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DT175 Low Compression


JW896
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I have a '74 DT175 Enduro that had been stored in a barn for many years. It had limited spark, so I replaced the plug, pulled the flywheel and cleaned the magneto and Stator plates, and I cleaned points and condenser and all of the electrical contacts. I got decent spark after all of that. I pulled and cleaned the carb (it was not too bad). After all of that I could not get it to fire. I checked the compresssion and it tests out at 70. So any suggestions for next steps?

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In the short term squirt some 2 stroke oil in the spark plug hole. Then try bump starting it.

If you get it running and still continue to get 70psi compression you will have to strip the top end and check the ring end gaps, it may need new rings. It may even need a re-bore.

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In the short term squirt some 2 stroke oil in the spark plug hole. Then try bump starting it.

If you get it running and still continue to get 70psi compression you will have to strip the top end and check the ring end gaps, it may need new rings. It may even need a re-bore.

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oldgitonabike - I'll give your suggestion a try. How would I tell if I need a rebore? Thanks.

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oldgitonabike - I'll give your suggestion a try. How would I tell if I need a rebore? Thanks.

As a rough guide read this

Specs for your bike will be in a manual for your bike, although I dont suppose they will be much different

...Paul

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As a rough guide read this

Specs for your bike will be in a manual for your bike, although I dont suppose they will be much different

...Paul

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In the short term squirt some 2 stroke oil in the spark plug hole. Then try bump starting it.

If you get it running and still continue to get 70psi compression you will have to strip the top end and check the ring end gaps, it may need new rings. It may even need a re-bore.

oldgitabike - I took your suggestion only I used some Marvel Mystery Oil and got it started. Ran it for a few miles to try and free up the rings, but I ran into two problems before I had a chance to recheck the compression: (1) I can't seem to get it to shift into neutral. Not sure what would cause that problem. (2) The kick starter locks at the lower end of the stroke. I checked the manual and I should be able to get to the clutch through the clutch plate, except the bolts were frozen, so I pulled the engine. I have the crankcase opened up I am proceeding with the diagnosis. As long as I have it torn down do you think I should pull the head and cylinder to check the piston and rings. Any other suggestions for things to check as long as I have it dismantled? What would I need to check to see what causes the failure to shift to neutral?

Thanks

JW896

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