Project DTZr.....a DT125R love story
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Time for a little update.I've finished the reed cage modification and will explain why did it.
I had 2 failures in fiber reed pedals,and you know how difficult is to take out the reed valve.My first set of boyesen dual stage where used but in very good condition,they bent in various places probably because of age but after doing 1000km,the second set was simple fiber pedals and even the adjustment's I did because of bad finish quality,they couldn't handle the tune of the engine at high rpm's.So i went back to basics,searched the yamaha 2 stroke engines with similar specs as my tuned and saw what reed valve they used. RZ350,RD125LC,YZ125(80's models),TZ750 had the same reed valve.
Purchased everything genuine,made the mod's to fit the DT rubber joint and already had done the widening to the engine cases as future plan.I preferred the above setup because of the shorter and wider steel pedals.Shorter pedals handle higher rpm better,wider are more robust,genuine yamaha made in japan quality steel.
For the long run,I asked a good friend and old timer mechanic in 2 strokes that helped me with his knowledge,if he has ever see failed steel reed pedals especially in Yamaha's.He said the the worst he saw was bent pedals to touch the stoppers from racing engine,never broken,but where genuine.
PS. Added bonus,this reed cage does not block the c-port in the back of the cylinder and you don't need spacers that are used in the DT reed cage for that reason.
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@MadGyver I believe the reason for changing reed petals from stainless steel to carbon/ GRP was not for fear of them breaking, though it would be catastrophic I think it's very rare. But more due to them suffering from metal fatigue and flutter.
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@markus-w said in Project DTZr.....a DT125R love story:
@MadGyver I believe the reason for changing reed petals from stainless steel to carbon/ GRP was not for fear of them breaking, though it would be catastrophic I think it's very rare. But more due to them suffering from metal fatigue and flutter.
I agree but I had to do the change by my bad experience with aftermarkets.Also it's easier to find genuine parts than aftermarket locally for me for the DT.
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@Calum said in Project DTZr.....a DT125R love story:
I fitted blaster V Force reeds to mine.
I must be not running my bike hard enough
When I was alone and had this bike in pieces I wanted to put v force.
Now I am with family,one kid and second on the way.My pockets are not running that hard.
To get the vforce it will cost me around 120 euros,I got this reed cage and 4 pedals (2 installed and 2 for backup)
for 70 euros. -
Very interesting Project. could you tell me current stage of bike? have checked dyno?
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Current stage partly disassembled because of electrical problems,checking wiring and everything from the ignition system. Had heavy misfires but not always until it died on me. Dyno is not checked yet.
I am recovering from health issue and everything is on hold. -
Have you got another CDI you can swap out? Or the pick-up from the stator? Could even be side stand related! I love ignition faults! Is it sparking at all now? Give us some deets bud, it’s been so slow I’ve been thinking about buying a newspaper lately!
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For 1000km everything worked fine,the last 200km were full of trouble.carb problems(solved),reed problems(solved) and last electrical problems(in progress).
CDI ok.
Side stand switch was removed from the beginning,electrical connection patched and tested ok.
Stator plate not tested after the incident but was tested and repaired before the bike was put together.
At first I had weak spark,it was faulty ignition coil,changed with used one,worked ok for 10km's, then heavy misfires and ok only on idle.Then never started again.Removed the ignition coil and tested it with multimeter, out of specs.
Order a new from Yamaha,arrived but health issue emerged and now I am on recovery and the bike on hold for recovery also. -
Project's problem update.
I installed the new ignition coil,fired right up after 3 months,but the problem remains,above 5-6k misfires and engines shuts off.Now I am troubleshooting the stator coils.
I also checked the entire electrical cabling of the DT and cleaned every connection.Didn't find anything but wanted to be calm from that point. -
Do you know which stator you have fitted? There were 3 different types. The first type has 3 separate windings bolted to the backplate, 1 for lights, 1 for ignition and 1 for charging the battery. As far as I know this is the only type that is repairable…
Don’t neglect checking the magnetic pick up and it’s wiring, especially where it exits the casing near the sprocket…
Though from your findings it sounds like the ignition part of the stator is off…
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@SpookDog
Yes I know,it's the repairable one,3NC stamp.I order a used in excellent condition from a trading site for vehicles and parts.I spoke with the guy that sells,it had 3,I choose from a photo the one that looked almost new,he told me that is from a low km's DT,it has the 3MB stamp but they are identical.
I checked the parts catalog from various models,the years I want have same codes. -
@MadGyver
You got the whole stator coming to you? It’s a lot easier than soldering in a new winding/coil I imagine!
I’m guessing yours is putting out erratic voltage/ampage. Have you looked for dry solder on the ignition winding?…Could you see anything hinky with the one fitted? I had a dud lighting coil that only had slight black discolouration to the varnish, but was totally fubar…
PS how did you check the CDI?
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@SpookDog
It's the same difficulty for me,replace coil or the whole stator,it needs to come off in both situations.
When restomod the bike I had repaired and checked everything electrical and was in specs by the manual.
Every connection was cleaned or re-soldered.
There is a possibility that source coil/pulser on stator didn't handle the 13000 rpm
some times after the run in first 1000km i did.
CDI checked for short circuit or infinite resistance only.
I am searching for the ohm specs that should have compared with the readings taken,if found will be posted here. -
Problem update
I've checked everything twice the last days,fixed a damaged connector from corrosion that seemed ok,cleaned every connector and earth point,resolder a cable that was holding by a hair of copper,all stator coil's is in specs and tested,the used stator I purchased is ok also but no change when used it.
Rectifier regulator checked and outputs the volts as it should (managed to start the bike for 10 mins run at idle,when gave some gas and reached 5000rpm engine shut off and did't run again,2 days have passed with trying).
So the only thing that cannot be fully tested is the CDI.and a Project update
I''ve managed to find a back wheel (17inch) from a TZR125 4FL that is exactly the same even in the lettering with the current 18inch from a TZR250 3MA.It's a little hard to find tires at good price for 18inches where I live.
Will post pics when ready.Now the bike will be 3.00x17 front and 3.50x17 back and not the 4.00x18 back wheel that has now. -
Are you using a genuine Yamaha ignition coil?
I've had this when I mistakenly bought a "Racing" coil off of eBay. Bike would initially run fine, then the coil would be saturated and the bike would barely idle let alone rev off! I had to ride back from Wales like this and it would struggle to do 50mph.
Bought a brand new genuine coil and the problem went away.
My brother had the exact same problem on his RD350, crappy Chinese coils...
