no compression, blowing back thru carb

[smadden]

i bought a atomik with a yx160. its got about 30 min on the motor. I had the thing WOT in top gear about to do a plug chop and then lights out!!!! The thing still has spark but sweet f all compression on the power stroke. ive pulled the rocker covers and valves are still intact. I imediatly thought it dropped a valve. there is no oil in the exhaust pipe either but blows back thru the carb now. Im gonna pull it down but i thought i'd ask the boys first for any ideas what it could be first...Terry or sean?? me thinks its either a bent valve or skipped a tooth on the cam gear...

P.S.
A bit of a clunk coming from the gearbox area as well when kicking.

cheers boys

 

[The_GDFP]

I'm guessing you floated and bent the intake valve. Check the lash. I bet it's opened up from valve not seating.

Clunk in the kick area? Pop the cover and take a peek, as long as you're waiting on a valve and gaskets :grinning-smiley-003

 

[smadden]

I'm guessing you floated and bent the intake valve. Check the lash. I bet it's opened up from valve not seating.

Clunk in the kick area? Pop the cover and take a peek, as long as you're waiting on a valve and gaskets :grinning-smiley-003

hmmm, i reckon your right..thats what you get when you make valve springs out of chewing gum. I'll check out the lash
Cheers mate

 

[smadden]

It droped the inake valve. Have not removed the head but stuck torch down intake and the cam rotates but intake valve does not. Its still sitting in the guide and i would have to asume its as bent as freddy mercury...so is it time for the v2 head and piston or rebuilt and who has the parts in Australia... if i rebuilt i would want real valve springs and collets and not china rubbish.

cheers boys

 

[motorman]

Check out our site sponsor:

Classic Honda 50's Australia

They will have all the parts you will need.

 

[smadden]

Check out our site sponsor:

Classic Honda 50's Australia

They will have all the parts you will need.

cheers I rang DHZ and they sounded as interested as a church sermon about selling me the kit. I'll try them

 

[DHZ_XR8cing]

cheers I rang DHZ and they sounded as interested as a church sermon about selling me the kit. I'll try them

Once you use the TB v2 all reliability and in some ways ride ability goes out the window. They become very temperamental to tune and keep tuned.
I myself have mine all sorted and so does allot of other people so i'm not saying it directed at everyone. For some one just getting into it all there will be allot of questions,mistakes and broken parts and that could be why DHZ did not seem really keen to sell to you.
Try getting a standard setup working and keep it working without break downs or damage then have a go at a v2 set up.
Basically what i'm saying is if your killing valves on a standard engine your going to make a real mess of a v2 and your wallet.

 

[sean01]

lesson to be learn't here...

even tho an engine going pah pah pah sounds good DO NOT OVER REV YOUR ENGINE

 

[ClassicHonda50]

We must just be lucky not to have had any reliability problems with the V2 set-ups on our sponsored race bikes over the past 3 years of racing in Australia and the US.

Set them up correctly for what you need (MX, SX, FMX, Speedway, Enduro, Trail Riding) and enjoy.

Rideability depends on how good you can hang on

Hi smadden, give me a call on 0401217210

We also sell rev limiters :ballchain:

Cheers

Jaimie Dodds

Australian TB Parts Distributor

 

[motard_16]

Once you use the TB v2 all reliability and in some ways ride ability goes out the window. They become very temperamental to tune and keep tuned.
I myself have mine all sorted and so does allot of other people so i'm not saying it directed at everyone. For some one just getting into it all there will be allot of questions,mistakes and broken parts and that could be why DHZ did not seem really keen to sell to you.
Try getting a standard setup working and keep it working without break downs or damage then have a go at a v2 set up.
Basically what i'm saying is if your killing valves on a standard engine your going to make a real mess of a v2 and your wallet.

me and my mate run v2s on your motards and we have had the same ones for about 2 years now and we do v/c every now and then and they have never let us down just jump on it and go

 

[The_GDFP]

Like Jamie said, the V2 is a very reliable item. The intake valve is a little soft and overrev will cause face recession, but unlike the Tak, the valves typically bend rather than break when you do some thing silly. Adding the TB Ti retainers and extra shim that comes with them adds a few hundred revs before float. Tak alloy rockers add nearly a thousand revs up top, by weighing a little under half. Properly modded, we run them on 125-251cc builds. Tak decomp cams allow kick-N-go riding, just like a real bike, saving the buttery kick gears in the process. Also there's four grinds, to suit your riding needs.

