front sprocket change I find slipping the clutch is a thing of the past. I find with careful throttle control, when I have reached 4th gear I can drop down to about 1800 rpm without snatch and will pull back up to 4 or 5k rpm smoothly. In reality this means I can ride in a 20 to 40mph zone in the same gear - 4th.
I realise the gearing change I made doesn't suit everyone, but as I use quite a lot of minor and B roads the bike is a pleasure to ride with this change.
I completely agree with you regarding other bikes. The only other injected twin I owned was a BMW 1100s and it was brilliant with no throttle snatch issues.
I also am not criticising the 900, having owned Yamahas for the last 25 years I was surprised Yamaha would release a bike with such an irritating problem out of the box so to speak.

#23 mgml

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Posted 31 July 2018 - 08:48 pm

Cheers.  4th gear, 4 or 5k rpm, 20-40 zones? 

 

I don't have any probs with anything there.  I purely have a snatchy throttle from tickover to about 2.5 maybe 3k, after that she's just fine.  It's a pig when you roll off but only around lower revs just below say 2/2.5k.  It's just that 1500 2.5/3000 band.



#24 Apache

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Posted 31 July 2018 - 10:00 pm

Never had a niner so no idea what your problem is but the debate about learning to ride differently with a big twin and it'll only be smooth above 3k doesn't add up. It's got to be something specific to the 900. I've just been out and clocked 150 miles trying my best to get my 4TX to snatch or jerk. In lower gears it'll pull away from 1500 rpm 4/5th it's good from 1800/2000. I don't habitually ride like that but it does it no problem. Absolutely no problems mid corner or after rolling the throttle off. So,apart from nikasil bores and an egg cup difference in capacity the two motors are identical.That leaves the bolt on stuff..ignition,air intake and fuelling. They got something wrong it seems. I had a bmw r100rt for 12 years,shaft drive granted but that would pull from tickover. I did 17000 miles in a year with a TRX with no such problems. It's nowt to do with big twins, it's inherent in the niner....just my two penneth.

#25 thelodger

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Posted 31 July 2018 - 10:38 pm

carbs ( 4TX)  v   fuel injection on the 900.



#26 wicklamulla

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Posted 31 July 2018 - 11:07 pm

wonder if it could do with a good service and get the throttle bodies synchronised at the same time?


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.

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#27 Apache

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Posted 01 August 2018 - 02:07 am

carbs ( 4TX)  v   fuel injection on the 900.


I give up

#28 TDM4ever

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Posted 01 August 2018 - 06:04 am

wonder if it could do with a good service and get the throttle bodies synchronised at the same time?

 

Probably a good idea  :)

 

A stock 9'er doesn't behave as bad as the OP describes, so something must be wrong.



#29 Hombre

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Posted 01 August 2018 - 06:47 am

 

 

If the ignition is too far advanced with low quality fuel, such as 91 octane then it suffers with preignition, So to accommodate that manufacturers retard the timing so that 91 fuel can be used.

 

But, but, but: if preignition (pinking) is an occurance before the controlled ignition from the timed spark.  Difficult to understand how delaying the spark can eliminate that occurance.  The spark timing is to ensure the maximum force from the peak pressure of the combustion period occurs just after TDC so either Yamaha messed up with that and your ignition advance corrects them or the combustion period for 91RON is shorter than for 95RON?

 

More likely that Yamaha want to avoid detonation (knocking) when using 91RON which will occur more readily than with 95RON.  As one of the soloutions for avoiding knocking is to retard the ignition, that leaves scope to advance the ignition when using 95RON and improve the timing of the combustion peak pressure.  Whether that would make a smoother response to throttle...?

 

Personaly, I think the low fuel consumption of the 9er gives the game away - it runs lean, assisted by retarded timing to accommodate the higher temperature from that.  The better performance would come from increasing the fuel-air mixture and then adjusting the timing for 95RON if it improves on that.  Might need hotter pugs too and an increased fuel budget for high-milers.

 

My 9er runs fine with the full removal of the airbox flap gubbins and the CO adjustment to low speed fuel-air ratio.  Many thanks to whoever worked that out.


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#30 Nog

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Posted 01 August 2018 - 07:54 am

But, but, but: if preignition (pinking) is an occurance before the controlled ignition from the timed spark.  Difficult to understand how delaying the spark can eliminate that occurance.  The spark timing is to ensure the maximum force from the peak pressure of the combustion period occurs just after TDC so either Yamaha messed up with that and your ignition advance corrects them or the combustion period for 91RON is shorter than for 95RON?

