DT125R ARCHIVE

dread123 · Moderator

RE: now a non runner

madrevs · DTR Senior Member

Oh really will give them a call andy did suggest them aswell just annoying theres no where local

dread123 · Moderator

yeah they only 30 min drive from me..been there a couple times-always good friendly advice. whereabouts are you from? you'd be suprised there are engineering firms all over the place lol

madrevs · DTR Senior Member

From norwich theres a few in norwich but most have bad reputations.

madrevs · DTR Senior Member

Just spoke to grampians works out at
72.00 for rebore and piston and modyfying powervalve and will have to get my own athena gasket kit and little end

AndyYam · Guru

Definitly get your own little end bearing and gasket set.

small end bearing should be about 5-8 quid
gasket set for gen / athena should be 18-20
piston kit mitaka should be about 35-45
rebore should be about 25-35
modding the pv should be an hours labour tops £30?

madrevs · DTR Senior Member

Spoke to both grampian motors and pjme
grampian quoted 72 for rebore and mitaka piston and modding pv but would need to get my own little end and gasket set which is 30 from pjme
pjme quoted 115 but that included everything little end athena gasket set etc and pv modding so grampian are about a tenner cheaper
also managed to get a excellent condition 3mb head for 25 delivered.
hopefully my cylinder can be repaired due to the damage on the exhaust port theres not that much bit something has definetly caught it

AndyYam · Guru

Sounds like you're doing well. What damage to the port? i thought the valve was damaged not the port?

madrevs · DTR Senior Member

Nah it caught the valve but something caught the inner lip of the exhaust port on its way out and has put a scrape mark on the port hopefully it wont make a difference

madrevs · DTR Senior Member

Sent the cylinder off to grampian motors so hopefully they will be able to repair it if not will have to hunt for another cylinder pref on a standard bore
heres a better pic where it caught the exhaust port

AndyYam · Guru

Id imagine the rebore will take most of that off.

Calum122 · Guru

Getting one on standard bore will be difficult. Yu'd actually be better off having a new liner in it if a rebore is not possible. It's costly but leaves you with a brand new Cylinder on original bore in perfect condition.

Just a thought.

madrevs · DTR Senior Member

Might look at relining if they cant rebore hopefully they can

AndyYam · Guru

that would be 150 quid plus. I personally would rather have an oversized barrel.

Calum122 · Guru

AndyYam wrote:
that would be 150 quid plus. I personally would rather have an oversized barrel.

He said it might not be able to be rebored. That's Why I said reline it.

AndyYam · Guru

madrevs wrote:
Sent the cylinder off to grampian motors so hopefully they will be able to repair it if not will have to hunt for another cylinder pref on a standard bore
heres a better pic where it caught the exhaust port

Can always rebore unless its already too large and would start getting too close to the water jacket. I think the rebore would remove alot of that damaged area in the photo. Then they can just smooth off the sharp edges of that port.

But what I mean was even if that cylinder was kaput, I'd prefer to get another barrel and rebore that to an OS bore than get it relined. It's £150 just for the new lining, so thats not including piston kit, bearing etc. Would be far more financially sensible to rebore a 2nd hand barrel. Each to their own though.

dread123 · Moderator

agree wit Andy there.. cheaper to get a barrel and rebore than reline - purchase barrel for 25 and then rebore 15-rather than £150+ does make sense :p

madrevs · DTR Senior Member

Hopefully they can repair it sebamax was selling a 56mm barrel cheap but I was too slow got my athena gasket kit little end bearing and new oil line pipe delivered from pjme today my old oil pipe split pulling it off the inlet went for a clear one so I can see the oil going through it for peace of mind

madrevs · DTR Senior Member

Also something else I really want to do is flush out the crank.after searching on the forum and using a few links ive been given I see alot ofbpeople use paraffin.i cant see or feel any metal fillings and have stuffed a clean rag in there while its been apart but am still a bit concerned about any dirt that may have got in there while its been apart is there anyway of flushing the top end out without removing the engine.also seems like a silly question but if I was to pour parrafin in the crank would it then drain out of the gearbox by undoing the drain screw

Calum122 · Guru

I've got problems lmao.

