No Power

[Bertie_Mollie]

Great news, Any idea what was wrong with the old KR1S pipes?

Hi Elf,

No, not yet. I whipped the cans off and they are clear. There is a lot of carbon build up down the pipes at the back end. I was thinking about clearing them out with caustic soda. I can't really think of anything else that can be wrong with them? After all they are pretty somple aren't they..... I suppose the baffles could have come loose in the pipes but there isn't any rattling going on.

They don't look like they have been messed with in any way???

Cheers

Andrew

[ScottaKR]

Congrats on finding the issue.

And well done KwakOn for your exercise in lateral thinking! =D> =D>
I know I personally NEVER would've thought of that one.

Andrew, give the caustic soda a go (the proceedure has been posted up a few times). If there is a LOT of carbon build up (possibly caused by running the wrong fuel/oil ratio) in the chamber section, it could be stuffing up the pressure waves being sent back to the engine

[Bertie_Mollie]

Just called a place that has a caustic bath and will clean them for a tenner. I'll give it a go and see how they come out. The pipes are solid so they are well worth saving.

[Bikemike]

A young lad I know had one of these Derbi 50cc supermoto style bikes, felt it was a bit flat so bought an 80cc barrel and piston kit, expecting almost 20 bhp. It made no difference at all, still flat as a pancake. We tried swapping all sorts of parts with a known good bike to no avail.
Last thing we tried was the exhaust- Bingo
When we cut open the exhaust to have a look the spannie was completely coked up except for a hole about the diameter of a penny running down the middle, amazing it ran at all.
Once we had chipped out all the cack and welded it back together it went a wee bit better!
He then sold it and bought a Clio but has now seen the light, done his test and bought a Zx6r

Mike

[mgtkr1]

almost ALWAYS overlooked but essentialy the single biggest priority in a two stroke performance engine for max performance and that be the exhaust. if there extremely blocked with carbon(they will be) then performance will suffer big style. imagine a layer of shit inside the pipes about 2-3mm thick all the way round, and try and picture how much it alters the dimensions of the pipe. the smaller parts of the pipe will obviously be more critical to carbon ie the stinger. at 24mm ish the stinger is already a small diameter to cope with all those spent gasses. now with crud make it 20 mm and it makes sense why ones bike should behave like a bag o nails. prob never had the luxury of a decoke in 20yrs!!! its a job worth doing every year if milaege is kept down/doesnt get regular thrashings. should feel crisp once your pipes have been dipped in caustic. i would revert back to 135's as your bike will be far more efficent now and require the extra juice. not worth the risk of a nip up. glad your bike is ok and needed nothing major.

[Bertie_Mollie]

Hi All,

Dropped the pipes in at the place I mentioned who specialize in all sorts of commercial stripping. They are going to stick the pipes in their oven and then put them in acid to clear out the carbon. When I looked down the the stinger there was about 3mm thick carbon build up i.e. 6mm on diameter .

I am expecting to have to paint the pipes when they are back but they should be clean LOL.

MGT - BTW when I got it running well it was on 135's with the air filter in .

Hope to collect them over the weekend.


Cheers

[mgtkr1]

was that on std airbox/filter and pipes(kr1 or 1s)?? sounds about right.

[Bertie_Mollie]

was that on std airbox/filter and pipes(kr1 or 1s)?? sounds about right.

With std airbox, lid on, air filter in and KR1 pipes so bog std .

[Bertie_Mollie]

Pipes are back and they are absolutely spotless inside. ALL of the carbon has gone. They had to have 2 goes at them as the first time after being in acid they still had a lot left in .

I believe the 2nd time they went in their oven first and then back in the acid. I should really have asked them more detail about the process i.e temp / time and acid etc.

Obviously the black finish came off which left them in the chrome / nickel plate finish. Cost me a tenner .

They are now re painted and I hope to get them back on Monday if I can source some gaskets locally.

I'll let you know if the bike them runs 100%.

Cheers

Andrew

[martin]

any chance you could pm me their adress andrew, sounds like they did a good job, need to get mine done at some point, i know they are in birmingham somewhere, just a shame i drive there every night in the truck and not in the day, when they are open,

[Bertie_Mollie]

any chance you could pm me their adress andrew, sounds like they did a good job, need to get mine done at some point, i know they are in birmingham somewhere, just a shame i drive there every night in the truck and not in the day, when they are open,

Hi Martin,

Here are their details.

http://www.touchbirmingham.co.uk/busine ... id/1961247

It might be easier if you look locally for someone who specialises in stripping things like doors, that is all I did. These guys don't specifically do bike or automotive stuff. They just operate out of a small unit on a trading estate. I would not describe them a "highly skilled" and if there were a problem I doubt you would have much come back. I have seen you pics and I know you have put a lot of time and effort into your bike and if something went wrong I would feel awful. Might be worth thinking about before you get them done?
Cheers

Andrew

[Bertie_Mollie]

Hi All,

Just to close the loop I can confirm the bike now goes like a rat up a drainpipe since the pipes have been cleaned. So much so that the clutch started slipping. It's now had a heavy duty clutch and springs fitted.

Just goes to show how big an effect gummed up pipes can have. Beforehand it wouldn't pull over about 85mph. I guess this was about 25bhp .

I am sure that you could easilly be losing 5 BHP without really realising so cleaning your pipes could give you easy BHP.

Cheers

Andrew