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Post Info TOPIC: Flat spot?


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Flat spot?
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Not sure what section to put under. but anyway, I get like a flat spot between 6-7K then it's ok once after power valve opens at 7,000rpm, no power between 6-7k. shall i buy some carb cleaner and see if that makes a difference? stuff that i can put into the petrol tank. or maybe redex? i literally have to drop a gear to get the power back if i stick 6-7k.



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When was the last time you renewed the air filter mate?

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I'd check for a Yeis bottle, this can be a side effect of missing one. Especilly if you are having weak compresstion, failing that, for instance if its always been like that I'd be thinking maybe someone hasn't set up the carb needles right.

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Haven't you not long done a engine rebuild? I'll do a quick plug chop.

Also if you use carb cleaner, pull it all apart and clean everything as a little bit of dirt will make it leak etc. I never had problems in terms of carb, other than leaking from sitting over winter. But I run premix so need to clean mine when it sits anyway.

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I've not renewed it, ive just cleaned it all out, snorkel is off, but made it proper **** putting it back on. off subject thing also..

was going along dual carriageway for a while, went over a roundabout, accelerated. and back wheel totally locked up on me, pulled over, bike was REALLY hot, i got a br9eix plug in, reckon it's making piston way too hot? it to why its locking back wheel up, maybe heat seizure? br9es i should of had in there really, i just wanted the better start up in mornings with the other plug

i checked top of piston from port, it's not melted at all, i should use the proper br9es plug u think and not the br9eix?


anyways, that was last night the lock up, started first thing this morning, rode 25 miles back from my girlfriends, and it seems fine now?! seems so weird, i've only got a 250 main jet with my full dep system (240 made no difference), i put redex in yesterday, maybe i shouldnt of done, going back to standard front pipe,. with standard 210 jetting in to be on safe side.

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240 is standard jetting mate.

Redex is never good. Let alone on a two stroke. You won't notice a difference of jetting unless you're correcting a problem.

If the bike ran worse with the snorkel out then the problem seems to be running lean. Putting redex in the fuel system will lean off the mixture since you're now injecting redx with your fuel and oil....less actual fuel same air and what not.

If the rear wheel seized then I'd be preparedto have a proper look over the bike before riding it.
If you're riding like you stole ot from cold then yes heat seizure. I run nothing but iridiums in my car and bike never have problems.

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nope i let it warm up first of all before i start riding long distance, just put normal br9es plug in which says from manual, started first time this morning, with no problems, i went 45/50mph on dual carriageway and it was pretty decent, i checked over piston it's okay. starts first time still, oils getting there, and also is water, the culprit is i would say the redex then,before hand it was perfectly fine! just thought i'd put a little redex in to see if it cleared system a bit, but for future reference i wont be using it again on 2 stroke!

Also: I found that running from br8es to a br9es was a big difference, it didnt misfire as much when de-revving. could of been bad fueling at the time though, who knows!



-- Edited by The_DtR_Maniac1991 on Friday 19th of September 2014 12:55:04 PM

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I think I run the bre8ix plug. When the tzr wants 9. Can't say I've ever noticed a difference.

Okay well at least you've checked. Keep us posted if you have any more issues.

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Cheers buddy, it seems okay now, no more weird lockups, also a loose chain can cause lock ups cant it? it was loose (cant spell) but not really bad, could of been the reasons

Is it possible to check which plug your running ? I may use the same, you seem to have no problems lol



-- Edited by The_DtR_Maniac1991 on Tuesday 23rd of September 2014 04:01:18 PM

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I checked mate. BR8EIX. The 9 was for the TZR but can read the manual to confirm.

