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Post by 29davyt on Apr 19, 2021 10:10:54 GMT 1
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Post by steve h on Apr 19, 2021 11:48:57 GMT 1
No. DT 175 pistons used and barrels bored out, and machined to allow for the differing height of the pistons. An extra 25cc.
The 250 to 370 mod does use a new liner to use the Blaster pistons.
Dont know what rebore(s) are left on those advertised barrels....
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Post by 29davyt on Apr 19, 2021 12:53:35 GMT 1
That’s what I meant really Steve, wonder how many bores left on those advertised ??
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Post by beardy on Apr 19, 2021 15:18:08 GMT 1
Mines a 375 and not been apart for a while as it’s running. Previous reading on this forum suggested they’re probably on the limit. Future plan for me is a re sleeve and some sort of spacer at the bottom to compensate for them being shaved down. If possible 🤷♂️ or a garage ornament 😂
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Post by midlifecrisisrd on Apr 19, 2021 16:41:38 GMT 1
According to the seller it's 67.5mm so that's 3.5mm oversize
Surely he means 66.5 as the liner is thin enough at that 😬
Steve
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Post by 29davyt on Apr 19, 2021 16:50:44 GMT 1
Hmmmm !! the boxes the pistons are in do say 67.5 mm ,, looks like another misleading eBay ad.
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Post by hicky375 on Apr 19, 2021 17:44:14 GMT 1
I had my 375 barrels re-lined and spacers made up by PJME last year but i've yet to put the thing back together. They were at 66.5mm and scored after the top ring peg went awal. The lads on here said they were too thin to take out any further which i thought was right and i hate binning stuff so i got them re-lined. Those barrels on ebay are another 1mm bigger than what mine were so the liners must be paper thin!! I think 67.5mm bore works out at 386cc doesn't it? Wayne.  |
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Post by beardy on Apr 19, 2021 18:09:40 GMT 1
I had my 375 barrels re-lined and spacers made up by PJME last year but i've yet to put the thing back together. They were at 66.5mm and scored after the top ring peg went awal. The lads on here said they were too thin to take out any further which i thought was right and i hate binning stuff so i got them re-lined. Those barrels on ebay are another 1mm bigger than what mine were so the liners must be paper thin!! I think 67.5mm bore works out at 386cc doesn't it? Wayne. That’s good to know it can be done 👍🏻 |
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Post by veg on Apr 19, 2021 18:50:21 GMT 1
What about the head though?
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Post by carioca656 on Apr 19, 2021 20:30:05 GMT 1
ive just bought some barrels exactly the same im going to get the head o ringed mine are 66.5mm im thinking they might need some extra cooling may fit a fan on rad
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Post by 29davyt on Apr 24, 2021 7:33:36 GMT 1
Barrels have now grow to 386 cc, still one more rebore left in them according to seller ( who must be on here 😉)
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Post by veg on Apr 24, 2021 7:55:50 GMT 1
So starting price of £450 with tops 2 rebores, and no cylinder head unsurprisingly no one has bid.
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Post by fletche36 on Apr 24, 2021 16:23:37 GMT 1
So starting price of £450 with tops 2 rebores, and no cylinder head unsurprisingly no one has bid. Maybe people arent as daft as we think. |
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Post by veg on Apr 24, 2021 16:27:32 GMT 1
God loves a trier they are readvertised at exactly the same price.
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Post by hicky375 on Apr 26, 2021 21:06:18 GMT 1
I've just put mine back together over the weekend with the spacers fitted and i'm pleased to say it's running the best it ever has! No gasket leaks around the spacers and it's so much easier to ride with the standard liners fitted. Smoother power delivery,more bottom end torque and it's lost the flat spot it used to have. Happy days.  Wayne. |
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Post by beardy on Apr 27, 2021 8:36:38 GMT 1
I’m glad that it all worked out ok for you. I now know I can save my barrels 👍🏻
Were you able to use the same cylinder head that was used when it was a 375?
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Post by hicky375 on Apr 27, 2021 18:14:01 GMT 1
Yes,it's the same cylinder head. It was on a standard head gasket which was on its limit. I'll get a picture put up of the gasket as it looks to have been burned partly around the ring on one of the cylinders.
Wayne. |
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Post by hicky375 on Apr 27, 2021 23:14:11 GMT 1
A few pics of the gasket here.First pic from the underside. Looks like the piston's been hitting it where it's bent down in this first pic. Second pic with the gasket the right way up. Camera wouldn't focus so good but you can make out how it's pushed it up. The other piston diddn't appear to damage the gasket strangely enough. Wayne. |
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Post by chippy348 on Apr 28, 2021 16:49:35 GMT 1
I've just put mine back together over the weekend with the spacers fitted and i'm pleased to say it's running the best it ever has! No gasket leaks around the spacers and it's so much easier to ride with the standard liners fitted. Smoother power delivery,more bottom end torque and it's lost the flat spot it used to have. Happy days. Wayne. Hi Wayne, Paul Here From PJME Happy to here all is good with your Job. Can i use your photo of the Spacer fitted please ? |
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Post by hicky375 on Apr 28, 2021 17:11:40 GMT 1
Hi Paul,Yes, by all means use the pics.
I did have to get the spacers skimmed down 1mm as they were 5.5mm thick for some reason.It wasn't a problem as i know someone locally that owed me a favour. The DT pistons are 5mm shorter than LC ones so i made the spacers 4.5mm allowing for a 0.5mm gasket. I've done around 100 miles on it so far and it's running sweet as a nut. 
Wayne. |
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Post by chippy348 on Apr 28, 2021 17:16:23 GMT 1
Hi Paul,Yes, by all means use the pics.
I did have to get the spacers skimmed down 1mm as they were 5.5mm thick for some reason.It wasn't a problem as i know someone locally that owed me a favour. The DT pistons are 5mm shorter than LC ones so i made the spacers 4.5mm allowing for a 0.5mm gasket. I've done around 100 miles on it so far and it's running sweet as a nut.
Wayne. Thanks, The spacers were made 5.5mm as that was the difference between what had been skimmed off your cylinders and a std one untouched one. Now the std cylinders have a massive squish like + 2.00 mm, did you check your squish on build up ? |
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Post by hicky375 on Apr 28, 2021 17:38:11 GMT 1
No i diddn't.  I just noticed that the piston seamed to be 1mm lower in the bore at tdc than the dt ones were before i took it apart when it broke.
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Post by midlifecrisisrd on Apr 28, 2021 17:58:00 GMT 1
You can check it approximately in situ
If you take some solder wire and bend it into an L shape with the bottom part 30mm you can insert it into the spark plug hole at the 12 o clock position while holding the end (do not let it fall in 😱) and turn the bike over with the kickstart
Repeat at 3, 6 and 9 o clock then check the thickness of the squashed end
This should give you the approx smallest squish reading. Make sure you position it so the end of the wire is at the edge of the combustion area)
If it is 1mm or under it will need measured accurately which means a head off job and maybe a thicker gasket
Steve
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Post by stusco on Apr 28, 2021 18:04:08 GMT 1
0.75mm squish probably did this  |
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Post by hicky375 on Apr 28, 2021 18:04:38 GMT 1
Cheers for that Steve. I'll check it out when i go into the garage later on.
Wayne. |
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Post by hicky375 on Apr 28, 2021 18:10:26 GMT 1
0.75mm squish probably did this Nightmare!  |
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I just noticed that the piston seamed to be 1mm lower in the bore at tdc than the dt ones were before i took it apart when it broke.
