Best beginner motorcycle

I think there’s something else going on… To answer your questions, the engine runs OK, I don’t think it’s the fuel since the last time it completely failed to start I could smell unburned gas from the exhaust pipe, and runs good when it’s started.

As of Wednesday it was tough to start both in the morning and after work, then on Friday morning it started overheating on the way to work (or at least throwing false positives; the engine didn’t feel terribly hot to the touch, and normally the fan kicking on would roast my right leg at a red light but the air was just merely warm), so as of Friday evening it’s back in the shop again, so we’ll see.

Thats also a sign of the fuel pump because when they are going they can also flood the engine. Could also be a leaking valve thats messing up the mix or letting fuel out.
the valves themselves may have gotten full of crap and maybe sticky.

Really need to get the ECU connected to a computer and see what’s going on (that could be on its way out also), what bike is it by the way

Pretty sure it is a

I had read that but some how blanked it out.

Just had a Quick Look online the overheating pops up a bit, a couple of the things to check, the coolant has a proper mix (not watered down) and to spec, a fully synthetic oil again up to spec. You mentioned its not actually getting hot, it just thinks it is. Did you replace the sensor when you were having problems? if so may need to check the wiring is ok (if it did overheat it could have been damaged) also ECU may not be trusting the new sensor.

You have it with the mechanic now so they should be working their way through the checklist and whatever codes it’s throwing up. if they can’t fix it on the 3rd time I would be looking for recommendations for a new place.

At one point it was the coolant temp sensor about 1.5 months ago, but they noticed that the sensor wasn’t properly tightened, the subsequent scan last week didn’t show anything having an error and they replaced the sensor the last time anyway.

That’s a thought, hope it isn’t the fuel pump but I’ll keep that in mind if it does break again… I’ll also see about throwing in some fuel system cleaner.

Thanks for all your help!

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Even though strictly speaking, this is derailing from the main topic, here’s an update if any reader is curious…

Both based on similar problems I had with a friend’s 1992 Isuzu Rodeo (but it was a 20 year old SUV that already reached “forbidden milkshake” status at the time, not a 2020 bike that’s 3.5 years old) and my own research, I finally got fed up and took it to friend’s friend’s shop a bit further out instead of the dealer less than a klick away, and told the shop owner “I don’t care if this is indeed the problem or not and I’ll spend any amount, but could you please change the head gasket and boil test the thermostat for me instead of just hooking it up to a computer and topping off the coolant?”

It turns out and as he confirmed, Yamaha’s QC outside of Japan is pretty bad (which as someone who works in IT, not the least bit surprised). The gasket indeed had a few minor failure points, but I forgot to take a pic of that.

He discovered that the coolant was actually spurting out from where the gasket is when he tried to start the bike, as well as bits of dried coolant and what appears to be oil on the engine, and best of all: When he took it apart, he discovered the cylinder head was very slightly warped so that was resurfaced, and also put in a new gasket and sealant. Thermostat was still working properly.

$8000 TWD later, picked it up on Monday evening and it’s running pretty good so far, but the big test is when I go back to work tomorrow after not riding it all day since Tuesday night, especially since the problem is more prevalent if I let it sit.

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As a random question. Not totally OT because its YAMAHA scooter. My RS-Z 100 the rear suspension is oily and scooter shop said 5000 ntd
to repair it. Basically the rear suspension, since there is only 1 damper, is losing oil and thats why its not as stiff as before anymore. Usually could be only a small O- gasket thats leaking or the whole unit is bend and need to change. I would like to double check some price for a rear suspension, but can not find online. Someone had similar situation before? 5000 is reasonable?

just for looking for a little more information what year is it? is it the 2009, rs-z100 or is it the one they reintroduced later as the RS-zero 100? The latter can have a rear shock with additional reserve (piggy back shocks)

if its the former I’m getting part number 5HK-F2210-10 and thats coming in at around 1000nt for the part alone

https://shopee.tw/俗俗賣YAMAHA山葉原廠-後緩衝器-白色-RS-Z-100-後避震器-後叉-料號:5HK-F2210-10-i.191701832.7943352442

for the latter I’m getting part number 1CG-F2210-30 that coming out around 2500nt for the part
https://shopee.tw/product/29930190/25655496693?srsltid=AfmBOoqQ8as6fKaUAyoJ0UvvcL0oKA1Q95aS1AV0bVPI1J3OiHACrRyQBoc

The one with the additional reserve should be more expensive still.
I suspect they are going for the better rated one whichever version you have,
don’t forget to take into consideration fitting if you buy yourself.

It may be worth looking around for an aftermarket part from one of the local dealers like below, contact them and see if they have a shop who fits there parts near you.

(I have no affiliation with the above company its just one I quickly found online so I don’t know their products)