Cylinder/exhaust problems

[Oisin]

Hi again everyone hope your all doing good.

My DT 125r exhaust bolt broke of in the cylinder so I had to drill it out and re-tap or thread the hole but now the bolt has become loose and so I took it out to find that the hole is far larger and has a much larger diameter. I ran the bike for a bit and I noticed a loss in power, I suspect its due to a lack of compression. There also seems to be a small bit of oil and exhaust fumes coming from where the exhaust meets the cylinder. So I'm wondering if I could get the problem fixed or if I will have to buy a new cylinder ? If so is anyone selling any cheap cylinders for a DT 125 r?

Please help thanks again Oisin

[Oisin]

@Oisin said in Cylinder/exhaust problems:

Hi again everyone hope your all doing good.

My DT 125r exhaust bolt broke of in the cylinder so I had to drill it out and re-tap or thread the hole but now the bolt has become loose and so I took it out to find that the hole is far larger and has a much larger diameter. I ran the bike for a bit and I noticed a loss in power, I suspect its due to a lack of compression. There also seems to be a small bit of oil and exhaust fumes coming from where the exhaust meets the cylinder. So I'm wondering if I could get the problem fixed or if I will have to buy a new cylinder ? If so is anyone selling any cheap cylinders for a DT 125 r?

Please help thanks again Oisin

Just found this tzr 125 cylinder and I'm wondering if it'll fit.

https://www.ebay.co.uk/itm/292869636955

[Calum]

It's not compression - See wikipedia

Love this GIF. explains it perfectly.

Any exhaust pressure lost through the manifold will result in a dramatic loss in power.

[Oisin]

@Calum So what would u recommend

[Calum]

Helicoil the cylinder.

[theportingmaster]

I have a mint condition cylinder from a 2003 that has been rebored and honed by Mick Abbey and with a new Mitaka Piston Kit, will post some photos if your interested. Has a full gasket kit with it.

[Oisin]

@theportingmaster Yes please do. What was rebored to or is it still 125cc?
Thanks very much

[Oisin]

@Calum Ok if u believe that's the best way to go then I'll definitely look into it.

Thanks a lot Calum

[theportingmaster]

Hi, was bored and honed by Mick Abbey to 137cc but still has rebores left.

[Oisin]

@theportingmaster how much u looking for

[theportingmaster]

Open to offers, cheers Terry

[Oisin]

@theportingmaster would u do €85 for the lot

[Calum]

@Oisin I mean, Mick Abbey charges like £150 for the porting working alone...so that would be like bargain of the century

[Oisin]

@theportingmaster Ok well I could do €125 for it

[Calum]

@Oisin Well, you ought to see what he comes back with first

[theportingmaster]

@Oisin cost me more than £125 so looking for £175 & postage.

[Oisin]

@theportingmaster how much would postage to Ireland be

[theportingmaster]

Hi, if you send me your postcode can get you a price for tracked delivery, think the price is about the same as posting in the uk. cheers Terry

[declan]

@Calum id take it for that price any day lol

[Oisin]

@theportingmaster I might be able to get my cylinder welded. Can I get back to u