First valve adjustment TT250..found out some things

Goob · 04-05-2020, 10:30 AM

Howdy,

Between yesterday and today I did my first valve adjustment on my TT250. I have done adjustments before (in 1977! on my Honda XL100), but a first on this bike.

What I found was that the left side plastic, seat, or gas tank don't have to be removed as in the CSC tutorial. I was able to easily remove the valve cover from the right side.

My tank plastics are already off, so if you have those they may have to be removed; if not for taking the valve cover off, then maybe for accessing the tappets.

I also found very tight valves. The PO said he did the adjustment at 500 miles, but I am doubting that; as in addition to the valves, the valve cover bolts and 3 bolts for the crank cover were pretty tight; sort of factory tight.

I thought I was going to be able to complete the job yesterday, but had to take the bike to a shop to get those 3 cover plate bolts removed. I tried a hand-held impact driver, but that didn't work. The shop had no issue with the right tools, and replaced the bolts with 4mm hex heads. They said to tighten snug, then a tad, that the O-ring would seal with very little torque on the cover. I think I will put some blue Loctite on them.

I am hoping that I don't have any damage to the valves; especially if the PO didn't do them at 500 miles; I have 2000 on the bike now and thought I was being pro-active doing them again after just 1500 miles (vs the 2500 CSC recommends).

We'll see. Bike still was running fine, but back-firing at the exhaust some and stalling when cold (after the choke was off, at the first couple of red lights). That is what prompted me to check things out.

UPDATE: No more backfiring. Started quickly on the 1st turnover, with no choke (its 60+ in Denver today, so that is not unusual). May be a combination of the valves and a new carb...should have done one at a time. Still dialing in the carb, but it ran pretty good right out of the box.

Louiey · 04-05-2020, 03:14 PM

I adjusted mine right out of the box. When I turned the motor over it felt like there was no compression, because there was not. My valves were so tight they held the valves open. Now I just listen to the clicking of the valves. In my experience clicky valves are happy valves.

Goob · 04-05-2020, 03:54 PM

Quote:

Originally Posted by Louiey

I adjusted mine right out of the box. When I turned the motor over it felt like there was no compression, because there was not. My valves were so tight they held the valves open. Now I just listen to the clicking of the valves. In my experience clicky valves are happy valves.

Wish I had the bike from new, then I could have made sure they were good from the start.

In my experience today, I thought I was going nuts because every time I rotated the engine 360 after adjusting the tappets to the T mark the clearance would change. One time it was very tight, another time ridiculously loose. Finally, on the 3rd try everything was good. Rotated 2 times and checked, then 2 more times and checked.

The other thing that was irritating is that CSC recommends 0.07mm for both valves (with a possible range of .04 to .07). Both sets of feeler gauges that I have don't have 0.07...skipping from 0.06 to 0.08. One would think that this is because 7 is odd, but there is a 0.05.

So I did 0.06mm and checked to make sure the 0.08 didn't fit.

I had also bought a nifty adjustment tool with a 10mm wrench and small square drive that slides inside of it. It is OK for the exhaust valve, but no room for the square drive on the intake because the frame is in the way.

I found the best tool for the square head was a set of needle-nose vice-grips and use an open end 10mm for the locking nut.

I also used the "captive" feeler gauge technique that I always used on my VW's...leaving the gauge in the opening while tightening the locking nut. Mine lays right on top of the head with the nut that holds the gauges together in the 1-1/4"+round port in the head to keep it from slipping off (not sure what the hole is for or I would call it by name). I forgot about the captive feeler technique the first time and kept on getting the gap too small even tho I thought I was holding the square drive in place.

Now that I am comfortable with the process again, I am going to make checking the valves a 1000 mile thing, whenever I change the oil.

Rocket tests · 04-05-2020, 04:58 PM

I'm unsure during breakin, i adjusted my valves before the first start up then again after 100miles. In that time the exhaust valve seemed to rest into its seat instead of wear in on the pushrod /rocker arm side because it was tight as a drum. I regapped it and will check it again in another 100miles.

The concept of the valve adjustment opening the gap as it breaks in is only relevant when assuming the valve seat is broken in or preseated with lap compound.

kingofqueenz · 04-06-2020, 09:53 AM

As a noob to valve adjustments, when I did mine ( TBR7 ).... I kept second guessing if I was on the compression stroke, did the same as you...checked it 4 friggin times.

Mind playing tricks on us I tell ya!

Kenstogie · 04-06-2020, 01:58 PM

i did my valve before the first start up and it currentl starts right up now.... will check again at 100miles i guess...

flopsweat · 04-18-2022, 09:39 AM

Just adding my hat into this ring from long ago, but I also just did my first valve adjustment on my TT. I rejetted it around 300 miles, and hit 500 last week so did the valves and oil. Same as it sounds elsewhere, they were too tight even for the smallest 0.002" gauge that I had, and I set them to the recommended 0.003"/0.076mm. Took it for a test ride, started right up, and finally got to hear her sing over 5k rpm. I know the 1000 mile is the true break-in so I still won't be going nuts but it's just nice to know I can finally keep up in the 45mph zones. I'm like a frickin' mechanic now or something!

buzz · 04-18-2022, 06:37 PM

Hi 1400 miles just gapped my valves ,and they were tight..oo3 worked for me a TBR7,has always run great. Just glad I checked them before something bad happened.Will check every 1000 miles from now on.

Thumper · 04-19-2022, 08:27 AM

Tight valves seem to be really common on new Chinese bikes. Fortunately the tools to check and adjust are not expensive and it is a simple job with these 1 cylinder engines.

