Hope someone can help me b4 me and my Bulgarian mechanic tear our hair out......
I have a 1998 TDM 850 with 35,000miles, bought 1 year ago and hasn't run right since.
Standard I think apart from an Arrow stainless 2-1, which isn't loud at all...
Lots of hesitation below 4000 rpm, after which it runs perfectly, plug chop reveals normal colour. Seems good on petrol, despite not needing choke to start, which it does easily.
Ticks over a little roughly and can be ridden, but not happy below 4000, nightmare round town, worse when hot.
Replaced 1 coil, 2 plugs, new carb rubbers, cleaned carbs and shimmed valves with no effect, although I think it was better for a short while after the new plugs and coil, might have been kidding myself though....
The mechanic proposes messing about with float bowl heights but I think electrics more likely, but really, God knows......
Where would people start???
Rough Running Below 4000 Rpm, Help!
Started by
bulgariantdm
, May 28 2010 04:38 pm
6 replies to this topic
#1
bulgariantdm
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- Member
- 16 posts
discovering Carpe
- Location:bulgaria
- TDM model: 1998
Posted 28 May 2010 - 04:38 pm
#2
TonyDevil
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- Supporting Member(thanks)
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- 9,336 posts
seagull squadron leader & founding member of GoatTracKrew
- Location:Saarfend-on-Sea, Essex
- TDM model: 1991
Posted 28 May 2010 - 04:47 pm
emulsion tubes/needle jets replaced?
do you have a dyno run with fuel/air mixture reading throughout the rev range?
do you have a dyno run with fuel/air mixture reading throughout the rev range?
"Never argue with an idiot. They just bring you down to their level and beat you with experience"
My TDM :
Black 1991 850 MK1, 160k+ miles(ish, best guess really, gave up trying to keep count after 3rd set of clocks and 3rd engine), PilotRoad2 tyres, custom stubby exhaust system, bluespot calipers & goodridge braided hoses with dunlopads, maxton forks, Ohlins shock, kedo handguards, stainless TDM grill, Scottoiler with lubetube & dual nozzle thingy, Givi Wingrack2 with E45 & 2xE36s, renntec crash bars, Autocom with blueteeth & PMR radio, TomTom Rider2, Optimate IIIsp, Bagster tank cover, anti-dazzle coating
to fit : led spotlights, heated grips, new braided lines and rear caliper that actually has bleed nipples
Silver-ish 2003 900, 70k miles, PilotRoad3 front tyre (new@65k) & PR2 rear(new at 69k), Renthal 755 bars with KTM handguards, oxford unheated grips, power commander 3usb, scorpion titanium exhausts, standard screen with vario winglet thingy, stainless grill, oem centre stand, bagster tank cover, givi monokey topplate mounted on grabrail with V46 topbox, Givi PL pannier rails with E21s, crash bungs, mirror extender thingys, Halfords Advanced Laser Blue brillance bulbs, 21w led spotlights, touring scottoiler with leehenty dual nozzle, Autocom with blueteeth & PMR radio, TomTom Rider3 Urban, winter style anti-dazzle coating
to fit : led brake light strip, replacement heated grips
current rides : TDM850 3vd/mk1=tourer&scratcher, TRX850=weekend twisty toy, 2003 TDM900=commuter, 2005 TDM900=unmolested. Gone but not forgotton : XTZ750=overland touring toy, GS500e, GS125
If a strange looking truck driver honks at you & gives you the thumbs up, its could be me 
#3
bulgariantdm
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- Member
- 16 posts
discovering Carpe
- Location:bulgaria
- TDM model: 1998
Posted 28 May 2010 - 05:01 pm
QUOTE(TonyDevil @ Fri 28th May 2010, 07:47 PM) <{POST_SNAPBACK}>
emulsion tubes/needle jets replaced?
do you have a dyno run with fuel/air mixture reading throughout the rev range?
do you have a dyno run with fuel/air mixture reading throughout the rev range?
well, the previous owner claimed that there were new carb parts fitted (did he say brass jets or something?) but now I'm beginning to doubt his word........
nothing so hi-tech as a dyno run here I'm afraid.......
I thought I read that emulsion tubes were linked with high fuel consumption.....I've just emptied a tank in 175 miles, mostly at 100mph + which doesn't sound too bad?
But I'll take any advice
#4
sweep
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- Member
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- 120 posts
Carpe Regular
- Location:Warrington
- TDM model: 1997
Posted 28 May 2010 - 08:30 pm
I can only go off what happened to me.
I had all your problems apart from yours getting worse when hot and tried to clean the carbs with what I had but it was still there.
In the end I paid for a mechanic to look at it and it ended up being one of the holes in the carb body that was blocked completley.
This was causing it to run on one cylinder, especially poor at low revs and town riding.
Seemed to be OK above 4000 rpm.
He was amazed I was able to ride it at all.
Mine went " CLUNK CLUNK CLUNK" at 2000 rpm and below in second.
It runs like a dream now and it's so nice to get those revs down around town and do a bit of filtering without ALWAYS using the clutch.
I had all your problems apart from yours getting worse when hot and tried to clean the carbs with what I had but it was still there.
In the end I paid for a mechanic to look at it and it ended up being one of the holes in the carb body that was blocked completley.
This was causing it to run on one cylinder, especially poor at low revs and town riding.
Seemed to be OK above 4000 rpm.
He was amazed I was able to ride it at all.
Mine went " CLUNK CLUNK CLUNK" at 2000 rpm and below in second.
It runs like a dream now and it's so nice to get those revs down around town and do a bit of filtering without ALWAYS using the clutch.
