TBR7 Won't start

[Johnny_Sardine]

Hey, everybody.

So I just got two bikes. Hawk and TBR7.

Got them put together yesterday and Hawk started up but wouldn't idle. So I figured I'd throw the new mikuni vm 26 ito the TBR7 from the get go. I just opened it up and threw the 110 main jet, left the rest. Tightened the fuel mix screw til it bottomed out and let it out 2 1/2 turns as per motocheez' advice.

Bike just won't start. After a night of letting the battery recharge, I put the stock carb on there just to see what's up. Still no luck. So at this point I'm thinking it must be something else.

Battery is charged. Plug is sparking. Gas is flowing. Checked all wires and grounds for connection and tightness. Tried it in every configuration, with the kickstand up, down, break on off, clutch in, neutral, with the kick start. Shit man.

It has given me a glimmer of hope a couple times but really just a whole lot of nothing. I'm at a loss. And the frickin hawk just started right up.

The battery is doing a weird clicking thing. Not sure if it's shorting? Pulling the throttle will almost always cause the starter to stop with a loud click.

you can see what I'm talking about in this video



Any tips?

[Bruces]

Is the plug wet ? Have you tried dropping a little fuel down the spark plug hole replacing the plug then starting it ?

[NzBrakelathes]

Swap Hawk carb to TBR - what is the result? try swapping things till you find either Hawk won't go or TBR will go etc

[timcosby]

wonder if the choke lever goes the opposite direction. wouldnt hurt to try the other direction

[Johnny_Sardine]

This is what we did.

Swapped hawk carb we knew worked (but wouldn’t idle). Bike acted the same, no go. Switched batteries and plug from hawk no luck.


removed the gas tank. Rerouted spark plug wire, filled up the bowl of the carb Manually. Choke on, she acted like she wanted to start. Half choke, gas throttle and it fired up. Had to keep the throttle pinned to keep her running. Exhaust pipe got red hot. Sounded great until the bowl ran dry. Hooked the tank back and no luck.

Seems like the beast ain’t getting fuel. Valves??? That’s the only thing that I can think. Everything else seems to be there. Gas flows out of the tank.....

Thanks

[Megadan]

Yeah, adjust the valves if you haven't. Exhaust shouldn't be glowing.

[NzBrakelathes]

Originally Posted by Johnny_Sardine

This is what we did.

Swapped hawk carb we knew worked (but wouldn’t idle). Bike acted the same, no go. Switched batteries and plug from hawk no luck.


removed the gas tank. Rerouted spark plug wire, filled up the bowl of the carb Manually. Choke on, she acted like she wanted to start. Half choke, gas throttle and it fired up. Had to keep the throttle pinned to keep her running. Exhaust pipe got red hot. Sounded great until the bowl ran dry. Hooked the tank back and no luck.

Seems like the beast ain’t getting fuel. Valves??? That’s the only thing that I can think. Everything else seems to be there. Gas flows out of the tank.....

Thanks

So the issue is with the bike as swapping parts isn't helping, try adj valves and if you like or need check my eBay listings for a tool set to make this task easier.

If moving parts doesn't solve the issue and the Hawk runs fine and TBR doesn't after swapping common parts then it isn't the parts lol - does help with knowing where to not look lol

[wheel spinner]

ok... I'm going out on a limb here... but sometimes something sooo simple as the kill switch can screw us up... check the kill switch and test it... change the plug... smell for gas in the cylinder... make sure you got spark... choke it... then take the choke off..

[Johnny_Sardine]

Alright... seems like maybe I'm getting closer, but still no luck.

I've swapped a lot of parts off the hawk by now and nothing is working on the TBR7. I did the valve clearances and they were super tight. now .002 for both. Still has the stock hawk carb. When I go to start it, it would putter for a second then die. It would not even try when the throttle was open or the choke was even half on or the air box was connected.

When I undid the air box hose, left the throttle alone, and no choke, it would putter. For a couple seconds max. Every time I give it gas, the starter just seizes... I have no idea what would be causing this because as far as I can tell there's not even an electrical component to the throttle. Why would it interfere with the starter??

If I got it to putter, and just very barely gave it the smallest amount of throttle, a couple times it started to rev. Then I was able to open it up. It revved and wasn't even, it backfired. The carb will also shoot gas out the intake when the choke is on.

So the mikuni that I rejetted? Threw that on the hawk and it runs like a champ. Idles and pulls. I have no idea what is going on with the TBR7...

How would I go about testing something like the killswitch or the ignition coil or...? At this point, the freaking bike just won't run, while the hawk hit the ground running. I'm at a loss.

Thanks for the advice, been listening to it all.

[NzBrakelathes]

tried swapping CDI and or ignition coil?

[Hellkitty]

It almost sounds like the cam timing is off by one tooth, unlikely but who knows with chinese quality controls or lack of. If you haven't already done so I would put a new,good quality spark plug in it, something you're going to want to do eventually anyway.

[KABANSKI]

Next time you get it to sputter for a few seconds,try turning the idle up and let it warm up for about 15-20 minutes before you mess with the throttle.Where ever you have the choke at that point;leave it, until the bike idle starts sounding super high on its own;then turn the choke off and adjust the idle to a smooth idle.I had to do this on my Tbr7 with the stock carb every time but never had to ride with any choke after I let it warm up good.I don’t know if it will work but my bike would make that sound too at first from cold start then soon as you throttle it’s like peewwwnnn;(cuts right off).Until I started doing the above.Then changed carbs at 100 miles.Hope you get it figured out.

[KABANSKI]

Oh yeah and what he said,new spark plug will probably help a bunch

[letsride]

SO, you have FUEL, AIR, and SPARK and you have adjusted the valves. First thing I would do is take that TORCH junk plug and throw it in the trash and replace it with an NGK and check the gap. In my experience I have seen bad spark plugs cause all sorts of headaches. If the bike acts the same, I would take the timing mark cover off and roll that crank around until you line up and center the "F" in the window or with the pointer. Then I would pop that valve cover off and make sure BOTH valves are closed and there is a slight amount of play in the rocker arms. In other words the rocker isn't putting any pressure on the valve. That should give you some clue as if the timing is right. When you roll on the throttle when starting the engine is trying to ignite the mix you just let into the engine, but it sure seems to me like it is trying to ignite it at the wrong time thus stalling the starter.

[NzBrakelathes]

Did you buy my kit? For first tune and basic mods etc?
Look in my eBay store

Swap plugs mate see if you can move the fault

Found this too and thought interesting