TDMR40 question

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dandywarhol
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TDMR40 question

Post by dandywarhol » Fri Nov 07, 2014 1:31 am

I've just picked up a pair of Mikuni TDM40 carbs stamped TDMR 40D6 T731.

The parts manual shows a linkage for accelerator pumps (part numbers 93/94) but there is no link and bellcrank on mine. What do others have on their TDMRs?

http://www.allensperformance.co.uk/images/exp-tdmr.gif
1996 TRX 850, blue, Ohlins 46HRCLS, Race Tech Gold Valves, 0.90 springs, Venom pipes, R6 brakes............
1974 Yamaha RD250A, Candy Blue
1998 Yamaha SZR660, blue of course
1967 Yamaha TD1C 250, Blue and white

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dandywarhol
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Re: TDMR40 question

Post by dandywarhol » Sat Nov 08, 2014 11:52 am

Think I'll answer my own question. The carbs were built from a bank of 4 for a ZZR1000. Only one of the carbs has the pumper and feeds the others by pipework.

Someone has a pair of carbs with a pumper and I've the other pair. :?

Has anyone used a set of TDMR40s without an accelerator pump? I'd be interested to know before \I send them back to Germany under Ebay misrepresentation rules

Cheers, Alan
1996 TRX 850, blue, Ohlins 46HRCLS, Race Tech Gold Valves, 0.90 springs, Venom pipes, R6 brakes............
1974 Yamaha RD250A, Candy Blue
1998 Yamaha SZR660, blue of course
1967 Yamaha TD1C 250, Blue and white

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Re: TDMR40 question

Post by Tarwetijger » Sat Nov 08, 2014 9:43 pm

I am using TDMRs with acc pump, yes. But I doubt if it will do worse without them.
All they do is just squirt a load of petrol in, getting the mixture too rich for a short moment.

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Re: TDMR40 question

Post by dandywarhol » Sat Nov 08, 2014 10:29 pm

Thanks Mr T. I was wondering if there would be a big flat spot under acceleration? I've dealt with auto engines where the accelerator pump has been faulty and the car has been a pig to drive through the "hole" in the fuelling.

The seller is willing to take them back - think I'll do it - unless anyone has used TDMRs without the pumper...........................................
1996 TRX 850, blue, Ohlins 46HRCLS, Race Tech Gold Valves, 0.90 springs, Venom pipes, R6 brakes............
1974 Yamaha RD250A, Candy Blue
1998 Yamaha SZR660, blue of course
1967 Yamaha TD1C 250, Blue and white

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M.V.
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Re: TDMR40 question

Post by M.V. » Tue Nov 11, 2014 2:02 am

Tried to set up a set of flatslides on a friends bike from a two stroke (no accelerator pump), don't do it. [-(

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dandywarhol
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Re: TDMR40 question

Post by dandywarhol » Tue Nov 11, 2014 3:01 am

Thanks MV. Out of interest, what 2 stroke had pumps?

I once had a racing RD200 with 32mm Amals which had powerjets fitted but they weren't mechanical pumps, they relied on vacuum to add the extra fuel at full throttle
1996 TRX 850, blue, Ohlins 46HRCLS, Race Tech Gold Valves, 0.90 springs, Venom pipes, R6 brakes............
1974 Yamaha RD250A, Candy Blue
1998 Yamaha SZR660, blue of course
1967 Yamaha TD1C 250, Blue and white

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M.V.
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Re: TDMR40 question

Post by M.V. » Tue Nov 11, 2014 5:17 am

Not sure, but these were jetted way too big stock, so I assume the two strokes are much richer but don't use a power jet, probably because they are usually at full throttle or off (or should be I guess!)

Even jetting them back to normal ish we still couldn't get consistent results with partial & quick WOT.

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Re: TDMR40 question

Post by misterdimwiddy » Fri Nov 14, 2014 4:58 pm

When my FCR41's had an accelerator pump fault (no fuel pumping) the motor ran dreadfully. The pump is there for a reason and it will be a pig to ride without it in my opinion.

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Re: TDMR40 question

Post by dandywarhol » Fri Nov 14, 2014 6:07 pm

Thanks for all your replies - I've sent the carbs back to Germany. Still looking around for a pair.................
1996 TRX 850, blue, Ohlins 46HRCLS, Race Tech Gold Valves, 0.90 springs, Venom pipes, R6 brakes............
1974 Yamaha RD250A, Candy Blue
1998 Yamaha SZR660, blue of course
1967 Yamaha TD1C 250, Blue and white

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brockzila
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Re: TDMR40 question

Post by brockzila » Fri Nov 14, 2014 8:24 pm

So if you got hold.of a.full bank of four carbs it would be possible to make a set of carbs for a trx with a 40mms bores?

Try a zzr forum. That motor.has an issue with spinning main bearings so there will.be a.few sets of carbc with out motors around.
Is it Brock friendly???

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dandywarhol
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Re: TDMR40 question

Post by dandywarhol » Fri Nov 14, 2014 11:11 pm

Yep, been looking down that route ☺
1996 TRX 850, blue, Ohlins 46HRCLS, Race Tech Gold Valves, 0.90 springs, Venom pipes, R6 brakes............
1974 Yamaha RD250A, Candy Blue
1998 Yamaha SZR660, blue of course
1967 Yamaha TD1C 250, Blue and white

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