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Alfredo3
09-23-2021, 02:22 PM
Need help

78 atc 90 has spark and new carburetor but it wont start. Check points and they seem to be in good shape what am i missing???
shortline10
09-23-2021, 06:46 PM
Check compression
Alfredo3
09-24-2021, 05:39 PM
Check compression

What should compression be
shortline10
09-24-2021, 08:45 PM
Should be anywhere from 150-190 but as long as your 100+ it should run .
Alfredo3
09-26-2021, 06:40 PM
Compression was 45lbs so definitely needs a rebuild. Who sells a top end kit
DAM shop
09-26-2021, 08:29 PM
Compression was 45lbs so definitely needs a rebuild. Who sells a top end kit

You can find a piston and rings on either this site or eBay. You’ll need to decide if you want to go hi Performnce with the piston or just a basic over bore. Going big ( high compression) will sip into the pocket book a bit because you will then want a performance cam, bigger carb and ported head. Decide what route you want to go and then start pricing your options
350for350
09-26-2021, 08:37 PM
Compression was 45lbs so definitely needs a rebuild. Who sells a top end kit

Before you dive into the top end, check your valve clearances to make sure that the valves are closing all the way.
Alfredo3
10-01-2021, 03:30 PM
https://www.ebay.com/itm/284148339024?_trkparms=amclksrc%3DITM%26aid%3D1110 013%26algo%3DHOMESPLICE.SIMRXI%26ao%3D1%26asc%3D20 191002091506%26meid%3D2cd81d4636f949d1a7388f49552f 9167%26pid%3D100935%26rk%3D2%26rkt%3D6%26sd%3D1546 12354768%26itm%3D284148339024%26pmt%3D1%26noa%3D0% 26pg%3D2332490%26algv%3DSIMRVIMLRV5WebV1_0&_trksid=p2332490.c100935.m2460&amdata=cksum%3A2841483390242cd81d4636f949d1a7388f4 9552f9167%7Cenc%3AAQAGAAAB8C0wg96GIDDlGzcsENbNrWiQ P%252F6zlnGfcsDROv8sK1%252BH6c6feu5F%252FehwgXc54x kkLEfaBXxEZ6sYIWAzT%252FmQWPQXH%252FTCfca7UEY8PMGe LC4AIIb5K9QXMg5MZh7wBEjJC3cIyHOsCS3otRmtcRpdf2xK82 vYzzjyqYvSbTML3NnBbc1Ph0H5EKrmtPifXkzBiYuhFuB6IEwk aVPh%252BjBMoMGTvsDfwiHydG%252F4i2yIH6LzUoKkdvIN04 Y5VyTIRppDG2M8bDGa41ZeLyYMYKmusdRUQ0PzYV9%252B%252 B%252BgIj%252BWHJItochXKx0gD8QL8zCwI7hrRLkRtJVnjNk b3xvUFa%252Ba%252BT7upilKi0mxVSAN%252B5DjtaGXu0QQe eyJoweC2NlbVEg%252FezrVkVNNb4165vjfzjnAhzM6TuRqqzL 6N%252FqqNAcdrxVA2WBFcysV%252FgtfniQZXpkmEY8NNNxMw %252Futc8R8UL04olsecApiMIjCiKA8wi6pDhYSaundV2mSaxs J9iud2UJnIqlU8MdJvOYkpsY%252Bijyx4mAr5TUCal%252BFh k%252BXqaYqp%252F3pG01ewjqI0AHjWF6g79kD%252Blv7rOM jwbxPG2d1cBMoDRr%252BrDut8W5PcE5Vz5DM1Pqdso5R7r7Bx Mqota075UvdoIBqGu5zoEggWgPJ256IT7Yo%253D%7Campid%3 APL_CLK%7Cclp%3A2332490

Will that work on the 78 atc 90
shortline10
10-01-2021, 05:44 PM
No that kit won’t work . A trx90 is a completely different motor .



https://www.ebay.com/itm/284148339024?_trkparms=amclksrc%3DITM%26aid%3D1110 013%26algo%3DHOMESPLICE.SIMRXI%26ao%3D1%26asc%3D20 191002091506%26meid%3D2cd81d4636f949d1a7388f49552f 9167%26pid%3D100935%26rk%3D2%26rkt%3D6%26sd%3D1546 12354768%26itm%3D284148339024%26pmt%3D1%26noa%3D0% 26pg%3D2332490%26algv%3DSIMRVIMLRV5WebV1_0&_trksid=p2332490.c100935.m2460&amdata=cksum%3A2841483390242cd81d4636f949d1a7388f4 9552f9167%7Cenc%3AAQAGAAAB8C0wg96GIDDlGzcsENbNrWiQ P%252F6zlnGfcsDROv8sK1%252BH6c6feu5F%252FehwgXc54x kkLEfaBXxEZ6sYIWAzT%252FmQWPQXH%252FTCfca7UEY8PMGe LC4AIIb5K9QXMg5MZh7wBEjJC3cIyHOsCS3otRmtcRpdf2xK82 vYzzjyqYvSbTML3NnBbc1Ph0H5EKrmtPifXkzBiYuhFuB6IEwk aVPh%252BjBMoMGTvsDfwiHydG%252F4i2yIH6LzUoKkdvIN04 Y5VyTIRppDG2M8bDGa41ZeLyYMYKmusdRUQ0PzYV9%252B%252 B%252BgIj%252BWHJItochXKx0gD8QL8zCwI7hrRLkRtJVnjNk b3xvUFa%252Ba%252BT7upilKi0mxVSAN%252B5DjtaGXu0QQe eyJoweC2NlbVEg%252FezrVkVNNb4165vjfzjnAhzM6TuRqqzL 6N%252FqqNAcdrxVA2WBFcysV%252FgtfniQZXpkmEY8NNNxMw %252Futc8R8UL04olsecApiMIjCiKA8wi6pDhYSaundV2mSaxs J9iud2UJnIqlU8MdJvOYkpsY%252Bijyx4mAr5TUCal%252BFh k%252BXqaYqp%252F3pG01ewjqI0AHjWF6g79kD%252Blv7rOM jwbxPG2d1cBMoDRr%252BrDut8W5PcE5Vz5DM1Pqdso5R7r7Bx Mqota075UvdoIBqGu5zoEggWgPJ256IT7Yo%253D%7Campid%3 APL_CLK%7Cclp%3A2332490

Will that work on the 78 atc 90