ST_SHP
Parting a wrecked '91
I've finished putting back together my '91 ST Universal Japanese Motorcycle project. I now have about 30 miles on it. It starts up & runs fine with a few backfires when cold, seems to make good power in the low range- getting up to around 60 in 2nd gear is quick. Once I get on the road in higher gears, it turns into a slug! If I'm riding at a constant 60-65 and roll on the throttle, it stumbles pretty badly and barely accelerates. I don't have a working tach as yet so I can't give an RPM range. On a long open road, it tops out at 95 MPH.
When I put the bike back together, I put in a new fuel pump (the mod using one from a Honda Civic that's posted here) & filter, bypassed the vacuum thing, and dipped each carb for 24 hours and used new seals from factory carb kits. The carbs on the bike (and air cleaner) had been modified by a PO. The carbs with #135 jets (stock is 128 as I recall)- the air cleaner had several holes drilled in it for more airflow. There's a writeup online somewhere about this- it was supposed to make more power. The bike has a fresh tank of premium fuel.
I need to recheck the compression, but it really seems like a carb issue. One other thing- I used a laser thermometer on the exhaust and the right side was reading a lot higher at idle than the left- running lean?
Does this sound like anything other than carbs? If they are the problem, is there a competent rebuilder I can ship them to?
Thanks for any help.
EDIT
The carbs were also synched using a flowmeter.
When I put the bike back together, I put in a new fuel pump (the mod using one from a Honda Civic that's posted here) & filter, bypassed the vacuum thing, and dipped each carb for 24 hours and used new seals from factory carb kits. The carbs on the bike (and air cleaner) had been modified by a PO. The carbs with #135 jets (stock is 128 as I recall)- the air cleaner had several holes drilled in it for more airflow. There's a writeup online somewhere about this- it was supposed to make more power. The bike has a fresh tank of premium fuel.
I need to recheck the compression, but it really seems like a carb issue. One other thing- I used a laser thermometer on the exhaust and the right side was reading a lot higher at idle than the left- running lean?
Does this sound like anything other than carbs? If they are the problem, is there a competent rebuilder I can ship them to?
Thanks for any help.
EDIT
The carbs were also synched using a flowmeter.