#5
Studley Ramrod
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- Root Admin(A)
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Monkey Boys Monkey
- Location:HELLO ! I'm in the Library...Notts
- TDM model: 1993
Posted 29 May 2010 - 09:59 am
I'd let the mechanic do the float bowl heights as they are critical, a millimeter or two makes a lot of difference.
Generally speaking, a problem that gets worse when the engine warms up is a sign that the bikes running rich. It could be bogging down at low revs and if the emulsion tubes are new and all the gaskets and o rings are good then I'd go with the mechanic's proposition.
As Sweep mentions also, it could be a blockage or air leak somewhere.
I doubt it's an electrical problem.
Generally speaking, a problem that gets worse when the engine warms up is a sign that the bikes running rich. It could be bogging down at low revs and if the emulsion tubes are new and all the gaskets and o rings are good then I'd go with the mechanic's proposition.
As Sweep mentions also, it could be a blockage or air leak somewhere.
I doubt it's an electrical problem.
Mk2a 2000 in Silver. Top end Refurb @ 41100 miles, Scottoiler, Renthal Road High Bars, Up & Back Bar Risers, Bellypan, DL650 Handguards, Capt. Picard Bar Ends, House of Henty SS Wheel spacers, New Seat Cover Fitted. 58 MPG !! Now owned by chrisbee ! Studley's mk2a Bloggerydoodaah ! Photos of my first MK1 Photos of my MK2a TPLQHCSRSFC No. 1 Fan
#6
bulgariantdm
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- Member
- 16 posts
discovering Carpe
- Location:bulgaria
- TDM model: 1998
Posted 30 May 2011 - 07:33 pm
QUOTE(bulgariantdm @ Fri 28th May 2010, 07:38 PM) <{POST_SNAPBACK}>
Hope someone can help me b4 me and my Bulgarian mechanic tear our hair out......
I have a 1998 TDM 850 with 35,000miles, bought 1 year ago and hasn't run right since.
Standard I think apart from an Arrow stainless 2-1, which isn't loud at all...
Lots of hesitation below 4000 rpm, after which it runs perfectly, plug chop reveals normal colour. Seems good on petrol, despite not needing choke to start, which it does easily.
Ticks over a little roughly and can be ridden, but not happy below 4000, nightmare round town, worse when hot.
Replaced 1 coil, 2 plugs, new carb rubbers, cleaned carbs and shimmed valves with no effect, although I think it was better for a short while after the new plugs and coil, might have been kidding myself though....
The mechanic proposes messing about with float bowl heights but I think electrics more likely, but really, God knows......
Where would people start???
Can I now add that carbs have been balanced, float needle valves replaced, float heights measured, new battery, but still the problem persists although not as bad - but trying to filter in traffic, hold a constant low speed or ride hairpins 2-up in anything other than 1st gear is all horrible!
It is slightly worse when hot, never needs choke and when it does cough/hesitate it gets better if I throttle off a little, leading me to suspect it's running rich...........
Incidentally, I ordered some of the emulsion tubes, but my Bulgarian mechanic (old-school engineer) reckoned the existing ones were better quality than these new special ones (at about 50 quid!) or should I just override him?
Anway, big thanks to all those offering help - I really want to enjoy this bike!
I have a 1998 TDM 850 with 35,000miles, bought 1 year ago and hasn't run right since.
Standard I think apart from an Arrow stainless 2-1, which isn't loud at all...
Lots of hesitation below 4000 rpm, after which it runs perfectly, plug chop reveals normal colour. Seems good on petrol, despite not needing choke to start, which it does easily.
Ticks over a little roughly and can be ridden, but not happy below 4000, nightmare round town, worse when hot.
Replaced 1 coil, 2 plugs, new carb rubbers, cleaned carbs and shimmed valves with no effect, although I think it was better for a short while after the new plugs and coil, might have been kidding myself though....
The mechanic proposes messing about with float bowl heights but I think electrics more likely, but really, God knows......
Where would people start???
Can I now add that carbs have been balanced, float needle valves replaced, float heights measured, new battery, but still the problem persists although not as bad - but trying to filter in traffic, hold a constant low speed or ride hairpins 2-up in anything other than 1st gear is all horrible!
It is slightly worse when hot, never needs choke and when it does cough/hesitate it gets better if I throttle off a little, leading me to suspect it's running rich...........
Incidentally, I ordered some of the emulsion tubes, but my Bulgarian mechanic (old-school engineer) reckoned the existing ones were better quality than these new special ones (at about 50 quid!) or should I just override him?
Anway, big thanks to all those offering help - I really want to enjoy this bike!
Edited by bulgariantdm, 01 June 2011 - 08:03 pm.
#7
Studley Ramrod
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- Root Admin(A)
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Monkey Boys Monkey
- Location:HELLO ! I'm in the Library...Notts
- TDM model: 1993
Posted 31 May 2011 - 08:07 am
Sounds like the emulsion tubes need replacing, also worth checking/replacing the choke plungers and also the pilot adjustment screws.
Mk2a 2000 in Silver. Top end Refurb @ 41100 miles, Scottoiler, Renthal Road High Bars, Up & Back Bar Risers, Bellypan, DL650 Handguards, Capt. Picard Bar Ends, House of Henty SS Wheel spacers, New Seat Cover Fitted. 58 MPG !! Now owned by chrisbee ! Studley's mk2a Bloggerydoodaah ! Photos of my first MK1 Photos of my MK2a TPLQHCSRSFC No. 1 Fan
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