No no got it now. The BR8EIX is for the TZR. Manual says 9 for the DTR. I've ran both on DTR/TZR. Never noticed difference/had problems



-- Edited by Calum122 on Tuesday 23rd of September 2014 04:39:54 PM

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The_DtR_Maniac1991 wrote:

I've not renewed it, ive just cleaned it all out, snorkel is off, but made it proper **** putting it back on. off subject thing also..

was going along dual carriageway for a while, went over a roundabout, accelerated. and back wheel totally locked up on me, pulled over, bike was REALLY hot, i got a br9eix plug in, reckon it's making piston way too hot? it to why its locking back wheel up, maybe heat seizure? br9es i should of had in there really, i just wanted the better start up in mornings with the other plug

i checked top of piston from port, it's not melted at all, i should use the proper br9es plug u think and not the br9eix?


anyways, that was last night the lock up, started first thing this morning, rode 25 miles back from my girlfriends, and it seems fine now?! seems so weird, i've only got a 250 main jet with my full dep system (240 made no difference), i put redex in yesterday, maybe i shouldnt of done, going back to standard front pipe,. with standard 210 jetting in to be on safe side.


If it's only happening at certain rpm then I'd suggest its probably not air filter related but its still something thats so cheap its hardly worth cleaning. replacing will ensure its not part of the problem.

Your incident sounds very much like a heat seizure. If you've checked the bore and piston and all looks ok then you got luck but you need to find out why it happened. The red ex could be the culprit but dont assume it is. Check the jetting and give the carb a good clean. Also I'd check for any air leaks.

The spark plug heat rating is the rating that the spark plug operates best at. It wont make your engine run hotter or cooler but will give you a better bang if you have the right plug in. The reccomened plug is stated for everyday general riding. You may well find one that 1 either way that suits your riding style more.



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Yeah I am going to save for a Full engine rebuild and get everything sorted. i had no problems for 2 years riding it EVERYDAY, i done a rebore and the problems arrised. it was honed also. i probably need to get it re-honed again. the sake of 25 can save me alot of money in the long run. also, it runs like a bag of **** at like 5-6k like NO power it doesnt freely rev past those revs. I could give the filter a clean and i can buy 2 stroke additive from bike shop. i had kinda same problem with my old RS 125 and it was slightly better after putting the additive stuff in.


PS. On my way home from work today it was mis-fireing at low RPM. what does that suggest? and on Idle it mis-fires then cuts out, but starts first kick again after.

Thanks for all your help.

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Fouled plug mate. Probably that redex stuff has destroyed the plug.

Probably doesn't need a hone mate if it's just had one and there is no damage to the bore. Very simple engines so it'll be something simple. If the engine rotates freely and there is good compression then it's probably bad fuel, damaged fuel filter, incorrect jetting settings.

What piston did you use? I know that Wossner pistons for whatever reason require upjetting. I had to take my DT to like 280 on wossner pistons. In order to get golden brown plug.

Have a look at the plug. Get a photo up here and I'll tell you what the crack is.

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okay buddy, ill get a pic up for you. I did change the plug a few days ago (cant remember if i put redex in with the current plug, or previous plug. ill whack a pic up though


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If there is redex in the system and you put a new plug in then the chances are it has fouled the plug. I'm just going on what you've said.

It was working fine, you gave it a nice rebuild (assumes that is done correctly), run the bike, put redex in, problems occur. So Redex seems to be causing the problem. Question is, is there any left in the tank....

I suppose it's possible that it's dirtied up the carb and what not. So would be worth getting that all cleaned.

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Okay. That is the plug , it's a BR9ES plug. My screw is ficked on bottom of carb so gotta try find say getting it off. But cutrebly has a 250 jetting in. I got a industrial piston in currentry. Rebored to 56.65. What you reckon on jetting. Little higher ? I'm pretty surs the redex fooled the plug! Would the plug right now in its condition be the reason why it was Misfiring ?SAM_0899.JPG

Sorry for bad photo!



-- Edited by The_DtR_Maniac1991 on Friday 26th of September 2014 11:34:54 AM

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So I know that you cannot clean iridium plugs. So maybe the redex is 'cleaning' the plug. Which is stripping it and that's why it's not working.

Industrial piston? Okay....Are you sure that's okay. You naturally want a piston that will expand at the same rate as the bore....So by that logical it needs to have the right carbon content. I'm not sure just banging in any old piston is a good idea. It wants the right silicone content and various other properties that allow it to expand sufficiently.