 

[smadden]

Once you use the TB v2 all reliability and in some ways ride ability goes out the window. They become very temperamental to tune and keep tuned.
I myself have mine all sorted and so does allot of other people so i'm not saying it directed at everyone. For some one just getting into it all there will be allot of questions,mistakes and broken parts and that could be why DHZ did not seem really keen to sell to you.
Try getting a standard setup working and keep it working without break downs or damage then have a go at a v2 set up.
Basically what i'm saying is if your killing valves on a standard engine your going to make a real mess of a v2 and your wallet.

Mate you should not spruik such rubbish and scare potential pundants of trying a V2 head...a engine is an air pump and the only temperamental aspect of tuning this air pump is the idiot on the end of the jets and stoich does not favour one brand of head for another. You have a point on reliability with regards to eg a clutch but this is also rpm related so any engine will wear out if reved to the moon. I am not new to bikes, its a mates engine i was plug choping so if i didn't do it, he would off 5 minutes later...must of been a friday engine.

I tore the thing down today and found 1 bad collet which dropped the intake valve. funnly enough there is sweet F.A damage, just a nick on the valve relief on the piston and a very bent intake. The springs are rubbish which im sure didn't help the bad collet sit in snug. I didn't check the valve guide but i suspect in may be hurt.

I noticed there are bigger reliefs in the chamber for valves but only small seats installed, you could easly fit a intake where the exhaust is along with said seat of course. these bigger reliefs do no favours for comp either.

Thanks for the phone number Jamie, i'll buzz you next week and discuss about purchasing some unreliability off you

 

[DHZ_XR8cing]

Mate you should not spruik such rubbish and scare potential pundants of trying a V2 head...a engine is an air pump and the only temperamental aspect of tuning this air pump is the idiot on the end of the jets and stoich does not favour one brand of head for another. You have a point on reliability with regards to eg a clutch but this is also rpm related so any engine will wear out if reved to the moon. I am not new to bikes, its a mates engine i was plug choping so if i didn't do it, he would off 5 minutes later...must of been a friday engine.

I tore the thing down today and found 1 bad collet which dropped the intake valve. funnly enough there is sweet F.A damage, just a nick on the valve relief on the piston and a very bent intake. The springs are rubbish which im sure didn't help the bad collet sit in snug. I didn't check the valve guide but i suspect in may be hurt.

I noticed there are bigger reliefs in the chamber for valves but only small seats installed, you could easly fit a intake where the exhaust is along with said seat of course. these bigger reliefs do no favours for comp either.

Thanks for the phone number Jamie, i'll buzz you next week and discuss about purchasing some unreliability off you

Take what I said as rubbish thats fine. I am not trying to scare anyone out of purchasing a v2. I encourage them and own 3 of them. You dont have to take anything I say on board as you clearly already know everything so that makes me wonder why you posted a thread asking for help in the 1st place.

 

[smadden]

Take what I said as rubbish thats fine. I am not trying to scare anyone out of purchasing a v2. I encourage them and own 3 of them. You dont have to take anything I say on board as you clearly already know everything so that makes me wonder why you posted a thread asking for help in the 1st place.

I posted a scenario here on what happened to this engine and didn’t prejudice with my knowing that the 2 most knowledgeable guys on here would confirm my own assumptions. Terry hit the nail on the head first and then Sean offered some sound advice and used this example as a lesson to be learned for all the young kids on here. I appreciate you taking the time to post and I know it was never your intention to scare anyone off buying a v2 head but my concern was that any young kid will take what you say as gospel and think twice about getting one. I full well knew that what you said was crap but for any young kids out there, a v2 head is bolt on power for the right motor and a jetting change with seans/Terrys recommendations,(maybe get dad to fit). There are Vendors who sponsor this site and make a quid by selling parts and funnily enough 2 vendors rebutted your claims about the head so next time you shoot from the hip, think about the bigger picture.

Thread closed