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My Suzuki DS 185


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It sounds like a great event, have a great ride!

We have a two day event on our schedule that I hope to ride this year. I checked last season on the first day then rode the next. This is my second season competing in motorcycle trials but my 50th of 2 wheel amateur dirt racing. Let me know how the weekend goes.

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  • 3 weeks later...

Quick update! I have had a number of small setbacks. At one point in the process I bonded in an aluminum bushing to support the shift shaft after the case had been damaged,  I don't remember hitting the shifter on anything but by the end of the second loop the gear shaft was flopping around and the oil had been let out.




When I got back to the shop I pulled out my "arc-less" resolution, ground out the goo and filled it with a high-zinc filler.














I then machined the weld away and reamed to 12mm





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At my next outing I kept having fuel delivery issues along with gear box oil making it into the crank case.




The red disc type filters are useless. I probably could have done a better job cleaning out the tank after switching to a bigger filler.

I think I have the bugs worked out. i removed the base gasket (.5mm) and found an improvement. I have another cylinder/head combo and am thinking planning a 2mm skim on the bottom of the cylinder and weld/rework the head to correct squish space and raise compression slightly.

Here is how it looks now.







More later, thanks for looking

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  • 4 weeks later...

I was on top of the world for a while! The bike has been running good buut I made a mistake and fell off a rock breaking some ribs. I figure now was a good time to try to make some improvements. I received some Betor fork upgrade parts from Gerry M. in the UK (which I have done nothing with so far (Get well soon to Gerry) and decided to make a new pipe and lower the cylinder by 1.0mm to lower the RPM of peak power.  I made the belly of the pipe much smaller and decreased the angle of both the cones. I took one quick painful test ride and the modification eliminated the hit at high RPM and added a little at low revs. 

I had been running without a base gasket for a while (.5mm) so I decided to remove 1.5mm from thee bottom of the cylinder and add the base gasket back for 1mm drop. I also machined away 1.5mm of squish band.

During that process I also opened up the clutch cush drive and found the bumpers were shot. I took apart a second one and added all solids rather than the torus (donut) shaped parts so there is no more play 

Cylinder mod then cush drive rebuild.





Next thing was to add the squish band clearance to the head. I drilled a 160mm disc with six holes and put it in a buck chuck (four jaw) 






Even before I started shaving the cylinder my carb was still contacting the gearbox and probably causing issues. I took this opportunity to raise the carb flange about 6mm my rotating the spigot up about 6mm at the bolt hole. I failed to get a photo of the finished product. 




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It could be. Around here there are more tools than people to use them so I don't pamper them and discard them at the first show of weakness. That particular one has a very wide blade for it's handle size and it's very tough.

I got the intake port flange cleaned up and also deburred the bottom of the barrel.

I always put way too much weld when I do build-ups which is usually still too little. Once The welding was done I bolted the cylinder to a 90* angle plate and tried my best to get it set with old flange parallel to the cutter face. It takes a while. Once faced it's just a matter of drilling a hole and tracing around the flange. I don't see a need to do anything further. 



I figured I would do a quick check that I had some carb clearance.




I had drawn the combustion chamber as a solid model but the area number was always weird till I realized most calculations give your surface area which is useless. I have been checking the areas manually as a reality check. 




Nothing like learning while doing. Youtube videos are very helpful but you find your own recipes as you go. 



More later, thanks for looking.

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  • 2 weeks later...
  • 2 weeks later...

It seems to be typical to remove some clutch springs to lighten up the action a bit. I figured I would give this a try but found that this model has seven springs so you can't remove an even amount. I figured that as long as the plates all clamped at the same time it didn't matter. The clutch is turning much slower than the crank and the engine is never really revved much. I made certain assumptions regarding the clamping pressure of asymmetrical springs and because these springs are held to the hub by their body I could adjust preload to test my theory so I bought a broken cover on ebay and cut huge holes through so I could measure the distance between pressure plate and frictions. 





I have had a set of gage blocks for years and was happy to get some use out of them finally,



The clutch lever has the same spline as the shifter so I used shifter to actuate the clutch to check the run-out of the pressure plate.



I have been chasing a tiny gear oil leak for a while and figured I should vent the gear box to see if it helped. The vent is in an with no splash.


I rode last weekend for a bit but decided to work after a couple observation loops. The bike is working well but the clutch isn't broken in yet. I am enjoying the lighter clutch pull with no side effects so far,




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  • 1 month later...

Rode a twinshock event in the weekend that 1 of the guys had his first ride on his converted TF125 which is a farmbike that is called a mudbug over here. For a first ride it went really well although he's realised building a airbox may be better for the carburation than the pod filter fitted at the moment

I'll have to save a photo of it & post it up for comparison


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19 hours ago, tony27 said:

Rode a twinshock event in the weekend that 1 of the guys had his first ride on his converted TF125 which is a farmbike that is called a mudbug over here. For a first ride it went really well although he's realised building a airbox may be better for the carburation than the pod filter fitted at the moment

I'll have to save a photo of it & post it up for comparison


I have heard of those TF bikes and seen a few photos of the stock version. They have an extra motor mount at the back of the engine and I think the kicker is situated higher in the case like the RM engines. They seem like a great platform for a conversion and I would love to see what the guy came up with!

Edited by Ftwelder
Added the letter "y"
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  • 8 months later...

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