Straight pipe valve adjustment

[757nick]

I straight piped my TBR7 until the new exhaust comes in and I was wondering what I should have the valves clearance set too? Some people say it shouldn’t hurt and some say it will. Please help!!

[Thumper]

If you haven't adjusted the valves, definitely adjust them ASAP. No change needed for pipe change. Exhaust gap 0.005 to 0.007", and intake 0.003 to 0.005" is all good (adjust when the engine is cold).

Edit... These gaps are too wide, should be closer to 0.002/0.003 (intake/exhaust), give or take 0.001"
Some run these on the narrow side. I have erred on the wide side to be sure that the valves seal, but I know too wide can damage the tappet surface in the long run.

[757nick]

I had just them every 500 miles I just wanted to know if I need to do anything different with a straight pipe

[buzz]

Why a straight plpe they are so cheap,would sell you mine for cheap. TOO loud for no more power just removed cat from stock plpe, And very happy , loud and no lmprovement

[Ol,fart]

Originally Posted by 757nick

I straight piped my TBR7 until the new exhaust comes in and I was wondering what I should have the valves clearance set too? Some people say it shouldn’t hurt and some say it will. Please help!!

exhaust type doesn't matter.set both about 005 a little loose is better than tight.

[Megadan]

.005 to .007 inches is a lot too big... Were you meaning to say .05 to .07 millimeters instead? I ask because that is the proper sec range to be working in. Technically .05 to .08mm.

[Thumper]

Originally Posted by Megadan

.005 to .007 inches is a lot too big... Were you meaning to say .05 to .07 millimeters instead? I ask because that is the proper sec range to be working in. Technically .05 to .08mm.

Yes, my valve lash is 2x (or almost 3x) too large. I should bring them down. I have only ~200 miles on the Templar, and wanted to be sure it wasn't too tight during early break in. I guess those are excessively wide gaps. Currently they are at about 0.006" (0.15mm) on both sides. I will tighten up the gaps and change the oil again soon.

[Megadan]

Originally Posted by Thumper

Yes, my valve lash is 2x (or almost 3x) too large. I should bring them down. I have only ~200 miles on the Templar, and wanted to be sure it wasn't too tight during early break in. I guess those are excessively wide gaps. Currently they are at about 0.006" (0.15mm) on both sides. I will tighten up the gaps and change the oil again soon.

Good lord, that has to sound like tiny blacksmiths working furiously after doing a line

[J4Fun]

That’s a good question. Also does it matter if you ride in cool country versus hot? Or does water cooled engines versus air cooled make a difference on one’s choice of valve clearance? Thinking out loud….

[Thumper]

ZS172-FMM-3A 249cc (Templar X):
This is an OHC engine, not pushrod. I set both at about 0.006" It gets hot (this blazing Summer), so I wanted to make sure the valves would close. Excessive, maybe, but I do NOT hear valve tappet noise from this head. I can probably close them up somewhat. High performance recommendations (Henner) are TIGHT (0.002"), but until I have at least 1000 miles on the engine, valves can "seat". And as I said, I don't hear valve noise from the head. Once I observe stable clearance, I will drop the spec accordingly. Keep in mind I am still under 250 miles on the bike!

The TBR7 and Storm are both pushrod CG clone (ZS167-FMM 229cc). My son's TBR7 is getting more miles now. I will begin to close the gap on these as well. Neither of them make much valve noise, and it isn't like any of these bikes are operating under rpm conditions that could cause them to float

I am more concerned about making sure there is good oil in them and that they are not overheating. All three of them are running great! Power level is close to best possible without head mods, and they start instantly.

[757nick]

Originally Posted by buzz

Why a straight plpe they are so cheap,would sell you mine for cheap. TOO loud for no more power just removed cat from stock plpe, And very happy , loud and no lmprovement

My exhaust rusted out so I straight piped it until my Amazon one comes

[Megadan]

Originally Posted by Thumper

ZS172-FMM-3A 249cc (Templar X):
This is an OHC engine, not pushrod. I set both at about 0.006" It gets hot (this blazing Summer), so I wanted to make sure the valves would close. Excessive, maybe, but I do NOT hear valve tappet noise from this head. I can probably close them up somewhat. High performance recommendations (Henner) are TIGHT (0.002"), but until I have at least 1000 miles on the engine, valves can "seat". And as I said, I don't hear valve noise from the head. Once I observe stable clearance, I will drop the spec accordingly. Keep in mind I am still under 250 miles on the bike!

The TBR7 and Storm are both pushrod CG clone (ZS167-FMM 229cc). My son's TBR7 is getting more miles now. I will begin to close the gap on these as well. Neither of them make much valve noise, and it isn't like any of these bikes are operating under rpm conditions that could cause them to float

I am more concerned about making sure there is good oil in them and that they are not overheating. All three of them are running great! Power level is close to best possible without head mods, and they start instantly.

The difference with the ohc engine is it has way less mass acting.on the rockers. A larger gap on an ohc motor won't make as much noise when out of spec because it has way less momentum behind it, so the impact force is lower.

[Thumper]

I was thinking that the rods are long, and since temperature causes a % deformation, any given % change of a long rod is absent from the OHC design. Both have rockers, no difference really there. Maybe the OHC design has less heat deformation (expansion), can be adjusted closer tolerance (0.002" Henner's recommendation on the 172FMM)

[Megadan]

Originally Posted by Thumper

I was thinking that the rods are long, and since temperature causes a % deformation, any given % change of a long rod is absent from the OHC design. Both have rockers, no difference really there. Maybe the OHC design has less heat deformation (expansion), can be adjusted closer tolerance (0.002" Henner's recommendation on the 172FMM)

The pushrods in the CG engine are aluminum so their expansion is almost identical to the rate of the cylinder. That is actually the reason the CG engines can run rather small valve gaps for a pushrod engine and are almost identical to the OHC engines. I run the same .002" on my CG lol.