Go for a non iridium one until you can be sure there is no redex in the system. Then go back to a new iridium plug.

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Lay the plug down and get the camera to focus on the end. I see black carbon round the edge and brown centre. So it's not bad.

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SAM_0900.JPGCan I get 2 stroke additive stuff? Ive used it before in my DT. It would help it flush the redex out. I've got a BR9EIX iridium plug. would that be okay? Or shall I go for the BR8EIX?



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That's what I've got in mine mate. Personally I'd stick to a normal plug.

No mate. It's not needed. Two strokes are DIRTY by nature. They don't require additives. Stick with decent low smoke two stroke oils and decent fuel. If you can get a normal plug then great. Otherwise limp it on iridium until you finish the tank then get a new one.

I know Iridiums don't like to be cleaned.

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Shall I use super unleaded? Maybe it'll help just a little. I've had bad fuel a couple of times. and the bikes conked out, For now I'll just clean this NGK R BR9ES. then once I fill up with fuel again, I'll continue to use the BR9EIX plug. But i will use super unleaded instead. The sake of 5p more paying for super unleaded could make it run little better.

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Oh, and also Shall I put my snorkel back on my airbox under the seat. only thing it runs like a bag of ****,

If you have the Full DEP. what are all the jettings you use for yours? I've only changed the Main jet, maybe changing the pilot jet and others will HELP much much more.

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I've got a TZR engine, aftermarket CDI, Dellorto VHSA carb and a ported engine, can't say I can give you much advice on jetting.

What worked for me way back when, 240-280 main jet, with needle clip raised.

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Hmm. I can't remember if the needle was raised at all. Maybe I should check which setting it is on, Middle setting is standard setting right? and Needle higher is richer, and leaner is lower?

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The lower the needle clip, the richer the mixture. Because if you lower the clip, you raise the taper. Which richens the mixture. That's how I remember it.

It shouldn't need it. There has got to be some sort of problem. The bike should run fine with the snorkel in. Is the YPVS setup correctly? You have the correct boost bottles and what not?

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Yeah, the boost bottle is in. Everything is standard Except the Full dep system. I was thinking of just going back standard and see if the problem still arrises. I still have the standard front pipe. and the DEP rear end can. I just stick a 240 jetting in. and see from there. I havent cleaned my air filter for a while. Not got a brand new filter for 3 years lol, maybe it's time for a new one !

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New nicely lubed air filter for sure, whack that 240 main in and never bother running super unleaded on a DT, it's not a race tuned engine by any stretch of the imagination, so there's no real point (imo).

If you're still having trouble just start again from standard like you said, that's always the best way to set things up right again.

*EDIT* I just bothered to read through a bit more, sounds like needle position....revert back to standard position (middle). You shouldn't really have to adjust the jetting with a DEP, Myself and 4+ of my friends have never had to. I only had to adjust the main jet when running my custom pipe as it was fuel starving in 6th gear, pinned.



-- Edited by Energized on Friday 26th of September 2014 01:59:04 PM



-- Edited by Energized on Friday 26th of September 2014 02:04:22 PM

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Okie dokie. thanks :) i can't remember if needle been adjusted. but it's always worth a try. If i remember , I upjetted to 250, then moved the needle down 1 notch. (240 didnt do any difference to standard jet ( strange) so i went to a 250. or even a 260, i really cant remember it was a long time ago. but i will defo get that brand new filter anyway

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Yes mate it will defo help and it's a service item so two birds with one stone (won't need touching again for ages). Aye fair enough mate, the best thing to do is revert the carb settings back to standard and use the standard plug size aswell. See how she runs then and it should be job's a good'un! If not then it's a different main jet/needle position depending on the diagnosis that you give us once you've rode her on standard settings! smile Do a few plug checks along the way aswell just to make sure and you can't go wrong.



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I didn't need to adjust the settings for my dep system. Only the wossner pistons. They were weird.

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