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TTR90 Questions

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Hi,

My son has a TTR90, and today it went from being difficult to shift to borderline impossible. Searching these forums, it seems that they are difficult to shift at the best of times. Does anybody have any suggestions or advice before I tear into this thing? Is there any aftermarket fixes?

2nd question, the thing takes forever to warm-up. I'm thinking of going a little richer on the pilot. Has anybody does this, and if so, what is the recommended size?

Thanks for any help.

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I had the shifting problem happen 1 time on my sons bike, but it never happened again so I'm not sure what the problem is. His bike takes a long time to warm up also. I have to run it at high idle with a 1/2 choke for several minutes before we ride. Once it is warmed up, it runs great. We rode in 30 degree weather last fall and it took forever to get it up to temp because those little engines don't produce much heat anyway.

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check the carb heater , its between the intake and the carb, its basically an electric heater that helps the problem . as for the shift problem , we never had one .

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check the carb heater , its between the intake and the carb, its basically an electric heater that helps the problem . as for the shift problem , we never had one .

I think the carb heater is just to keep the inside of the carb from icing up in cooler weather. It is similar to the carb heaters that airplanes use to keep the carb venturi from icing with the high velocity air fuel mix in a small opening. I don't think it is going to help heat the engine up any.

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Update:

After tearing into the right side cover, and watching the shift mechanism in action, I came to the conclusion that there was nothing obviously wrong. Then it dawned on me. The shifting problems started immediately after my last oil change. The last change I used the same super-slippery Motul stuff that I use in my WR. MISTAKE. I re-assembled it, filled it with the cheapest dinosaur 10W30 I could buy, and it shifts like a champ.

I then read the manual (which is always good to do after you've screwed everything up), which in as many words said don't use high quality or synthetic oil because it affects the clutch. What they don't say is that it won't shift any more.

Still haven't tried changing the jetting.

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Update:

After tearing into the right side cover, and watching the shift mechanism in action, I came to the conclusion that there was nothing obviously wrong. Then it dawned on me. The shifting problems started immediately after my last oil change. The last change I used the same super-slippery Motul stuff that I use in my WR. MISTAKE. I re-assembled it, filled it with the cheapest dinosaur 10W30 I could buy, and it shifts like a champ.

I then read the manual (which is always good to do after you've screwed everything up), which in as many words said don't use high quality or synthetic oil because it affects the clutch. What they don't say is that it won't shift any more.

Still haven't tried changing the jetting.

I don't think I have seen anything in the manual that says not to use a synthetic and that you should use a low quality oil??? The only thing that I read was to use a motorcycle rated oil (JASO MA) or a non-energy conserving oil. Was the Motul you used a friction modifier free motorcycle oil? I have been using Mobil 1 MX4T or Amsoil Motorcycle 10W40 in mine. They are both high quality synthetics and mine shifts fine.

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I use Castrol 5w-30 energy conserving in both TTR50 and TTR90 and they run and shift beautifully. The "energy conserving" myth, if you look in your manual, calls for non-USA/Canadadian oils and it states to avoid "Energy Conserving II" oils. I don't think they have those "II" oils in North America.

Karl

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