1st post! Potential KDX owner. Compression question.?

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Matt_T10506
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1st post! Potential KDX owner. Compression question.?

Post by Matt_T10506 »

Hi all, I'm a potential kdx owner living in wv. I currently ride a warrior, rebuilding an rm125(to sell), and hopefully a kdx soon. I have found what seems to be a good deal on a 95 kdx. It does have some boot rub but plastics and etc. seem well. So far all is checking out. However, the compression reads 140. I thought 140 was good according to manuals and some owners, but MOST people over at thumper talk are telling me it's too low. My guess is they are comparing mx motors to these? Anyways, I figured this is the best place to ask. Hopefully I'll be a kdx owner soon! :supz:
david
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Re: 1st post! Potential KDX owner. Compression question.?

Post by david »

IIRC, my manual says the usable range is 119-185 so I would say you are fine.
'81 KDX 175
'90 KDX 200
'07 Vulcan 2000 Classic LT (totaled 4/25/15)
'82 Honda GL500 (sold)
'96 ZXi 1100 JetSki
'98 STX 1100 JetSki
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KDXohio
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Re: 1st post! Potential KDX owner. Compression question.?

Post by KDXohio »

Welcome I wouldnt worry about 140 I start thinking about a top end at 125psi.
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
pumpguy
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1st post! Potential KDX owner. Compression question.?

Post by pumpguy »

How's the rest of it? Check out the swing arm and linkage bearings. They seem to go out pretty quickly if neglected.

If you do buy, be sure to get a service manual. It will tell you everything you need to know about your new ride.
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bufftester
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Re: 1st post! Potential KDX owner. Compression question.?

Post by bufftester »

The service manual states 90-151, so 140 is at the top of the range. As KDXOhio said, I wouldn't worry till you get down in the 110 range (and you'll be noticing it by then). The H series didnt change from 95-07 so overall condition is the more important factor. All your bearings (especially the linkage/swingarm/head) should be checked too.

And as Pumpguy said, a manual is a must, along with a torque wrench if you don't already own one. Oh, and more garage space, because once you start riding the bikes just seem to multiply lol :lol:
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