 

More likely that Yamaha want to avoid detonation (knocking) when using 91RON which will occur more readily than with 95RON. 

 

It's getting a bit pedantic but yes it's to avoid knock.  Lower grade fuel is more prone to knock so delaying ignition timing is the solution (as you mention).  Modern engines have knock sensors and will adjust the timing accordingly.

With these 'older' engines if you advance timing slightly it will be more suited to mdoern fuel as long as you don't advance too much.  On my ZRX I have a 4 degree advanced rotor which does exactly the same and it works great.



#31 Hombre

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Posted 01 August 2018 - 10:08 am

 

It's getting a bit pedantic...

Not really.  Preignition is ignition of the fuel-air before the plug fires: pinking.  Detonation is within the fuel-air but ahead of the flame front from the fired plug: knock.  The latter can occur by over-advancing the timing just as retarding the timing can reduce it.


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#32 fixitsan

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Posted 01 August 2018 - 07:21 pm

I don't want to get drawn into the ifs and buts, but here's a timing map for the TDM, showing ignition advance VS throttle %. Clearly there's a big red patch , starting at just under 3000rpm, where the timing jumps to 56 degrees of advance at small throttle openings, and the blending off for wider throttle openings is very steep.

 

http://i.imgur.com/cudGLsK.png?1

 

 

It's pretty clear to me, from observation through riding, from playing with the timing, and from playing with other variables that the timing is indeed very unsmooth, very 'blocky'  

 

A lot of people complain about a surge at about 3000rpm which make it difficult to ride in town.....and those people weren't imagining it, once the ignition map was recovered it was pretty clear what the main contributing factor was. (I didn't recover it, that works was a joint effort by several well known tuners, who figured out that the ECU in the TDM900 is the same Denso 16 bit unit used in Early GSXR 600's and many other bikes of the day, such as the early R6 and R1) . It is not an ECU which as some people might think is a crude  primitive device, it even has Alpha-n throttle control where the rate of change of throttle is used to increase fueling proportionately. A quick twist of throttle to 50% causes a greater surge in fueling than a slow change to 50% throttle....this mimics the accelerator pump of many carbs.

 

Samios don't share their map (for obvious reasons) , but it is smoother in the same region of interest, the throttle has a more linear response.


Edited by fixitsan, 02 August 2018 - 07:37 am.

900 with better bits. Owes me nothing, Makes me smile


#33 TKH

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Posted 03 August 2018 - 12:25 pm

Assume the PC is working ok and not the root cause of your problem? Don't know how you test but someone on here likely will. Also, there's a few PC maps on here, maybe that would help. I don't have a PC so can't comment further.


Edited by TKH, 03 August 2018 - 12:26 pm.


#34 mgml

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Posted 04 August 2018 - 06:30 pm

Cheers for all this info', my heads full up now.  I'll sit on this for a while and mull over what if any action I take to 'smooth' things out a bit.  The samios remap would be nice but it's a lot of bucks to solve the problem and I'm not that impressed with the bike presently to go that far.



#35 wicklamulla

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Posted 05 August 2018 - 08:09 am

Cheers for all this info', my heads full up now.  I'll sit on this for a while and mull over what if any action I take to 'smooth' things out a bit.  The samios remap would be nice but it's a lot of bucks to solve the problem and I'm not that impressed with the bike presently to go that far.

 

 

My advice is to digest what yew have read thus far.

 

Check the TCI (CDI brain thing) and tell us what part number it is, check the paperwork / service history to see if any mention has been made with reference to the Throttle Position Sensor having been replaced,  in the ideal world the mechanic that would have fitted the newer type TPS will have marked the frame around the head stock i believe with some punch marks (People of Carpe please chip in and tell me if this is the case).

 

Have a look here and read up about the modified cam chain tensioner,  i hope yer timing is spot on.  http://www.carpe-tdm...hain tensioner

 

Always start with the cheapest most basic advice. I reckon some people throw money at problems in the hope that power commanders, filters and exhaust systems will fix every issue there is going! 

 

There are people on here that run bog stock TDM 900's that have ironed out poor running problems by synchronizing the throttle bodies, adjusting the throttle free play, correct chain tension etc. 


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


#36 mgml

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Posted 05 August 2018 - 09:42 am

Yeah there's a few things I'm yet to check. The ecu/tci is ok


Edited by mgml, 05 August 2018 - 09:42 am.



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