The valves on my Strom had close to 0 clearance when I checked them after about 50 miles, and same with the valves in my son's new TBR7 this year. We checked his before even starting it.

If you haven't checked your valves, do it!!

04-05-2020, 10:30 AM	#1
Goob Join Date: Nov 2019 Posts: 353	First valve adjustment TT250..found out some things Howdy, Between yesterday and today I did my first valve adjustment on my TT250. I have done adjustments before (in 1977! on my Honda XL100), but a first on this bike. What I found was that the left side plastic, seat, or gas tank don't have to be removed as in the CSC tutorial. I was able to easily remove the valve cover from the right side. My tank plastics are already off, so if you have those they may have to be removed; if not for taking the valve cover off, then maybe for accessing the tappets. I also found very tight valves. The PO said he did the adjustment at 500 miles, but I am doubting that; as in addition to the valves, the valve cover bolts and 3 bolts for the crank cover were pretty tight; sort of factory tight. I thought I was going to be able to complete the job yesterday, but had to take the bike to a shop to get those 3 cover plate bolts removed. I tried a hand-held impact driver, but that didn't work. The shop had no issue with the right tools, and replaced the bolts with 4mm hex heads. They said to tighten snug, then a tad, that the O-ring would seal with very little torque on the cover. I think I will put some blue Loctite on them. I am hoping that I don't have any damage to the valves; especially if the PO didn't do them at 500 miles; I have 2000 on the bike now and thought I was being pro-active doing them again after just 1500 miles (vs the 2500 CSC recommends). We'll see. Bike still was running fine, but back-firing at the exhaust some and stalling when cold (after the choke was off, at the first couple of red lights). That is what prompted me to check things out. UPDATE: No more backfiring. Started quickly on the 1st turnover, with no choke (its 60+ in Denver today, so that is not unusual). May be a combination of the valves and a new carb...should have done one at a time. Still dialing in the carb, but it ran pretty good right out of the box. __________________ CSC TT250 Orion RXB 150XL Last edited by Goob; 04-05-2020 at 03:57 PM.
	0

04-05-2020, 03:14 PM	#2
Louiey Join Date: Apr 2020 Posts: 3	I adjusted mine right out of the box. When I turned the motor over it felt like there was no compression, because there was not. My valves were so tight they held the valves open. Now I just listen to the clicking of the valves. In my experience clicky valves are happy valves. __________________ 2019 Hawk 250 Mikuni carb, gutted cat, pro tapper bars 2004 Yamaha r6 Slip-on exhaust 2008 Mitsubishi Evo X FBO 505 ponies
	1

04-06-2020, 01:58 PM	#6
Kenstogie Join Date: Apr 2019 Posts: 336	i did my valve before the first start up and it currentl starts right up now.... will check again at 100miles i guess... __________________ been around bikes for a while.... honda 72 cb200t, zuki 96?/2002 katana, 12 vstrom,09 vstar, kawi ltd440, 82 zuki Gs1100, Tao Tbr7 all about the Tao MotorsTBR7 http://www.chinariders.net/showthread.php?t=25553
	0

04-05-2020, 04:58 PM	#4
Rocket tests Join Date: Mar 2020 Location: Pennsylvania Posts: 87	I'm unsure during breakin, i adjusted my valves before the first start up then again after 100miles. In that time the exhaust valve seemed to rest into its seat instead of wear in on the pushrod /rocker arm side because it was tight as a drum. I regapped it and will check it again in another 100miles. The concept of the valve adjustment opening the gap as it breaks in is only relevant when assuming the valve seat is broken in or preseated with lap compound.
	0

04-06-2020, 09:53 AM	#5
kingofqueenz Join Date: Apr 2019 Location: Strong Island New Yawk Posts: 464	As a noob to valve adjustments, when I did mine ( TBR7 ).... I kept second guessing if I was on the compression stroke, did the same as you...checked it 4 friggin times. Mind playing tricks on us I tell ya!
	1

04-18-2022, 09:39 AM	#7
flopsweat Join Date: Oct 2021 Location: The burbs of Chicago Posts: 237	Just adding my hat into this ring from long ago, but I also just did my first valve adjustment on my TT. I rejetted it around 300 miles, and hit 500 last week so did the valves and oil. Same as it sounds elsewhere, they were too tight even for the smallest 0.002" gauge that I had, and I set them to the recommended 0.003"/0.076mm. Took it for a test ride, started right up, and finally got to hear her sing over 5k rpm. I know the 1000 mile is the true break-in so I still won't be going nuts but it's just nice to know I can finally keep up in the 45mph zones. I'm like a frickin' mechanic now or something!
	0

04-18-2022, 06:37 PM	#8
buzz Join Date: Dec 2020 Location: Dayton Pa. Posts: 880	Hi 1400 miles just gapped my valves ,and they were tight..oo3 worked for me a TBR7,has always run great. Just glad I checked them before something bad happened.Will check every 1000 miles from now on.
	1

04-19-2022, 08:27 AM	#9
Thumper Join Date: Feb 2021 Location: Kansas City Posts: 2,421	Tight valves seem to be really common on new Chinese bikes. Fortunately the tools to check and adjust are not expensive and it is a simple job with these 1 cylinder engines. The valves on my Strom had close to 0 clearance when I checked them after about 50 miles, and same with the valves in my son's new TBR7 this year. We checked his before even starting it. If you haven't checked your valves, do it!!
	2