It's not that cost is an issue. Its the fact I can't chuck away something that isn't being built anymore.

AndyYam · Guru

madrevs wrote:
Also something else I really want to do is flush out the crank.after searching on the forum and using a few links ive been given I see alot ofbpeople use paraffin.i cant see or feel any metal fillings and have stuffed a clean rag in there while its been apart but am still a bit concerned about any dirt that may have got in there while its been apart is there anyway of flushing the top end out without removing the engine.also seems like a silly question but if I was to pour parrafin in the crank would it then drain out of the gearbox by undoing the drain screw

Good idea.

No the gearbox is seperate from the crank. You should change the gear oil every year or so. Some people never change it and dont get problems. On motocross bikes its usually changed every 3 rides.

You'll have to literally turn the lump upside down and pour it out.

AndyYam · Guru

Calum122 wrote:
I've got problems lmao.

It's not that cost is an issue. Its the fact I can't chuck away something that isn't being built anymore.

Yeah I know the feeling mate. I've got a few DTR rads and no one wants them and it'd cost more to list and post that anyone would pay but I cant chuck. When those barrels are rare in the future then relining might be a viable option so dont chuck it!

madrevs · DTR Senior Member

Good idea
N the gearbox is seperate from the crank. You should change the gear oil every year or so. Some people never change it and dont get problems. On motocross bikes its usually changed every 3 rides.
You'll have to literally turn the lump upside down and pour it out.

Might see if i can turn the bike upside down rather than take the engine out will paraffin damage the crank bearings or seals.is there anything better i can use.

as for the gearbox oil have already changed it 4 or 5 times lol as when i refitted the clutch cover i missed a bit with the gasket sealent and the gearbox filled with about 10l of coolant lol

NEV · Guru

Petrol will damage the rubber seals, paraffin is much kinder on them.

madrevs · DTR Senior Member

Ah ok do I need to make sure I get every last drop out afterwards .one mistake I have made so far is I didnt wash the engine down before I removed the cylinder so have got to be extra carefull when putting back together

madrevs · DTR Senior Member

Cleaned my dep pipe up yesterday with wet and dry as was going to spray it.after scuffing it up with 180 grit and getting all the rust off actually prefer it to the polished look so am going to spray it with some clear vht to hopefully stop the rusting issue

madrevs · DTR Senior Member

Should have my barrel back tomorow from grampian motors they had to bore it to the last oversize.one thing I am worried about though is they couldnt get a japanese mitaka to fit it so had to use a taiwan mitaka and japanese rings will this be ok or am I better trying to find a japanese one to fit.grampian motors assured me it will be ok with the japanese rings but dont know what to do know

Calum122 · Guru

Check the piston ring end gap, and that the piston ring pins are solid in place. As far as my memory serves me that's the problem with the lower quality ones are the piston ring stoppers.

Not 100% on that one though.

Wossner do very high quality pistons. Also PJME use a high quality cheap piston kit.

Personally I probably wouldn't run anything other than Wossner but I have in the past used Mitaka and they have been excellent pistons.

Ring end gap and stoppers I'd say just double check.

madrevs · DTR Senior Member

Ok will do bit frustrating though as I was really after a japanese mitaka.trouble is as the cylinders now been bored to that piston doubt I will get anything else to fit.think im just going to have to put it all back together and see what happens.in the athena kit there looks to be a inlet gasket.does this go in between the inlet and reed block or between reed block and engine

-- Edited by madrevs on Saturday 1st of March 2014 04:42:59 PM

NEV · Guru

What size is it you're after? I think I have a brand new either 2.0 o/s or 2.5 o/s, in the garage, think that its a mitaka, I'd need to go check it cost around £42 quid iirc, you can have it £25 if it's any use.